[Interaction between gender and visceral adiposity index-associated risk of type 2 diabetes]

Objective: To examine the interaction between gender and the visceral adiposity index (VAI) in relation to the risk of type 2 diabetes mellitus (T2DM). Methods: This retrospective cohort study utilized data from the public Dryad database derived from the NAGALA (NAFLD in the Gifu Area, Longitudinal Analysis) project (1994-2016). Participants were stratified into quartiles based on VAI levels. A multivariate Cox proportional hazards regression model was employed to evaluate whether VAI independently predicts T2DM risk. Kaplan-Meier survival curves and receiver operating characteristic (ROC) curves were constructed for each VAI quartile. Subgroup analyses were conducted to examine associations across age and body mass index categories. Both multiplicative and additive interaction effects between gender and VAI were assessed. Additionally, gender-specific Cox models were fitted to further explore these associations. Results: A total of 15 453 participants [8 419 males and 7 034 females; mean age, (43.7±8.9) years] were included, with a median follow-up duration of 5.39 years. During follow-up, 373 participants (2.4%) developed T2DM. After adjustment for potential confounders, higher VAI levels were independently associated with increased T2DM risk (HR=1.16; 95%CI 1.11-1.21), consistent with the results across VAI quartiles. Kaplan-Meier analysis revealed a significant trend of increasing T2DM incidence across VAI quartiles (P<0.001). The area under the ROC curve for VAI in predicting T2DM at 3, 5, and 10 years was 0.755, 0.735, and 0.696, respectively. Sensitivity analyses showed that elevated VAI was associated with increased T2DM risk across all age and body mass index subgroups (all P<0.05). Regarding interaction analysis, the HR (95%CI) for the multiplicative interaction between VAI and gender was 1.22 (1.19-1.26). The relative excess risk of interaction was -1.08 (95%CI -2.96 to -0.06), the attributable proportion of interaction was -0.54 (95%CI -1.35 to -0.01), and the synergy index was 0.48 (95%CI 0.26-0.91), indicating a negative additive interaction. Using low-VAI women as the reference group, the risk of T2DM in high-VAI women was higher (HR=2.53, 95%CI 1.59-4.02) compared to high-VAI men (HR=2.01, 95%CI 1.49-2.72). In gender-specific analyses, increasing VAI remained significantly associated with elevated T2DM risk after adjustment in both females (HR=1.43, 95%CI 1.21-1.68) and males (HR=1.16; 95%CI 1.11-1.22), with consistent findings across VAI quartiles. Conclusions: VAI and gender demonstrated multiplicative and additive interaction in relation to T2DM risk. The association between increasing VAI and T2DM risk was more pronounced in women than in men.