Motherhood, migration and mortality in Dikgale: modelling life events among women in a rural South African community

Objectives: Although particular types of life events in populations are often studied separately, this study investigated the joint effects of three major event types in South African women's lives: motherhood, migration and mortality.

Study design: Data were taken from a health and demographic surveillance site (HDSS) over an 11-year period, reflecting the entire population of a defined geographic area as an open cohort, in which individuals participated in regular longitudinal surveillance for health and demographic events. This HDSS is a member of the Indepth Network.

Methods: Multivariate Poisson regression models were built for each of the three life event types, in which individual person-time observed out of the total possible 11-year period was used as a rate multiplier. These models were used to calculate adjusted incidence rate ratios for each factor.

Results: In the 21,587 person-years observed for women aged 15-49 years, from 1996 to 2006, adjusted rate ratios for mortality and migration increased substantially over time, while motherhood remained fairly constant. Women who migrated were less likely to bear children; temporary migrants were at greater risk of dying, while permanent in-migrants had higher survival rates. Women who subsequently died were much less likely to bear children or migrate.

Conclusions: The associations between motherhood, migration and mortality among these rural South African women were complex and dynamic. Extremely rapid increases in mortality over the period studied are presumed to reflect the effects of the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic. Understanding these complex interactions between various life events at population level is crucial for effective public health planning and service delivery.