Cigarette smoking and the risk of mucinous and nonmucinous epithelial ovarian cancer

BACKGROUND: The association between cigarette smoking and ovarian cancer may vary according to the histologic type of tumor. METHODS: We examined cigarette smoking as a risk factor for both mucinous and nonmucinous tumors in a population-based case-control study comparing 767 incident cases of epithelial ovarian cancer with 1,367 community controls frequency matched to cases by age and race. RESULTS: Smoking was associated with mucinous tumors (odds ratio [OR] = 1.9; 95% confidence interval [CI] = 1.3-2.9) but not with nonmucinous tumors (OR = 1.1; CI = 0.9-1.3). Furthermore, the odds ratios for smokers with mucinous tumors increased with increasing pack-years of smoking (OR = 1.0, 1.9, and 2.7 for <5, 5-24, and > 24+ pack-years, respectively; P for trend = 0.01) CONCLUSIONS: Cigarette smoking appears to be a risk factor for mucinous but not for nonmucinous tumors.     

Smoking and risk of incident psoriasis among women and men in the United States: a combined analysis

The authors evaluated the association between smoking and the incidence of psoriasis among 185,836 participants from a cohort of older women (the Nurses' Health Study, 1996-2008), a cohort of younger women (the Nurses' Health Study II, 1991-2005), and a cohort of men (Health Professionals' Follow-up Study, 1986-2006). Information on smoking was collected biennially during follow-up. The authors identified a total of 2,410 participants with incident psoriasis. Compared with never smokers, past smokers had a relative risk of incident psoriasis of 1.39 (95% confidence interval (CI): 1.27, 1.52) and current smokers had a relative risk of 1.94 (95% CI: 1.64, 2.28). For current smokers who smoked 1-14 cigarettes/day, the relative risk was 1.81 (95% CI: 1.38, 2.36); for those who smoked 15-24 cigarettes/day, the relative risk was 2.04 (95% CI: 1.68, 2.47); and for those who smoked 25 or more cigarettes/day, the relative risk was 2.29 (95% CI: 1.74, 3.01). There was a trend toward an increased risk of psoriasis with increasing pack-years or duration of smoking (P(trend) < 0.0001). The risk was highest among smokers who had 65 or more pack-years of smoking (relative risk = 2.72, 95% CI: 2.05, 3.60) and among those with a smoking duration of 30 or more years (relative risk = 1.99, 95% CI: 1.75, 2.25). The authors observed a graded reduction of risk with an increase in time since smoking cessation (P(trend) <0.0001). In this study, smoking was found to be an independent risk factor for psoriasis in both women and men. Psoriasis risk was particularly augmented for heavy smokers and persons with longer durations of smoking.     

Cigarette smoking and breast cancer.

An epidemiological case-control study was conducted in New York State, with 1617 primary breast cancer patients and an equal number of controls, to examine the relationship between cigarette smoking and breast cancer. Results showed no overall association between ever smokers versus never smokers and breast cancer risk (odds ratio [OR] = 1.03, 95% confidence interval [CI]: 0.90-1.19), nor was there any dose response trend observed with increased levels of smoking. In addition, no association was found with risk and age started smoking, age stopped smoking, amount smoked or total years smoked. Controlling for previously identified risk factors for breast cancer in the analysis did not significantly alter these relationships. Previous studies have found a difference in menopausal age among smokers compared to nonsmokers. The mean menopausal age was only slightly lower in smokers than in never smokers for both cases and controls. Breast cancer risk was observed to be close to unity for premenopausal women (OR = 0.97, 95% CI: 0.74-1.34) and postmenopausal women (OR = 1.06, 95% CI: 0.91-1.26). A recent study suggested breast cancer risk was more strongly related to starting smoking at a young age among women who smoked at least 25 or more cigarettes per day in the most recent year of smoking. This hypothesis was not supported by these data.     

Cigarette smoking and glycaemia: the EPIC-Norfolk Study. European Prospective Investigation into Cancer.

