Air pollutants are negatively associated with vitamin D-synthesizing UVB radiation intensity on the ground

Abdur Rahman,Abdirashid Elmi

doi:10.1038/s41598-021-00980-6

Abstract

Atmospheric levels of pollutants may reduce the UVB intensity at the earth’s surface, with a subsequent reduction in cutaneous vitamin D synthesis. We investigated the association of various pollutants with UVB intensity on the ground. Four-year data obtained from four weather stations from across Kuwait were analyzed by median regression. Pollutants that were negatively associated with UVB were [β (95% CI)]: benzene [− 2.61 (− 4.13, − 1.09)], ethyl-benzene [− 2.20 (− 3.15, − 1.25)], ozone [− 0.23 (− 0.28, − 0.17)], nitric oxide [− 0.11 (− 0.15, − 0.06)], sulfur dioxide [− 0.10 (− 0.17, − 0.04)] and particulate matter PM10 [− 0.002 (− 0.003, − 0.002)]. Pollutants that were negatively associated with the UVB/UVA ratio were [β (95% CI)]: benzene [− 15.57 (− 24.94, − 6.20)], nitric oxide [− 0.53 (− 0.81, − 0.25)], ozone [− 0.38 (− 0.70, − 0.06)], and total hydrocarbon [− 0.02 (− 0.04, − 0.01)]. Furthermore, benzene and nitric oxide levels were higher in the morning and evening hours, which are the times of most solar exposure in this region due to high temperature during midday. In addition to other known factors, attenuation of UVB by these pollutants may contribute to lower vitamin D levels in populations. In addition to direct public health hazard, these pollutants may contribute to the very high prevalence of VDD in this region.

Highlights

Vitamin D deficiency (VDD) is wide spread in all age groups, both genders, all ethnicities, and all geographical locations[1,2]
Cultural practices, such as clothing that covers most of the body, sun-avoidance behavior due to hot climate most of the year, and the use of sun screen are some of the factors that may be responsible for this high prevalence of VDD
Solar radiation in the UVB range (290–315 nm) photoisomerizes 7-DHC in the skin to precholecalciferol. This unstable metabolite is quickly converted in the skin, by thermal isomerization, to cholecalciferol[24], which gets into the blood stream and is transported to various tissues by vitamin D binding protein (DBP)

Summary

Introduction

Vitamin D deficiency (VDD) is wide spread in all age groups, both genders, all ethnicities, and all geographical locations[1,2]. It is generally assumed that populations in areas where there is ample sunshine throughout the year, would have adequate vitamin D levels[18] Contrary to this popular assumption, there is a high prevalence of VDD and vitamin D insufficiency in the Middle East, an area with abundant s unshine[19,20]. In addition to limited exposure to the sun, the efficiency of solar radiation to synthesize vitamin D in the skin may be a factor in the high prevalence of VDD This is evident from the fact that vitamin D levels in populations is on a decreasing trajectory despite the use of fortified foods[22,23]. For every 300 m increase in altitude, the amount of UVB that reaches the surface increases by 4%26

Methods

Results

Discussion

Conclusion