HEALTH NEWS

Study Title:

Vitamin C, Children and Mold Exposure

Study Abstract

Background
We previously found a significant benefit of vitamin C supplementation in asthmatic children. Purpose: To test whether the effect of vitamin C on asthma is heterogeneous over the participant population.

Methods
Egyptian asthmatic children between 7 and 10 years of age (n = 60) were included in the cross-over trial. They were administered 0.2 grams per day of vitamin C and placebo for separate 6-week periods. The variation in the vitamin C effect on two clinically relevant outcomes was analyzed: the childhood asthma control test (C-ACT), which measures the severity of asthma symptoms (the scale ranges from 0 to 27 points, <20 points indicating unsatisfactory asthma control), and FEV1. We used linear modeling to examine the variation of the vitamin C effect in the subgroups.

Results
The effect of vitamin C on the C-ACT was significantly modified by age and baseline C-ACT levels. In the children aged 7.0-8.2 years with a baseline C-ACT of 18 to 19 points, vitamin C increased the C-ACT score by 4.2 points (95% CI: 3.3-5.3), whereas in the children aged 8.3-10 years who had a baseline C-ACT of 14 to 15 points, vitamin C increased the C-ACT score by only 1.3 points (95% CI: 0.1-2.5). The effect of vitamin C on the FEV1 levels was significantly modified by age and exposure to dampness. In the children aged 7.0-8.2 years with no exposure to dampness, vitamin C increased the FEV1 level by 37% (95% CI: 34-40%), whereas in the children aged 8.3-10 years with exposure to dampness or mold in their bedroom more than one year prior to the study, vitamin C increased the FEV1 level by only 21% (95% CI: 18-25%).

Conclusions
We found strong evidence that the effect of vitamin C on asthmatic children is heterogeneous. Further research is needed to confirm our findings and identify the groups of children who would receive the greatest benefit from vitamin C supplementation. Key words: age factors, ascorbic acid, asthma, child, effect modifiers, forced expiratory volume, obstructive lung diseases, quality of life, controlled trials

From press release:
Depending on the age of asthmatic children, on their exposure to molds or dampness in their bedroom, and on the severity of their asthma, vitamin C has greater or smaller beneficial effect against asthma, according to a study published in the journal Clinical and Translational Allergy.

Proposals that vitamin C might be beneficial in the treatment of asthma date back to the 1940s, but the findings from controlled trials have been conflicting.

Drs Mohammed Al-Biltagi from the Tanta University in Egypt and Harri Hemila from the University of Helsinki in Finland analyzed the effect of 0.2 grams per day of vitamin C on 60 asthmatic children aged 7 to 10 years. The effect of vitamin C on the forced expiratory volume per one second (FEV1) was modified by age and exposure to molds or dampness. In the younger children aged 7.0 to 8.2 years with no exposure to molds or dampness, vitamin C administration increased the FEV1 level by 37%. In the older children aged 8.3 to 10 years with exposure to molds or dampness in their bedroom more than one year before the study, vitamin C increased the FEV1 level by only 21%.

The effect of vitamin C on the asthma symptoms was modified by age and the severity of asthma symptoms. In the younger children aged 7.0 to 8.2 years with mild asthma symptoms, the benefit of vitamin C was greatest. In the older children aged 8.3 to 10 years who had severe asthma symptoms, the benefit of vitamin C was smallest.

Drs Al-Biltagi and Hemila conclude that there is strong evidence that the effect of vitamin C on asthmatic children is heterogeneous. They consider that it is important to carry out further research to confirm their findings and to more accurately identify the groups of children who would receive the greatest benefit from vitamin C supplementation.

Study Information

1.Harri Hemila, Mohammed Al-Biltagi, Ahmed Baset.
Vitamin C and asthma in children: modification of the effect by age, exposure to dampness and the severity of asthma.
Clinical and Translational Allergy
2011 August
University of Helsinki in Finland.