The association between preceding birth interval and childhood stunting in Benin

Stunting affects approximately 32% of children under five years in Benin. While birth intervals shorter than 33 months are a recognized risk factor for childhood malnutrition, the birth interval associated with the lowest odds of stunting in the Beninese context is still unclear. This study examined the association between preceding birth interval (PBI) and stunting among children aged 6–59 months in Benin. This study is a secondary analysis of nationally representative data from the cross-sectional 2017-18 Benin Demographic and Health Survey. We included 10,153 children aged 6–59 months. Stunting was defined as height-for-age z-score below 2 standard deviations from World Health Organization standards. Preceding birth interval (PBI), the interval between the index birth and the preceding live birth, was categorized into six groups: <24, 24–32, 33–44, 45–56 and > 56 months, and a separate category for first-born children with no preceding birth interval. Survey-adjusted multivariable logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the association between PBI and stunting, controlling for child, maternal, and household-level covariates. PBI categories were also compared directly with one another. Potential effect modification by child age group (6–23 vs. 24–59 months) was assessed with a design-based Wald test of the interaction terms. Compared with children born after an interval of < 24 months, those born after 45–56 months (aOR: 0.61; 95% CI: 0.49–0.74) and > 56 months (aOR: 0.63; 95% CI: 0.51–0.77) had significantly lower odds of stunting (both p < 0.001). Intervals of 24–32 months and 33–44 months were not significantly associated with stunting, nor was first-born status. Compared directly with one another, adjusted odds were similar for 33–44 vs. 24–32 months (OR: 1.03; 95% CI: 0.91–1.17) and for > 56 vs. 45–56 months (OR: 1.04; 95% CI: 0.83–1.31), whereas 45–56 months differed from 33 to 44 months (OR: 0.66; 95% CI: 0.55–0.79). No evidence of effect modification by child age group was found (design-based Wald test p = 0.363), and stratified analyses by age group are reported as exploratory. Longer preceding birth intervals, particularly of 45 months or more, were associated with lower odds of stunting. This cross-sectional analysis of a single child outcome supports further investigation into whether longer intervals may provide additional nutritional benefits. Alongside this, nutritional support for pregnant and breastfeeding women, including adequate dietary supplementation and counselling, may further contribute to improved child growth outcomes.