The 10/66 Dementia Research Group INDEP study (The Economic and Social Effects of Care Dependence in Later Life) was funded by the ESRC/ DFID joint poverty alleviation programme. We planned to investigate the impact of care dependence upon social and economic functioning at the household level in China, Mexico, Peru and Nigeria (1). In a nested cohort study design, households were pre-selected as engaged in incident care, chronic care, or no care (control households) of older adults, on the basis of findings from our previous 10/66 DRG baseline and incidence wave population-based surveys in rural and urban sites in Mexico, Peru and China (2;3). All care households and an equivalent number of randomly selected control households (batch matched for the age of the oldest qualifying resident) were invited for the INDEP follow-up. Design (sampling) and response weights are provided, to weight back to the overall composition of the population-based sample for the 10/66 incidence wave surveys in these sites. This mixed methods project is nested within the baseline and incidence phases of the 10/66 Dementia Research Group population-based studies in Mexico, Peru, China and Nigeria. The objective is to study whether, and if so how, the onset of care-dependence in an older household member leads to household impoverishment and vulnerability. Households with an older person who has developed needs for care (incident care households) will be compared with those with older residents with long-standing needs for care (chronic dependence) and no needs for care (control households). Detailed household interviews will be used to assess consumption, income and assets, including changes that might be attributable to the onset or intensification of care-dependence. Detailed case studies of selected households will be used to elucidate the pathways involved. An additional focus is intra-household effects and wider social dynamics: (1) How is the care burden for dependent older people distributed across household members and wider kinship networks? (2) What factors influence the distribution of the care burden inside and outside the household? (3) How are decisions about the allocation of care made and justified? (4) To what extent does this depend on the external policy environment, including the reach of social protection and health services?

Quantitative data collection comprised household interviews, and individual older person interviews, and a key informant interview for each older person. The household interview included some data on the household as a whole (e.g. housing quality and type, assets, and consumption), and grids to be completed with information (sociodemographic, employment, income, savings, loans, debts, health and needs for care) on every resident. The quantitative data set therefore comprises information on 872 households (196 in Peru, 356 in Mexico, and 220 in China); 3176 residents (842 in Peru, 735 in Mexico and 1039 in China); and 942 older adults (225 in Peru, 366 in Mexico and 351 in China). We also carried out (in Peru, Mexico, China and Nigeria) detailed qualitative case studies of care households purposively selected with varying characteristics of interest, relevant to the research questions. These comprised 25 household case studies (6 in Peru, 6 in Mexico, 6 in China and 7 in Nigeria) including narratives from individual or group open-ended interviews guided by evolving topic guides from 63 individual key informants (16 in Peru, 13 in Mexico, 16 in China and 18 in Nigeria).