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Objective: To characterize further the relationship between smoking history and Parkinson disease (PD) risk by considering temporal and qualitative features of smoking exposure, including duration, average intensity, and recentness, as well as the relative importance of smoking during different periods of life., Methods: We prospectively assessed incident PD from 1992 to 2001 among 79,977 women and 63,348 men participating in the Cancer Prevention Study II Nutrition Cohort, according to their cigarette smoking status and lifetime smoking histories., Results: During follow-up, 413 participants had definite or probable PD confirmed by their treating neurologists or medical record review. Compared with never smokers, former smokers had a relative risk (RR) of 0.78 (95% CI 0.64 to 0.95) and current smokers had an RR of 0.27 (95% CI 0.13 to 0.56). On average, participants with more years smoked, more cigarettes per day, older age at quitting smoking, and fewer years since quitting smoking had lower PD risk. The relative risks and trends did not vary significantly by sex. The cumulative incidence of PD was lowest among participants who quit smoking at later ages. A 30% to 60% decreased risk of PD was apparent for smoking as early as 15 to 24 years before symptom onset, but not for smoking 25 or more years before onset., Conclusions: The lower risk of Parkinson disease among current and former smokers varied with smoking duration, intensity, and recentness. The dependence of this association on the timing of smoking during life is consistent with a biologic effect.

Cigarette smoking has been proposed as a risk factor for amyotrophic lateral sclerosis (ALS), but because of the low incidence of ALS this association has been examined only with case-control methods. The authors prospectively assessed the relation between cigarette smoking and ALS mortality among participants in the Cancer Prevention Study II cohort of the American Cancer Society, a cohort of over 1 million people enrolled in 1982 who completed a lifestyle questionnaire including a detailed smoking history at baseline. Causes of deaths were ascertained through death certificates; ALS was not identified separately until 1989. From January 1, 1989, through 1998, 291 women and 330 men died from ALS. The relative risk of ALS among current smokers compared with never smokers was 1.67 (95% confidence interval: 1.24, 2.24; p = 0.002) in women and 0.69 (95% confidence interval: 0.49, 0.99; p = 0.04) in men. The difference in the relative risk estimates between the sexes was statistically significant (p < 0.0003). This large prospective study provides limited evidence that current cigarette smoking may be associated with increased death rates from ALS in women but not in men., (Copyright 2004 Johns Hopkins Bloomberg School of Public Health)

Alcohol and tobacco consumption are closely correlated and published results on their association with breast cancer have not always allowed adequately for confounding between these exposures. Over 80% of the relevant information worldwide on alcohol and tobacco consumption and breast cancer were collated, checked and analysed centrally. Analyses included 58,515 women with invasive breast cancer and 95,067 controls from 53 studies. Relative risks of breast cancer were estimated, after stratifying by study, age, parity and, where appropriate, women's age when their first child was born and consumption of alcohol and tobacco. The average consumption of alcohol reported by controls from developed countries was 6.0 g per day, i.e. about half a unit/drink of alcohol per day, and was greater in ever-smokers than never-smokers, (8.4 g per day and 5.0 g per day, respectively). Compared with women who reported drinking no alcohol, the relative risk of breast cancer was 1.32 (1.19-1.45, P<0.00001) for an intake of 35-44 g per day alcohol, and 1.46 (1.33-1.61, P<0.00001) for >/=45 g per day alcohol. The relative risk of breast cancer increased by 7.1% (95% CI 5.5-8.7%; P<0.00001) for each additional 10 g per day intake of alcohol, i.e. for each extra unit or drink of alcohol consumed on a daily basis. This increase was the same in ever-smokers and never-smokers (7.1% per 10 g per day, P<0.00001, in each group). By contrast, the relationship between smoking and breast cancer was substantially confounded by the effect of alcohol. When analyses were restricted to 22 255 women with breast cancer and 40 832 controls who reported drinking no alcohol, smoking was not associated with breast cancer (compared to never-smokers, relative risk for ever-smokers=1.03, 95% CI 0.98-1.07, and for current smokers=0.99, 0.92-1.05). The results for alcohol and for tobacco did not vary substantially across studies, study designs, or according to 15 personal characteristics of the women; nor were the findings materially confounded by any of these factors. If the observed relationship for alcohol is causal, these results suggest that about 4% of the breast cancers in developed countries are attributable to alcohol. In developing countries, where alcohol consumption among controls averaged only 0.4 g per day, alcohol would have a negligible effect on the incidence of breast cancer. In conclusion, smoking has little or no independent effect on the risk of developing breast cancer; the effect of alcohol on breast cancer needs to be interpreted in the context of its beneficial effects, in moderation, on cardiovascular disease and its harmful effects on cirrhosis and cancers of the mouth, larynx, oesophagus and liver.

