This is the meta-subject of a new paper in PLoS ONE by myself and my buddy/co-author Brendan Maughan Brown. Here is the abstract, which mostly explains everything:
Objectives
We examined whether knowledge of the HIV-protective benefits of male circumcision (MC) led to risk compensating behavior in a traditionally circumcising population in South Africa. We extend the current literature by examining risk compensation among women, which has hitherto been unexplored.
Methods
We used data on Xhosa men and women from the 2009 Cape Area Panel Study. Respondents were asked if they had heard that MC reduces a man’s risk of contracting HIV, about their perceived risk of contracting HIV, and condom use. For each gender group we assessed whether risk perception and condom use differed by knowledge of the protective benefits of MC using bivariate and then multivariate models controlling for demographic characteristics, HIV knowledge/beliefs, and previous sexual behaviors. In a further check for confounding, we used data from the 2005 wave to assess whether individuals who would eventually become informed about the protective benefits of circumcision were already different in terms of HIV risk perception and condom use.
Results
34% of men (n = 453) and 27% of women (n = 690) had heard that circumcision reduces a man’s risk of HIV infection. Informed men perceived slightly higher risk of contracting HIV and were more likely to use condoms at last sex (p<0.10). Informed women perceived lower HIV risk (p<0.05), were less likely to use condoms both at last sex (p<0.10) and more generally (p<0.01), and more likely to forego condoms with partners of positive or unknown serostatus (p<0.01). The results were robust to covariate adjustment, excluding people living with HIV, and accounting for risk perceptions and condom use in 2005.
Basically, our results show that women react to information on circumcision's protective benefits in a manner consistent with risk compensation, which is a phenomenon where individuals undertake risky behaviors if they feel that they are protected from its consequences somehow. Why do women respond differently from men? We aren't sure, but we theorize that it could be related to (some combination of):
-Misinformation among women about the protective benefits of circumcision as far as male-to-female HIV transmission (circumcision has only been shown to impact female-to-male transmission).
-Lack of opportunities for women to discuss circumcision, sex, and HIV in public places.
-Higher prior probabilities of contract HIV in women (which means risk information will be more likely to shift beliefs about HIV on the margin - good ole' Bayes's Theorem)
-A sense of reduced need among women to have to negotiate condoms, which could be tricky in a world where there is imbalance in power across genders.
Some new research by other groups (more on this in a later post) provides evidence that the first of these could be at play. Watch this space for more, as we attempt to find some explanations!
Showing posts with label global health. Show all posts
Showing posts with label global health. Show all posts
Friday, August 10, 2012
Sunday, July 15, 2012
PEPFAR on the Mind
The July 31st issue of Health Affairs devotes itself to the President's Emergency Plan for AIDS Relief (PEPFAR) and explores the aid program from a number of interesting viewpoints. The highlights for me includes a piece by Harsha Thirumurthy and coauthors on the economic benefits of treating HIV and a wonderful piece of research by Karen Grepin examining the effects of PEPFAR aid on other domains on health care (she finds positive spillovers for certain maternal health services, but crowd-out for child vaccines). The article by John Donnelly discusses the origin of PEPFAR within the (W) Bush administration, which I am sure would make most send some positive vibes to this otherwise beleaguered president.
The articles on the future of PEPFAR (how the funding streams can be better targeted, how much funding is needed and for how much longer) are quite interesting, as well. Certainly, if you have a particular interest in PEPFAR, the whole issue is worth reading.
The articles on the future of PEPFAR (how the funding streams can be better targeted, how much funding is needed and for how much longer) are quite interesting, as well. Certainly, if you have a particular interest in PEPFAR, the whole issue is worth reading.
Thursday, May 17, 2012
Global Health Focus in This Week's JAMA
Some interesting new op-ed and research pieces on global health in the latest issue of JAMA. Perhaps the most interesting is this piece by Eran Bendavid and co-authors, who examine PEPFAR (The United States President's Emergency Plan for AIDS Relief) and its impact on all-cause mortality in Africa. This is important because some have argued that intense spending on HIV in this manner has crowded out spending on other important health problems. The authors use a differences-in-differences strategy (comparing mortality rates within countries before and after PEPFAR, with some areas getting funding and others not as much, holding context fixed factos across countries) and find that increased PEPFAR funding was associated with lower all cause mortality rates. (HT: Paula Chatterjee)
Saturday, March 3, 2012
Preventing HIV and STDs with Cash Transfers - Both Abroad and Here?
So on the heels of my post a few days ago comes a brand new study in The Lancet where women in Malawi randomized to receive unconditional cash transfers were less likely to contract HIV or other STDs than their unpaid counterparts. Here is a very nice summary piece on the study.
The mechanism linking cash transfers to reduced HIV may have something to do with the fact that women with access to such resources need not depend on men for the same. That is, women who are cash strapped or who lack opportunities in the labor market may need to depend on relationships where the partner can support them financially. Financial support, in turn, may reduce their ability to negotiate safe sex practices (this is the so-called "transactional sex").
Cash transfer programs of this nature may not just be useful overseas. A forthcoming article in the Journal of Adolescent Health shows that young African American women in Atlanta who have boyfriends who give them gifts are less likely to use condoms than those without such boyfriends or those with boyfriends who go on to find another source of spending money. The authors conclude that "receiving spending money from a boyfriend is common among adolescent women in populations targeted by pregnancy and sexually transmitted infection prevention interventions, and may undermine interventions' effectiveness." (HT: Paula C for the Atlanta paper).
The mechanism linking cash transfers to reduced HIV may have something to do with the fact that women with access to such resources need not depend on men for the same. That is, women who are cash strapped or who lack opportunities in the labor market may need to depend on relationships where the partner can support them financially. Financial support, in turn, may reduce their ability to negotiate safe sex practices (this is the so-called "transactional sex").
