Protecting Infants Against Secondhand Smoke

Blackburn C, Spencer N, Bonas S, et al. Effect of strategies to reduce exposure of infants to environmental tobacco smoke in the home: cross sectional survey. BMJ. 2003;327:257-261.

Clinician Reviews 13(10):35-36, 2003. © 2003 Clinicians Group, LLC

Posted 01/30/2004

No less than a complete ban of smoking in the home can reduce infants' risk of respiratory illnesses and sudden infant death syndrome caused by exposure to environmental tobacco smoke, according to study results published in BMJ. Less strict harm-reduction methods, such as restricting smoking around the infant and taking steps to freshen the air following smoking, had little or no effect, it was found.

Blackburn and colleagues used a cross-sectional survey to collect data on 314 UK households in which an infant lived with at least one smoker. Interviews were conducted in the home by a trained nurse when the infants were ages 1 to 4 months. (Infants with major perinatal illnesses were excluded.) Parents were questioned about their knowledge of tobacco smoke exposure-reduction methods and which, if any, they employed. These methods were classified as "strict" (ie, smoking banned in the home), "less strict," and "none used" or "not aware" of such strategies.

Ninety percent of parents were aware of harm-reduction methods, and more than half reported using more than one method to limit their infants' exposure to tobacco smoke. Almost 20% of parents reported that smoking was not allowed in the house.

To determine infants' exposure levels, the researchers studied urine samples from the 164 infants in the cohort who were bottle-fed. (Prior research has shown that nicotine and cotinine are transmitted through breast milk.) There were no significant differences in mean log urinary cotinine-to-creatinine ratios in the less-strict, none-used, and not-aware groups; these were combined for comparison with the strict group. The mean cotinine-to-creatinine ratio among infants in households following strict measures was 1.26 -- significantly lower than the ratio for the combined less-strict and no-measures groups (2.58).

It is possible that parents need more information on different ways to reduce their infants' exposure to tobacco smoke; many parents surveyed reported using ineffective methods (eg, opening windows when smoking or using a fan), the researchers note. They further acknowledge that studies with larger samples must be conducted to verify their results.

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