# Weakness Status is Differentially Associated with Time to Diabetes in Americans

## TL;DR

This study found that muscle weakness adjusted for body size is linked to a higher risk of developing diabetes in Americans.

## Contribution

The study introduces body size-normalized weakness cut-points to better assess diabetes risk independent of body size.

## Key findings

- Body weight and BMI-normalized weakness was significantly associated with increased diabetes risk.
- Absolute weakness without body size adjustment showed no significant diabetes risk association.
- Compounded weakness across multiple cut-points increased diabetes risk incrementally.

## Abstract

The purpose of this study was to evaluate the associations of (1) individual absolute and body size normalized weakness cut-points, and (2) the collective weakness classifications on time to diabetes in Americans.

We analyzed data from 9577 adults aged at least 50-years from the Health and Retirement Study. Diabetes diagnosis was self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males with HGS <35.5 kg (absolute), <0.45 kg/kg (normalized to body weight), or <1.05 kg/kg/m2 (normalized to BMI) were categorized as weak. Females were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg/kg/m2. Compounding weakness included falling below 1, 2, or all 3 cut-points.

Persons below the body weight normalized weakness cut-points had a 1.29 (95% confidence interval (CI): 1.15–1.47) higher hazard for incident diabetes, while those below the BMI normalized cut-points had a 1.30 (CI: 1.13–1.51) higher hazard. The association between absolute weakness and incident diabetes was insignificant (hazard ratio: 1.06; CI: 0.91–1.24). Americans below 1, 2, or all 3 collective weakness categories had a 1.28 (CI: 1.10–1.50), 1.29 (CI: 1.08–1.52), and 1.33 (CI: 1.09–1.63) higher hazard for the incidence of diabetes, respectively.

Our findings indicate that while absolute weakness, which is confounded by body size, was not associated with time to diabetes, adjusting for the influence of body size by normalizing HGS to body weight and BMI was significantly associated with time to diabetes. This suggests that muscle strength, not body size, may be driving such associations with time to diabetes.