Keywords: asthma prevalence, spectrum, seasonal variations, ozone production, India, children, child health, ozone production, automobile emissions, respiratory problems
Asthma in children: seasonal variations
Asthma has shown a steady increase in prevalence globally for the past two and a half decades. The environmental factors strongly tilt the balance over genetic factors as causative factors. To find out the current prevalence, spectrum and seasonal variation of asthma, and to compare with the previous studies from the same place, prospective hospital-based study based on respiratory evaluation of 6677 children under 18 years of age was carried out. 26.7% (1781/6677) showed evidence for asthma, 67% (1190/1781) were under 5 years and 33% (591/1781) over 5 years of age. The sex ratio is male 60% (1060/1781) and female 40% (721/1781) a ratio of 3:2. 63.4% (1129/1781) had intermittent asthma and 36.6% (652/1781) had persistent asthma and 19.8% (349/1781) experienced asthma summer. Compared with the previous study done a decade ago, the values showed that intermittent asthma decreased from 80% to 63.4% and persistent asthma increased from 20% to 36.6%. The seasonal episodes of asthma increased in summer from 2.8% in 1994 to 19.8% in 2004. The present study supports the view that the persistent asthma is increasing in prevalence and that there is significant increase in summer, possibly due to the increase in ozone production from automobile emissions. More research is needed to assess the hypothesis of this paper.