Cohort Study on the Association Between Chinese Visceral Adiposity Index and All-cause and Cause-specific Mortality in the Elderly of Wuhan postprint

Abstract: Background　Visceral fat accumulation is closely associated with health outcomes in the elderly. As an indicator specific to the Chinese population, the Chinese Visceral Adiposity Index (CVAI) has not been fully validated in large cohort studies regarding its association with mortality risk in the elderly. Objective　To investigate the relationship between CVAI and all-cause and cause-specific mortality among the elderly population in Wuhan. Methods　Data were obtained from the 2014 Wuhan Basic Public Health Service Elderly Health Examination Program. From May 2014 to February 2015, a total of 332 389 elderly people aged 65 years and older participated in the program under the principle of informed consent and voluntary participation. After excluding data with logical errors, 330 474 subjects were included in the analysis. Baseline information was collected, including demographic characteristics, lifestyle, medical history, physical examination and laboratory test results. Participants were divided into four groups according to quartiles of baseline CVAI: Q1 (<78.11), Q2 (78.11-108.44), Q3 (108.45-140.74), and Q4 (>140.74). Using the ID number as the unique identifier, physical examination data were linked to the China CDC Cause of Death Registration Database for survival follow-up. The endpoint was death or December 31, 2019. Missing data were handled by multiple imputation. Log-logistic accelerated failure time models and stratified analyses were performed to explore the associations of CVAI with all-cause and cause-specific mortality. Sensitivity analysis was conducted to test the robustness of the results. Results　The mean baseline age of the 330 474 elderly participants was (71.6±5.8) years, including 152 551 males (46.16%) and 177 923 females (53.84%). The mean follow up duration was (5.0±1.0) years, and 46 007 deaths were documented by the end of follow up. Results from log-logistic accelerated failure time models showed that, compared with the Q1 group (CVAI<78.11), the Q2 (78.11-108.44, TR=1.06, 95%CI=1.04-1.09), Q3 (108.45-140.73, TR=1.13, 95%CI=1.10-1.15) and Q4 (>140.74, TR=1.14, 95%CI=1.11-1.17) groups had longer survival time for all cause mortality. In cause specific mortality analysis, CVAI also showed protective effects on survival time: a consistent protective effect was observed for cancer mortality (P<0.05); for cardiovascular and cerebrovascular disease mortality, significant protective effects were found in the Q3 and Q4 groups (P<0.05). Restricted cubic spline analysis revealed a significant inverted U shaped relationship between CVAI and all cause mortality (Poverall<0.001), with the optimal survival time observed at CVAI ranging from 110.3 to 195.0. Stratified analyses indicated that the protective effect of CVAI was most prominent in participants aged 65-69 years and females. After excluding individuals with less than 1 year of follow up and refitting the model, the positive association between higher CVAI and longer survival time remained significant (P<0.05). Conclusion　Among people aged 65 years and older in Wuhan, higher CVAI is associated with a lower risk of all cause mortality. The optimal survival time is achieved when CVAI ranges from 110.3 to 195.0. CVAI can be used as a reference indicator for predicting mortality risk in the elderly.