It is not just lack of exercise or an improper diet that can lead to weight gain, but even exposure to high levels of air pollution can make one overweight, according to a new study.
Worldwide research has indicated air pollution as a cause of obesity, but this is the first time a new study in the country has shown how exposure to high levels of air pollution can lead to weight gain. This is also one of the first studies in India among adolescent school children that has shown a strong association between obesity and asthma, and that air pollution may have a direct link with the two.
Dr Sundeep Salvi, director of Pune-based Pulmocare Research and Education Foundation and lead author of the study, told The Indian Express,“The association between obesity/overweight in children and higher prevalence of asthma is being reported for the first time in any study from India.”
Breathing polluted air can make children overweight and this may increase their risk of developing asthma, Dr Salvi said.
Lung Care Foundation and Pulmocare Research and Education (PURE) Foundation conducted the study across 12 randomly selected schools in Delhi, Kottayam, and Mysuru. “The study assessed the respiratory health of 3,157 adolescent school children studying in private schools in the city of Delhi and compared them with relatively cleaner cities in terms of particulate matter air pollution – Kottayam and Mysuru,” said Dr Arvind Kumar, founder- trustee of Lung Care Foundation.
As many as 39.8% children from Delhi were obese/overweight as compared to 16.4% children from Kottayam and Mysuru. Obese/overweight children had a 79% greater chance of having asthma across all three sites combined. This association was 38% higher in Delhi children as compared to their counterparts, according to the findings of the study that was conducted a few months prior to the nationwide lockdown last year.
The study was funded by Shakti Sustainable Energy Foundation and published in the medical journal Lung India on August 31. The researchers also presented study findings at a webinar held on Wednesday.
While there could be many causes for obesity/overweight in children from Delhi, particulate ambient air pollution could be an important contributing factor. The much higher prevalence of overweight/obesity observed in Delhi and much lower prevalence in Kottayam and Mysuru correlate very well with the reported particulate matter (PM2.5 and PM 10) levels in these cities, researchers said.
Another key finding was that Delhi school children have significantly higher prevalence of asthma and allergy symptoms as compared to school children in Kottayam and Mysuru,. In Delhi, 52.8% school children reported sneezing, 44.9% reported itchy watery eyes, 38.4% reported significant cough, 33% reported itchy rash, 31.5% reported shortness of breath, 11.2% reported chest tightness, and 8.75% reported eczema. In Kottayam and Mysuru, 39.3% school children reported sneezing, 28.8% reported itchy watery eyes, 18.9% reported significant cough, 12.1% reported itchy rash, 10.8% reported shortness of breath, 4.7% reported chest tightness, and 1.8% reported eczema.
The study also found that 29.3% children from Delhi reported airflow obstruction/asthma on spirometry (a breathing test) as compared to 22.6% children in Kottayam and Mysuru. This difference was despite the fact that two factors associated with childhood asthma — family history of asthma and smokers in the family — were more prevalent in Kottayam and Mysuru, researchers said.
On spirometry, boys were observed to have a two-fold higher prevalence of asthma than girls. In Delhi, 37.2% boys had airflow obstruction/ asthma as compared to 19.9% girls. Among the 29.3% children observed to have asthma on spirometry in Delhi, only 12% reported to have been diagnosed with asthma and only 3% used some form of inhalers. In contrast, among the 22.6% children observed to have asthma on spirometry in Kottayam and Mysuru, 27% reported to have been diagnosed and 8% were using some form of inhalers.
A resident of Delhi-NCR can gain 9.7 years in life expectancy if WHO guidelines on air quality index are met, Dr Kumar said, and pointed out that there was an urgent need for air pollution control measures by the government.
Dr Anurag Agarwal, director of CSIR – Institute of Genomics and Integrative Biology, New Delhi, who was a speaker at the webinar, said “This study has shown that around 85% of adolescent children who were found to have asthma in Delhi did not know that they had asthma, and less than 3% of them were receiving appropriate treatment. Clearly, we need to create more awareness about asthma among parents and teachers, so that underdiagnosis and undertreatment of asthma can be significantly overcome.”