(2)" Hit -Hit-, = H (Cit -CGtI , Cjt - Cjt l, Ckt - Cktl1, Pkt - Pkt-1, Wkt - Wkt-l, **Ijt** - Ijt-) Note that when we do this, all time-invariant variables (like Ei, ri and time-invariant variables in the vectors of household and community characteristics) disappear from the model. This model expresses changes in BMI as a function of _all other variables that have changed_ between time t - 1 and time t .3 Our main interest is in the impact of the death of a prime-aged adult in the household. An adult death can shock the health of the elderly person through two channels - the budget constraint and the health production function. In this reduced form context, it appears as a component of Cj , and the sign of the coefficient on adult deaths cannot be predicted a priori. If the deceased adult produced more than he/she consumed, then holding other things constant the death could result in lower household income and human capital, reducing nutrients and health care of surviving household members. However, these reductions could be compensated for by increased transfers from other households, inheritance, and increased labor force participation/productive activities by the remaining household members. The fatal illness and death of an adult will also divert time and household resources away from the elderly to care for the terminally ill adult and to compensate for the patient's tasks in the household. To the extent that the adult death is due to an extended illness like AIDS, the major impact for other household members may occur prior to the death; following the death a reallocation of household resources to the health and nutrient intake of other household members may be possible, improving outcomes. Thus, while we cannot predict the direction of the impact of an adult death on the elderly, we expect that adverse impacts are more likely to be observed in the short run, because of lower disposable income, greater demand for medical expenditure for the ill adult at the expense of health inputs for other household members, possible diversion of the elderly person's time away from production of their own health, and the shorter time frame for mitigation measures.<sup>4</sup> We do not dismiss the possibility, however, that the AIDS epidemic has hit some communities so hard and repeatedly that their coping mechanisms are permanently depleted and they are unable to recover. Thus, in addition to an indicator of recent and future adult deaths in the household, we will include in our model a measure of the community-level adult mortality rate the number of living children of each elderly person.

The literature on the economic determinants of BMI of adults and especially the elderly is scarce in both industrialized and developing countries. From our priors based on economic

> **3** For example, since variables like the distance to a health center did not change in the course of the survey, we will not be able to analyze the impact of a reduction in the distance on a change in BMI.

**4** There are also epidemiological and emotional reasons why the BMI of the elderly could decline with an adult AIDS patient in the household. Tuberculosis is the major AIDS opportunistic infection in Africa and it can be passed on to caregivers who are HIV-negative. Grief and depression could also produce a negative impact on BMI.

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