ArticlePloS one2021
Lower serum 25(OH)D levels associated with higher risk of COVID-19 infection in U.S. Black women.
Article in PloS one, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
10 citing papers in PubMed, 1 synthesis or guideline pooled it, 14 citations in OpenAlex.
- Effect of vitamin D supplementation on COVID-19 outcomes: an umbrella review of systematic reviews.Frontiers in nutrition · 2025Pooled it
- A Pilot, Randomised, Placebo-Controlled, Double-Blind Trial of a Single Oral Dose of Ivermectin for Post-Exposure Prophylaxis of SARS-CoV-2.Pharmaceutics · 2025Article
- Vitamin D and COVID-19: where are we now?Postgraduate medicine · 2023Review
- Vitamin D and COVID-19-Revisited.Journal of internal medicine · 2022Review
- Associations between predicted vitamin D status, vitamin D intake, and risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) severity.The American journal of clinical nutrition · 2022Article
- Vitamin D: A Potential Mitigation Tool for the Endemic Stage of the COVID-19 Pandemic?Frontiers in public health · 2022Review
- Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness.PloS one · 2022Article
- Relationship between Vitamin D Status and Antibody Response to COVID-19 mRNA Vaccination in Healthy Adults.Biomedicines · 2021Article
- Vitamin D-related polymorphisms and vitamin D levels as risk biomarkers of COVID-19 disease severity.Scientific reports · 2021Article
- Previous Vitamin D Supplementation and Morbidity and Mortality Outcomes in People Hospitalised for COVID19: A Cross-Sectional Study.Frontiers in public healthArticle
Corrections and comments
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Authors and funding
6 authors at 2 institutions in 1 country.
Funding
Abstract
objectiveLimited evidence suggests that higher levels of serum vitamin D (25(OH)D) protect against SARS-CoV-2 virus (COVID-19) infection. Black women commonly experience 25(OH)D insufficiency and are overrepresented among COVID-19 cases. We conducted a prospective analysis of serum 25(OH)D levels in relation to COVID-19 infection among participants in the Black Women's Health Study.
methodsSince 1995, the Black Women's Health Study has followed 59,000 U.S. Black women through biennial mailed or online questionnaires. Over 13,000 study participants provided a blood sample in 2013-2017. 25(OH)D assays were performed in a certified national laboratory shortly after collection of the samples. In 2020, participants who had completed the online version of the 2019 biennial health questionnaire were invited to complete a supplemental online questionnaire assessing their experiences related to the COVID-19 pandemic, including whether they had been tested for COVID-19 infection and the result of the test. We used logistic regression analysis to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association of 25(OH)D level with COVID-19 positivity, adjusting for age, number of people living in the household, neighborhood socioeconomic status, and other potential confounders.
resultsAmong 5,081 eligible participants whose blood sample had been assayed for 25(OH)D, 1,974 reported having had a COVID-19 test in 2020. Relative to women with 25(OH)D levels of 30 ng/mL (75 nmol/l) or more, multivariable-adjusted ORs for COVID-19 infection in women with levels of 20-29 ng/mL (50-72.5 nmol/l) and <20 ng/mL (<50 nmol/l) were, respectively, 1.48 (95% CI 0.95-2.30) and 1.69 (95% CI 1.04-2.72) (p trend 0.02).
conclusionThe present results suggest that U.S. Black women with lower levels of 25(OH)D are at increased risk of infection with COVID-19. Further work is needed to confirm these findings and determine the optimal level of 25(OH)D for a beneficial effect.
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