Most of Children Are Exposed to Tobacco Smoke at Home

Published on July 18, 2008 3:47 AM

According to a University of Leicester study, children who have at least one parent who smokes have 5.5 times higher levels of cotinine. Cotinine is a metabolite of nicotine. The word 'cotinine' is an anagram of 'nicotine'. It is used to measure the grade of tobacco smoking, but might also improve mental function.

Cotinine has an in vivo half life of approximately 20 hours, and is typically detectable for several days to up to one week after the use of tobacco. The level of cotinine in the blood is proportionate to the amount of exposure to tobacco smoke, so it is a valuable indicator of tobacco smoke exposure, including secondary smoke.

Scientists have detected cancer-causing chemicals associated with tobacco smoke in the urine of nearly half the babies of smoking parents.

Having a mother that smokes was found to have the biggest independent effect on cotinine in the urine. Having a smoking father doubled the amount of cotinine.

Sleeping with parents and lower temperature rooms were also associated with increased amounts of cotinine. Cotinine was measured in 100 urine samples taken from infants aged 12 weeks. Seventy one of the babies had at least one parent that smoked and the parents of the other 33 were non-smokers.

Researchers found that babies affected by smoke tend to come from poorer homes, which may have smaller rooms and inadequate heating. Higher cotinine levels in colder times of year may be a reflection of the other key factors which influence exposure to passive smoking, such as poorer ventilation or a greater tendency for parents to smoke indoors in winter.

Sleeping with a parent is a know risk factor for cot death and the scientists suggest that one reason for this could be inhalation of, or closeness to clothing or other objects contaminated with, smoke particles during sleep.

According to a study the home is the most significant source of exposure to environmental tobacco smoke for children. In the US estimates suggest that almost 40 per cent of children younger than five years live with a smoker.