# Diabetes and all-cause mortality among middle-aged and older adults in China, England, Mexico, rural South Africa, and the USA: a population-based study of longitudinal aging cohorts

## TL;DR

This study finds that diabetes significantly increases the risk of death among middle-aged and older adults in five countries, emphasizing the need for global health interventions.

## Contribution

The study provides a cross-national comparison of diabetes-related mortality using standardized methods across diverse populations.

## Key findings

- Diabetes was associated with increased all-cause mortality in five countries.
- Mortality rate ratios ranged from 1.53 in the USA to 2.02 in Mexico.
- Mortality rate differences varied from 11.9 in England to 24.6 in South Africa.

## Abstract

There is a need for comparable worldwide data on the impact of diabetes on mortality. This study assessed diabetes and all-cause mortality among middle-aged and older adults in five countries.

We analyzed adults aged 51 years or older followed between 2010 and 2020 from population-based cohorts from China, England, Mexico, rural South Africa, and the USA. The cohorts are part of an international network of longitudinal aging studies with similar sampling designs, eligibility, and assessment methods. Diabetes was defined by self-report or an elevated diabetes blood-based biomarker meeting the clinical criteria for diabetes. All-cause mortality was assessed through linkages or informant interviews. We used Poisson regression models to estimate mortality rate ratios and mortality rate differences, comparing people with diabetes to those without diabetes. Models were adjusted for age, gender, education, smoking status, body mass index, economic status, and, in South Africa, HIV status.

We included 29 397 individuals, of whom 4916 (16.7%) died during the study period. The median follow-up time ranged from 4.6 years in South Africa to 8.3 years in China. The adjusted all-cause mortality rate ratios for people with diabetes versus those without diabetes ranged from 1.53 (95% CI: 1.39 to 1.68) in the USA to 2.02 (95% CI: 1.34 to 3.06) in Mexico. The adjusted mortality rate differences (per 1000 person-years) for people with diabetes vers those without diabetes ranged from 11.9 (95% CI: 4.8 to 18.9) in England to 24.6 (95% CI: 12.2 to 37.0) in South Africa.

Diabetes was associated with increased all-cause mortality in population-based cohorts in China, England, Mexico, rural South Africa, and the USA. Limitations included differences in diabetes biomarkers and selection criteria across cohorts. The results highlight the urgent need to implement clinical and public health interventions worldwide to reduce excess diabetes mortality.