Impact of interaction between family history of diabetes and abnormal waist-to-height ratio on risk of type 2 diabetes mellitus

Objective To explore the interaction between family history of diabetes and abnormal waist-to-height ratio (WHtR) on risk of type 2 diabetes mellitus (T2DM). Methods The Jinchang cohort (established in June, 2012) was used in this study, and the baseline data were collected in December 2013. For case-control study, 1 109 male patients and 834 female patients with T2DM were included in diabetic group, whereas 1 943 healthy subjects matched with gender were included in control group. The additive model was used to study the interaction; the adjusted OR values of risk factors and regression coefficient were analyzed by multivariate logistic regression analysis; and the interaction between the factors were analyzed by the EXCEL software developed by Andersson et al. Results After excluding 26 706 cases without data of waist circumeference, a total of 21 292 cases were included in our study. The prevalence of diabetes was 9.13% (1 943/21 292) in all subjects, but 9.11% (1 109/12 175) in male subjects and 9.15% (834/9 117) in female subjects. After adjusting for age, smoking, drinking and other confounding factors, there was positive additive interaction between family history of diabetes and abnormal WHtR on risk of T2DM. While the family history of diabetes and abnormal WHtR existing at the same time, the risk of diabetes was 9.09 (95%CI: 5.64-14.64) in male and 13.08 (95%CI: 6.99-24.47) in female compared with control. In male, the index of synergistic effect, the attribution of interaction effect, and the percentage of attribution of interaction effect was 1.58, 2.98 and 32.8%, respectively. In female, the index of synergistic effect, the attribution of interaction effect, and the percentage of attribution of interaction effect was 1.90, 5.72 and 43.7%, respectively. Conclusion Family history of diabetes and abnormal WHtR may have synergistic effect on risk of T2DM.