Early exposure to tobacco smoke may lead to early emphysema later

http://www.eurekalert.org/pub_releases/2009-05/ats-eet051209.php

Public release date: 19-May-2009
Contact: Keely Savoie
American Thoracic Society

ATS 2009, SAN DIEGO— Chronic exposure to tobacco smoke in childhood may contribute to early emphysema later in life, according to new research. Environmental tobacco smoke (ETS) is known to be associated with a variety of serious health problems, but it had not previously been associated with the development of emphysema over the life course. The data will be presented on Tuesday, May 19, at the 105th International Conference of the American Thoracic Society in San Diego.
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To determine whether chronic exposure to ETS in childhood could lead to the development of early emphysema later in life, Dr. Lovasi and colleagues analyzed data from a diverse sample of 3,964 relatively healthy adults recruited as part of the Multi-Ethnic Study of Artherosclerosis (MESA) study, focusing on 1,781 adults who had never smoked. The MESA-lung study assessed childhood exposure to ETS by asking each participant "In your childhood, did you live with a regular cigarette smoker who smoked in your home?"

The MESA-lung study was also the first large study of healthy adults to collect CT images that show most of the lungs, allowing for the classification of some areas of the lungs as having indications of early emphysema: large contiguous areas of air-like density ("holes", in contrast to lung tissue, which is more dense than air) or the total percentage of lung volume with air-like density.

After adjusting for a number of potentially confounding variables, including childhood asthma and living with a smoker as an adult, the researchers found that non-smokers who reported childhood exposure to ETS were more likely to have CT patterns that looked like early emphysema: large holes were relatively more common, and more of the lung volume appeared to have low, air-like density. The association was not detectable among current or former smokers, perhaps due to the relatively strong influence of one's own smoking history. They did not find an association for childhood ETS exposure and lung function as measured by spirometry.