AsthmaVitamin D levels

There are a number of reports regarding risk of asthma and its exacerbation with respect to serum 25(OH)D levels.

A randomized controlled trial involving school children in Japan found a reduced risk of asthma attack with respect to vitamin D supplementation. There were 2 cases/167 children (1.2%) for those taking 1200 international units (IU)/day of vitamin D compared to 12/167 (7.2%) for those taking those taking 200 IU/day, yielding a relative risk of 0.17 (95% confidence interval, 0.04, 0.73, p = 0.006)1.

In a multi-center observational study in Costa Rica of baseline serum 25(OH)D levels and the odds of any hospitalization or emergency department visit during the 4 years of the trial, researchers found that 28% had insufficient levels of vitamin D (2

In secondary analyses of data from a multi-center clinical trial of asthma therapy in the United States, 35% of patients had serum 25(OH)D levels 3

An indirect indication that low serum 25(OH)D level is a risk factor for asthma is found in a report that those with osteoporosis in Sweden have a greatly increased risk of asthma4

A recent study measured maternal serum vitamin D levels at time of birth and found a beneficial effect of cord blood 25(OH)D levels; infants had reduced risk of wheezing, although there was no effect on incidents of asthma by age 5 years5.

A meta-analysis showed that high maternal dietary vitamin D intake during pregnancy protected infants from developing wheezing (OR, 0.56, 95% CI, 0.42-0.73)6.

On the other hand, a study in Finland found an increased risk of asthma at age 31 for those supplemented with vitamin D in infancy (odds ratio = 1.35, 95% CI, 0.99-1.8)7. Another study in the U.K. found an increased risk of asthma at 9 years of age for those whose mothers had serum 25(OH)D levels >30 ng/mL during pregnancy (OR 5.40, 95% CI, 1.09-26.65, P=0.04).

Page last edited: 08 May 2011


  1. Urashima, M. Segawa, T. Okazaki, M. Kurihara, M. Wada, Y. Ida, H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 May; 91 (5): 1255-60.
  2. Brehm, J. M. Celedon, J. C. Soto-Quiros, M. E. Avila, L. Hunninghake, G. M. Forno, E. Laskey, D. Sylvia, J. S. Hollis, B. W. Weiss, S. T. Litonjua, A. A. Serum vitamin D levels and markers of severity of childhood asthma in Costa Rica. Am J Respir Crit Care Med. 2009 May 1; 179 (9): 765-71.
  3. Brehm, J. M. Schuemann, B. Fuhlbrigge, A. L. Hollis, B. W. Strunk, R. C. Zeiger, R. S. Weiss, S. T. Litonjua, A. A. Serum vitamin D levels and severe asthma exacerbations in the Childhood Asthma Management Program study. J Allergy Clin Immunol. 2010 Jul; 126 (1): 52-8 e5.
  4. Ji, J. Hemminki, K. Sundquist, K. Sundquist, J. Seasonal and regional variations of asthma and association with osteoporosis: possible role of vitamin D in asthma. J Asthma. 2010 Nov; 47 (9): 1045-8.
  5. Camargo, C. A. Jr. Ingham, T. Wickens, K. Thadhani, R. Silvers, K. M. Epton, M. J. Town, G. I. Pattemore, P. K. Espinola, J. A. Crane, J. New Zealand Asthma and Allergy Cohort Study Group , Cord blood 25-hydroxyvitamin D levels and risk of respiratory infection, childhood wheezing, and asthma. Pediatrics. 2010, in press;
  6. Nurmatov U, Devereux G, Sheikh A. Nutrients and foods for the primary prevention of asthma and allergy: Systematic review and meta-analysis. J Allergy Clin Immunol. 2010 Dec;
  7. Hypponen, E. Sovio, U. Wjst, M. Patel, S. Pekkanen, J. Hartikainen, A. L. Jarvelinb, M. R. Infant vitamin d supplementation and allergic conditions in adulthood: northern Finland birth cohort 1966. Ann N Y Acad Sci. 2004 Dec; 103784-95.