Vitamin D is associated with lower limb muscle strength and grip strength in Middle Eastern- and African-born immigrants in Sweden.

There is increasing evidence that vitamin D status is associated with muscle function. Vitamin D deficiency is common in immigrants. We hypothesized that there was a positive association between vitamin D status and muscle strength in immigrants. The aim of this study was to examine associations between vitamin D status and muscle strength in an immigrant population in Sweden. All immigrants aged 25-65 years, born in 9 African or Middle East countries, and living in a district in Umeå (n = 1306) were invited. A total of 111 men and 105 women (16.5%) completed the study. Lower limb muscle strength was examined using a standardized muscle function indices of muscle strength. Grip strength was examined using a JAMAR hand dynamometer. Serum 25-hydroxyvitamin D [25(OH)D] was measured using liquid chromatography-tandem mass spectrometry. The analyses were adjusted for sex, age, height, body mass index, years since immigration, 25(OH)D, vitamin D deficiency, physical activity, and medical and socioeconomic factors. Twelve percent of the immigrants had vitamin D deficiency [25(OH)D levels <25 nmol/L]. In multivariable analyses, reduced lower limb muscle strength remained linearly associated with lower 25(OH)D concentrations (P = .008) and weaker grip strength remained associated with vitamin D deficiency (P = .022) after adjustments. The association between vitamin D deficiency and reduced lower limb muscle strength did not reach statistical significance (P = .052). The results demonstrate that vitamin D deficiency and low 25(OH)D concentrations were associated with muscle weakness in immigrants.