Impact of abdominal obesity indices on all-cause and cardiovascular mortality in individuals with pre-diabetes and diabetes: insights from a prospective cohort study.

AIMS

To examine the relationships of abdominal obesity indices [visceral adiposity index (VAI), lipid accumulation product (LAP), and waist circumference (WC)] with all-cause and cardiovascular disease (CVD) mortality in varying glucose metabolism statuses populations.

METHODS

This study utilized NHANES data (1999-2018), including 17,718 participants, and linked mortality documents from the National Death Index through December 31, 2019. Participants were categorized by glucose metabolism status into diabetes mellitus (DM), prediabetes (Pre-DM), or normal glucose regulation (NGR), and separately categorized as quartiles based on abdominal obesity indices. Cox proportional hazards regression models assessed the associations between glucose metabolism status, abdominal obesity indices, and all-cause and CVD mortality. The joint effect of glucose metabolism status and abdominal obesity was also analyzed. Restricted cubic splines (RCS) were applied to investigate potential non-linear relationships. The predictive performance of the models was evaluated using C-statistics to assess improvements with the inclusion of LAP or WC across different glucose metabolism statuses.

RESULTS

Across a median follow-up period of 9.4 years, 2,685 deaths (846 from CVD) were documented. Compared to NGR, Pre-DM and DM were associated with increased all-cause mortality [adjusted HR = 1.249 (1.132, 1.377) and 1.628 (1.429, 1.853)] and CVD mortality [HR = 1.321 (1.105, 1.579) and 1.665 (1.322, 2.097)]. As well as WC, were significant predictors of all-cause [HR = 1.527 (1.255, 1.859)] and CVD mortality [HR = 1.576 (1.104, 2.249)], while LAP was only associated with all-cause mortality [HR = 1.199 (1.029, 1.395)]. Combined analysis revealed that individuals with Pre-DM or DM in the highest quartiles of WC had 1.567-fold and 2.493-fold elevated risks of all-cause mortality, in contrast with individuals having NGR in the lowest quartiles. The inclusion of WC into the baseline models enhanced the C-statistics for assessing all-cause mortality in Pre-DM groups (p < 0.001).

CONCLUSIONS

WC and LAP are important predictors of mortality, especially in those with impaired glucose metabolism. Integrating WC into predictive models enhances risk assessment for all-cause mortality in Pre-DM groups. These findings emphasize the importance of comprehensive risk assessments that incorporate both abdominal obesity and glucose metabolic health.