Childhood exposure to secondhand smoke linked to bladder cancer

Children and adolescents may be even more susceptible to the harmful effects of tobacco smoke than adults – according to new research into bladder cancer published in next week’s edition of the International Journal of Cancer*.

Results from the study, part-funded by Cancer Research UK, suggest that exposure to secondhand smoke at a young age increases the risk of bladder cancer in later life.

Bladder cancer is the fourth most common cancer affecting men and the tenth most common affecting women in the UK. Over 10,000 new cases are diagnosed, and more than 4,800 people die from the disease in the UK each year.

The research team looked at data from nearly 430,000 people** and found that exposure to secondhand smoke during childhood was associated with an almost 40 per cent increased risk of bladder cancer in later life compared to no exposure.

They also found that for every five years later in life that people started smoking, their risk of developing bladder cancer was reduced by 19 per cent. This suggests that the younger a person is when they take up smoking, the greater their risk of the disease.

Report co-author, Cancer Research UK’s Dr Naomi Allen of Oxford University, said: “Previous research has shown that there’s a strong link between smoking and bladder cancer. But this study also suggests that young people who are exposed to secondhand smoke are more at risk of going on to develop the disease in later life. This adds to the growing body of evidence that children and adolescents may be even more vulnerable to the harmful effects of tobacco smoke than adults.”

The team also found that for smokers – who were overall four times more likely to develop bladder cancer – both the intensity and duration of smoking affected their risk. Every five cigarettes a day increased risk by 18 per cent and every five years of smoking increased risk by 14 per cent.

Ex-smokers were found to be twice as likely to develop the disease as non-smokers. Their risk slowly declined over many years from the time of quitting.

Dr Allen added: “This means that quitting works. Ex-smokers have a lower risk of developing bladder cancer than current smokers, and even heavy smokers will be able to reduce their risk of bladder cancer if they stop smoking.”

Professor John Toy, Cancer Research UK’s medical director, said: “Although more research is needed to confirm the seeming effects of childhood exposure to secondhand smoke, the study’s findings support the health value of the smoking ban in public places. Evidence shows that smokefree places encourage smokers to give up or reduce cigarette consumption and, so, will reduce passive smoke at home.”

ENDS

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