Infections, Animal-Source Foods, and Micronutrient Status as Correlates of Serum IGF-1 in Children with Stunting: A Cross-sectional Study in Uganda

Background: Serum insulin-like growth factor-1 (serum IGF-1) is important for growth in childhood. Inflammation downregulates serum IGF-1, but the roles of intake of animal-source foods and micronutrient status are not well known. Objectives: We assessed the associations of infections, intake of animal-source foods, iron, B12, folate, and vitamin A status with serum IGF-1 among stunted children. Methods: We conducted a cross-sectional study, using data from a nutrition trial among 12–59-mo-old stunted Ugandan children. Data on sociodemography, anthropometry, breastfeeding, dietary intake, and morbidity were collected. Serum IGF-1 and markers of micronutrient status and inflammation were determined. A rapid malaria test was done. Fat and fat-free mass were measured using bioimpedance. Tobit regression was used to assess correlates of serum IGF-1. Results: Of 750 children, 45.1% (n = 338) were girls and 29.6% (n = 222) were <2 y. Serum IGF-1 was available on 98.7% (n = 740). Median (interquartile range) serum IGF-1 was 37.4 (24.2, 53.3) μg/L, 11.8 [95% confidence interval (CI): 8.8, 14.9] μg/L lower in males, and 0.6 (95% CI: 0.5, 0.6) μg/L higher per month higher age. Inflammation markers were strong negative correlates of serum IGF-1. Positive malaria test was associated with lower serum IGF-1 (−4.7 μg/L, 95% CI: −7.8, −1.6), but not after inflammation adjustment (1.3 μg/L, 95% CI: −1.9, 4.6). Serum IGF-1 was associated with height-for-age z and fat-free mass. Serum retinol-binding protein <0.70 and 0.70–1.05, compared with >1.05 μmol/L was associated with 14.3 (95% CI: 9.6, 19.1) and 6.1 (95% CI: 1.6, 10.6) μg/L lower serum IGF-1 after adjustments for age, sex, and inflammation. Markers of other micronutrients were not. Intake of milk, but not meat or eggs, was associated with 3.9 (95% CI: 0.7, 7.1) μg/L higher serum IGF-1. Conclusions: Milk intake and vitamin A status were positively associated with serum IGF-1. In contrast to milk, vitamin A has not consistently been associated with growth. This requires further investigation.