Obesity in children may be triggering an asthma epidemic reveals a new study.
According to the joint study, conducted by researchers at University of Bristol, UK and University of Queensland, Australia, extra weight and fat in children could lead to the risk of developing asthma, which is responsible for chronic inflammation of air passages, by an alarming 55 percent for every extra unit of body mass index (BMI).
The researchers observed 5,000 children who were suffering from asthma by the time they were seven and half and were registered for a long-term study of both children and parents in the U.K.
The team led by Dr. Raquel Granell scored the children on the basis of 32 independent "BMI-related generic variants." The researchers assessed the associations of the score with fat mass, lean mass, BMI and asthma.
"Higher BMI increases the risk of asthma in mid-childhood. Higher BMI may have contributed to the increase in asthma risk toward the end of the 20th century," explain the study authors.
Granell also said that while previously several studies had delved into the importance of environmental factors like pollen and fumes on asthma during childhood, the correlation between asthma and being overweight was not shown, but only suspected.
"In the past we haven't been sure whether a high BMI causes asthma, or if asthma causes high BMI, or another variable entirely is responsible for both," said David Evans, co-author of the study "We tested genes that we knew were related to BMI. If increased BMI were truly responsible for increased risk of asthma, then we would expect that these genes would also show a relationship with increased risk of asthma, which is exactly what we found."
The study authors raise the question if the increase in obesity all over the world could be a contributing factor in the rise of asthma. However, the researchers also point out that it is not clear why obesity could cause asthma and Granell opines that more research is required to establish the causal correlation between asthma and BMI. A possibility exists that the inflammation caused due to obesity, as well as its effect on the immune system of the individual could be the triggers of asthma.
The study has been published in the journal PLOS Medicine on Wednesday, July 1.