Air pollution while pregnant associated with lower vitamin D (perhaps indoors more)

Particulate Air Pollution Exposure and Plasma Vitamin D Levels in Pregnant Women: A Longitudinal Cohort Study.

J Clin Endocrinol Metab. 2019 Mar 21. pii: jc.2018-02713. doi: 10.1210/jc.2018-02713.

Zhao Y1, Wang L2, Liu H3, Cao Z1, Su X1, Cai J4, Hua J1.

* Vitamin D level: 27 ng if low pollution, 12 ng if high pollution (Delhi children) – June 2018 * Higher air pollution associated with 7 ng lower vitamin D levels – Aug 2013 * Air Pollution reduces Vitamin D production - many studies * Decrease in UVB: ratio of polluted sky in Tokyo vs clear sky in New Zealand * Note: Tokyo is much closer to equator, so should have much more UVB than NZ * Note: Ignore the blue = winter line *

CONTEXT: No studies have assessed the associations 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.

INTERVENTIONS: None.

MAIN OUTCOME MEASURES: Serum 25(OH)D levels.

RESULTS: 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 third trimester and the entire pregnancy. A 10 μg/m3 increase in PM2.5 and 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 UVB radiation mediated 69.5% and 66.4% of the inverse association between PM2.5 and PM10 exposure and circulating 25(OH)D levels.

CONCLUSION: 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.