Purpose of the Study. This study was conducted to determine if environmental tobacco smoke (ETS) exposure during childhood had an impact on the prevalence of asthma in adults.
Study Population. A random sample of 8008 residents aged 15 to 69 of Orebro, Sweden (age matched from a total population of 80 569).
Methods. A questionnaire was sent to the randomly selected study group during the winter from 1995–1996. It included questions about respiratory symptoms and disease, use of asthma drugs, symptoms with various exposures, and questions about smoking history, occupation, and family history of respiratory diseases. They were also asked about childhood ETS exposure with the question, “Do or did any of your parents/relatives smoke at home when you grew up?” Current and former smokers were excluded from the evaluation of effects of childhood ETS exposure on asthma because of the confounding effects of active smoking on respiratory disease.
Results. The questionnaire return rate was 84%. The total sample included 3556 never-smokers (52.8%), 1676 smokers (24.9%) and 1257 ex-smokers (18.7%); 243 did not respond to the question. Subjects 30 to 49 years old were most likely to have childhood ETS exposure and those that had ETS exposure were significantly more likely to be ever-smokers (54.5%) versus those without childhood ETS exposure (33.8%). In subjects with childhood ETS exposure, almost all airway-related symptoms were more prevalent compared with nonexposed subjects. Subjects with physician-diagnosed asthma were significantly more likely to have had childhood ETS exposure (7.6% asthma prevalence) versus the nonexposed group (5.8% asthma prevalence). The difference in asthma prevalence between ETS exposed and nonexposed subjects was most pronounced in the younger age group (age: 15–39), 8.8% prevalence for exposed versus 6.3% nonexposed. Subjects aged 15 to 19 with ETS exposure were more likely to be smokers themselves (36.9%) versus nonexposed (13.1% smokers). ETS exposure was a significant risk factor for physician-diagnosed asthma (odds ratio [OR]: 1.82), breathing difficulties with exercise (OR: 1.45), breathing difficulties from cigarette smoke (OR: 1.25), and breathing difficulties from pets (OR: 1.41).
Conclusions. Childhood ETS exposure increases the likelihood of asthma in adulthood. The risk of an individual to take up smoking is increased by 60% if they had childhood ETS exposure.
Reviewer’s Comments. Childhood ETS exposure was strongly associated with asthma in nonsmoking adults. This was especially true of nonsmoking adults without a family history of asthma. The authors note the limitations of this study in that details of the ETS exposure (duration and amount) were not obtained and possible bias issues that asthmatics may be more likely to report childhood ETS exposure than nonasthmatics. This article adds to the existing literature demonstrating the detrimental effects of childhood ETS exposure. It should again encourage us as child advocates to continue to address this important issue with our patients and their families.
- Copyright © 2002 by the American Academy of Pediatrics