World Oil Prices and Child Health

Yale Political Science graduate student Brian Fried and I have a new working paper looking at how fluctuations in world fuel prices impact child respiratory health. Here is the abstract:

Acute respiratory infections secondary to indoor air pollution from the use biomass fuels such as wood, dung and crop residues, are an important but under-explored cause of morbidity and mortality among children in the developing world. Designing policies to address this issue requires an understanding of the determinants of household fuel choice. This study explores one particular determinant, fluctuations in world fuel prices, which impact the local prices of clean-burning fuels such as liquid propane gasoline (LPG). Using a rich, nationally representative survey dataset from Guatemala, we explored the association between shocks to world fuel prices, measures of household biomass fuel use, and the respiratory health of children under the age of six. Our core finding was that a $1 (3.6%) increase in the (one week lagged) world oil price was associated with nearly a 3 percentage point increase in the likelihood of a child under the age of six experiencing respiratory symptoms. This association is likely driven by changes in household fuel use: increases in oil prices were associated with increases in the time spent cooking by the child’s mother and by the likelihood that the household collected firewood, both of which indicate a switch to biomass fuels. In addition, the fuel price effect on child respiratory health was strongest among very young children, who are more dependent on their mothers and therefore are more exposed to cooking smoke, and was nonexistent in areas that did not have markets for LPG, where substitution across clean and dirty fuels is not possible. Our results have important implications for policies aimed at reducing the burden of disease from respiratory illnesses secondary to exposure to pollutants from biomass fuels.

Worthy Links on Health Care Reform

1. An article in Slate about physician incentives and their relationship to salary, all in the context of health care reform. The punchline: health care reform likely won't make a dent in physician reimbursement given the power of the doctor lobby and that fact that the government cannot interfere easily when much of health care is funded privately. I think the former point is true, and very sad, since doctors need to realize they respond to incentives just like anyone else. The latter seems like an overstatement: a fair amount of health care dollars (45%) come from public sources. Not a typo.

2. Another interesting piece in Slate, measuring up the US health care reform against our nation's deepest core economic and social values. The juxtaposition is interesting because it is at once jarring and at once perfectly consistent. I will let you read the piece to see what I mean. It's completely worth it: I haven't seen the health care reform debate phrased in this manner and it's definitely a refreshing perspective.

Economic Shocks, Risky Sexual Behavior and the HIV/AIDS Epidemic

The relationship between poverty and HIV/AIDS is a tricky one to pin down empirically. Studies have found widely different associations between SES and the likelihood of having been infected, though the positive association between education and HIV risk appears to be stable across time and space (see this excellent paper by Jane Fortson).

Aside from permanent economic status, transitory shocks may have some impact on the HIV/AIDS epidemic, as well. The idea is that bad times may induce people to engage in riskier sex because of market returns to such behaviors. The possibility of transient shocks in driving sexual behavior and, consequently, the HIV/AIDS epidemic is an intriguing one, especially given the potential prominence of "transactional sex" - sex in exchange for gifts, favors, etc (i.e., not necessarily prostitution!) - in African countries.

Two recent papers having examined this issue in the context of commercial sex workers. A study by Pascaline Dupas and Jonathan Robinson looks at the effects of political instability in Kenya circa 2007, which led to civil conflict and adverse economic times, on the behavior of commercial sex workers (CSWs). They find that CSWs were more likely to engage in unprotected sex after the adverse shock. A paper by Robinson and Ethan Yeh tells a similar story: CSWs in Kenya were more likely to have a variety of different types of riskier sex in response to income shocks. Both of these studies are well done from the stand point of data collection (how many people have panel data on CSWs??) and statistics (causality is plausibly inferred from both pieces).

In some African countries, however, CSW is not a common practice while transactional sex, more broadly, is. In such areas, it would be interesting to look at how the sexual behaviors of the general population respond to income shocks. My colleague Brendan Maughan-Brown, from the University of Cape Town, and I are working on this in the context of Khayelitsha, a township of Cape Town, SA, where antenatal clinic data indicates an HIV/AIDS of over 30%. Using longitudinal data from an effectively random sample of the township, we found (from individual fixed effects models) that people responded to income shocks by reducing condom usage. Interestingly, we found the same result when looking at individuals who were on anti-retroviral therapy for HIV/AIDS (draft forthcoming - will keep you posted).

We are currently trying to understand whether our results reflect a price mechanism (individuals cannot afford to pay the cost of obtaining and using condoms during bad times) or a consumption smoothing mechanism (individuals engage in riskier sex to get by during bad times). Either way, we have compelling evidence that economic shocks may play a role in driving the HIV/AIDS epidemic.

"Sin Taxes," Public Health, and Targeting

"Sin taxes" have been all the rage for some time, with the idea being that people respond to hikes in the prices of various deleterious substances by reducing their unhealthy behaviors. Taxes on goods such as tobacco and alcohol are often justified on the grounds that people's unhealthy behaviors have social costs: one man's boozing and smoking adversely affects those around him.

Conventional wisdom suggests that, on average, such taxes work. However, taxes may work differently for different people. As far as health promotion, one would expect sin taxes to be most powerful if they can effectively help change among individuals who have more severe and intractable problems with smoking and drinking.

Some of my colleagues at Yale (including two of my advisers, Jason Fletcher and Jody Sindelar) have produced some interesting work looking into the effectiveness of tobacco and alcohol taxes on different types of smokers and drinkers, respectively. To explore heterogeneity among smokers and drinkers, they use a latent class method (finite mixture models - discussed two posts ago) to identify different groups of people. What the find is striking: for tobacco use among adolescents and alcohol use among adults, taxes are least effective among groups that tend to smoke or drink more heavily and who generally have the least willpower to quit. The authors make use of very detailed data on people's behaviors, preferences and outlook on life to build these interesting stories.

The results suggest that, among those least likely to quit on their own, taxes appear to have little power in inducing behavior change. Basically, from a public health standpoint, if one is interested in reducing unhealthy behaviors in these populations, policies other than/in addition to taxes will likely be required.

Two Year Anniversary

Having found myself short on sleep and time over the last few weeks, I forgot to write a note here about the two year anniversary of my blog. Basically, I started this whole thing in July 2007 as a travel blog and somehow continued with it through my prospectus and dissertation writing. I'm really happy with how the blog has turned out and am grateful for your thoughtful comments.

I should point out that I fully intend to continue blogging at my usual pace once I achieve an optimal work-sleep-eat equilibrium here in med school! In the meantime, please bear with me and continue to check this space from time to time for new content.

Thank you again for your readership and support. It's been a fun two years and I look forward to more.

Links: Problems with American Health Care, Job Loss and Unhealthy Behaviors

1. A really interesting piece in the NYT about inefficiency in American health care. The piece, by David Leonhardt, uses prostate cancer as a lens to highlight the gaps between clinical practice and the existing research evidence (or lack thereof). Pretty eye opening stuff.

2. More on American health care: a great piece from The Economist about the challenges awaiting health care reform.

3. My colleagues at Yale, Padmaja Ayyagari, Bill Gallo, Jason Fletcher and Jody Sindelar, along with Partha Deb from CUNY Hunter, have an interesting new paper looking at how job loss influences subsequent unhealthy behaviors. Aside from the interesting research question, this paper is pretty interesting from a methodological standpoint in that they use plausibly (more) exogenous in job loss by exploiting information on business closings as well as employ finite mixture models to model the underlying heterogeneity in effects and people's propensity for unhealthy behaviors. The latter technique is becoming quite hot in health economics now as there is increasing interest in trying to understand how individuals may differ in their underlying propensities towards different behaviors and disease.