The findings provide the strongest evidence to date of a link between smoking and cot deaths. They have prompted calls for smoking in the presence of a pregnant woman or a small child to be made socially unacceptable.
The number of deaths from Sudden Infant Death Syndrome (Sids) has fallen by more than 50 per cent following the "Back to sleep" campaign launched in 1991, which advised parents to encourage their babies to sleep on their backs and not on their fronts.
However, 10 babies still die from cot death each week, and for the past two years the death rate has remained stable. Poor living conditions and social deprivation are also factors, although the Government has not highlighted this aspect in its latest report, which concentrates on cigarettes.
Peter Fleming, professor of infant health and developmental physiology, working with colleagues at Bristol University, found the risk of cot death rises with the number of cigarettes smoked by pregnant women, mothers, fathers, and anyone else who lights up around a baby. They say more than 60 per cent of cot deaths may be attributable to exposure to tobacco smoke before and after birth. The risk of death for babies who share a bed with a smoker is four times higher than for those who do not.
The findings have prompted the Department of Health and the Foundation for Study of Infant Deaths to launch a new advice leaflet for parents. It incorporates the findings of the National Advisory Body's confidential inquiry into stillbirths and deaths in infancy, which was led by Prof Fleming, a more detailed summary of which will appear in the British Medical Journal later this week.
Writing in the journal, Prof Fleming says: "The responsibility of minimising the risk of sudden infant death syndrome lies not just with the mother who smokes but all smokers. An appropriate public health message might be that smoking in the same environment as a pregnant mother or child is as unacceptable as drinking and driving ... Parents who have been unable to give up or reduce their smoking habit should be strongly advised to keep their baby in a smoke-free zone. This, however, should not be regarded as an alternative to the much better precaution of not smoking at all."
The researchers looked at the circumstances of 195 babies who died and 780 survivors, in Yorkshire, the south west and Trent during 1993 and 1995. The scientists also found that cot deaths were higher among parents who used illegal drugs.
The new leaflet emphasises the following advice:
Putting babies to sleep on their backs, rather than on their sides, is safer;
The baby should be in a smoke-free zone;
Placing the baby with its feet against the bottom of the cot - the "feet-to-foot" position - may be the best way to avoid the baby's head being covered. A fifth of Sids babies are found with their heads covered (duvets increase the risk);
Sharing a bed with your baby is risky if you are a smoker.Reuse content