The Associations of Age at First Marriage, Poverty, and Total Fertility Rate with Infant Mortality in Indonesia

Infant mortality is an important indicator of population health and development outcomes. This study examines the associations between age at first marriage, poverty, total fertility rate (TFR), and provincial level infant mortality in Indonesia. Using an ecological cross-sectional design based on provincial level secondary data from 35 provinces, this study applies multiple linear regression to examine how demographic and socioeconomic indicators are associated with variations in infant mortality rate (IMR) across provinces. The regression model explained 77.1% of the variation in provincial IMR (R2=0.771). Poverty and total fertility rate showed positive and statistically significant associations with infant mortality, indicating that provinces with higher poverty rates and higher fertility levels tended to report higher IMR. In contrast, age at first marriage showed a negative but statistically non-significant association with IMR after controlling for poverty and fertility. These findings indicate that socioeconomic and fertility-related conditions showed stronger statistical associations with provincial differences in infant mortality than age at first marriage within the present model. However, the findings should be interpreted cautiously because the study uses aggregated provincial level data and an ecological cross-sectional design, which does not permit causal or individual-level inference.