Vitamine D voor betere longfuncties*
Uit een Amerikaanse studie onder 626 mannen die ruim 20 jaar gevolgd werden blijkt dat goede bloedwaarden vitamine D zorgen voor betere longfuncties bij rokers. Zij met lage
bloedwaarden vitamine D (<20 ng/ml) gingen duidelijk sneller achteruit in longfuncties dan zij met goede bloedwaarden vitamine D. Alhoewel vitamine D belangrijk is voor rokers is niet
roken natuurlijk veel beter aldus de onderzoekers en verder onderzoek is nodig of vitamine D ook beschermd tegen longschade als gevolg van andere oorzaken zoals luchtvervuiling.
Vitamin D May Protect Lung Function in Smokers
Vitamin D deficiency is associated with worse lung function and more rapid decline in lung function over time in smokers, suggesting that vitamin D may have a protective effect against the effects of smoking on lung function, according to a new study from researchers in Boston.
"We examined the relationship between vitamin D deficiency, smoking, lung function, and the rate of lung function decline over a 20 year period in a cohort of 626 adult white men from the Normative Aging Study," said lead author Nancy E. Lange, MD, MPH, of the Channing Laboratory, Brigham and Women's Hospital. "We found that vitamin D sufficiency (defined as serum vitamin D levels of >20 ng/ml) had a protective effect on lung function and the rate of lung function decline in smokers."
The findings were published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
In the study, vitamin D levels were assessed at three different time points between 1984 and 2003, and lung function was assessed concurrently with spirometry.
In vitamin D deficient subjects, for each one unit increase in pack-years of smoking, mean forced expiratory volume in one second (FEV1) was 12 ml lower, compared with a mean reduction of 6.5 ml among subjects who were not vitamin D deficient. In longitudinal models, vitamin D deficiency exacerbated the effect of pack years of smoking on the decline in FEV1 over time.
No significant effect of vitamin D levels on lung function or lung function decline were observed in the overall study cohort, which included both smokers and non-smokers.
"Our results suggest that vitamin D might modify the damaging effects of smoking on lung function," said Dr. Lange. "These effects might be due to vitamin D's anti-inflammatory and anti-oxidant properties."
The study has some limitations, including that the data is observational only and not a trial, that vitamin D levels fluctuate over time, and that the study has limited generalizability due to the cohort being all elderly men.
"If these results can be replicated in other studies, they could be of great public health importance," said Dr. Lange. "Future research should also examine whether vitamin D protects against lung damage from other sources, such as air pollution."
"While these results are intriguing, the health hazards associated with smoking far outweigh any protective effect that vitamin D may have on lung function ," said Alexander C. White MS, MD, chair of the American Thoracic Society's Tobacco Action Committee. "First and foremost, patients who smoke should be fully informed about the health consequences of smoking and in addition be given all possible assistance to help them quit smoking."
Vitamin D Deficiency, Smoking, and Lung Function in the Normative Aging Study
1. Nancy E. Lange1,2,3, 2. David Sparrow4, 3. Pantel Vokonas4 and 4. Augusto A. Litonjua1,2,3+ Author Affiliations
1. 1Channing Laboratory and
2. 2Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
3. 3Harvard Medical School, Boston, Massachusetts; and
4. 4Veterans Affairs Boston Healthcare System and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
1. Correspondence and requests for reprints should be addressed to Nancy E. Lange, M.D., M.P.H., Channing Laboratory, Brigham and Women’s Hospital, 181 Longwood Avenue, rm 454, Boston, MA 02115. E-mail: renal@channing.harvard.edu
Abstract
Rationale: Vitamin D has immunomodulatory and antiinflammatory effects that may be modified by cigarette smoke and may affect lung function.
Objectives: To examine the effect of vitamin D deficiency and smoking on lung function and lung function decline.
Methods: A total of 626 men from the Normative Aging Study had 25-hydroxyvitamin D levels measured at three different times between 1984 and 2003 with concurrent spirometry. Vitamin D deficiency was defined as serum level ≤ 20 ng/ml. Statistical analysis was performed using multivariable linear regression and mixed effects models.
Measurements and Main Results: In the overall cohort, there was no significant effect of vitamin D deficiency on lung function or on lung function decline. In both cross-sectional and longitudinal multivariable models, there was effect modification by vitamin D status on the association between smoking and lung function. Cross-sectional analysis revealed lower lung function in current smokers with vitamin D deficiency (FEV1, FVC, and FEV1/FVC; P ≤ 0.0002), and longitudinal analysis showed more rapid rates of decline in FEV1 (P = 0.023) per pack-year of smoking in subjects with vitamin D deficiency as compared with subjects who were vitamin D sufficient.
Conclusions: Vitamin D deficiency was associated with lower lung function and more rapid lung function decline in smokers over 20 years in this longitudinal cohort of elderly men. This suggests that vitamin D sufficiency may have a protective effect against the damaging effects of smoking on lung function. Future studies should seek to confirm this finding in the context of smoking and other exposures that affect lung
function. (Oktober 2012)
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