The aim of this proposal is to enhance the scientific value of the forthcoming 5th round of the Malawi Diffusion and Ideational Change Project (MDICP) by collecting data on the non-resident parents of respondents in the MDICP. The MDICP has received funding from NIH to examine the consequences of AIDS-related morbidity and mortality for the adult respondents in the longitudinal study begun in 1998, including a new sample of the coresident elderly parents of the adult respondents. Collecting data only from parents residing in households in the MDICP sample, however, raises sample selection issues that this proposal addresses in a cost-effective way. Thus, the specific aim of this proposal is to track non-resident elderly parents and to collect the same survey, anthropo-metric, biomarker and qualitative data from them as from the resident elderly parents. Surveys based on prime-age adults (rather than aging surveys such as MHAS and HRS) rarely directly interview non-resident elderly. Since these may be quite different from resident elderly parents, analyses that omit them are likely to be biased.