Cash transfer programs of this nature may not just be useful overseas. A forthcoming article in the Journal of Adolescent Health shows that young African American women in Atlanta who have boyfriends who give them gifts are less likely to use condoms than those without such boyfriends or those with boyfriends who go on to find another source of spending money. The authors conclude that "receiving spending money from a boyfriend is common among adolescent women in populations targeted by pregnancy and sexually transmitted infection prevention interventions, and may undermine interventions' effectiveness." (HT: Paula C for the Atlanta paper).
Monday, February 6, 2012
Does Discrimination Make You Sick? And How?
Interesting new paper, forthcoming in the Journal of Health Economics, that uses 9/11 as a quasi-experimental source of variation to try and get at the causal effect of discrimination (here, against Muslims in the UK) on health outcomes. It also goes a bit further than this and tries to get at some of the mechanisms. The findings are, sadly, along the lines of what I expected:
The attitudes of the general British population towards Muslims changed post 2001, and this change led to a significant increase in Anti-Muslim discrimination. We use this exogenous attitude change to estimate the causal impact of increased discrimination on a range of objective and subjective health outcomes. The difference-in-differences estimates indicate that discrimination worsens blood pressure, cholesterol, BMI and self-assessed general health. Thus, discrimination is a potentially important determinant of the large racial and ethnic health gaps observed in many countries. We also investigate the pathways through which discrimination impacts upon health, and find that discrimination has a negative effect on employment, perceived social support, and health-producing behaviours. Crucially, our results hold for different control groups and model specifications.
So in addition to the deadweight loss of underutilizing potentially talented men and women, as well as increasing social unrest and the potential political costs that might have, we can now add health to the slew of negative impacts from discrimination.
In a later post, I'll go over a paper that Sonia Bhalotra and I are working on that looks at how discrimination can prevent children who have better childhoods into tapping into that wellspring as adults.
The attitudes of the general British population towards Muslims changed post 2001, and this change led to a significant increase in Anti-Muslim discrimination. We use this exogenous attitude change to estimate the causal impact of increased discrimination on a range of objective and subjective health outcomes. The difference-in-differences estimates indicate that discrimination worsens blood pressure, cholesterol, BMI and self-assessed general health. Thus, discrimination is a potentially important determinant of the large racial and ethnic health gaps observed in many countries. We also investigate the pathways through which discrimination impacts upon health, and find that discrimination has a negative effect on employment, perceived social support, and health-producing behaviours. Crucially, our results hold for different control groups and model specifications.
So in addition to the deadweight loss of underutilizing potentially talented men and women, as well as increasing social unrest and the potential political costs that might have, we can now add health to the slew of negative impacts from discrimination.
In a later post, I'll go over a paper that Sonia Bhalotra and I are working on that looks at how discrimination can prevent children who have better childhoods into tapping into that wellspring as adults.
Wednesday, December 14, 2011
Health Expenditures in the US: Are We Not Spending Enough?
According the Elizabeth Bradley, a Professor of Health Policy and Administration at Yale, the answer is no. As she and Lauren Taylor point out in a recent New York Times editorial:
We studied 10 years’ worth of data and found that if you counted the combined investment in health care and social services, the United States no longer spent the most money — far from it. In 2005, for example, the United States devoted only 29 percent of gross domestic product to health and social services combined, while countries like Sweden, France, the Netherlands, Belgium and Denmark dedicated 33 percent to 38 percent of their G.D.P. to the combination. We came in 10th.
Bradley and Taylor put forth the argument that the things that make people healthy go beyond what we typically think of as health care. That is, access to employment, good housing, food security, and educational institutions all contribute to population health. I don't think this is a revolutionary thought.
But what is revolutionary is that they authors imply that the answer to our central question for US health care - "Do we get what we pay for?" - might not be the "no" we've always assumed, but a "yes." We just aren't spending enough, at least not on the proximal things that really matter. I don't think that it is that simple - it's hard to know what portion of social service spending actually improves health. But the discourse does need to move in this direction.
Furthermore, another neat aspect of this piece is that Bradley and Taylor's contention doesn't just apply to the macro-level health policy sphere. Imagine a primary care system that takes into account the socioeconomic realities of patients and creates interventions that use these insights to better provide care. A developing country example: subsidizing the transportation fees for HIV/AIDS patients who would otherwise find this to be a barrier and be unable to seek much needed health care. This sort of intervention may be equally important to any medications or lab tests in advancing the health of these patients. I'll talk more about this sort of "economic hotspotting" in a later post.
We studied 10 years’ worth of data and found that if you counted the combined investment in health care and social services, the United States no longer spent the most money — far from it. In 2005, for example, the United States devoted only 29 percent of gross domestic product to health and social services combined, while countries like Sweden, France, the Netherlands, Belgium and Denmark dedicated 33 percent to 38 percent of their G.D.P. to the combination. We came in 10th.
Bradley and Taylor put forth the argument that the things that make people healthy go beyond what we typically think of as health care. That is, access to employment, good housing, food security, and educational institutions all contribute to population health. I don't think this is a revolutionary thought.
But what is revolutionary is that they authors imply that the answer to our central question for US health care - "Do we get what we pay for?" - might not be the "no" we've always assumed, but a "yes." We just aren't spending enough, at least not on the proximal things that really matter. I don't think that it is that simple - it's hard to know what portion of social service spending actually improves health. But the discourse does need to move in this direction.
Furthermore, another neat aspect of this piece is that Bradley and Taylor's contention doesn't just apply to the macro-level health policy sphere. Imagine a primary care system that takes into account the socioeconomic realities of patients and creates interventions that use these insights to better provide care. A developing country example: subsidizing the transportation fees for HIV/AIDS patients who would otherwise find this to be a barrier and be unable to seek much needed health care. This sort of intervention may be equally important to any medications or lab tests in advancing the health of these patients. I'll talk more about this sort of "economic hotspotting" in a later post.
