Vitamin D deficiency linked to asthma exacerbation’s
Asthma is a chronic disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person.
During an asthma attack, the lining of the bronchial tubes swell, causing the airways to narrow and reducing the flow of air into and out of the lungs. Recurrent asthma symptoms frequently cause sleeplessness, daytime fatigue, reduced activity levels and school and work absenteeism. Asthma has a relatively low fatality rate compared to other chronic diseases.
According to WHO estimates, 235 million people suffer from asthma.
Dr. Ronit Confino-Cohen, MD, of TAU’s Sackler Faculty of Medicine, Meir Medical Center, and the Clalit Research Institute, and Dr. Becca Feldman of the Clalit Research Institute along with colleagues examined the associations between serum 25-hydroxyvitamin D level and prevalent asthma as well as asthma exacerbations in adults.
The research team examined the medical records of nearly four million members of Clalit Health Services, Israel’s largest health care provider. The Vitamin D levels of 307,900 people aged 22–50 years were measured between July 1, 2008 and July 1, 2012. Among this population, those with physician-diagnosed asthma and asthma exacerbation’s were identified. Asthma exacerbation were defined as any of the following: prescription for oral corticosteroids, over five prescriptions for short acting beta agonist and more than four visits to a physician for asthma. Researchers also took into account key predictors of asthma, such as obesity, smoking, and other chronic diseases.
The results showed among the 308,000 members 6.9 percent (21 237) had physician-diagnosed asthma compared to 5.7 percent in the general population. Serum 25-OHD levels across both groups were similar. However, among those with vitamin D deficiency, the odds of having an exacerbation were 25% greater compared to those with levels in the normal range. This association remained significant after controlling for known confounders.
According to Dr. Confino-Cohen “Our results add more evidence to the link between Vitamin D and asthma, suggesting beneficial effects of Vitamin D on asthma exacerbation’s.” “We expect that further prospective studies will support our results. In the meantime, our results support a recommendation for screening of Vitamin D levels in the subgroup of asthma patients who experience recurrent exacerbation’s. In those with Vitamin D deficiency, supplementation may be necessary.”
Vitamin D Is produced in the body in response to skin being exposed to sunlight. Few foods contain naturally occurring vitamin D so the biggest dietary sources of vitamin D are fortified foods; dairy products and breakfast cereals (both of which are fortified with vitamin D), and fatty fish such as salmon and tuna. For most people the best way to get vitamin D is through vitamin D supplements. For men and women under 50 years need 400 to 800 IU daily and age 50 and older 600 to 1,000 IU daily.
“We know a lot about this disease and many therapeutic options are available. So it’s quite frustrating that the prevalence of asthma is not decreasing and many patients suffer exacerbation’s and significant impairment in their quality of life,” Dr. Confino-Cohen, an allergy and clinical immunology specialist, said. “Increasing Vitamin D levels is something we can easily do to improve patients’ quality of life.”
Based on the findings, the researchers recommend that people whose asthma cannot be controlled with existing treatments have their Vitamin D levels tested. For those with a vitamin D deficiency, supplements may make sense.
In closing Dr. Confino-Cohen stated “This study provided an exceptional opportunity to research asthma. I received a research grant from Clalit Health Services, which provided us with the opportunity to use their very large database and to conduct the study with the professional staff of Clalit Research Institute.” “We anticipate further prospective research that will support our findings and open a new treatment modality to the population of uncontrolled asthmatics.”
World Health Organization
Vitamin D, asthma prevalence and asthma exacerbations: a large adult population-based study. Allergy, 2014; DOI: 10.1111/all.12508
Tel Aviv University American Friends News Room