Chronic obstructive pulmonary diseaseExposure to sunlight

Solar UVB is the primary source of vitamin D, so at higher latitudes, serum 25(OH)D levels are lowest in late winter or early spring. As a result, respiratory viral infections are most common in winter or spring12. Viral infections are frequently found associated with exacerbations of COPD3.

A study in Finland on hospitalization for the acute exacerbation phase of COPD found 62.8% of the treatment periods ending in death took place between December and May4. That period is the time when viral respiratory infection rates are highest125.

There is some additional evidence that UVB and vitamin D reduce the risk of COPD exacerbations from studies of occupation and COPD. Two studies reported that farmers had lower rates of COPD exacerbations.

One, a study in Ohio and North Carolina reported lower mortality rates for farmers6.

The other, for COPD hospitalizations in Denmark, reported lower rates for farmers7.

However, farmers in general have higher rates of COPD, likely due to occupational exposure to organic matter and chemicals89. Farmers generally have lower rates of lung cancer61011, likely due to higher solar UVB doses and serum 25(OH)D levels. 

Page last edited: 06 May 2011


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