Objective: Only a few prospective studies have examined the relationship between the frequency of cigarette smoking and the incidence of diabetes mellitus. The purpose of this study was to determine whether greater frequency of cigarette smoking accelerated the development of diabetes mellitus, and whether quitting reversed the effect., Methods: Data were collected in the Cancer Prevention Study I, a prospective cohort study conducted from 1959 through 1972 by the American Cancer Society where volunteers recruited more than one million acquaintances in 25 US states. From these over one million original participants, 275,190 men and 434,637 women aged > or = 30 years were selected for the primary analysis using predetermined criteria., Results: As smoking increased, the rate of diabetes increased for both men and women. Among those who smoked > or = 2 packs per day at baseline, men had a 45% higher diabetes rate than men who had never smoked; the comparable increase for women was 74%. Quitting smoking reduced the rate of diabetes to that of non-smokers after 5 years in women and after 10 years in men., Conclusions: A dose-response relationship seems likely between smoking and incidence of diabetes. Smokers who quit may derive substantial benefit from doing so. Confirmation of these observations is needed through additional epidemiological and biological research.

Background: Recent studies suggest that long-term cigarette smoking is associated with an increased risk of colorectal cancer. Whether the association is causal or due to confounding remains unclear., Methods: We examined cigarette smoking in relation to colorectal cancer mortality, evaluating smoking duration and recency and controlling for potential confounders in the Cancer Prevention Study II. This prospective nationwide mortality study of 1 184 657 adults (age > or =30 years) was begun by the American Cancer Society in 1982. After exclusions, our analytic cohort included 312 332 men and 469 019 women, among whom 4432 colon or rectal cancer deaths occurred between 1982 and 1996 among individuals who were cancer free in 1982. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated by fitting Cox proportional hazards models. All statistical tests were two-sided., Results: Multivariate-adjusted colorectal cancer mortality rates were highest among current smokers, were intermediate among former smokers, and were lowest in lifelong nonsmokers. The multivariate-adjusted RR (95% CI) for current compared with never smokers was 1.32 (1.16-1.49) among men and 1.41 (1.26-1.58) among women. Increased risk was evident after 20 or more years of smoking for men and women combined as compared with never smokers. Risk among current and former smokers increased with duration of smoking and average number of cigarettes smoked per day; risk in former smokers decreased significantly with years since quitting. If the multivariate-adjusted RR estimates in this study do, in fact, reflect causality, then approximately 12% of colorectal cancer deaths among both men and women in the general U.S. population in 1997 were attributable to smoking., Conclusions: Long-term cigarette smoking is associated with increased risk of colorectal cancer mortality in both men and women. Clear reduction in risk is observed with early smoking cessation.

Objectives: Cigarette smoking is considered an important risk factor for pancreatic cancer, but other purported risk factors are less well established. To learn more about the epidemiology of this important cause of mortality we examined associations with a variety of possible risk factors for death from pancreatic cancer in a large, prospective study of United States adults., Methods: We used proportional hazards models to obtain adjusted estimates of relative risks (hazards ratios). During 14 years of follow-up, 3751 persons died of pancreatic cancer in a cohort of 483,109 men and 619,199 women who had no reported history of cancer at enrollment in 1982., Results: Cigarette smoking at baseline was associated with fatal pancreatic cancer among men (multivariate relative risk [RR] = 2.1, 95% confidence interval [CI] 1.9-2.4) and among women (RR = 2.0, 95% CI 1.8-2.3). A trend in risk was observed with increasing number of cigarettes smoked per day among current smokers at baseline. With several variables included in separate models for men and women, we found additional factors to be predictive of pancreatic cancer mortality, including family history of pancreatic cancer, black race, diabetes, and increased body mass index. History of gallstones was predictive of pancreatic cancer among men. An inverse association with vegetable consumption was observed among men, that was not statistically significant., Conclusion: Our findings confirm that cigarette smoking is an important predictor of pancreatic cancer mortality, and identify several other factors that may contribute to increased risk.

