Age patterns in overweight and wasting prevalence of under 5-year-old children from low- and middle-income countries

OBJECTIVES: To describe how overweight and wasting prevalence varies with age among children under 5 years in low- and middle-income countries (LMICs). METHODS: Nationally representative Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS) from 2010–2019 were analyzed. Overweight and wasting were defined as weight-for-length/height (WHZ) > +2 SD and < −2 SD from the 2006 WHO standards median, respectively. Descriptive analyses provided national estimates of overweight, wasting, mean WHZ, and WHZ standard deviations by single-year age groups; national results were pooled weighting by country under-5 populations. Fractional polynomials compared mean WHZ with overweight and wasting prevalence. RESULTS: Ninety national LMIC surveys were included. Overall overweight prevalence declined with age from 6.3% at 0–11 months to 3.0% at 48–59 months (p = 0.03). In all age groups, overweight prevalence was lower in low-income than in upper-middle-income countries. Wasting was also more frequent among infants, decreased slightly from the first to second year of life, and showed little variation thereafter; lower-middle-income countries had the highest wasting prevalence across ages. Mean WHZ was stable across ages, but the median standard deviation decreased from 1.39 in infants to 1.09 in 4-year-olds (p < 0.001). For any given mean WHZ, both overweight and wasting prevalence were higher in infants than in older children. CONCLUSION: Elevated WHZ standard deviations in infants suggest that the observed age-related declines in overweight and wasting may be partly due to measurement error or rapid crossing of growth channels in infancy.