Independent and joint associations of physical activity, sedentary behavior, and sleep with vitamin D status in US adults: a cross-sectional NHANES study

Background Emerging evidence links movement behaviors to vitamin D status. This study investigated associations between physical activity (PA), sedentary behavior (SB), and sleep with vitamin D status and explored sex differences in these relationships.Methods This cross-sectional study included 3195 adults (49.1 ± 17.1 years, 45.5% males) from the 2021–2023 National Health and Nutrition Examination Survey with complete data. Self-reported PA, SB, and sleep duration were assessed. Serum 25-hydroxyvitamin D was measured using high-performance liquid chromatography-tandem mass spectrometry. Generalized linear and logistic regression models were performed.Results SB was negatively associated with vitamin D levels in the whole sample (β = −0.006; 95% confidence interval [CI]: −0.012, −0.001) and males (β = −0.008; 95% CI: −0.014, −0.002), but not females. Sleep duration was positively associated with vitamin D among males only (β = 0.023; 95% CI: 0.003, 0.043). Meeting both PA and SB guidelines showed the strongest and most consistent association with vitamin D sufficiency, observed across the whole sample (odds ratio [OR] = 2.129; 95% CI: 1.504, 3.012), males (OR = 2.013; 95% CI: 1.021, 3.967), and females (OR = 2.214; 95% CI: 1.360, 3.605).Conclusions Movement behaviors demonstrate independent and joint associations with vitamin D status in US adults, with modest sex-specific patterns that warrant replication. Combined adherence to PA and SB guidelines was consistently associated with greater odds of vitamin D sufficiency across sexes.