Researchers have warned that constant exposure to tobacco smoke puts children at a higher risk of developing early emphysema later in life.
"Emphysematous 'holes' in the lung that begin as small areas of damage or impaired development may expand according to a fractal trajectory after an earlier insult," said Dr Gina Lovasi, of Columbia University.
"We hypothesized that environmental tobacco smoke in childhood may be one such early insult, associated with signs of early emphysema detectable on computed tomography (CT) scan in adulthood and perhaps lower lung function detectable by spirometry," Lovasi added.
To determine whether chronic exposure to environmental tobacco smoke (ETS) in childhood could lead to the development of early emphysema, the researchers analyzed 1,781 adults who had never smoked from Multi-Ethnic Study of Artherosclerosis (MESA).
The CT images showed that some of the areas of lungs had 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.
The researchers found that non-smokers exposed to ETS in childhood more likely to have CT patterns that looked like early emphysema.
"The take-home message from our analysis is that exposure to tobacco smoke during childhood may be associated with detectable differences in lung structure, and perhaps early emphysema, later in life among people who do not themselves smoke," said Lovasi.
"These findings might also help researchers to understand how lung damage develops," Lovasi added.