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Vitamin D levels correlate with cardiorespiratory fitness
Higher vitamin D levels are associated with greater cardiorespiratory fitness, according to a study published in the European Journal of Preventive Cardiology.
“Our study shows that higher levels of vitamin D are associated with better exercise capacity,” Amr Marawan, MD, assistant professor of internal medicine at the Virginia Commonwealth University School of Medicine, said in a press release. “The relationship between higher vitamin D levels and better exercise capacity holds in men and women, across the young and middle age groups, across ethnicities, regardless of body mass index or smoking status, and whether or not participants have hypertension or diabetes.”
To investigate the association between vitamin D levels and cardiorespiratory fitness, researchers analyzed data from the 2001-2004 NHANES survey comprising a representative sample of the U.S. population (n = 1,995; mean age, 33 years; 45% women; 49% white; mean standard deviation [SD] vitamin D level, 58 nmol/L; mean SD maximal oxygen consumption [VO2 max], 40 mL/kg/min).
Survey-weighted linear regression was used to assess the relationship between VO2 (used as a surrogate for cardiorespiratory fitness) and vitamin D levels. Researchers conducted the analyses with and without adjusting for age, sex, race, BMI, hypertension, diabetes, smoking, C-reactive protein, hemoglobin and glomerular filtration rate.
Researchers found that participants in the highest quartile of vitamin D levels had a higher level of cardiorespiratory fitness than participants in the lowest quartile (difference, 4.3; 95% CI, 3-5.5).
The difference between the lowest and highest vitamin D quartiles was still significant after adjusting for potential confounders (difference, 2.9; 95% CI, 1.6-4.1).
When the researchers looked at both unadjusted and adjusted linear regression, they observed that each 10-nmol/L increase in vitamin D level was associated with an increase in VO2 max (unadjusted: beta = 0.78; 95% CI, 0.55-1.01; adjusted: beta = 0.51; 95% CI, 0.23-0.79).
“We know the optimum vitamin D levels for healthy bones, but studies are required to determine how much the heart needs to function at its best,” Marawan said in the release. “Randomized controlled trials should be conducted to examine the impact of differing amounts of vitamin D supplements on cardiorespiratory fitness. From a public health perspective, research should look into whether supplementing food products with vitamin D provides additional benefits beyond bone health.” – by Melissa J. Webb
Disclosures: The authors report no relevant financial disclosures.