Higher HDL cholesterol levels are positively associated with vitamin D in women, while in men this correlation follows a more complex pattern, according to a recent study.

The cross-sectional study utilized data from the National Health and Nutrition Examination Survey (2003-2018) to explore the association between high-density lipoprotein cholesterol (HDL-C) and serum 25-hydroxyvitamin D [25(OH)D] in 28,084 adults aged 20–59 years. The findings revealed a significant positive association between HDL-C and serum 25(OH)D levels (β = 8.3, 95% confidence interval [CI]: 7.24–9.35; P < .0001).

Participants with higher HDL-C levels were younger, had a lower body mass index, and displayed healthier metabolic markers. Additionally, they were more likely to be female and Non-Hispanic White. When comparing HDL-C quartiles, individuals in the highest HDL-C quartile (Q4) had serum 25(OH)D levels that were 9.74 mmol/L higher than those in the lowest quartile (Q1) (95% CI: 8.50–10.98; P < 0.0001).

Gender-stratified analysis revealed notable differences, published in BMC Endocrine Disorders. Females showed a consistent positive association between HDL-C and 25(OH)D (β = 9.69, 95% CI: 8.66–10.72; P < .001). In contrast, males exhibited an inverted U-shaped relationship. Specifically, when HDL-C levels were below 2.07 mmol/L, a strong positive correlation with 25(OH)D was observed (β = 10.07; 95% CI: 8.49–11.65; P < 0.0001). However, beyond this threshold, the association was not significant (β = -0.80; 95% CI: -5.32–3.72; P = 0.7294).

For males specifically, the inflection points where this shift occurs was identified at 1.66 mmol/L, indicating a change from a positive to a non-significant or negative correlation. In females, the positive association persisted across all HDL-C levels. An inflection point was noted at 1.84 mmol/L, with a β of 13.40 below this point and a β of 3.66 above it, both with P < 0.001, indicating a consistently strong association throughout.

The researchers recommended that clinicians consider simultaneous monitoring of HDL-C and vitamin D levels to enhance cardiovascular risk assessment, especially in males with lower HDL-C levels. Additionally, the study suggested that increasing vitamin D intake could be considered for its potential impact on cardiovascular and skeletal health outcomes, particularly for men with lower HDL-C levels.

The authors noted some limitations to their study, including its cross-sectional design, which prevents establishing causal relationships, and the potential for unadjusted confounding factors affecting the results.

Full disclosures can be found in the published study.