Association Between Serum 25-Hydroxyvitamin D Levels And The Risk Of Sarcopenia In Older Adults

Objective:The aim of this study was to investigate the association between serum 25(OH)D levels and sarcopenia in community-dwelling older adults aged≥60 years.To provide a reference for nutrition to improve sarcopenia and promote healthy aging in the elderly.Methods:A total of 66 sarcopenia patients were enrolled in this case-control study,and 66 healthy elderly controls without sarcopenia were matched1:1 by sex and age(±5 years).Questionnaires and physical measurements were used to collect relevant indicators for study subjects.Skeletal muscle mass index and other body compositions were assessed using a bioimpedance analyzer(bioimpedance analysis,BIA)device;Grip strength of the dominant hand was determined using a Jamar Plus+dynamometer;Muscle function was assessed using the 6-m gait speed test.Serum 25(OH)D levels were measured by enzyme-linked immunosorbent assay(ELISA).The basic data of the groups were analyzed using descriptive analyses;Theχ~2test,paired-t test,Wilcoxon signed rank test,Mc Nemar test were used for comparison of differences between groups;Pearson and Spearman rank correlation analyses were used to determine correlations between quantitative variables;A directed acyclic graph(DAG)was used to select potential confounders,and univariate and multivariate conditional logistic regression analyses were used to explore the risk factors of sarcopenia.A restricted cubic spline(RCS)was used to explore the dose-response relationship between serum 25(OH)D levels and sarcopenia.Results:1.Patients with sarcopenia had median 25(OH)D levels that were lower than those in the sarcopenic group(P<0.05).2.Categorizing serum25(OH)D levels according to clinical significance,conditional logistic regression analysis showed that the elderly with vitamin D deficiency had a significantly higher risk of sarcopenia than those with vitamin D sufficiency(OR=7.749,95%CI:1.955～30.714);Convert data to tertiles,the elderly with serum25(OH)D levels<22.78 ng/ml had a significantly higher risk of sarcopenia than those with levels>36.74 ng/ml(OR=6.703,95%CI:1.623～27.678).3.Serum25(OH)D levels were both significantly and positively correlated with the SMI in older men(r=0.450,P<0.001)and women(r=0.286,P<0.001),respectively;serum 25(OH)D levels were significantly and positively correlated with SMM(r=0.395,P<0.001)and FMM(r=0.412,P<0.001)in older women,whereas this correlation was not observed in men.There was a significant inverse correlation between serum 25(OH)D levels and gait speed in older men(r=-0.282,P=0.032),whereas this correlation was not observed in women.4.The results of the dose-response relationship curve showed that in men,the risk of sarcopenia rose with increasing serum 25(OH)D levels before 29.01ng/ml;after reaching29.01ng/ml,the risk of sarcopenia gradually decreased with increasing serum25(OH)D levels.In women,the risk of sarcopenia rose with increasing serum25(OH)D levels before 30.43 ng/ml;After reaching 30.43 ng/ml,the risk of sarcopenia gradually decreased with increasing 25(OH)D levels.5.Taking regular nutritional supplements as a reference reduced the risk of sarcopenia by94.8%(OR=0.052,95%CI:0.003～0.801);Performing daily exercise was associated with a 91.7%lower risk of sarcopenia compared to those who did not perform daily exercise(OR=0.083,95%CI:0.009～0.796).BMI≥24 kg/m~2was associated with a 97.7%lower risk of sarcopenia compared to those with BMI<24 kg/m~2(OR=0.023,95%CI:0.001～0.370).Conclusion:Vitamin D deficiency may be associated with an increased risk of sarcopenia;Serum 25(OH)D levels are positively correlated with muscle mass;The dose-response relationship suggested that within a certain range,the risk of sarcopenia gradually decreased with increasing serum 25(OH)D levels,suggesting that vitamin D supplementation can help prevent sarcopenia.In addition,taking nutritional supplements,daily exercise and higher BMI may be protective factors for sarcopenia in the elderly.