RESUMEN
OBJECTIVE: To explore the association between serum 25-hydroxyvitamin D [25(OH)D] and handgrip strength in middle-aged and elderly people in 5 cities of Western China. METHODS: Based on the data of a cross-sectional survey conducted in the 5 cities of Western China from February to July 2023, the relevant demographic characteristics of people were collected by questionnaire, handgrip strength was collected by physical examination, and serum 25(OH)D was detected by HPLC-MS/MS. The association between the serum 25(OH)D and handgrip strength was analyzed using Logistic regression and Chi-square test for between-group comparisons models. RESULTS: The prevalence of 25(OH)D deficiency and insufficiency among the middle-aged and elderly people in the 5 cities of Western China was 52.9% and 34.5%, respectively. The people who were older, female, and sampled in winter had lower serum 25(OH)D levels (P < 0.05). The prevalence of loss of handgrip strength among the middle-aged and elderly people was 25.3%. The prevalence of handgrip strength loss was higher in the aged 65-80 participants with 25(OH)D deficiency (45. 0%) than in those with 25(OH)D insufficiency (32.6%) and 25(OH)D sufficiency (20.6%). The highest prevalence of loss of handgrip strength was found in the aged 75-80 participants with 25(OH)D deficiency (62. 1%), followed by the 25(OH)D insufficient group (11.1%, P < 0.05). The study found that middle-aged and elderly people with 25(OH)D deficiency had a 1.4-fold increased risk of handgrip strength loss compared with those with 25(OH)D sufficiency (OR=2.403, 95%CI: 1.202-4.804, P=0.013). No significant association was found between 25(OH)D insufficiency and handgrip strength status in the middle-aged and elderly people. For every 5 µg/L increase in total serum 25(OH)D, the risk of handgrip strength loss reduced by 13.1% (OR=0.869, 95%CI: 0.768-0.982, P=0.025). For every 5 µg/L increase in serum 25(OH)D2, the risk of handgrip strength loss reduced by 24.1% (OR=0.759, 95%CI: 0.582-0.990, P=0.042). No significant association was found between serum 25(OH)D3 levels and the risk of handgrip strength loss. The risk of handgrip strength loss in middle-aged and elderly people was reduced by 25.2% for each incremental increase in the total serum 25(OH)D levels (deficient, insufficient and sufficient) (OR=0.748, 95%CI: 0.598-0.936, P=0.011). The risk of handgrip loss was reduced by 40.0% for each incremental increase in serum 25(OH)D levels in the aged 65-80 and aged 65-69 participants, and by 80.0% for each incremental increase in 25(OH)D levels in the aged 75-80 parti-cipants. CONCLUSION: Serum total 25(OH)D and 25(OH)D2 levels are associated with handgrip strength status in middle-aged and elderly people in the 5 cities of Western China.