Second Trimester Sunlight and Asthma: Evidence from Two Independent Studies

50 Pages Posted: 22 Oct 2014 Last revised: 15 Apr 2023

See all articles by Nils Wernerfelt

Nils Wernerfelt

Harvard University - Harvard Kennedy School (HKS); Meta Platforms Inc

David Slusky

University of Kansas; IZA Institute of Labor Economics

Richard J. Zeckhauser

Harvard University - Harvard Kennedy School (HKS); National Bureau of Economic Research (NBER)

Date Written: October 2014

Abstract

One in twelve Americans suffers from asthma and its annual costs are estimated to exceed $50 billion. Simultaneously, the root causes of the disease remain unknown. A recent hypothesis speculates that maternal vitamin D levels during pregnancy affect the probability the fetus later develops asthma. In two large-scale studies, we test this hypothesis using a natural experiment afforded by historical variation in sunlight, a major source of vitamin D. Specifically, holding the birth location and month fixed, we see how exogenous within-location variation in sunlight across birth years affects the probability of asthma onset. We show that this measurement of sunlight correlates with actual exposure, and consistent with pre-existing results from the fetal development literature, we find substantial and highly significant evidence in both datasets that increased sunlight during the second trimester lowers the subsequent probability of asthma. Our results suggest policies designed to augment vitamin D levels in pregnant women, the large majority of whom are vitamin D insufficient, could be very cost-effective.

Suggested Citation

Wernerfelt, Nils and Slusky, David and Zeckhauser, Richard J., Second Trimester Sunlight and Asthma: Evidence from Two Independent Studies (October 2014). NBER Working Paper No. w20599, Available at SSRN: https://ssrn.com/abstract=2513159

Nils Wernerfelt (Contact Author)

Harvard University - Harvard Kennedy School (HKS) ( email )

79 John F. Kennedy Street
Cambridge, MA 02138
United States

Meta Platforms Inc ( email )

David Slusky

University of Kansas ( email )

1300 Sunnyside Drive
Lawrence, KS 66045-7585
United States

IZA Institute of Labor Economics ( email )

P.O. Box 7240
Bonn, D-53072
Germany

Richard J. Zeckhauser

Harvard University - Harvard Kennedy School (HKS) ( email )

79 John F. Kennedy Street
Cambridge, MA 02138
United States
617-495-1174 (Phone)
617-384-9340 (Fax)

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States
617-495-1174 (Phone)
617-496-3783 (Fax)

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