Cotinine levels raised in babies whose parents smoke
Half of all children in the UK live in a household with at least one smoker, and many children are still exposed to second-hand smoke in the home.1 A new study has found that infants living in smoking households accumulate high levels of nicotine metabolites.
The research, published in Archives of Disease in Childhood, looked at 104 infants, aged 10-12 weeks, and measured levels of cotinine in their urine. Cotinine is a breakdown product of nicotine, and provides a measure of the extent to which the chemicals in tobacco smoke are being absorbed into the body. The infants were categorised as those from smoking (68% of participants) and non-smoking (32% of participants) households, and the levels of cotinine were compared. For parents who smoked, the average cigarette consumption was 16 cigarettes per day.
Infants with at least one smoking parent were found to have mean cotinine levels more than five times higher than those from non-smoking households. Maternal smoking was the highest contributor, quadrupling the level of cotinine in the urine. Paternal smoking almost doubled the cotinine level.
Co-sleeping was found to increase cotinine levels, and there was also a suggestion of seasonal variability, with higher cotinine levels found in samples taken during the winter.
As the authors point out, nicotine is just one of many thousands of chemicals found in tobacco smoke, so the finding that so much is taken into infants' bodies is cause for concern.
It is already known that exposure of children to secondhand smoke increases the risk of sudden infant death syndrome, asthma, glue ear, bronchitis and pneumonia.1 The finding of higher cotinine levels in the winter could be one factor that contributes to the higher rates of sudden infant death seen during winter months.
While legislation now protects people from exposure to secondhand smoke in public places, children are still routinely exposed to tobacco smoke in the home. It may not be practicable to legislate against this, but as doctors we can at least draw parents' attention to the risks. Put simply, when a parent smokes, the baby smokes too.
Joseph DV, Jackson JA, Westaway JA et al. Effect of parental smoking on cotinine levels in newborns. Arch Dis Child Fetal Neonatal Ed 2007 doi:10.1136/adc.2006.108506Dr Kevin LewisDr Kevin Lewis Reviewer
Dr Kevin Lewis
Former GP, Clinical Director of Smoking Cessation, Shropshire County Primary Care Trust