Table 2. Unadjusted Association Between Vitamin D Levels and SARS-CoV-2 Seropositivity.

Vitamin D level comparison and year	OR (95% CI)	P value
<30 vs ≥30 ng/mL
2019	1.44 (1.25-1.66)	<.001
2020	1.35 (1.17-1.55)	<.001
<20 vs ≥20 ng/mL
2019	1.47 (1.28-1.70)	<.001
2020	1.28 (1.10-1.48)	.001

Abbreviation: OR, odds ratio.

SI conversion factor: To convert vitamin D level to nanomoles per liter, multiply by 2.496.