The body of research on passive smoking continues to grow. In addition to the health effects described in the conclusions of the major reviews cited above, research evidence has linked passive smoking with the following effects on health:
[Asthma]
[Parental smoking during pregnancy and risk of cancer in childhood]
[Cancer of the uterine cervix in non-smokers]
[Snoring and night cough in children]
A recent study estimated that non-smokers are at a 26% greater risk of lung cancer if they are married to a smoker. The risk of lung cancer in the non-smoker who lives with a smoker increases with the number of cigarettes smoked by the smoker and with the number of years they have lived together.
An Australian review of the medical evidence has confirmed that exposure to environmental tobacco smoke contributes to the incidence of childhood asthma. It may do this in the following three ways: by inducing asthma in a genetically predisposed child, by maintaining a state of increased hyper-responsiveness following exposure to an allergen, virus or irritant, and by provoking acute attacks of asthma.
Measures of airways responsiveness (that is, the ability of the airways to constrict in response to certain stimuli), provide a useful indicator of the presence of asthma. Australian research has shown that the level of airway responsiveness in early life is increased with a family history of asthma, parental smoking, or both.
Parental smoking during pregnancy and risk of cancer in childhood
A number of studies have pointed to an elevated risk of cancer in children of smokers, particularly
leukaemia. Recent research has suggested that smoking by either parent during pregnancy is
associated with a higher incidence of all childhood cancers combined, but especially acute lymphocytic
leukaemia and lymphoma. There may be an association between paternal smoking and brain
cancer. At this stage, these findings should be considered tentative.
Individuals with cystic fibrosis, an inherited condition present from birth, have abnormal secretions,
particularly in the lungs and intestine. For this reason, sufferers are prone to recurrent lung infections
and malabsorption of food. They are frequently relatively malnourished and, typically, are shorter and
lighter than unaffected individuals. They usually have increased food requirements to offset the poor
absorption of food. Research has shown that children with cystic fibrosis who are exposed to tobacco
smoke in the home are smaller and lighter than those not exposed, suggesting a possible link between
passive smoking and growth and appetite.
Cancer of the uterine cervix in non-smokers
There is evidence that passive exposure to tobacco smoke, as well as active smoking, is a risk factor
for the development of cancer of the cervix. American research has shown that nicotine is present
in the cervical fluid of non-smokers following exposure to passive smoking, although active smokers,
who draw smoke directly into their lungs, have higher levels still. The authors conclude that even
low level exposure to environmental tobacco smoke may result in systemic effects.
Snoring and night cough in children
Children exposed to tobacco smoke are more likely to be snorers and cough during the night, probably
due to a chronic effect of smoke on the upper airways.