Association Between Relative Leg Length and Insulin Resistance in Rural, Urban and Rural–Urban Migrant Populations of Peru

• Published in: American journal of human biology Vol. 37; no. 7; pp. e70105 - n/a
• Main Authors: Mucching‐Toscano, Sergio, Moscoso‐Porras, Miguel, Zafra‐Tanaka, Jessica Hanae, Anza‐Ramirez, Cecilia, Bernabé‐Ortiz, Antonio, Wells, Jonathan C. K., Miranda, J. Jaime
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2025; Wiley Subscription Services, Inc
• Subjects: Adult; Body fat; Cross-Sectional Studies; Female; Humans; Insulin; Insulin Resistance; internal migration; Leg; Leg - anatomy & histology; leg length; Male; Metabolic disorders; Middle Aged; Obesity; Peru - epidemiology; Physical activity; Regression analysis; Regression models; Rural areas; Rural Population - statistics & numerical data; Rural populations; Transients and Migrants - statistics & numerical data; Urban areas; Urban Population - statistics & numerical data; Urban populations; Peru; insulin resistance; leg length; internal migration
• ISSN: 1042-0533; 1520-6300; 1520-6300
• DOI: 10.1002/ajhb.70105

ABSTRACT Objective To determine the association between relative leg length and insulin resistance according to rural, urban, and rural–urban migrant groups. Methods Cross‐sectional study using data from the PERU MIGRANT study (2007–2008). The exposure was relative leg length categorized as short, normal, or long, and the outcome was insulin resistance (logarithm of homeostatic model assessment log‐HOMA2‐IR). Linear regression models with log transformation, adjusted for sex, age, parental education, hip circumference, and physical activity level, were employed to estimate geometric mean ratios of insulin resistance across leg length categories. Interaction effects of population groups (rural, urban, and migrants) on insulin resistance were explored, along with mediation analysis of central obesity and excess body fat in the main relationship. Results Using data from 947 participants, 52.7% female, mean age 47.7 years (SD = 11.9), we found a robust inverse association between relative leg length and insulin resistance. The geometric mean of insulin resistance in subjects with long leg length was 43% (eβ1: 0.57, 95% CI: 0.47–0.69) lower than those in the normal category. A significant interaction effect of the population group on relative leg length categories (p < 0.001) was observed, particularly in the migrant and rural groups. Excess body fat and abdominal obesity explained 33% and 12% of the association between relative leg length and insulin resistance, respectively. Conclusions Longer leg length was associated with lower insulin resistance values, with a greater interaction effect observed among the rural–urban migrant and urban groups. These findings support the hypothesis that metabolic disorders in adults may be traceable to nutritional and developmental conditions early in life.