"The research assistants kept coming to follow me up; I counted myself as a lucky person": Social support arising from a longitudinal HIV cohort study in Uganda.

Longitudinal study participation resulted in instrumental and emotional social support for participants. The depth of support participants experienced has implications for observational study design in resource-limited settings, including need to assess potential effects on study outcomes; consideration of social support during risk/benefit assessment in study ethics review and consent; and vigilance for consequences of social support loss when studies end.