Cross-sectional and longitudinal associations between glycaemic measures and grip strength in people without diabetes in the UK Biobank cohort study.

Purpose: To investigate associations between glycaemic measures (HbA1c, random glucose), and grip strength (GS) in adults without prevalent diabetes.

Methods: We included 381,715 UK Biobank participants aged 38-73 years without diabetes (any type) with complete baseline measures for GS and HbA1c (main analyses), and glucose (supplementary analyses). Cross-sectional sex- and age-stratified associations between each glycaemic measure, GS, and probable sarcopenia (low GS) were examined with regression analyses. Changes in GS over 8.9 years were classified into four groups (decline, stable low, stable high, or reference (increase or maintained within the normal range)) in 36,228 participants and associations with baseline glycaemic measures explored using multinomial regression.

Results: Higher HbA1c (mmol/mol) was associated with weaker mean GS (kg) (regression coefficient and 95% confidence intervals (CI): - 0.08 (- 0.09, - 0.07)), and increased odds of probable sarcopenia (odds ratio (OR) and 95% CIs: 1.02 (95% CI: 1.01, 1.02)) in males and across the age groups. In females, higher HbA1c was associated with weaker mean GS only in mid-life (e.g., 50-59 years: - 0.06 (- 0.07, - 0.05)). In males, but not in females with repeated GS, higher HbA1c was associated with decreased odds of stable high (0.97 (0.96, 0.99) and increased odds of stable low (1.03 (1.01, 1.04)) GS pattern (0.98 (0.97, 0.980)) over the follow-up. The results for glucose in supplementary analyses were mixed, especially in females.

Conclusions: The associations between HbA1c and GS in people without diabetes warrant replication and consideration of the effect on muscle strength when interventions to promote normoglycaemia are trialled.