The clinical characteristics of the study samples in all six cohorts are shown in Table 1. Due to the nature of sample collection, the cohorts consisted of community non-diabetic (cohorts 1 and 3), community-based (cohort 6) or diabetic subjects (cohorts 2, 4 and 5). The distributions of BMI are comparable among all cohorts, except for higher mean BMI (35.3 kg m−2) and higher prevalence of obesity (74.3%) in the Diabetes Heart Studies (cohort 5). In view of the heterogeneous phenotypes among the study cohorts, BMI Z-scores were calculated in sex- and disease-specific strata and then combined in each cohort separately for association analyses.
