Relative leg length is associated with type 2 diabetes differently according to pubertal timing: The Brazilian longitudinal study of adult health

Objectives: Studies from developed societies have shown that individuals with short legs relative to height have higher risk of type 2 diabetes. This has been much less explored in less developed populations where influences on relative leg length and diabetes may differ. The Brazilian Longitudinal Study of Adult Health (in Portuguese, ELSA-Brasil) allows us to test, in a cohort born (1934-1975) and raised when undernutrition was common, whether short legs relative to height is positively associated with diabetes, independent of early-life factors, including birth weight, age at menarche, and young-adult BMI. Methods: We used baseline, cross-sectional data from 15,105 participants aged 35-74 years participating in ELSA-Brasil. We created age-and-sex-specific Z scores for leg length index (leg length/height × 100) according to an external reference. Diabetes was defined by self-reported physician diagnosis, medication use, fasting and 2-h post-75-g-load glucose, and A1C. Results: A one-unit decrement in leg-length-index Z score was associated with 12% (8-17%) higher prevalence of diabetes in Brazilian adults, after adjustment through Poisson regression for confounders, including race, maternal education, and birth weight. This association persisted after further adjustment for menarche age, BMI (at age 20), buttocks circumference, and waist circumference. It was stronger among women with early menarche (P interaction=0.02). Leg length index was also inversely associated with fasting glucose, fasting insulin, 2-h glucose, and A1C (P<0.05). Conclusions: In contemporary Brazilian adults, short legs relative to height is positively associated with diabetes independent of measures of intrauterine growth, pubertal timing, and young-adult adiposity. This association is stronger in women with early menarche. Am. J. Hum. Biol. 27:219-225, 2015.