BEIJING, June 20 (Xinhuanet) -- Parents who smoke nearby put their children in great danger of breathing problems or even cot death,, UK researchers said Tuesday.

    Their study showed that children with at least one parent who smokes have five times as much cotinine, a nicotine byproduct, in their urine than those whose parents are non-smokers.

    It's not clear how cotinine levels affect babies, but exposure to tobacco smoke isn't healthy, said the study. 

    The study of 104 12-week-old infants (71 with at least one parent who smoked and 33 with nonsmoking parents) also found that having a mother who smokes quadrupled urine cotinine levels while having a father who smokes doubled the levels.

    "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," the study wrote.

    "This is the first time we've got direct information on the effect of smoking in homes on babies," Mike Wailoo, M.D., FRCP, a senior lecturer in the child health department of the University of Leicester said. "It clarifies and I think it firms up information that we all thought we had."

    Also, nearly 40 percent of under-fives are believed to be exposed to tobacco smoking at home, which may be responsible for up to 6,000 deaths a year in the U.S. alone in young children.

    (Agencies)