Sunday, December 4, 2011
Male Circumcision, HIV/AIDS and the "Real World"
This past week, PLoS Medicine put forth multi-piece expose (start with this lead/summary article) on medical male circumcision, its cost-effectiveness in combating HIV/AIDS and methods and challenges to scaling up this practice in Sub-Saharan Africa, where the epidemic is at its worst. The upshot of this series of papers was covered in a recent Scientific American piece (which quotes yours truly). To summarize, the argument is that medical male circumcision works (as demonstrated in three large randomized clinical trials, all conducted in Africa) and is cost-effective. Indeed, it may even be cost-saving, with high upfront costs that are easily recovered over a 10 year period. Challenges to scale-up include finding health care workers to carry out circumcisions (in a way that doesn't crowd-out provision of other important health care services), getting people to adopt the practice in a respectful, non-coercive yet effective way, especially in areas where there are strong traditional norms over circumcision, and dealing with any risk compensating behavior (if circumcised individuals think circumcision is protective, they may be more likely to engage in riskier sexual behaviors than they otherwise would - more on this in a later post).
Circumcision is one of those topics that seems to always bring with it a vociferous debate. Those opposed to the practice make their stance known quite vehemently. In my opinion, much of what is being spouted against medical male circumcision as a tool for HIV prevention is based on an incomplete understanding of the available evidence and already strong negative priors against the practice that are almost impossible to shift (for example, see this clip or refer to any of the comments to the aforementioned Scientific American article).
However, I think there is one oft-cited argument against medical male circumcision that is worth discussing further. In particular, opponents point to evidence from a 2009 UNAIDS study that uses recent survey data from 18 African countries and concludes that "there appears no clear pattern of association between male circumcision and HIV prevalence—in 8 of 18 countries with data, HIV prevalence is lower among circumcised men, while in the remaining 10 countries it is higher." This is contrast to the large randomized clinical trials mentioned above which show that circumcision reduces HIV rates by greater than 50%. The fact that the clinical trial results are not borne out in the sample survey data, opponents argue, means that circumcision does not work in "real world settings."
In a recent study, Brendan Maughan-Brown, Nicoli Nattrass, Jeremy Seekings, Alan Whiteside and I offer a different explanation for this differential set of findings. It has to do with the fact that the UNAIDS study looks at population that were circumcised in a multitude of settings (clinics, traditional healers) whereas the clinical trials focus on medical circumcision only. In practice, there great deal of heterogeneity in traditionally circumcising populations: some people do not have all of their foreskin removed, and others are circumcised several years after their peers. In our study population of blacks living in the Cape Town metro area, when we don't account for this heterogeneity, we find only a weak negative effect of circumcision on HIV positivity. However, once we "unpack" circumcision, we find that the practice actually has a strong negative association with the probability of testing HIV positive, provided it is done earlier and that there is complete removal of the foreskin.
These results suggest that the UNAIDS results may simply be due to measurement error. In a traditional setting, a circumcision is not a circumcision is not a circumcision. Treating every circumcised person the same introduces measurement error, and statistically it is well known that this would deflate the estimates of the impacts of the practice towards zero. So, the differential results between the UNAIDS findings and the randomized clinical trial findings is not that circumcision doesn't work in the real world. Rather, it is that we really need to understand better the heterogeneity in male circumcision and what can be done to ensure better outcomes for everyone involved.
Circumcision is one of those topics that seems to always bring with it a vociferous debate. Those opposed to the practice make their stance known quite vehemently. In my opinion, much of what is being spouted against medical male circumcision as a tool for HIV prevention is based on an incomplete understanding of the available evidence and already strong negative priors against the practice that are almost impossible to shift (for example, see this clip or refer to any of the comments to the aforementioned Scientific American article).
However, I think there is one oft-cited argument against medical male circumcision that is worth discussing further. In particular, opponents point to evidence from a 2009 UNAIDS study that uses recent survey data from 18 African countries and concludes that "there appears no clear pattern of association between male circumcision and HIV prevalence—in 8 of 18 countries with data, HIV prevalence is lower among circumcised men, while in the remaining 10 countries it is higher." This is contrast to the large randomized clinical trials mentioned above which show that circumcision reduces HIV rates by greater than 50%. The fact that the clinical trial results are not borne out in the sample survey data, opponents argue, means that circumcision does not work in "real world settings."
In a recent study, Brendan Maughan-Brown, Nicoli Nattrass, Jeremy Seekings, Alan Whiteside and I offer a different explanation for this differential set of findings. It has to do with the fact that the UNAIDS study looks at population that were circumcised in a multitude of settings (clinics, traditional healers) whereas the clinical trials focus on medical circumcision only. In practice, there great deal of heterogeneity in traditionally circumcising populations: some people do not have all of their foreskin removed, and others are circumcised several years after their peers. In our study population of blacks living in the Cape Town metro area, when we don't account for this heterogeneity, we find only a weak negative effect of circumcision on HIV positivity. However, once we "unpack" circumcision, we find that the practice actually has a strong negative association with the probability of testing HIV positive, provided it is done earlier and that there is complete removal of the foreskin.
These results suggest that the UNAIDS results may simply be due to measurement error. In a traditional setting, a circumcision is not a circumcision is not a circumcision. Treating every circumcised person the same introduces measurement error, and statistically it is well known that this would deflate the estimates of the impacts of the practice towards zero. So, the differential results between the UNAIDS findings and the randomized clinical trial findings is not that circumcision doesn't work in the real world. Rather, it is that we really need to understand better the heterogeneity in male circumcision and what can be done to ensure better outcomes for everyone involved.
