Study of doctors?smoking habits shows links to 11 types of cancer
http://www.100md.com
《英国医生杂志》
Eleven types of cancer are significantly related to smoking, according to data from a 50 year study of more than 30 000 male British doctors.
And at least two other types of cancer may be linked to the habit, according to the latest analysis of deaths among 34 439 doctors who first reported their smoking habits at the end of 1951, says the study, which was published online ahead of print publication on 25 January in the British Journal of Cancer (www.bjcancer.com, doi:10.1038/sj.bjc.6602359).
"In all, 11 of the 13 types in men that the agency classed as liable to be caused by smoking were significantly related to smoking and the findings for the other two, which caused only few deaths, suggested they might be," wrote the authors, Richard Doll, Richard Peto, and colleagues from the Radcliffe Infirmary, Oxford.
The doctors have been monitored since 1951, including periodic updates about changes in habits. The recorded data included whether they ever smoked, how much they smoked, and whether they were current or former smokers. The researchers also recorded information about mortality for different types of cancer.
The results of the 50 year analysis show that lung cancer was the malignancy responsible for the largest number of deaths related to smoking. The number of deaths per year per 100 000 men who were heavy smokers (25 or more cigarettes a day) was 25 times that among their colleagues who never smoked (415.2 versus 16.9).
For lung cancer, like a number of other cancers, there was a progressive increase in risk with the number of cigarettes smoked. Mortality from lung cancer was three times higher among heavy smokers than among light smokers (fewer than 15 cigarettes a day) (130.6 deaths per year per 100 000 men).
Similar differences in mortality between heavy smokers and men who never smoked were shown for cancers of the oesophagus (50.0 versus 5.7 deaths per year per 100 000 men), bladder (51.4 versus 13.7), the larynx (17.3 versus 0), and the pancreas (52.9 versus 20.6).
Two types of cancer—nasopharyngeal and nasal—contributed only small numbers of cases, but the evidence, say the authors, indicates a positive relation with smoking.
No firm link was found for prostate cancer: "Our data, now based on nearly 900 deaths, show some increasing risk with increasing numbers of cigarettes smoked per day, but only among smokers; there is no appreciable difference between non-smokers and continuing smokers and the lowest risk is recorded in ex-smokers. They tend, therefore, to support the idea that smoking is unrelated to the disease," the study says.
The authors say that some evidence is shown that rectal, but not colon, cancer is related to smoking: "For colorectal cancer, our data confirm a relatively weak relationship with smoking, which could not be explained by confounding with the consumption of alcohol," say the authors.(Abergavenny Roger Dobson)
And at least two other types of cancer may be linked to the habit, according to the latest analysis of deaths among 34 439 doctors who first reported their smoking habits at the end of 1951, says the study, which was published online ahead of print publication on 25 January in the British Journal of Cancer (www.bjcancer.com, doi:10.1038/sj.bjc.6602359).
"In all, 11 of the 13 types in men that the agency classed as liable to be caused by smoking were significantly related to smoking and the findings for the other two, which caused only few deaths, suggested they might be," wrote the authors, Richard Doll, Richard Peto, and colleagues from the Radcliffe Infirmary, Oxford.
The doctors have been monitored since 1951, including periodic updates about changes in habits. The recorded data included whether they ever smoked, how much they smoked, and whether they were current or former smokers. The researchers also recorded information about mortality for different types of cancer.
The results of the 50 year analysis show that lung cancer was the malignancy responsible for the largest number of deaths related to smoking. The number of deaths per year per 100 000 men who were heavy smokers (25 or more cigarettes a day) was 25 times that among their colleagues who never smoked (415.2 versus 16.9).
For lung cancer, like a number of other cancers, there was a progressive increase in risk with the number of cigarettes smoked. Mortality from lung cancer was three times higher among heavy smokers than among light smokers (fewer than 15 cigarettes a day) (130.6 deaths per year per 100 000 men).
Similar differences in mortality between heavy smokers and men who never smoked were shown for cancers of the oesophagus (50.0 versus 5.7 deaths per year per 100 000 men), bladder (51.4 versus 13.7), the larynx (17.3 versus 0), and the pancreas (52.9 versus 20.6).
Two types of cancer—nasopharyngeal and nasal—contributed only small numbers of cases, but the evidence, say the authors, indicates a positive relation with smoking.
No firm link was found for prostate cancer: "Our data, now based on nearly 900 deaths, show some increasing risk with increasing numbers of cigarettes smoked per day, but only among smokers; there is no appreciable difference between non-smokers and continuing smokers and the lowest risk is recorded in ex-smokers. They tend, therefore, to support the idea that smoking is unrelated to the disease," the study says.
The authors say that some evidence is shown that rectal, but not colon, cancer is related to smoking: "For colorectal cancer, our data confirm a relatively weak relationship with smoking, which could not be explained by confounding with the consumption of alcohol," say the authors.(Abergavenny Roger Dobson)