BACKGROUND: Previous prospective studies have suggested that cigarette smoking may be associated with an increased risk of type 2 diabetes, but the possibility of confounding, particularly by dietary factors has not been fully examined. METHODS: Cross-sectional analysis of the association between cigarette smoking and HbA(1C), a marker of long-term glucose homeostasis in 2704 men and 3385 women, aged 45--74 years who were recruited to a population-based study of diet and chronic disease. RESULTS: Twelve per cent of men and 11% of women reported being current smokers. Mean HbA(1C) was lowest in never smokers, intermediate in former smokers and highest in current smokers. There was a dose-response relationship between HbA(1C) levels and number of cigarettes smoked per day and a positive association with total smoking exposure as measured by pack-years. The unadjusted increase in HbA(1C) for 20 pack-years of smoking was 0.12% (95% CI : 0.09--0.16) in men and 0.12% (95% CI : 0.08--0.17) in women. After adjustment for possible confounders including dietary variables, the values were 0.08% (95% CI : 0.04--0.12) and 0.07% (95% CI : 0.02--0.12) for men and women, respectively. Mean HbA(1C) was inversely related to time since quitting smoking in men. CONCLUSIONS: These results add support to the hypothesis that smoking has long-term effects on glucose homeostasis, an association that cannot be explained by confounding by dietary factors as measured in this study.     

Cigarette smoking and the risk of breast cancer

The authors examined the relation between cigarette smoking and breast cancer in the Centers for Disease Control Cancer and Steroid Hormone Study, a multicenter, population-based case-control study. The study compared 4,720 women aged 20-54 years with newly diagnosed breast cancer identified through population-based tumor registries with 4,682 women randomly selected from the same geographic areas. Women who reported ever smoking cigarettes had a risk of breast cancer of 1.2 (95 percent confidence interval 1.1-1.3) compared with never smokers. There was no consistent dose-response pattern with any measure of smoking (pack-years of smoking, average number of cigarettes per day, or total years smoked) and little difference in risk between current and former smokers. There was some variation in risk by age, with slightly higher risk estimates for younger women than for older women. Although current smokers had an earlier natural menopause than did never smokers, the authors found no evidence of a protective effect of cigarette smoking on breast cancer risk. These findings suggest that the risk of breast cancer in women who smoke is the same as, or perhaps slightly higher than, women who have never smoked.     

Cigarette smoking and incidence of multiple sclerosis.

Experimental data suggest that cigarette smoking may play a role in the development of multiple sclerosis (MS), but epidemiologic studies have been small and inconclusive. The authors assessed the association between MS incidence and smoking in two cohort studies of US women, the Nurses' Health Study (121,700 women aged 30-55 years at baseline in 1976) and the Nurses' Health Study II (116,671 women aged 25-42 years at baseline in 1989). Smoking history was assessed at baseline and updated on biennial questionnaires. A total of 315 definite or probable cases of MS were documented. Compared with that for women who never smoked, the relative incidence rate was 1.6 (95% confidence interval: 1.2, 2.1) among current smokers and 1.2 (95% confidence interval: 0.9, 1.6) among past smokers after adjustment for age, latitude, and ancestry. The relative rate increased significantly with cumulative exposure to smoking (p for trend < 0.05), from 1.1 (95% confidence interval: 0.8, 1.6) for 1-9 pack-years to 1.5 (95% confidence interval: 1.2, 2.1) for 10-24 pack-years and 1.7 (95% confidence interval: 1.2, 2.4) for 25 or more pack-years. Similar results were obtained after adjustment for other potential confounding factors. Although these prospective results do not prove a cause-and-effect relation, they suggest that smoking is associated with an increased risk of MS.     

Parkinson's disease risks associated with cigarette smoking, alcohol consumption, and caffeine intake

A reduced risk for Parkinson's disease (PD) among cigarette smokers has been observed consistently during the past 30 years. Recent evidence suggests that caffeine may also be protective. Findings are presented regarding associations of PD with smoking, caffeine intake, and alcohol consumption from a case-control study conducted in western Washington State in 1992-2000. Incident PD cases (n = 210) and controls (n = 347), frequency matched on gender and age were identified from enrollees of the Group Health Cooperative health maintenance organization. Exposure data were obtained by in-person questionnaires. Ever having smoked cigarettes was associated with a reduced risk of PD (odds ratio (OR) = 0.5, 95% confidence interval (CI): 0.4, 0.8). A stronger relation was found among current smokers (OR = 0.3, 95% CI: 0.1, 0.7) than among ex-smokers (OR = 0.6, 95% CI: 0.4, 0.9), and there was an inverse gradient with pack-years smoked (trend p < 0.001). No associations were detected for coffee consumption or total caffeine intake or for alcohol consumption. However, reduced risks were observed for consumption of 2 cups/day or more of tea (OR = 0.4, 95% CI: 0.2, 0.9) and two or more cola drinks/day (OR = 0.6, 95% CI: 0.3, 1.4). The associations for tea and cola drinks were not confounded by smoking or coffee consumption.     