Saturday, November 5, 2011
Infections and IQ
A well known fact about our world is that there are great disparities in average IQ scores across countries. In the past, some have tried to argue that this pattern be explained by innate differences in cognition across populations - some people are just innately smarter than others. Others have tried to attribute these to cultural factors. However, genetics and culture are likely not driving these differences in any meaningful sense. After all, another stylized fact is that average IQ scores have been going up markedly, within one or two generations, within any given country. These changes, also known as the Flynn Effect after the researcher who painstakingly documented them, speak against the genes story because they occurred far more quickly than one would expect from population-wide changes in the distribution of cognition-determining genes. The have occured too quickly to be explained by paradigm shifting social changes, as well.
So what gives? Enter Chris Eppig, a researcher at the University of New Mexico. In a recent piece in The Scientific American , he proposes that cross-country differences in IQ, as well as changes in IQ rates within a country over time, can be explained by exposure to infectious diseases early in life. The story goes something like this: infections early in life require energy to fight off. Energy during this age is primarily used for brain development (in infancy, it is thought that over 80% of calories are allocated to neurologic development). So if energy is diverted to fend off infections, it can't be used to develop cognitive endowments, and afflicted infants and children end up becoming adults that do poorly on IQ tests.
In the piece, Eppig cites some of his work linking infectious disease death rates in countries to average IQ scores. His models control for country income and a few other important macroeconomic variables. His evidence, while not proof of a causal relationship, is certainly provocative. So provocative in fact that I ended up trying to build a stronger causal story between early childhood infections and later life cognitive outcomes. In a recent paper (cited in the above Scientific American article), I examine the impact of early life exposure to malaria on later life performance on a visual IQ test. I use a large-scale malaria eradication program in Mexico (1957) as a quasi-experiment to prove causality. Basically, I find that individuals born in states with high rates of malaria prior to eradication - the area that gained most from eradication - experienced large gains in IQ test scores after eradication relative those born in states with low pre-intervention malaria rates, areas that did not benefit as much from eradication (see this Marginal Revolution piece for a slightly differently worded explanation).
My paper also looks at the mechanisms linking infections and cognition. One possibility is the biological model described above - infections divert nutritional energy away from brain development. However, I also find evidence of a second possibility: parents respond to initial differences in cognition or health due to early life infections and invest in their children accordingly. In the Mexican data, children who were less afflicted by malaria thanks to the eradication program started school earlier than those who were more afflicted. Because a child's time is the domain of parental choice, this suggests that parents reinforce differences in the way their children are (- erhaps they feel that smarter children will be smarter adults, and so investments in their schooling will yield a higher rate of return - and that this can modulate the relationship between early life experiences and adulthood outcomes.
So what gives? Enter Chris Eppig, a researcher at the University of New Mexico. In a recent piece in The Scientific American , he proposes that cross-country differences in IQ, as well as changes in IQ rates within a country over time, can be explained by exposure to infectious diseases early in life. The story goes something like this: infections early in life require energy to fight off. Energy during this age is primarily used for brain development (in infancy, it is thought that over 80% of calories are allocated to neurologic development). So if energy is diverted to fend off infections, it can't be used to develop cognitive endowments, and afflicted infants and children end up becoming adults that do poorly on IQ tests.
In the piece, Eppig cites some of his work linking infectious disease death rates in countries to average IQ scores. His models control for country income and a few other important macroeconomic variables. His evidence, while not proof of a causal relationship, is certainly provocative. So provocative in fact that I ended up trying to build a stronger causal story between early childhood infections and later life cognitive outcomes. In a recent paper (cited in the above Scientific American article), I examine the impact of early life exposure to malaria on later life performance on a visual IQ test. I use a large-scale malaria eradication program in Mexico (1957) as a quasi-experiment to prove causality. Basically, I find that individuals born in states with high rates of malaria prior to eradication - the area that gained most from eradication - experienced large gains in IQ test scores after eradication relative those born in states with low pre-intervention malaria rates, areas that did not benefit as much from eradication (see this Marginal Revolution piece for a slightly differently worded explanation).
My paper also looks at the mechanisms linking infections and cognition. One possibility is the biological model described above - infections divert nutritional energy away from brain development. However, I also find evidence of a second possibility: parents respond to initial differences in cognition or health due to early life infections and invest in their children accordingly. In the Mexican data, children who were less afflicted by malaria thanks to the eradication program started school earlier than those who were more afflicted. Because a child's time is the domain of parental choice, this suggests that parents reinforce differences in the way their children are (- erhaps they feel that smarter children will be smarter adults, and so investments in their schooling will yield a higher rate of return - and that this can modulate the relationship between early life experiences and adulthood outcomes.
Sunday, October 23, 2011
Battling the Bulge
Some innovative social policy this week in Mexico, where the federal government been expressing some palpable alarm over rising obesity among children and adults. I'm sure that Mexico now is the fattest nation in the world and, if they aren't, they are right behind the US in this dubious regard. From a country that was worried about infectious disease deaths just a generation ago to one that is increasingly burdened by diabetes and heart disease comes a new social policy that aggressively seeks to reduce obesity in children by banning junk food, increase hours of physical education, and provide nutritional education in a school based setting. Only time will tell whether they can get people to substitute agua for refrescas, but I like where they are headed with this multi-pronged approach. I know there is some evidence that each of these interventions could provide positive benefits alone (see, for example, here), so perhaps there will be a bigger kick from all three together.
