Boys Are More Stunted than Girls from Early Infancy to 3 Years of Age in Rural Senegal

Background: Girls tend to have a lower risk of stunting than boys do in low-income countries. Objective: We evaluated differences in height status and complementary food (CF) intake between sexes from ages 2 to 39 mo in Senegal. Methods: Length and weight measurements were taken at ages 2-3, 4-5, 6-8, and 9-10 mo (n = 7319). Qualitative 24-h and 7-d food recalls were conducted in a subgroup (n = 2512). A smaller subsample was followed up to age 39 mo (n = 512). Height was measured, and intake of CF was noted. Boys and girls were compared in terms of height-for-age z score (HAZ) of WHO standards and National Center for Health Statistics growth reference, height-for-age difference, stunting, and consumption of CF by using chi-square tests, general linear models, and mixed-effects linear models (MLMs). Results: By using WHO standards, the mean HAZ was lower for boys than for girls in infancy, i.e., at 2-3 mo of age (-0.65 compared with -0.57; P = 0.002) and beyond, i.e., at 24-29 mo of age (-2.01 compared with -1.65; P < 0.001). Overall risk of stunting was 24.5% and 19.4% for boys and girls, respectively, during infancy (P < 0.001) compared with 59.2% and 47.9%, respectively, at 12-39 mo (P = 0.010). In MLMs from ages 2 to 39 mo, boys had a lower mean HAZ than girls had at age 2 mo (beta(0) = -0.19; P = 0.035), and sex differences increased with increasing age (beta(1) = -0.007 z scores/mo; P < 0.001). At 2-3 mo of age, boys were more likely to have been fed CF every day during the past week (15.8% compared with 11.2% for girls; P = 0.005) and to have eaten >= 2 meals in the past 24 h (13.4% compared with 8.2% for girls; P < 0.001). Conclusions: In Senegalese infants, CF intake differed by sex, with boys more likely to consume CF. Boys had lower HAZs than girls had during infancy, and sex differences increased up to age 39 mo. The importance of sex in complementary feeding and growth warrants further attention in low-income countries.