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Smoking and asthma

Exposure to Cigarette Smoke Can Impair Asthma Treatment in Children

Published February 18,  2014

According to new findings, children with asthma show reduced response to medications if they are exposed to cigarette smoke at home.

Asthma is a chronic inflammatory disease and its prevalence is increasing throughout the world. Corticosteroids are considered to be an effective anti-inflammatory therapy for the treatment of asthma. However, people who smoke show reduced response to these agents. Interestingly, exposure to parental smoking may worsen asthma symptoms in children and can be a risk factor for the persistence of asthma later in childhood. A team of scientists recently performed a study to understand the reason behind reduced corticosteroid sensitivity on exposure to cigarette smoke.

The study involved 19 children with uncontrolled severe asthma, out of which 10 were exposed to non-passive smoking and nine to passive smoking (exposure to second-hand smoke). Exposure to passive smoke was assessed on the basis of information reported by parents. The scientists conducted various tests in study participants to determine the presence of certain inflammatory markers and enzymes. After thorough analysis it was found that children with severe asthma with a parent who smokes (exposure to passive smoke) at home have lower levels of the enzyme Histone deacetylase (HDAC2) compared with those whose parents don't smoke. HDAC2 is required for steroids to exert their beneficial anti-inflammatory effects in asthma.

This was an important finding that explains the molecular mechanisms which causes reduced response to corticosteroids on exposure to cigarette smoke. The scientists further explained that children with asthma who are passively exposed to tobacco smoke had the same molecular abnormalities as seen with adults who actively smoke. The molecular abnormalities seen in either case lead to steroid resistance.

The study has highlighted an important health hazard smoking can cause. This calls for an action to protect children with severe asthma from being exposed to cigarette smoke.



  1. Kobayashi Y, Bossley C. Passive smoking impairs histone deacetylase-2 in children with severe asthma. Chest. 2014; 145(2):305-312.
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