On our side of the border comes some new evidence that your neighborhood matters as far as obesity goes. A study in this week's New England Journal of Medicine finds that poor households randomized to receiving housing vouchers enabling them to move to nicer neighborhoods were significantly less likely to be obese and have elevated hemoglobin A1c levels (a marker of blood sugar content used to diagnose, and track response to treatment for, diabetes). This experiment validates a long-standing hunch that neighborhoods matter for obesity. The question now is what exactly matters, i.e., what is the mechanism behind this causal pathway? We obviously need to know this in order to design targeted policies? Is it that better neighborhoods have better designed streets that encourage walking? The presence of parks? Are there positive peer effects from health nuts? Better grocery stores and more healthy food options relative to junk food options? Better access to primary care docs? I'm awaiting the follow up study which tries to tease these different possibilities apart.
On our side of the border comes some new evidence that your neighborhood matters as far as obesity goes. A study in this week's New England Journal of Medicine finds that poor households randomized to receiving housing vouchers enabling them to move to nicer neighborhoods were significantly less likely to be obese and have elevated hemoglobin A1c levels (a marker of blood sugar content used to diagnose, and track response to treatment for, diabetes). This experiment validates a long-standing hunch that neighborhoods matter for obesity. The question now is what exactly matters, i.e., what is the mechanism behind this causal pathway? We obviously need to know this in order to design targeted policies? Is it that better neighborhoods have better designed streets that encourage walking? The presence of parks? Are there positive peer effects from health nuts? Better grocery stores and more healthy food options relative to junk food options? Better access to primary care docs? I'm awaiting the follow up study which tries to tease these different possibilities apart.
Friday, August 19, 2011
Absolutely Lovely Paper About Esther Duflo
Esther Duflo, hands down, is one of my favorite economists. Her work spans a rich swath of development economics, touching subjects as diverse (and, ultimately, as related!) as microfinance, education, health care, corruption, women's agency, and, central to a good deal of her work, randomized field experiments. She is also the founder of the Jameel Poverty Action lab and co-wrote the incredible Poor Economics.
Recently, she won the American Economic Association's John Bates Clark Medal, an bi-yearly award given to the topic economist under the age of forty. Chris Udry, one of my favorite professors at Yale, ruminates on Duflo's work in a beautiful essay in the Journal of Economic Perspectives. Reading it, one is amazed about the impact one person can have on an entire field - disruptive technological change at its finest! My favorite part about the piece is how Duflo has remained an incredible academician while also serving as a public intellectual and activist. Excellent stuff.
Recently, she won the American Economic Association's John Bates Clark Medal, an bi-yearly award given to the topic economist under the age of forty. Chris Udry, one of my favorite professors at Yale, ruminates on Duflo's work in a beautiful essay in the Journal of Economic Perspectives. Reading it, one is amazed about the impact one person can have on an entire field - disruptive technological change at its finest! My favorite part about the piece is how Duflo has remained an incredible academician while also serving as a public intellectual and activist. Excellent stuff.
Saturday, August 6, 2011
Can Research on Measurement Provide Insights into the Poverty Experience?
Great paper, forthcoming in the Journal of Development Economics on how the length of recall periods in surveys leads to different measurements of health, wellness and health care seeking behavior. Also interesting is how the recall period length effect differs by income status. The authors use their findings to suggest that experiences with illness have become disturbingly become the normal among the poor vis-a-vis the rich:
Between 2000 and 2002, we followed 1621 individuals in Delhi, India using a combination of weekly and monthly-recall health questionnaires. In 2008, we augmented these data with another 8 weeks of surveys during which households were experimentally allocated to surveys with different recall periods in the second half of the survey. We show that the length of the recall period had a large impact on reported morbidity, doctor visits; time spent sick; whether at least one day of work/school was lost due to sickness and; the reported use of self-medication. The effects are more pronounced among the poor than the rich. In one example, differential recall effects across income groups reverse the sign of the gradient between doctor visits and per-capita expenditures such that the poor use health care providers more than the rich in the weekly recall surveys but less in monthly recall surveys. We hypothesize that illnesses--especially among the poor--are no longer perceived as "extraordinary events" but have become part of “normal” life. We discuss the implications of these results for health survey methodology, and the economic interpretation of sickness in poor populations.
Between 2000 and 2002, we followed 1621 individuals in Delhi, India using a combination of weekly and monthly-recall health questionnaires. In 2008, we augmented these data with another 8 weeks of surveys during which households were experimentally allocated to surveys with different recall periods in the second half of the survey. We show that the length of the recall period had a large impact on reported morbidity, doctor visits; time spent sick; whether at least one day of work/school was lost due to sickness and; the reported use of self-medication. The effects are more pronounced among the poor than the rich. In one example, differential recall effects across income groups reverse the sign of the gradient between doctor visits and per-capita expenditures such that the poor use health care providers more than the rich in the weekly recall surveys but less in monthly recall surveys. We hypothesize that illnesses--especially among the poor--are no longer perceived as "extraordinary events" but have become part of “normal” life. We discuss the implications of these results for health survey methodology, and the economic interpretation of sickness in poor populations.
Wednesday, August 3, 2011
Inaccurate Public Health Messages from Politicians = Very Bad
Those of you who either follow public health and/or know South Africa have certainly heard about the "AIDS-denialist" bent of former President Mbeki and his Health Minister, Manto Tshabalala-Msimang. If you don't, basically the two of them (mainly the latter with support from the former) put forth a view that HIV does not cause AIDS and that anti-retrovirals on balance confer negative health benefits (see this earlier post). Clearly, this flies in the face of science and common-sense. But what are the effects of these espousals on risky behaviors? Do people actually listen to this stuff? Did these beliefs lead to changes in behavior and, ominously, more HIV infections, in the general public?
