Breathing Better and Soaking Up Sun

Vitamin D connected to better lung function in Korean study

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) Could catching more rays help you breathe better? According to a recent Korean study, it may be possible.

The study found an association between higher levels of vitamin D in the blood and better breathing function.

Vitamin D is mainly absorbed into the body through sunlight, but a healthy diet contributes as well.

"Get some vitamin D to stay healthy."

Led by Chang-Jin Choi, MD, PhD, of the College of Medicine at the Catholic University of Korea in Seoul, researchers analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES), which gathered data throughout Korea from 2008 to 2010. This study looked at 10,096 people over the age of 19.

Researchers measured a vitamin D biomarker, called serum 25-hydroxyvitamin D (25(OH)D), using blood tests. Lung function was measured using breathing tests called spirometry tests.

After analyzing the data, the researchers reported, “We found a robust positive association between serum 25(OH)D level and lung function in Korean adults. This association was independent of age, sex, BMI, lifestyle (smoking and regular exercise), occupation, residence, season and some respiratory diseases.”

The subjects fell into four different groups of serum 25(OH)D levels: 6.3 percent had levels below 10 ng/mL (nanograms per milliliter), 53.3 percent had levels between 10 and 20 ng/mL, 32.4 percent had levels between 20 and 30 ng/mL and 7.9 percent measured above 30 ng/mL.

According to the researchers, previous Korean studies have classified serum 25(OH)D levels over 20 ng/mL as sufficient for bone health, meaning that 59.6 percent of the people tested would be considered deficient.

"Additional research is needed to determine the required vitamin D level for respiratory health," write the researchers.

The authors also noted that the averages found in this study of people in Korea (18.7 ng/mL) were lower than the averages found in previous studies of people in the US (31.0 ng/mL) and the United Kingdom (21.0 ng/mL). 

Interestingly, people with an obstruction of the airway or with a history of tuberculosis (TB) had significantly lower levels of the vitamin D biomarker. 

For example, among people who had a history of TB (556 people), average serum 25(OH)D levels were 18.2 ng/mL, while average levels for those with no history of the disease were 19.1 ng/mL, a statistically significant difference.

The same was not true for asthma, as researchers found no significant difference in serum 25(OH)D levels in people with a history of this respiratory problem.

These asthma patients (335 people) had an average serum measurement of 18.6 ng/mL, which was was not a statistically significant difference from the average of those without the condition (19.1 ng/mL).

“These results suggest that the susceptibility of pulmonary TB might be related to vitamin D deficiency and also that vitamin D therapy may be beneficial for lung function in this population,” the authors concluded.

More research is needed to determine the nature of this association and further explore how vitamin D and lung function, particularly in regards to diseases like tuberculosis, might be related.

The study was published in The Journal of Clinical Endocrinology & Metabolism. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
March 25, 2013
Last Updated:
March 28, 2013