Four decades of socio-economic inequality and secular change in the physical growth of Guatemalans

Objective: To investigate changes in socio-economic inequalities in growth in height, weight, BMI and grip strength in children born during 1955-1993 in Guatemala, a period of marked socio-economic-political change. Design: We modelled longitudinal data on height, weight, BMI and hand grip strength using Super-Imposition by Translation and Rotation (SITAR). Internal Z-scores summarising growth size, timing and intensity (peak growth velocity, e.g. cm/year) were created to investigate inequalities by socio-economic position (SEP; measured by school attended). Interactions of SEP with date of birth were investigated to capture secular changes in inequalities. Setting: Urban and peri-urban schools in the region of Guatemala City, Guatemala. Participants: Participants were 40 484 children and adolescents aged 3-19 years of Ladino and Maya ancestry (n(observations) 157 067). Results: The difference in height (SITAR size) between lowest and highest SEP decreased from -2 center dot 0 (95 % CI -2 center dot 2, -1 center dot 9) sd to -1 center dot 4 (95 % CI -1 center dot 5, -1 center dot 3) sd in males, and from -2 center dot 0 (95 % CI -2 center dot 1, -1 center dot 9) sd to -1 center dot 2 (95 % CI -1 center dot 3, -1 center dot 2) sd in females over the study period. Inequalities also reduced for weight, BMI and grip strength, due to greater secular increases in lowest-SEP groups. The puberty period was earlier and shorter in higher-SEP individuals (earlier SITAR timing and higher SITAR intensity). All SEP groups showed increases in BMI intensity over time. Conclusions: Inequality narrowed between the 1960s and 1990s. The lowest-SEP groups were still >1 sd shorter than the highest. Risks remain for reduced human capital and poorer population health for urban Guatemalans.