A recent paper by Eduard Grebe and Nicoli Nattrass at the University of Cape Town strongly suggests that denialist claims played a role in reducing condom use among a sample of young adults in South Africa. Here's the abstract:
This paper uses multivariate logistic regressions to explore: (1) potential socio-economic, cultural, psychological and political determinants of AIDS conspiracy beliefs among young adults in Cape Town; and (2) whether these beliefs matter for unsafe sex. Membership of a religious organisation reduced the odds of believing AIDS origin conspiracy theories by more than a third, whereas serious psychological distress more than doubled it and belief in witchcraft tripled the odds among Africans. Political factors mattered, but in ways that differed by gender. Tertiary education and relatively high household income reduced the odds of believing AIDS conspiracies for African women (but not men) and trust in President Mbeki's health minister (relative to her successor) increased the odds sevenfold for African men (but not women). Never having heard of the Treatment Action Campaign (TAC), the pro-science activist group that opposed Mbeki on AIDS, tripled the odds of believing AIDS conspiracies for African women (but not men). Controlling for demographic, attitudinal and relationship variables, the odds of using a condom were halved amongst female African AIDS conspiracy believers, whereas for African men, never having heard of TAC and holding AIDS denialist beliefs were the key determinants of unsafe sex.
The study makes a few good points:
1) Bad information can lead to bad public health outcomes. (The ridiculous measles vaccines-autism scare did something very similar, more on that later)
2) These negative effects can depend on the level of education. (Here it is decreasing in education. For the measles vaccine-autism link, more educated people were more likely to decline the vaccine for their kids. Again, more on that later)
3) Social organizations, NGOs and activists can play a major role in reducing the effects of noisy or bad information.
A recent paper by Eduard Grebe and Nicoli Nattrass at the University of Cape Town strongly suggests that denialist claims played a role in reducing condom use among a sample of young adults in South Africa. Here's the abstract:
This paper uses multivariate logistic regressions to explore: (1) potential socio-economic, cultural, psychological and political determinants of AIDS conspiracy beliefs among young adults in Cape Town; and (2) whether these beliefs matter for unsafe sex. Membership of a religious organisation reduced the odds of believing AIDS origin conspiracy theories by more than a third, whereas serious psychological distress more than doubled it and belief in witchcraft tripled the odds among Africans. Political factors mattered, but in ways that differed by gender. Tertiary education and relatively high household income reduced the odds of believing AIDS conspiracies for African women (but not men) and trust in President Mbeki's health minister (relative to her successor) increased the odds sevenfold for African men (but not women). Never having heard of the Treatment Action Campaign (TAC), the pro-science activist group that opposed Mbeki on AIDS, tripled the odds of believing AIDS conspiracies for African women (but not men). Controlling for demographic, attitudinal and relationship variables, the odds of using a condom were halved amongst female African AIDS conspiracy believers, whereas for African men, never having heard of TAC and holding AIDS denialist beliefs were the key determinants of unsafe sex.
The study makes a few good points:
1) Bad information can lead to bad public health outcomes. (The ridiculous measles vaccines-autism scare did something very similar, more on that later)
2) These negative effects can depend on the level of education. (Here it is decreasing in education. For the measles vaccine-autism link, more educated people were more likely to decline the vaccine for their kids. Again, more on that later)
3) Social organizations, NGOs and activists can play a major role in reducing the effects of noisy or bad information.
Tuesday, July 19, 2011
Random Links
1. "Frying big fish" - My colleague and good friend Paul Lagunes has a wonderful piece on the problem of, and solutions to, police corruption.
2. A trip across one of the bridges crossing Chennai's Buckingham Canal brings the familiar site of people defecating along the side of the road. Clearly a public health program. Karen Grepin on how the Gates' Foundation is bringing this to public attention.
3. A piece on sportswriter Bill Simmons' new website "Grantland" about the genius that is Friday Night Lights. I love how the article is structured as an "oral history."
2. A trip across one of the bridges crossing Chennai's Buckingham Canal brings the familiar site of people defecating along the side of the road. Clearly a public health program. Karen Grepin on how the Gates' Foundation is bringing this to public attention.
3. A piece on sportswriter Bill Simmons' new website "Grantland" about the genius that is Friday Night Lights. I love how the article is structured as an "oral history."
Sunday, July 10, 2011
Global Health Data Exchange [!]
For your viewing and researching pleasure. The data exchange is courtesy of the University of Washington's Institute for Health Metrics and Evaluation. The goal is to collect all the random and not-so-random datasets floating around out there, thereby creating a "one-stop shopping" space for those interested in both tabulated and raw (census, survey, macro-health) data.
I found out about this just today while reading Sanjay Basu's latest blog post (a good one on global health data sources), and spent a better part of the browsing the site. At a first pass, the data exchange seems really comprehensive. As a grad student, I prided myself on knowing about every random dataset out there, something that took a lot of effort and time. Now, there is a nice, comprehensive external brain for such an endeavor. I hope this project continues along its current trajectory because it has a ton of promise. I would say that even in its current state it will prove quite useful for interested lay-people, policymakers, and hard-core researchers alike.
I found out about this just today while reading Sanjay Basu's latest blog post (a good one on global health data sources), and spent a better part of the browsing the site. At a first pass, the data exchange seems really comprehensive. As a grad student, I prided myself on knowing about every random dataset out there, something that took a lot of effort and time. Now, there is a nice, comprehensive external brain for such an endeavor. I hope this project continues along its current trajectory because it has a ton of promise. I would say that even in its current state it will prove quite useful for interested lay-people, policymakers, and hard-core researchers alike.
Friday, July 8, 2011
Noisy/Bad Information and Health Care Decisions
There was an interesting post on the Wall Street Journal's Health Blog about medical professionals and the use of social networks a few days ago. Much of it dealt with issues related to privacy (don't tweet about interesting cases in a manner that might identify patients, etc). However, I thought the most interesting part came at the end:
Montori says institutions and practitioners can raise awareness about conditions or available treatments, and also to counteract misinformation floating around online [using social networks]. “A lot of my colleagues say they don’t have time for distractions” like social media, he says. “But if folks who are really on the front lines of care cannot engage in this space, their thoughts, insights and experience will not be flowing through the network.”
