Secondhand smoke has been linked to the intensifying of asthma symptoms in children. It has also been linked to middle ear infection, bronchitis, pneumonia, coughing and wheezing and worse lung function as compared to those children who were not exposed to secondhand smoke. A new study is confirming the association between secondhand smoke and asthma, but the authors' analyses of the data are questionable.
Dr. Kenneth Quinto and colleagues from the National Center for Health Statistics in Hyattsville, Maryland looked at NHANES data from 1999 to 2010, specifically attempting to analyze environmental tobacco smoke exposure in children with and without asthma. They found that the children with asthma who had the greatest exposure to tobacco smoke were Mexican-American girls between the ages of 6 and 11 whose family income level was below 350 percent of the federal poverty line. Exposure to secondhand smoke did not differ in those children between the ages of 3 and 5 or 12 and 19. There was also no difference in exposure found between children whose families made 350 percent or more above the poverty line.
The authors of the study believe that next steps should involve studies to try to understand why these trends exist. However, ACSH s Dr. Gilbert Ross believes that the authors analyses of these data are arbitrary and are a prime example of data dredging. He adds, There is no biological plausibility to explain why children ages 6 to 11 should demonstrate differences in their susceptibility to the adverse effects of tobacco smoke exposure that were not seen among any other age groups. Furthermore, I would like to know how the authors settled on the income classification of 350 percent of the federal poverty line.It seems to me that they just used this number because it tended to confirm the results that they were seeking. I m not doubting the link between secondhand smoke and asthma by any means, but I do not believe that this study can be used to further confirm this link.