Background: Adenocarcinoma of the lung, once considered minimally related to cigarette smoking, has become the most common type of lung cancer in the United States. The increased incidence of this cancer might be explained by advances in diagnostic technology (i.e., increased ability to perform biopsies on tumors in smaller, more distal airways), changes in cigarette design (e.g., the adoption of filtertips), or changes in smoking practices. We examined data from the Connecticut Tumor Registry and two American Cancer Society studies to explore these possibilities., Methods: Connecticut Tumor Registry data from 1959 through 1991 were analyzed to determine whether the increase in lung adenocarcinoma observed during that period could be best described by birth cohort effects (i.e., generational changes in cigarette smoking) or calendar period effects (i.e., diagnostic advances). Associations between cigarette smoking and death from specific types of lung cancer during the first 2 years of follow-up in Cancer Prevention Study I (CPS-I), initiated in 1959) and Cancer Prevention Study II (CPS-II, initiated in 1982) were also examined., Results: Adenocarcinoma incidence in Connecticut increased nearly 17-fold in women and nearly 10-fold in men from 1959 through 1991. The increases followed a clear birth cohort pattern, paralleling gender and generational changes in smoking more than diagnostic advances. Cigarette smoking became more strongly associated with death from lung adenocarcinoma in CPS-II compared with CPS-I, with relative risks of 19.0 (95% confidence interval [CI] = 8.3-47.7) for men and 8.1 (95% CI = 4.5-14.6) for women in CPS-II and 4.6 (95% CI = 1.7-12.6) for men and 1.5 (0.3-7.7) for women in CPS-I., Conclusions: The increase in lung adenocarcinoma since the 1950s is more consistent with changes in smoking behavior and cigarette design than with diagnostic advances.

The authors examined the relation between smoking and the risk of fatal prostate cancer in a large prospective mortality study of 450,279 men who were cancer free at enrollment in 1982. During 9 years of follow-up, 1,748 deaths occurred from prostate cancer. Cox proportional hazards modeling was used to adjust for other risk factors. Current cigarette smoking was associated with fatal prostate cancer (rate ratio = 1.34, 95% confidence interval (CI) 1.16-1.56). The rate ratio was greater at younger ages, decreasing from 1.83 (95% CI 1.04-3.24) among men below the age of 60 years to 1.11 (95% CI 0.79-1.58) among men aged 80 years and above (p for trend = 0.16). No trend in risk was observed with the number of cigarettes per day or with the duration of smoking among current smokers at baseline, and no increased risk was found among former smokers. Race did not significantly modify the association between cigarette smoking and fatal prostate cancer. These data, together with those of three other large prospective studies that find higher death rates from prostate cancer in current cigarette smokers, and inconsistent findings in incidence studies suggest that smoking may adversely affect survival in prostate cancer patients.

Objectives: This study was undertaken to examine changes in smoking-specific death rates from the 1960s to the 1980s., Methods: In two prospective studies, one from 1959 to 1965 and the other from 1982 to 1988, death rates from lung cancer, coronary heart disease, and other major smoking-related diseases were measured among more than 200,000 current smokers and 480,000 lifelong non-smokers in each study., Results: From the first to the second study, lung cancer death rates (per 100,000) among current cigarette smokers increased from 26 to 155 in women and from 187 to 341 in men; the increase persisted after current daily cigarette consumption and years of smoking were controlled for. Rates among nonsmokers were stable. In contrast, coronary heart disease and stroke death rates decreased by more than 50% in both smokers and nonsmokers. The all-cause rate difference between smokers and nonsmokers doubled for women but was stable for men., Conclusions: Premature mortality (the difference in all-cause death rates between smokers and nonsmokers) doubled in women and continued unabated in men from the 1960s to the 1980s. Lung cancer surpassed coronary heart disease as the largest single contributor to smoking-attributable death among White middle-class smokers.

The authors examined the association of fatal breast cancer and cigarette smoking in a large, prospective mortality study of US adults. After 6 years of follow-up, 880 cases of fatal breast cancer were observed in a cohort of 604,412 women who were cancer-free at interview in 1982. Cox proportional hazards modeling, adjusted for other risk factors, found that current smoking was significantly related to fatal breast cancer risk (adjusted rate ratio (RR) = 1.26, 95% confidence interval (CI) 1.05-1.50). A negative association was observed for former smokers, but this was not statistically significant (RR = 0.85, 95% CI 0.70-1.03). The association of current smoking with fatal breast cancer risk increased with increasing numbers of cigarettes per day and with total number of years smoked. For smokers of 40 or more cigarettes per day, the rate ratio was 1.74 (95% CI 1.15-2.62). The authors hypothesize that these results may be due to either a poorer prognosis among breast cancer cases who smoke or a delayed diagnosis among current smokers who do not receive mammograms as often as never or former smokers. Women who smoke should be targeted for breast cancer screening services.