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Importance: Vitamin D treatment has been found to decrease the incidence of viral respiratory tract infection, especially in patients with vitamin D deficiency. Whether vitamin D is associated with coronavirus disease 2019 (COVID-19) incidence is unknown., Objective: To examine whether the last vitamin D status before COVID-19 testing is associated with COVID-19 test results., Design, Setting, and Participants: This retrospective cohort study at an urban academic medical center included patients with a 25-hydroxycholecalciferol or 1,25-dihydroxycholecalciferol level measured within 1 year before being tested for COVID-19 from March 3 to April 10, 2020., Exposures: Vitamin D deficiency was defined by the last measurement of 25-hydroxycholecalciferol less than 20 ng/mL or 1,25-dihydroxycholecalciferol less than 18 pg/mL before COVID-19 testing. Treatment changes were defined by changes in vitamin D type and dose between the date of the last vitamin D level measurement and the date of COVID-19 testing. Vitamin D deficiency and treatment changes were combined to categorize the most recent vitamin D status before COVID-19 testing as likely deficient (last level deficient and treatment not increased), likely sufficient (last level not deficient and treatment not decreased), and 2 groups with uncertain deficiency (last level deficient and treatment increased, and last level not deficient and treatment decreased)., Main Outcomes and Measures: The outcome was a positive COVID-19 polymerase chain reaction test result. Multivariable analysis tested whether vitamin D status before COVID-19 testing was associated with testing positive for COVID-19, controlling for demographic and comorbidity indicators., Results: A total of 489 patients (mean [SD] age, 49.2 [18.4] years; 366 [75%] women; and 331 [68%] race other than White) had a vitamin D level measured in the year before COVID-19 testing. Vitamin D status before COVID-19 testing was categorized as likely deficient for 124 participants (25%), likely sufficient for 287 (59%), and uncertain for 78 (16%). Overall, 71 participants (15%) tested positive for COVID-19. In multivariate analysis, testing positive for COVID-19 was associated with increasing age up to age 50 years (relative risk, 1.06; 95% CI, 1.01-1.09; P = .02); non-White race (relative risk, 2.54; 95% CI, 1.26-5.12; P = .009), and likely deficient vitamin D status (relative risk, 1.77; 95% CI, 1.12-2.81; P = .02) compared with likely sufficient vitamin D status. Predicted COVID-19 rates in the deficient group were 21.6% (95% CI, 14.0%-29.2%) vs 12.2%(95% CI, 8.9%-15.4%) in the sufficient group., Conclusions and Relevance: In this single-center, retrospective cohort study, likely deficient vitamin D status was associated with increased COVID-19 risk, a finding that suggests that randomized trials may be needed to determine whether vitamin D affects COVID-19 risk.

The study investigates the association of trabecular bone score (TBS) and fractures among minority populations. In NHANES 2005-2008, TBS was associated with history of fractures in Caucasian subjects but demonstrated somewhat weaker associations in African American and Mexican American women., Introduction: Trabecular bone score (TBS), a textural analysis of the lumbar spine DXA image, predicts fractures well in Caucasian (CA) and Asian populations but is less well studied in African American (AA) and Mexican American (MA) subjects. It is not clear whether TBS is associated with or is predictive of fragility in these racial/ethnic groups., Methods: We analyzed data from subjects from NHANES 2005-2008 over the age of 40 who had TBS: 1178 CA, 467 AA, and 397 MA women and 1200 CA, 502 AA, and 386 MA men. TBS was categorized into normal, ≥ 1.310, partially degraded < 1.310, and > 1.230, or degraded, ≤ 1.230. History of fracture was assessed by questionnaire., Results: Among women, there was an increasing prevalence of fracture with worsening TBS category. However, when controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA women (OR 1.49 per worsening category, 95% CI 1.20-1.85). In men, there was also an increase in the prevalence of fracture with worsening TBS category in all races/ethnicities. When controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA men (OR 1.47 per worsening category, 95% CI 1.10-1.95), though analysis was somewhat limited by small fracture numbers., Conclusions: The association of fracture and TBS varies by race/ethnicity and gender with weaker association observed in AA and MA women. More research is needed to define the proper use of TBS for predicting fractures in minority groups.