Heritability of features of the insulin resistance syndrome in a community-based study of healthy families

Aims To investigate genetic and environmental influences on anthropometric, metabolic and fibrinolytic traits of the insulin resistance syndrome (IRS) in a population not characterized by a high degree of insulin resistance. Methods We recruited 537 adults from 89 randomly ascertained healthy families of white north European origin from the general population. We used maximum likelihood analysis to estimate the heritabilities and effects of environmental covariates on traits of the IRS in these families. Results Adjusted forage, sex and body mass index, the traits showed considerable heritability. For waist-hip ratio, heritability was 15%. The heritabilities of fasting glucose, insulin and estimated insulin resistance were 20%, 23% and 23%, respectively. Heritabilities were 20%, 24% and 43% for triglycerides, LDL-cholesterol and HDL-cholesterol, respectively. For PAI-1 Ag and t-PA Ag they were 20% and 26%. Covariates explained 20-25% of the variance of lipids and insulin resistance and 35-36% of fibrinolytic factors. Childhood household influences significantly affected variance for waist-hip ratio (4%), fasting insulin (11%) and estimated insulin resistance (12%). Conclusions These family data demonstrate significant genetic influence on anthropometric, fibrinolytic and glucose-related traits of the IRS in a healthy white North European population.