Short Birth Intervals and Long-Term Stunting Risk in Indonesian Children: A Retrospective Cohort Study Using the Indonesian Family Life Survey.

Background/Objectives: Optimal birth spacing plays an important role in supporting children's growth and nutritional outcomes. However, evidence on the long-term effects of short birth intervals on stunting from childhood to adolescence in Indonesia is limited. This retrospective cohort study used longitudinal data from waves 3, 4, and 5 of the Indonesian Family Life Survey (IFLS) (2000, 2007, 2014) to examine the association between short birth intervals and stunting trajectories among Indonesian children. Methods: We analyzed 1401 children aged 0-59 months with complete anthropometric data using longitudinal data from IFLS waves 3, 4, and 5 (2000, 2007, 2014). Stunting was defined as a height-for-age z-score (HAZ) below -2 standard deviations (SDs) according to the WHO Child Growth Standards (2006) for children under five years and the WHO Growth Reference (2007) for children and adolescents. The impact of short birth intervals on stunting status was evaluated using multilevel binary logistic regression. Results: Stunting distribution showed significant improvement between 2000 and 2014. In 2000, 37.7% of children were stunted, which decreased to 33.9% in 2007 and nearly 25% in 2014. The majority of mothers (77.7%) gave birth between 20 and 35 years of age, while 12.7% gave birth too early (<20 years) and 9.6% gave birth too late (>35 years). In addition, 16.2% of parents had too many children (parity ≥ 4), and 6.8% had too close birth intervals (<24 months). Multilevel logistic analysis revealed that short birth intervals (odds ratio (OR) = 1.60-1.63) were significantly associated with stunting after adjusting for child, household, socioeconomic, and environmental factors. However, maternal age and parity were not significantly associated with stunted growth. Conclusions: Birth spacing is a critical risk factor for stunting in early childhood and remains significant as children age. Longitudinal analyses highlight the importance of sustained interventions targeting maternal health, education, and child nutrition to address stunting in Indonesia.