And meantime, Montori says, “the thoughts of those who aren’t that busy, or who are paid to be in that space” will dominate. “Patients are receiving what they think is a signal but in fact it’s noise,” he says.
That last bit, about noisy signals, is an important one. It turns out that when health care professionals provide incorrect information, people learn from it in a way that is counterproductive. One of the most poignant illustrations of this comes from my friend and colleage Achyuta Adhvaryu, an economist who works on global health issues at Yale University. Adhvaryu was struck by how slowly people adopted new, highly effective anti-malarials in Tanzania after a brisk rate of uptake in the first year they were available. This is all the more weird given what we know about what malaria does to economic productivity.
Using an elegant and convincing set of theoretical and empirical techniques, he uncovers an interesting phenomenon: adoption rates are far lower in areas where the rate of misdiagnosis is higher. The story goes something like this: you have a fever, and go seek treatment. You get diagnosed with malaria and handed antimalarials. Now, if you actually have malaria, the treatment will make you feel better and you'll learn from that experience. If you don't have malaria, the treatment won't really help you and you'll lose belief in the new therapy. Adhvaryu's estimates suggests that this misdiagnosis effect is quite large and important.
We remain very interested in why people in developing countries don't adopt things like better vaccinations, malarial bednets, circumcision, etc. At a first glance, failure to adopt these cheap but potentially life-saving/enhancing interventions seem irrational. However, in a world where people respond to information, good or bad, accuracy in education and diagnosis can go a long way in encouraging socially optimal behaviors.
By the way, this is not just a developing country issue. When the medical journal Lancet published a startlingly dubious study linking measles vaccines to autism, a non-trivial number of people stopped vaccinating their kids. It all seems silly, but it emphasizes greatly the role of information, good or bad, in the decision making process.
Montori says institutions and practitioners can raise awareness about conditions or available treatments, and also to counteract misinformation floating around online [using social networks]. “A lot of my colleagues say they don’t have time for distractions” like social media, he says. “But if folks who are really on the front lines of care cannot engage in this space, their thoughts, insights and experience will not be flowing through the network.”
And meantime, Montori says, “the thoughts of those who aren’t that busy, or who are paid to be in that space” will dominate. “Patients are receiving what they think is a signal but in fact it’s noise,” he says.
That last bit, about noisy signals, is an important one. It turns out that when health care professionals provide incorrect information, people learn from it in a way that is counterproductive. One of the most poignant illustrations of this comes from my friend and colleage Achyuta Adhvaryu, an economist who works on global health issues at Yale University. Adhvaryu was struck by how slowly people adopted new, highly effective anti-malarials in Tanzania after a brisk rate of uptake in the first year they were available. This is all the more weird given what we know about what malaria does to economic productivity.
Using an elegant and convincing set of theoretical and empirical techniques, he uncovers an interesting phenomenon: adoption rates are far lower in areas where the rate of misdiagnosis is higher. The story goes something like this: you have a fever, and go seek treatment. You get diagnosed with malaria and handed antimalarials. Now, if you actually have malaria, the treatment will make you feel better and you'll learn from that experience. If you don't have malaria, the treatment won't really help you and you'll lose belief in the new therapy. Adhvaryu's estimates suggests that this misdiagnosis effect is quite large and important.
We remain very interested in why people in developing countries don't adopt things like better vaccinations, malarial bednets, circumcision, etc. At a first glance, failure to adopt these cheap but potentially life-saving/enhancing interventions seem irrational. However, in a world where people respond to information, good or bad, accuracy in education and diagnosis can go a long way in encouraging socially optimal behaviors.
By the way, this is not just a developing country issue. When the medical journal Lancet published a startlingly dubious study linking measles vaccines to autism, a non-trivial number of people stopped vaccinating their kids. It all seems silly, but it emphasizes greatly the role of information, good or bad, in the decision making process.
Tuesday, June 28, 2011
The Persistence of Inequalities at Birth
The Economix blog at the New York Times has a great post on how differences in birth weight early in life lead to persistent differences in well-being (measured any way you'd like) in adulthood.
The article does a great job of highlighting studies exploring the causes of birthweight differences. Some of them are somewhat unexpected: did you know that EZ-pass is associated with higher birth weights and less risk of prematurity? (Hat tip: AKN)
The article does a great job of highlighting studies exploring the causes of birthweight differences. Some of them are somewhat unexpected: did you know that EZ-pass is associated with higher birth weights and less risk of prematurity? (Hat tip: AKN)
Wednesday, June 22, 2011
Sex and Measurement
We know with a good deal of certainty that unprotected sex exposes individuals to potentially life-threatening illness. We also know that all sexual encounters are not the same and, especially since the HIV/AIDS epidemic, researchers have been trying to figure out what sexual behaviors are riskiest and how to use this information towards better micro and macro-focused prevention efforts.
As with all research, a key issue is measurement. Our models to predict individual behavior are usually only as good as our data. As you might imagine, sex can be a personal topic. One may be reluctant to tell a survey interviewer/doctor/friend about their sexual activities, obscuring the whos, hows and whens that are oh-so-important for public health.
Some recent work provides insight into the scale of the measurement problem. A paper by Alexandra Minnis and colleagues compared self-reported sexual activity with biomarkers of exposure (a test based on PSA which can detect exposure to semen in the previous two days) in a sample of Zimbabwean women. The results were sobering: 52% of women who had positive biomarkers said that they engaged in protected sex in the last two days; 23% reported having no sex at all!
