Vitamin D status of the Russian adult population from 2013 to 2018

Association between vitamin D status, physical performance, sex, and lifestyle factors: a cross-sectional study of community-dwelling Kosovar adults aged 40 years and older

PURPOSE

Vitamin D status and its association with age-related decline in physical performance and strength have already been highlighted in various ways, but data on the situation in developing countries are scarce. This study aimed to investigate vitamin D status, its association with muscle mass and function, and other potential determinants such as age, sex, lifestyle factors (physical activity, dietary behavior), self-perceived health status, medication intake, education and financial situation in adults from Kosovo.

METHODS

This cross-sectional study included 297 participants (54.5% women), aged ≥ 40 years. Serum 25-hydroxyvitamin D (25(OH)D) concentration, hand grip strength and physical performance tests, body composition, vitamin D dietary intake and knowledge were assessed. The interaction between serum 25(OH)D status, lifestyle factors and muscle traits was investigated.

RESULTS

Vitamin D deficiency (< 50 nmol/L) was observed in 47.5% of the total population, of whom 14.7% of them were severely deficient (< 30 nmol/L). No associations were found between 25(OH)D concentration and age. Daily dietary intake of vitamin D was low (1.89 ± 0.67 µg) and 87.6% of individuals did not take vitamin D supplements. However, vitamin D supplementation was the only variable that added statistical significance (p < 0.05) to the prediction of vitamin D status (3.8%). On the other hand, age, medication intake and vitamin D level contributed significantly to the overall regression model, explaining 24.9% of the 30-s chair stand performance as an indicator of lower-body strength endurance.

CONCLUSION

Vitamin D deficiency is highly prevalent among community-dwelling adults in Kosovo and low serum 25(OH)D has been associated with low muscle strength. This implies an urgent need for the development of comprehensive prevention strategies, focusing on pharmacological (supplementation) but also on non-pharmacological strategies such as education, food fortification or lifestyle advices.

Evaluation of the deficiency status of 25-hydroxyvitamin D and associated factors in Southwest China: A hospital-based retrospective cross-sectional analysis of a low-latitude, high-altitude, multiracial region

Vitamin D deficiency is widespread in different populations and regions worldwide and has become a global health issue. The vitamin D status of the population in the Yunnan Province of Southwest China has not been evaluated to date. Therefore, in this study, we evaluated the vitamin D status according to the serum concentrations of 25-hydroxyvitamin D (25(OH)D) in individuals of Yunnan Province, a low-latitude, high-altitude and multiracial region in China. The data on 25(OH)D concentrations from October 2012 to December 2017 were retrospectively collected and assessed using the laboratory information system from 52 950 hospital-based participants (age, 1 day-96 years; females, 73.74%). The serum concentration of 25(OH)D was evaluated using a chemiluminescent immunoassay. The analysis was stratified by sex, age, sampling season, testing year, minority, residential district, latitude, altitude and meteorological factors. Vitamin D status was classified as follows: severe deficiency: <10 ng/mL; deficiency: <20 ng/mL; insufficiency: <30 ng/mL; and sufficiency: ≥30 ng/mL. The results showed that vitamin D deficiency is highly prevalent in Yunnan Province in a hospital-based cohort, with a deficiency and severe deficiency rate of 65.1% and a sufficiency rate of 5.30%. Significantly lower vitamin D levels and sufficiency rates were observed in females than in males (20.13 ± 7.22 ng/mL vs. 17.56 ± 6.66 ng/mL and 8.20% vs. 4.20%; p < 0.01, respectively); in spring and winter (16.93 ± 6.24 ng/mL; 2.97% and 16.38 ± 6.43 ng/mL; 3.06%, respectively) than in summer and autumn (20.23 ± 7.14 ng/mL; 8.02% and 19.10 ± 6.97 ng/mL; 6.61% [p < 0.01], respectively); and in older individuals (0-6 years: 28.29 ± 13.13 ng/mL vs. >60 years: 14.88 ± 8.39 ng/mL; p < 0.01). Relatively higher vitamin D levels were observed in individuals of Yi, Zhuang, Hani, Dai, Miao and Lisu minorities and lower levels in individuals of Hui and Zang minorities compared with those of the Han nationality (p < 0.01). The mean sunlight duration, mean air temperature, maximum ultraviolet value and latitude were significantly correlated with vitamin D levels (r = -0.53, 0.60, 0.31, -0.68, respectively; p < 0.05). These results suggest that vitamin D status is influenced by sex, age, minority, latitude and some meteorological factors in areas with high and low altitudes. Hence, new public health policies, such as advice on sunshine exposure, food fortification and nutrition education, as well as the implementation of vitamin D supplementation programmes must be considered to alleviate vitamin D deficiency in Yunnan province, Southwest China.

Associations of serum 25-hydroxyvitamin D with serum folate, cobalanin, and homocysteine concentrations and methylene tetrahydrofolate reductase (MTHFR) gene polymorphisms in healthy adults

AIM

The aim of this study was to investigate the associations of serum 25-hydroxyvitamin D [25(OH)D] with various demographic, anthropometric, and genetic characteristics and biochemical parameters in healthy Greek adults.

METHODS

Demographic (age and sex), anthropometric (body mass index/BMI), and genetic (MTHFR gene polymorphisms) characteristics and biochemical parameters (serum folate, cobalamin/Cbl, and total homocysteine/tHcy concentrations), which had been recorded and measured, among others, in the framework of periodic medical examination (military personnel) or check-up (non-military personnel) of 383 healthy Greek adults (199 men and 184 women) were analyzed. Serum 25(OH)D, tHcy, folate, and Cbl levels were determined using immunoassay methods. The MTHFR C677T and A1298C gene polymorphisms were genotyped using polymerase chain reaction and reverse hybridization.

RESULTS

Serum 25(OH)D concentrations were correlated with Cbl levels and MTHFR C677T gene polymorphism, while they had a reverse correlation with serum tHcy levels, age, and BMI. There was no significant correlation between serum 25(OH)D concentrations and sex, serum folate levels, and smoking status. Individuals with the 677TT genotype had statistically significantly lower serum 25(OH)D levels than those with the 677CC or 677CT genotype, while individuals with the 1298CC genotype had statistically significantly higher serum 25(OH)D levels than those with 1298AA or 1298AC genotype. Moreover, the reverse correlation between the serum 25(OH)D and tHcy levels was statistically significant in all six MTHFR genotypes.

CONCLUSIONS

Serum 25(OH)D levels are associated with age, BMI, serum tHcy, and Cbl levels and MTHFR C677T gene polymorphism. The most significant finding of our study is the observed reverse correlation of serum 25(OH)D levels with serum tHcy levels. Considering that vitamin D deficiency and hyperhomocysteinemia (HHcy) are associated with an increased risk for cardiovascular diseases (CVDs), we suggest that individuals with high serum tHcy levels should be further investigated for, inter alia, their serum 25(OH)D levels.