Associations of cigarette smoking and alcohol consumption with advanced or multiple colorectal adenoma risks: a colonoscopy-based case-control study in Korea

The associations between alcohol consumption and cigarette smoking habits and the risk for colorectal adenomatous polyps according to the detailed clinical information about polyps were assessed in a large colonoscopy-based study. The study enrolled participants who visited the National Cancer Center of the Republic of Korea for cancer screening between April 2007 and April 2009. In 1,242 newly diagnosed colorectal adenoma patients and 3,019 polyp-free controls, past smokers (odds ratio (OR) = 1.31, 95% confidence interval (CI): 1.04, 1.65) and current smokers (OR = 1.70, 95% CI: 1.37, 2.11) had increased risks for adenomas compared with nonsmokers. Cigarette smoking conferred an even higher risk for advanced adenomas and 3 or more adenomas than for low-risk adenomas or a single adenoma. Dose-response relations were observed among the daily number of cigarettes smoked, the duration of smoking, the pack-years of smoking, and the risk for adenomas. A longer duration of alcohol consumption was associated with a higher risk for advanced adenomas (for >28 years of consumption: OR = 2.0, 95% CI: 1.10, 3.64) and 3 or more adenomas (OR = 2.19, 95% CI: 1.27, 3.76). In conclusion, cigarette smoking and alcohol consumption play roles in colorectal carcinogenesis, and the association differs by the clinical features of the adenomas.     

Some life-style factors and the risk of invasive epithelial ovarian cancer in Swedish women

The objective of this nationwide case-control study was to examine body mass index (BMI), alcohol use, coffee consumption, cigarette smoking, and leisure-time physical activity in relation to epithelial ovarian cancer (EOC) risk. Subjects were 655 newly diagnosed EOC cases and 3899 population controls, all 50-74 years of age at recruitment between 1993 and 1995. Data were collected through mailed questionnaires. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Women with a BMI 30 kg/m² compared with those with a BMI < 22 kg/m² appeared to have an elevated EOC risk (OR = 1.37, 95% CI: 1.01-1.85), particularly of mucinous (OR = 2.76, 95% CI: 1.15-6.61) and clear-cell histologies (OR = 2.68, 95% CI: 0.96-7.48). The OR for EOC among coffee users reporting 6 daily cups compared with non-users was 0.68 (95% CI: 0.42-1.10). Alcohol consumption was unrelated to EOC risk. Compared to non-smokers the ORs of EOC among current smokers were 0.70 (95% CI: 0.52-0.94) for those who smoked 1-10 cigarettes/day and 0.74 (95% CI: 0.53-1.02) for heavier smokers, while former smokers were at an unaltered risk (OR = 0.83, 95% CI: 0.66-1.04). Reduced EOC risks were observed among women in the highest compared with the lowest physical activity levels both at age 18-30 years (OR = 0.67, 95% CI: 0.52-0.87) and during the last years preceding study enrollment (OR = 0.68, 95% CI: 0.53-0.87). We conclude that women may avoid an excess risk of EOC through maintaining a normal BMI and reduce their risk by participation in leisure-time physical activity. The use of coffee, alcohol, or cigarette smoking does not appearto increase the risk of EOC.     

Smoking cessation and risk of cataract extraction among US women and men.

Although the observational evidence linking cigarette smoking with risk of senile cataract is well-established, it is unclear whether any benefit is obtained from quitting smoking. Therefore, in this study, the authors examined the association between time since quitting smoking and incidence of cataract extraction in women and men enrolled in the Nurses' Health Study and the Health Professionals Follow-up Study, respectively. There were 4,281 incident physician-confirmed cases of cataract and 1,038,493 accumulated person-years of follow-up. Compared with current smokers, former smokers who had quit smoking 25 or more years previously had a 20% lower risk of cataract extraction after adjustment for age, average number of cigarettes smoked per day, and other potential risk factors (relative risk (RR) = 0.80, 95% confidence interval (CI): 0.71, 0.91). However, risk among past smokers did not decrease to the level seen among never smokers (for never smokers, RR = 0.64, 95% CI: 0.52, 0.79). The observed relation was similar when data were examined by cataract subtype (>25 years since quitting vs. current smoking: primarily nuclear cataract, RR = 0.82, 95% CI: 0.68, 0.97; primarily posterior subcapsular cataract, RR = 0.90, 95% CI: 0.71, 1.13). These findings suggest that any healing from damage due to cigarette smoking occurs at a very modest pace, and they emphasize the importance of never starting to smoke or quitting early in life.     

