mlk_man
10-12-2005, 06:33 AM
Smoking Reduction, Dietary Phytoestrogens May Reduce Lung Cancer Risk
NEW YORK (Reuters Health) Sept 27 - Heavy smokers can decrease their risk of lung cancer if they substantially cut down the number of cigarettes they smoke per day, investigators report in the Journal of the American Medical Association for September 28. The results of a second Journal study suggest that a diet high in phytoestrogens is associated with a lower risk of lung cancer, in both nonsmokers and smokers.
Dr. Nina S. Godtfredsen, from Hvidovre Hospital, and her associates in Denmark conducted a population-based cohort study among 19,714 subjects with up to 31 years of follow-up.
Subjects who reduced their tobacco consumption from 20 to 10 cigarettes per day experienced a 27% reduced risk for lung cancer compared with unchanged heavy smokers.
Among subjects who were light smokers throughout (average 9 cigarettes per day), the risk was reduced by 56% compared with heavy smokers, while those who quit reduced their risk by 50%. The risk among those who never smoked was 91% less than among heavy smokers.
Clearly, smoking cessation is the best method for decreasing harm from tobacco, Drs. Lawrence J. Dacey and David W. Johnstone, from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, point out in a related editorial.
"Nonetheless," they write, "because only a minority of smokers are able to quit smoking completely, it is important to inform them that the more they can reduce the number of cigarettes they smoke, the more they will decrease their risk of lung cancer."
In the second Journal report, Dr. Margaret R. Spitz and colleagues at the University of Texas M. D. Anderson Cancer Center in Houston conducted a case-control study of 1674 patients with lung cancer and 1735 matched healthy control subjects. Food frequency questionnaires were used to assess intake of several classes of phytoestrogens.
Patients with lung cancer tended to consume lower amounts of phytoestrogens than controls (median 265.1 versus 390.3 mg/day, p < 0.001). Men appear to benefit more phytoestrogen intake than did women, with p values of < 0.001 and of 0.06, respectively. In women, only intake of phytoestrogens from food sources (excluding coffee and tea) significantly affected risk (p = 0.01).
For each individual class of phytoestrogens -- coumesterol, isoflavone and ligans -- and for phytosterols, men appeared to benefit significantly from increased intake (p = 0.004 to > 0.001). Although there were trends toward reduced risk in women, the associations did not reach statistical significance.
The protective effects of phytoestrogens were strongest for never smokers, although current smokers also appeared to benefit. Protective effects were not statistically significant in previous smokers.
"Patients should be informed that they may further reduce their risk of developing cancer by adopting a diet rich in fruits and vegetables," Dr. Dacey and Johnstone remark in their editorial.
JAMA 2005;294:1493-1510,1550-1551.
NEW YORK (Reuters Health) Sept 27 - Heavy smokers can decrease their risk of lung cancer if they substantially cut down the number of cigarettes they smoke per day, investigators report in the Journal of the American Medical Association for September 28. The results of a second Journal study suggest that a diet high in phytoestrogens is associated with a lower risk of lung cancer, in both nonsmokers and smokers.
Dr. Nina S. Godtfredsen, from Hvidovre Hospital, and her associates in Denmark conducted a population-based cohort study among 19,714 subjects with up to 31 years of follow-up.
Subjects who reduced their tobacco consumption from 20 to 10 cigarettes per day experienced a 27% reduced risk for lung cancer compared with unchanged heavy smokers.
Among subjects who were light smokers throughout (average 9 cigarettes per day), the risk was reduced by 56% compared with heavy smokers, while those who quit reduced their risk by 50%. The risk among those who never smoked was 91% less than among heavy smokers.
Clearly, smoking cessation is the best method for decreasing harm from tobacco, Drs. Lawrence J. Dacey and David W. Johnstone, from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, point out in a related editorial.
"Nonetheless," they write, "because only a minority of smokers are able to quit smoking completely, it is important to inform them that the more they can reduce the number of cigarettes they smoke, the more they will decrease their risk of lung cancer."
In the second Journal report, Dr. Margaret R. Spitz and colleagues at the University of Texas M. D. Anderson Cancer Center in Houston conducted a case-control study of 1674 patients with lung cancer and 1735 matched healthy control subjects. Food frequency questionnaires were used to assess intake of several classes of phytoestrogens.
Patients with lung cancer tended to consume lower amounts of phytoestrogens than controls (median 265.1 versus 390.3 mg/day, p < 0.001). Men appear to benefit more phytoestrogen intake than did women, with p values of < 0.001 and of 0.06, respectively. In women, only intake of phytoestrogens from food sources (excluding coffee and tea) significantly affected risk (p = 0.01).
For each individual class of phytoestrogens -- coumesterol, isoflavone and ligans -- and for phytosterols, men appeared to benefit significantly from increased intake (p = 0.004 to > 0.001). Although there were trends toward reduced risk in women, the associations did not reach statistical significance.
The protective effects of phytoestrogens were strongest for never smokers, although current smokers also appeared to benefit. Protective effects were not statistically significant in previous smokers.
"Patients should be informed that they may further reduce their risk of developing cancer by adopting a diet rich in fruits and vegetables," Dr. Dacey and Johnstone remark in their editorial.
JAMA 2005;294:1493-1510,1550-1551.