Some fraction of the reason for the decrease would be the women staying indoors more during times of high pollution
- Air Pollution reduces Vitamin D 16 studies as of June 2019
Particulate Air Pollution Exposure and Plasma Vitamin D Levels in Pregnant Women: A Longitudinal Cohort Study
J of Clinical Endocrinology & Metabolism, V 104, Issue 8, Pages 3320–3326, https://doi.org/10.1210/jc.2018-02713
Yan Zhao Lei Wang Hongjiao Liu Zhijuan Cao Xiujuan Su Jing Cai Jing Hua
Context: No studies have assessed the association between air pollution exposure and vitamin D status in pregnant women.
Objective: To examine the association between particulate air pollution exposure and circulating 25-hydroxyvitamin 25(OH)D levels in pregnant women.
Design: A longitudinal cohort study.
Participants: A total of 3285 pregnant women were recruited at a maternal and child health hospital.
Main Outcome Measures: Serum 25(OH)D levels.
We observed trimester-specific associations between particulate air pollution exposure and circulating 25(OH)D levels. The associations were most pronounced for the periods of the third trimester and the entire pregnancy. A 10 μg/m3 increase in fine particulate matter (PM2.5) and particulate matter with aerodynamic diameter ≤10 μm (PM10) exposure during the entire pregnancy was associated with a 4.62% (95% CI, −6.31% to −2.93%) and 5.06% (95% CI, −6.50% to −3.62%) decrease in 25(OH)D levels, respectively. Particulate air pollution exposure was also associated with elevated odds of maternal vitamin D deficiency.
A 10 μg/m3 increase in PM2.5 and PM10 exposure during the entire pregnancy was associated with a
- 45% (OR = 1.45, 95% CI, 1.29 to 1.63) and
- 48% (OR = 1.48, 95% CI, 1.33 to 1.64) increase in the odds of maternal vitamin D deficiency.
Mediation analysis estimated that decreased solar UV-B radiation mediated 69.5% and 66.4% of the inverse association between PM2.5 and PM10 exposure and circulating 25(OH)D levels.
Our results suggest that prenatal exposure to particulate air pollution may play an independent role in maternal vitamin D deficiency. The role of air pollution should be incorporated into future guidelines for the prevention of maternal vitamin D deficiency.