The Effect of Gender and Altitude on Vitamin D Status Among Saudi Population : A Cross Sectional Study

Vitamin D deficiency is a major public health concern worldwide, resulting mainly due to insufficient sunlight exposure. The objective of this study was to assess the prevalence of vitamin D deficiency among the Saudi population living at different altitudes. A cross-sectional study was conducted to compare the level of vitamin D deficiency between 3402 (2110 female and 1292 male) population from Jeddah, 12 m above the sea level and with 3957 population (2202 female and 1755 male) from Asir, 2270 m above sea level. Data were collected from the biochemical investigation for total serum 25-hydroxyvitamin D and the serum calcium. Hypovitaminosis D (insufficiency and deficiency) was prevalent in 84.1% of females (n = 1775) and 81.7% of males (n = 1056) from Jeddah while 77.02% females (n = 1696) and 80% males (n = 1404) from Asir region. A negative correlation between Vitamin D and altitude was observed for gender (R = -0.894, P = 0.261) and age (R = -0.812, P = 0.382); the risk of hypovitaminosis D generally increases with decreasing altitude. The probability of Vitamin D deficiency was higher among female populations and study subjects living at the low altitudes, i.e., from the Jeddah region.