Abstract
BACKGROUND: Adequate serum 25-hydroxyvitamin D [25(OH)D] concentrations are essential for overall health. OBJECTIVES: The objective of this analysis was to assess national trends in vitamin D status. METHODS: We conducted cross-sectional analyses of National Health and Nutrition Examination Survey (NHANES) data from 2007-2008 through August 2021-August 2023 for participants aged ≥1 y. Vitamin D status was based on serum 25(OH)D and defined as "at risk of deficiency" [25(OH)D <30 nmol/L], "at risk of inadequacy" [25(OH)D 30-49 nmol/L], "sufficiency" [25(OH)D 50-125 nmol/L], and "may be of concern" [25(OH)D >125 nmol/L]. Participants self-reported dietary supplement use in the past 30 d. Prevalence of vitamin D status was adjusted for season using predicted marginals from logistic regression models. RESULTS: Overall, from 2007-2008 to August 2021-August 2023, the prevalence of "at risk of inadequacy" declined from 18.8% (95% CI: 16.9, 20.9) to 15.6% (95% CI: 14.2, 17.1) and the prevalence of "may be of concern" increased from 2.2% (95% CI: 1.6, 2.9) to 7.6% (95% CI: 6.8, 8.5). Among individuals reporting use of 1 vitamin D-containing supplement in the past 30 d, the prevalence of "at risk of inadequacy" declined from 12.8% (95% CI: 11.0, 14.9) to 5.8% (95% CI: 4.4, 7.7) and the prevalence of "may be of concern" increased from 2.0% (95% CI: 1.3, 3.0) to 11.4% (95% CI: 9.4, 13.7). Among individuals reporting use of 2+ vitamin D-containing supplements in the past 30 d, the prevalence of "may be of concern" increased from 4.7% (95% CI: 2.5, 8.7) to 30.6% (95% CI: 27.8, 33.6). CONCLUSIONS: The proportion of the population with inadequate vitamin D concentrations continues to decline, and the proportion of the population with high vitamin D concentrations continues to rise. These trends are especially apparent among individuals reporting use of vitamin D-containing supplements.