Supplementary Material for: Rural to urban migration is associated with increased leptin resistance: The RODAM study

Background: Sub-Saharan African (SSA) migrant populations are exposed to new environmental factors, both of which have been linked to increased rates of obesity and insulin resistance. Given the complex relationship between adipokines and cardiometabolic traits, we hypothesized that these associations may vary depending on geographical context. Objective: To examine the influence of geographic location on the association between serum leptin and adiponectin and cardiometabolic traits. Method: Cross-sectional analysis among 2640 participants from the RODAM study living in Amsterdam, the Netherlands, and urban and rural Ghana. Correlation and linear regression models were used to examine the relationship between adipokines and cardiometabolic traits, including body composition, insulin resistance, inflammation, and lipid metabolism per location. Results: Body composition was the key determinant of serum leptin, less so for serum adiponectin. There was a significant(p< 0.001) interaction in the association between BMI and serum leptin according to geographic location in women and in the association between waist circumference (WC) and serum leptin in men, suggesting increased leptin resistance during rural to urban transition, but with similar slopes for urban Ghanaians living in tropical and temperate climates. There was no significant interaction with location in the association between body composition and adiponectin. Inflammation and lipid metabolism explained the least amount of variance in serum adipokines across the locations. Conclusion: There was significant variability in the relationship between serum leptin and the cardiometabolic traits examined across locations. These findings suggest that rural to urban transition significantly affects this relationship. Future studies may help to further delineate the effects of environmental factors on adipokine production, obesity and cardiometabolic disease.