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Asthma in the elderly: a study of the role of vitamin D

Asthma in the elderly: a study of the role of vita
Photo: Asthma in the elderly: a study of the role of vita
Background: Asthma in the elderly is poorly understood and vitamin D deficiency and insufficiency are very common in older individuals. We studied the role of vitamin D in elderly asthmatics.

Methods: Asthmatics subjects, age 65 and older, were followed every 4 weeks for 12 weeks in the late fall and winter. During the study period they took 2,000 I.U. vitamin D3 daily. Serum 25-Hydroxyvitamin D and calcium were measured at baseline and study end.

Results: Twenty nine percent of subjects were deficient and 50% insufficient in serum vitamin D at baseline. Serum vitamin D increased from 24.3±9.2 ng/ml (60.7±23 nmol/L) to 34±7.1 ng/ml (84.9±17.7 nmol/L) at the end of the study (p<0.001), whereas calcium was unchanged. We found no significant association between vitamin D and subjects' demographics. Vitamin D was similar in men and women. There was no association between serum vitamin D and inhaled steroid dose. Vitamin D was significantly lower in subjects with uncontrolled asthma (Asthma Control Test, ACT≤19) compared to the ones with well controlled symptoms (p<0.05). In subjects with uncontrolled asthma at baseline, ACT scores increased significantly at the end of the study (p<0.04), but not at 4 and 8 weeks. Spirometric values remained unchanged throughout the study.

Discussion: In the present study we investigated the role of vitamin D in a group of elderly subjects with asthma. Similar to our study, it has been recently reported that allergic sensitization is very common in asthmatic patients older than 55 years old [12].

In our study, 79% of the subjects had lower than normal serum vitamin D at baseline. These results confirm in elderly subjects that vitamin D deficiency and insufficiency are extremely common in patients with asthma and respiratory disease [13,14]. Vitamin D deficiency is more common with obesity, and serum vitamin D levels are inversely related to BMI [10]. We did not find an association between serum vitamin D and BMI, age or duration of asthma, and its values were similar in men and women. Such difference may be explained by the fact that only two of our study subjects had a BMI of 30 or higher.

Serum vitamin D has been found to be inversely, although weakly correlated with inhaled steroid dose in children [13]. Our results failed to show such an association and are in agreement with previous results in asthmatic adults [13]. Serum vitamin D did not vary in subjects treated with long-acting bronchodilators or montelukast.

In children, serum vitamin D was positively associated with the ACT scores [15]. We found that in elderly subjects with uncontrolled asthma (<19) serum vitamin D was significantly lower than in the subjects whose asthma was controlled. Our results are in agreement with a recent study of adult asthmatics that showed that serum vitamin D was lower in subjects with uncontrolled symptoms [16]. We have very recently found that in elderly subjects with uncontrolled symptoms of perennial allergic rhinitis serum vitamin D is inversely related to nasal symptoms (unpublished observations).

FEV1% values have been found positively, albeit weakly associated with serum vitamin D in asthmatic children and adults [15,17]. In our study, no significant association was found between serum vitamin D and spirometric values, and vitamin D was similar in subjects with lower FEV1% (<70%). It is possible that a larger number of observations would have produced a weak, yet significant association with FEV1% similar to previous studies.

Vitamin D3 supplementation in asthmatic children reduces the risk of recurrent respiratory infections and asthma exacerbations [18]. A small study in mostly non-white children with an average ACT score of 18 failed to show an effect of one year vitamin D supplementation (1,000 I.U./day) on ACT scores and FEV1% [19]. Similarly, we did not find a variation of the spirometric values and ACT scores after a 12 week vitamin D3 supplementation. However, we did find a significant improvement of the ACT scores at the end of the study in the subjects with uncontrolled asthma (ACT < 19). These results may have occurred because of a placebo effect or by chance. However, such findings may encourage studies of vitamin D in uncontrolled elderly asthmatics. A larger study of vitamin D supplementation in adults with asthma with serum vitamin D of less than 30 ng/ml was very recently published [20]. In this study, vitamin D 4,000 I.U./day for 28 weeks did not reduce treatment (inhaled steroid) failure and exacerbations nor did it improve FEV1 and asthma control. However, this study differed from ours in that it involved a younger patient population (average age 40 years old), in the obese range (average BMI 32), almost 50% non-white, and enrolled subjects throughout the different seasons[20]. Another very recent study of adult asthmatics reported an association between vitamin D sufficiency and decreased exacerbations and emergency room visits over a five year period [21].

Whereas expectedly vitamin D3 supplementation was well tolerated, we found a mild elevation of the serum calcium in two subjects after 12 weeks. This suggests that in elderly subjects it would be reasonable to measure serum calcium before and after several months of vitamin D supplementation.

Limitations of our study include the relatively small number of subjects, almost exclusively caucasian with well controlled asthma, and the lack of a placebo group. However, the results of our study in elderly asthmatics appear to confirm previous findings about the importance of vitamin D in asthma and may encourage larger studies in this patients group.

This article is adapted from Michele Columbo, Reynold A Panettieri and Albert S Rohr, Asthma in the elderly: a study of the role of vitamin D. Source article. This work is licensed under a Creative Commons Attribution 4.0 License.

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