Rise in BMI Ups the Risk of Developing Asthma During Mid-Childhood

A rise in the body mass index (BMI) elevates the risk of developing asthma during mid-childhood, a new study reveals.

Researchers at the University of Bristol, U.K., have for the first time provided genetic evidence that higher fat mass ups the risk of asthma, common chronic inflammatory disease that inflames and narrows airways, in mid-childhood. In this study, the researchers evaluated the casual effects of BMI, fat mass and lean mass of the children who were a part of the Avon Longitudinal Study of Parents and Children.

The 4,835 children were aged 7.5 years. A weighed genetic score was based on 32 independent BMI-related DNA sequence variations.

The researchers noticed that a rise in BMI increased the risk of asthma in mid-childood. The public intervention that aims at lowering obesity may also help curb the global rise of asthma that had been steadily increasing over the past few decades.  It is estimated that worldwide 200 million adults and children are affected by asthma. Though the underlying cause of asthma remains a mystery, experts believe that obesity could be a major cause of asthma.

The researchers noticed that with every extra unit of BMI the relative risk of developing asthma increased by 55 percent.

The authors concluded: "Environmental influences on the development of asthma in childhood have been extensively investigated in epidemiological studies, but few of these provide strong evidence for causality... [higher BMI in mid-childhood] could help explain some of the increase in asthma risk toward the end of the 20th century, although the continued rise in obesity but with a slowing in the rise in asthma prevalence in some countries implies that other non-BMI-related factors are also likely to be important."

The study was documented in PLOS Medicine.