A review on the relation between obesity and vitamin D with pediatric asthma, and a report of a pilot study in Tehran, Iran: review article

Asthma is an inflammatory and chronic disease that affects about 300 million people globally. The disease is more common in developed countries. The increase in the prevalence of asthma is not only due to genetic factors, but also to many environmental factors related to urbanization and type of nutrition. It has been reported that obesity is an independent risk factor for asthma and obese children are at higher risk of asthma. The researchers found that many of the common phenotypes of obesity and asthma are due to genetic effects and some genetic component is common to asthma and obesity. Genetic data suggest that there are areas of genetic overlap between the obesity and asthma genes. These children experience more severe asthma and have a poor treatment outcome. On the other hand, there is an association between vitamin D deficiency in the earlier stages of life and incidence of asthma in the following years. Interestingly, obesity is a common risk factor for both asthma and vitamin D deficiency. Therefore, study on the interaction of asthma, obesity, and vitamin D deficiency may play an important role in unraveling the intricate nature of asthma. Prevalence of Pediatric asthma in 6-7 and 13-14 years-old children has been reported more than 10% in Iran. In this review we aimed to assess the latest findings about pediatric asthma and its association with obesity and vitamin D in Iran and the other countries. In addition, the results of a pilot study that has examined the frequency of overweight and obesity, as well as vitamin D deficiency in children with asthma in Tehran, are briefly presented. Enrolling a national study on obesity and vitamin D levels in children with asthma, can provide excellent information on the effects of obesity and vitamin D deficiency on asthma in Iranian children. Also the results could provide a basis for ecological studies to measure correlation between pediatric asthma and Sunlight and food and cultural habits in different parts of the country. Also, it is recommended that for a better understanding of the subject, experimental studies examine the effect of vitamin D supplementation and vitamin D-rich diets on the prevention and treatment of pediatric asthma in different age groups as well as different ethnicities of Iran.