Summary
Objective
Handgrip strength (HGS) begins an accelerating decline around 50 years. Many of the studies performed in old adults have demonstrated a significant relationship between vitamin D and HGS, but the studies performed in participants with a broad age range have yielded conflicting results. The purpose of the study was to investigate the relationship between vitamin D and HGS using age 50 as a specific cut‐off.
Design
Population‐based, cross‐sectional study.
Participants
Totally 5102 participants (2911 males, 2191 females) from the TCLSIH Cohort.
Measurements
Serum concentration of 25‐hydroxyvitamin D (25(OH)D) was measured using an enzyme immunoassay. We divided participants into quartiles according to 25(OH)D, and the ranges for increasing quartiles were as follows: (males [≥50 years]: 10.94‐31.85, 31.88‐43.01, 43.20‐56.06, 56.20‐143.0; males [<50 years]: 11.11‐34.68, 34.71‐46.91, 46.96‐59.45, 59.50‐143.7; females [≥50 years]: 7.21‐30.01, 30.02‐40.18, 40.21‐52.44, 52.49‐275.4; females [<50 years]: 5.29‐28.91, 28.92‐40.19, 40.20‐51.90, 51.91‐140.2). HGS was measured with a hydraulic hand‐held dynamometer. Analysis of covariance was employed to explore the relationship.
Results
Among males aged above 50 years, the means (95% confidence interval) for HGS per body weight across the categories of serum 25(OH)D concentration were 0.523 (0.430‐0.638), 0.545 (0.447‐0.664), 0.543 (0.446‐0.661), 0.546 (0.449‐0.664) (Ptrend < 0.01) after adjustment for potential confounding factors. However, no relationships were observed between serum 25(OH)D concentration and HGS in males aged below 50 years and females in the whole age range.
Conclusions
Serum 25(OH)D concentration was significantly related to HGS in males aged above 50 years, independent of confounding factors. Future studies are needed to clarify the age and sex relationship between serum 25(OH)D concentration and HGS.