目的: 探究中国西部5城市中老年人血清25羟基维生素D [25-hydroxyvitamin D, 25(OH)D]与握力的相关性。方法: 基于2023年2—7月在中国西部5个城市开展的横断面调查数据，通过问卷收集中老年人的相关人口学特征，通过体格检查记录握力，采集空腹血液样本分离血清并使用高效液相色谱串联质谱法测定血清25(OH)D浓度，使用卡方检验进行组间比较，使用Logistic回归分析西部5城市中老年人血清25(OH)D与握力的相关性。结果: 我国西部5城市中老年人维生素D的缺乏率和不足率分别为52.9%和34.5% [维生素D缺乏定义为血清25(OH)D总浓度 < 20 μg/L，维生素D不足定义为血清25(OH)D总浓度为20~30 μg/L]，高龄、女性、采样季节在冬季的中老年人血清25(OH)D水平更低(P < 0.05)。25.3%的中老年人发生了握力减退，65~80岁25(OH)D缺乏的老年人握力减退的发生率高于25(OH)D不足的老年人(45.0% vs. 32.6%)和25(OH)D充足的老年人(45.0% vs. 20.6%)；25(OH)D缺乏的75~80岁老年人握力减退的发生率最高(62.1%)，25(OH)D不足组次之(11.1%，P < 0.05)。与25(OH)D充足的中老年人相比，25(OH)D缺乏的中老年人发生握力减退的风险增加1.4倍(OR=2.403，95%CI：1.202~4.804，P=0.013)，未发现25(OH)D不足与中老年人握力状况存在显著相关关系；血清总25(OH)D每增加5 μg/L，其发生握力减退的风险降低13.1%(OR=0.869，95%CI：0.768~0.982，P=0.025)；血清25(OH)D₂每增加5 μg/L，其发生握力减退的风险降低24.1%(OR=0.759，95%CI：0.582~0.990，P=0.042)；未发现血清25(OH)D₃含量与握力减退风险存在显著相关关系。血清25(OH)D水平每增加一个等级(缺乏、不足和充足)，中老年人发生握力减退的风险降低25.2%(OR=0.748，95%CI：0.598~0.936，P=0.011)。在65~80岁和65~69岁的两组调查对象中，血清25(OH)D水平每增加一个等级，发生握力减退的风险降低40.0%，而在75~80岁的调查对象中，25(OH)D水平每增加一个等级，发生握力减退的风险降低80.0%。结论: 中国西部5城市中老年人血清总25(OH)D和25(OH)D₂含量与握力状况存在一定关联。

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.