Dynapenic abdominal obesity and the risks of heart disease and all-cause mortality: a 7-year longitudinal study among middle-aged and older Chinese adults.

Background: Research on the impact of dynapenic abdominal obesity (DAO) on heart disease and mortality in Asian populations is limited. Given the distinct muscle strength and visceral adiposity profiles in Asians compared to other populations, it is important to investigate these associations in this context. This study aimed to assess the impact of DAO on heart disease and all-cause mortality in middle-aged and older Chinese adults.

Methods: Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS), which recruited 17,708 participants at baseline and followed them for 7 years. DAO was defined as the coexistence of dynapenia (handgrip strength < 28 kg for men and < 18 kg for women) and abdominal obesity (waist circumference ≥ 90 cm for men and ≥ 80 cm for women). Participants were categorized into four groups: DAO, non-dynapenic/abdominal obesity (ND/AO), dynapenic/non-abdominal obesity (D/NAO), and neither condition (ND/NAO). Logistic regression assessed the association between DAO and heart disease, while Cox regression evaluated its relationship with all-cause mortality. Additionally, subgroup analyses explored potential variations by age and sex. For sensitivity analyses, multiple imputation was performed to address missing covariates and assess the robustness of the findings.

Results: A total of 8,526 participants were included in the heart disease analysis, with 1,136 incident cases recorded. Compared to the ND/NAO group, the DAO group did not exhibit a significantly increased risk of heart disease (OR = 0.96, 95% CI: 0.68-1.33). For all-cause mortality analysis, 11,980 individuals were included, with 1,162 deaths occurred during follow-up. The DAO group (HR = 1.84, 95% CI: 1.45-2.33) and D/NAO group (HR = 1.58, 95% CI: 1.35-1.86) had significantly higher all-cause mortality risk compared to the reference group. Subgroup analyses found no significant interactions by age or sex. Sensitivity analyses produced consistent results for both incident heart disease and all-cause mortality.

Conclusions: DAO was associated with increased all-cause mortality in middle-aged and older Chinese adults, highlighting the need for targeted interventions to address both abdominal obesity and dynapenia. However, the lack of association with heart disease, likely due to confounding factors, warrants further investigation to clarify this relationship.