Genetic and environmental associations between insulin resistance and weight-related traits and future weight change

The aims of this study were to investigate the association between initial insulin resistance (IR), weight status, and precedent weight change (PWC) and future weight change and the genetic and environmental contributions affecting these relationships in a prospective cohort of Korean twins and their family members.

The PWC (weight change from 20 y of age), baseline body mass index (BMI), baseline homeostasis model assessment of IR (HOMA-IR) score, and future weight change (follow-up interval 3.28 ± 1.32 y) of 1565 adults were assessed. The mixed linear model was applied after adjusting for intrafamilial relationship, age, education, health behaviors, chronic diseases, dietary intake, eating restraint, and menopausal status of women at baseline. A bivariate genetic analysis was performed after adjusting for age and sex.

In the model that simultaneously included all predictors and confounding factors, inverse associations were observed between PWC and baseline HOMA-IR score and future weight change in men, and only baseline BMI was inversely associated with future weight change in women. Men and women with BMI ≥25 kg/m², HOMA-IR score ≥2.5, and PWC greater than or the same as the sex-specific median of PWC were more likely to lose weight than those with the combination of the counterparts. Approximately 63.6% of the correlation between the baseline HOMA-IR score and future weight change was attributed to genetic effects, and 68.4% to 91.3% of the correlations between weight-related traits and future weight change were correlated to environmental effects.

An inverse association was observed between the initial IR, weight status, and PWC and future weight change, and genetic or environmental factors contributed to these relationships.