Blood Serum 25-Hydroxyvitamin D in Various Populations of Russia, Ukraine, and Belarus: A Systematic Review with Elements of Meta-analysis

Abstract

We analyzed published data on the serum level of 25-hydroxyvitamin D (25(OH)D in healthy subjects in Russia, Ukraine and Belarus (lat. 45°–65° N). The primary list included 158 publications. Reports with insufficient sample size and incomplete statistical descriptions were excluded from the analysis. The review covers 41 publications comprising 8569 individual assessments. The meta-analysis showed that the average levels of 25(OH)D were the highest among children under the age of 5 years, varied slightly between the age of 6 and 60 years, and decreased in older adults (60+). Gender differences become apparent at the postpuberty stage. The level of 25(OH)D was higher in men. No correlation between the level of 25(OH)D and latitude was found, but the relationship with the season and the duration of daylight was significant. No differences were revealed between ethnic and social groups.