Muscle Weakness Thresholds for Prediction of Diabetes in Adults.

Background: Despite the known links between weakness and early mortality, what remains to be fully understood is the extent to which strength preservation is associated with protection from cardiometabolic diseases, such as diabetes.

Purpose: The purposes of this study were to determine the association between muscle strength and diabetes among adults, and to identify age- and sex-specific thresholds of low strength for detection of risk.

Methods: A population-representative sample of 4066 individuals, aged 20-85 years, was included from the combined 2011-2012 National Health and Nutrition Examination Survey (NHANES) data sets. Strength was assessed using a handheld dynamometer, and the single highest reading from either hand was normalized to body mass. A logistic regression model was used to assess the association between normalized grip strength and risk of diabetes, as determined by haemoglobin A1c levels ≥6.5 % (≥48 mmol/mol), while controlling for sociodemographic characteristics, anthropometric measures and television viewing time.

Results: For every 0.05 decrement in normalized strength, there were 1.26 times increased adjusted odds for diabetes in men and women. Women were at lower odds of having diabetes (odds ratio 0.49; 95 % confidence interval 0.29-0.82). Age, waist circumference and lower income were also associated with diabetes. The optimal sex- and age-specific weakness thresholds to detect diabetes were 0.56, 0.50 and 0.45 for men at ages of 20-39, 40-59 and 60-80 years, respectively, and 0.42, 0.38 and 0.33 for women at ages of 20-39, 40-59 and 60-80 years, respectively.

Conclusions And Clinical Relevance: We present thresholds of strength that can be incorporated into a clinical setting for identifying adults who are at risk of developing diabetes and might benefit from lifestyle interventions to reduce risk.