Vitamin D deficiency linked to worse lung function in men

Even in apparently healthy men, vitamin D deficiency may aggravate the risk of worsening lung function, reports a recent Korea study.

The study included 68,457 overtly healthy middle-aged Korean adults (mean age, 37.7±6.6 years; 36,759 men). Participants underwent spirometry for the measurement of lung function and were subsequently grouped into quartiles. Serum vitamin D levels were measured from blood samples using a competitive immunoassay.

Vitamin D deficiency was defined as levels <20 ng/mL, with prevalence rates of 69.2 percent and 80.6 percent in men and women, respectively. In the overall sample, deficiency was correlated with body mass index, education level, physical activity, total cholesterol, and insulin resistance.

The prevalence of vitamin D deficiency varied across quartiles of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), but only in men; no such interaction was reported in women.

Multiple regression analysis found that in the overall sample, both FVC (p<0.01) and FEV1 (p<0.01) interacted significantly with the odds of having vitamin D deficiency.

Those in the bottom quartile of both lung function parameters were 10-percent more likely to also have vitamin D deficiency (FVC: odds ratio [OR], 1.10, 95 percent confidence interval [CI], 1.05–1.16; p<0.01; FEV1: OR, 1.10, 95 percent CI, 1.04–1.16; p<0.01).

Stratification by sex showed that this was likely driven by the interaction between lung function and vitamin D deficiency in men (Q1 vs Q4; FVC: OR, 1.17, 95 percent CI, 1.09–1.25; p<0.01; FEV1: OR, 1.13, 95 percent CI, 1.05–1.20; p<0.01). Neither lung function marker was linked to vitamin D status in women.