DUNDEE, UNITED KINGDOM--Children with asthma whose parents smoke heavily may not receive adequate treatment. A recent study associates high levels of parental smoking in the home with a reduced number of health care contacts for asthma.[1] But whether these children have an increased risk of asthma morbidity remains unclear.

"Children with asthma whose parents smoke may not make as many office visits as would be desired. Doctors should be alert to missed visits in this group," Iain K. Crombie, PhD, told REVIEWS REVIEWS.

Dr. Crombie and colleagues from the University of Dundee in the United Kingdom wanted to investigate the effect of passive smoking on asthma morbidity in children. Like many other researchers, these investigators used health service contacts as a surrogate for morbidity. After reviewing case notes, they identified 438 children (ages 2 to 12 years) from 73 general practices in Scotland who had asthma and who had one or more parents who smoked. The parents of these children completed a questionnaire on their smoking, their child's asthma, and the child's exposure to smoking.

In addition, data on health service contacts over a 12-month period were identified by reviewing the children's case notes. Exposure to smoke was assessed by measuring cotinine levels in saliva samples obtained from both the parents who smoked and their children. Cotinine levels ranged from undetectable levels to 21.2 ng/mL.

REDUCED HEALTH CARE VISITS

During the 12-month study, 77% of the children had between one and six office visits, 10% had more than six visits, and 14% had no visits. Not surprisingly, asthma severity (as reflected in the type of maintenance therapy the child was receiving) correlated strongly with number of health care contacts. However, the relationship between salivary cotinine levels and number of such contacts was inconsistent.

What did surprise Dr. Crombie and colleagues was that high levels of smoking (as measured by the frequency of smoking in front of the child, the amount the parent[s] smoked at home, or the number of parents who smoked) were associated with decreased number of health care contacts. There was a 34% reduction in office visit frequency among the children who lived in the homes in which the level of smoking was highest.

Parents' perception of their child's asthma, independent of actual severity, was also associated with the number of health care contacts; the worse parents perceived their child's disease to be, the more likely they were to bring the child in for office visits. Other factors that influenced frequency of office visits include age of the child and number of children in the family. Younger children had more visits, whereas children of large families had fewer visits.

The investigators suggest that parents who smoke heavily might be less concerned about respiratory symptoms associated with smoking. Another possibility is that parents may fear criticism about exposing their child to passive smoke, and therefore they avoid taking the child to see a physician.

Because of the variety of nonclinical factors that were shown to influence the rate of health care contacts, Dr. Crombie and colleagues suggest that the number of office visits should not be used as a surrogate for asthma morbidity.

--Jennifer A. McConnon

References
1. Crombie IK, Wright A, Irvine L, et al. Does passive smoking increase the frequency of health service contacts in children with asthma? Thorax. 2001;56:9-12.