In another paper, Brendan Maughan-Brown and I looked at a sample of young adults in Cape Town, South Africa. Our study focused on concurrent sexual partnerships, intuitively defined as the presence of (temporal) overlap between sexual relationships with two distinct partners. There is a hot debate right now on whether such partnerships have been driving the HIV/AIDS epidemic in sub-Saharan Africa. Unfortunately, this debate has been held back by the availability of good data.
Recently, UNAIDS came out with some guidelines on how to standardize and better measure concurrency. We assessed the effectiveness of these guidelines by assessing whether individuals who reported having concurrent relations also reported more than one sexual partner. What we found was surprising: among those who reported only one sexual partner in the last year, nearly 1 out of 6 reported having concurrent sexual relations during this period! We conclude that the UNAIDS methods, which involves asking individuals about each sexual partner they've had and the start and end dates of those partnerships, may actually underestimate the prevalence of concurrency by a significant amount by not fully accounting for all sexual partners.
As both these papers suggest, we have a long way to go before we can credibly claim that we have precise, unbiased estimates of sexual behavior. It would be useful to divert some of time we all spend on linking specific sexual behaviors to health outcomes to figuring out how to get the measurements of those behaviors right in the first place.
As with all research, a key issue is measurement. Our models to predict individual behavior are usually only as good as our data. As you might imagine, sex can be a personal topic. One may be reluctant to tell a survey interviewer/doctor/friend about their sexual activities, obscuring the whos, hows and whens that are oh-so-important for public health.
Some recent work provides insight into the scale of the measurement problem. A paper by Alexandra Minnis and colleagues compared self-reported sexual activity with biomarkers of exposure (a test based on PSA which can detect exposure to semen in the previous two days) in a sample of Zimbabwean women. The results were sobering: 52% of women who had positive biomarkers said that they engaged in protected sex in the last two days; 23% reported having no sex at all!
In another paper, Brendan Maughan-Brown and I looked at a sample of young adults in Cape Town, South Africa. Our study focused on concurrent sexual partnerships, intuitively defined as the presence of (temporal) overlap between sexual relationships with two distinct partners. There is a hot debate right now on whether such partnerships have been driving the HIV/AIDS epidemic in sub-Saharan Africa. Unfortunately, this debate has been held back by the availability of good data.
Recently, UNAIDS came out with some guidelines on how to standardize and better measure concurrency. We assessed the effectiveness of these guidelines by assessing whether individuals who reported having concurrent relations also reported more than one sexual partner. What we found was surprising: among those who reported only one sexual partner in the last year, nearly 1 out of 6 reported having concurrent sexual relations during this period! We conclude that the UNAIDS methods, which involves asking individuals about each sexual partner they've had and the start and end dates of those partnerships, may actually underestimate the prevalence of concurrency by a significant amount by not fully accounting for all sexual partners.
As both these papers suggest, we have a long way to go before we can credibly claim that we have precise, unbiased estimates of sexual behavior. It would be useful to divert some of time we all spend on linking specific sexual behaviors to health outcomes to figuring out how to get the measurements of those behaviors right in the first place.
Wednesday, May 25, 2011
Poor Economics
I am working through this great book by MIT economists Abhijit Banerjee and Esther Duflo called Poor Economics. This beautifully written tome goes through various problems in economic development and discusses how evidence from the fast growing array of randomized field experiments in development economics can be used towards designing incisive policy interventions. What I love about this book is that it is theoretical and practical all at once. While there is still a healthy debate over the utility of experiments in development economics (see this recent post by Chris Blattman, and this one), what can't be argued is the importance of this methodology as at least a complementary tool in our quest to understand why some places are poor and others are not.
One of my favorite aspects of this new book is the accompanying website (linked above). In addition to access to various tables and datasets for 18 different countries, the website has a link to lectures on Banerjee and Duflo. The lectures on health, in particular, are quite interesting: they cover prevention, deworming, the importance of information, and the role of health in development. Some of these are practical resources that would be highly useful for health care practitioners who are interested in global health.
One of my favorite aspects of this new book is the accompanying website (linked above). In addition to access to various tables and datasets for 18 different countries, the website has a link to lectures on Banerjee and Duflo. The lectures on health, in particular, are quite interesting: they cover prevention, deworming, the importance of information, and the role of health in development. Some of these are practical resources that would be highly useful for health care practitioners who are interested in global health.
Tuesday, February 16, 2010
Interesting Global Health Policy Articles
The January 2010 issue of PLoS Medicine contains four interesting articles on the "global health system" The articles define what this system is, discusses the role of nations within this larger system and talks about how to strengthen it's effectiveness. These pieces are written by leaders in the field and provide some concrete discussion on a concept that has gained currency over the last few years, that global health is a policy domain of importance and that nations can be thought interlinked as part of a larger "health ecology" when developing policies to address morbidity and mortality the world over.
For more on global health and global health governance, you may want to check out this interview of one of my thesis committee members, Yale University Professor Jennifer Prah Ruger. Her work (linked here) focuses on this broader global health system, linking insights from ethics, politics, policy and economics to understand how and when investments in international health are and should be made.
Finally, for a topical piece on health care worker shortages worldwide, and the role of the United States in alleviating these, see this great essay by Yale medical student (and my former roommate!) Dayo Fadelu.
For more on global health and global health governance, you may want to check out this interview of one of my thesis committee members, Yale University Professor Jennifer Prah Ruger. Her work (linked here) focuses on this broader global health system, linking insights from ethics, politics, policy and economics to understand how and when investments in international health are and should be made.
Finally, for a topical piece on health care worker shortages worldwide, and the role of the United States in alleviating these, see this great essay by Yale medical student (and my former roommate!) Dayo Fadelu.
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