Mentholated cigarette smoking and lung-cancer risk

PURPOSE: Menthol smoking may lead to a greater increase in lung-cancer risk than smoking of nonmentholated cigarettes. Mentholation of cigarettes adds additional carcinogenic components to cigarette smoke and increases retention times for cigarette smoke in the lungs. Only two epidemiologic studies have been conducted on menthol smoking and lung cancer, and their results are conflicting. Of note, African American males have much higher rates of lung cancer than Caucasian males despite smoking fewer cigarettes per day. Because the consumption of menthol cigarettes is much more frequent among African Americans, it is of interest to examine the possible association between menthol smoking and lung-cancer risk in this population. METHODS: We examined the association between menthol cigarette smoking and lung-cancer risk among smokers by comparing 337 incident cases of lung cancer with 478 population controls enrolled in a case-control study of lung cancer. Information on smoking history and other known and potential risk factors for lung cancer, including dietary intake, was obtained by in-person interviews. RESULTS: The adjusted odds ratios did not differ appreciably between smokers of mentholated cigarettes versus exclusive nonmentholated cigarette smokers in the overall study group of smokers. The odds ratio (OR) for 32 pack-years or more of mentholated vs. nonmentholated cigarettes was 0.90 (95% confidence interval (CI) = 0.38-2.12) in African Americans and 1.06 (95% CI = 0.47-2.36) in Caucasians, and did not differ for either ethnic group (p = 0.98). CONCLUSIONS: Our results suggest that the lung-cancer risk from smoking mentholated cigarettes resembles the risk from smoking non-mentholated cigarettes. Our data do not support the hypothesis that the increased risk of lung cancer among African Americans is due to the increased prevalence of menthol smoking.     

Breast cancer and cigarette smoking: a hypothesis

In many studies, cigarette smoking has been associated with a small increase in breast cancer risk. The authors evaluated the relation of smoking to breast cancer risk in two case-control studies carried out from 1982 through 1986. In Canada, 607 women with breast cancer and 1,214 controls matched on decade of age and neighborhood were interviewed at home. In the United States, 1,955 cases of breast cancer and 805 controls with other cancers were interviewed in the hospital. In both studies, breast cancer risk was associated weakly with cigarette smoking overall. The odds ratio for women who had smoked 25 or more cigarettes per day as compared with never smokers was 1.2 (95% confidence interval (CI) 0.9-1.6) in the Canadian study and 1.2 (95% Cl 0.9-1.6) in the US study. In both studies, breast cancer risk was more strongly related to commencement of smoking at a young age. Among women who smoked at least 25 cigarettes per day in the most recent year of smoking, the odds ratios for commencement before age 16 years were 1.7 (95% Cl 1.0-2.9) in the Canadian data and 1.8 (95% Cl 1.0-3.4) in the US data, and the odds ratios for commencement at even younger ages were higher. The associations were not explained by duration of smoking, by the time elapsed since commencement, or by factors associated with cigarette smoking such as alcohol consumption or oral contraceptive use. Our findings raise the hypothesis that exposure to cigarette smoke during adolescence may increase a woman's risk of breast cancer. The hypothesis has biologic plausibility: cigarette smoke contains known carcinogens, and the developing breast is especially susceptible to cancer initiation.     

Cigarette smoking and erectile dysfunction among Chinese men without clinical vascular disease

The authors examined the association between cigarette smoking and risk of erectile dysfunction among 7,684 Chinese men aged 35-74 years without clinical vascular disease. Cigarette smoking and erectile dysfunction were assessed by questionnaire. Vascular risk factors were measured according to standard methods. After adjustment for age, education, alcohol consumption, physical inactivity, diabetes, hypertension, overweight, and hypercholesterolemia, the odds ratio of erectile dysfunction was 1.41 (95% confidence interval (CI): 1.09, 1.81) for cigarette smokers compared with never smokers. There was a statistically significant dose-response relation between cigarette smoking and risk of erectile dysfunction (p(trend) = 0.005). Multivariate-adjusted odds ratios of erectile dysfunction were 1.27 (95% CI: 0.91, 1.77), 1.45 (95% CI: 1.08, 1.95), and 1.65 (95% CI: 1.08, 2.50) for those who smoked 1-10, 11-20, and more than 20 cigarettes per day, respectively, compared with never smokers. The association was stronger in participants with diabetes (odds ratio = 3.29, 95% CI: 1.49, 7.27) than in participants without diabetes (odds ratio = 1.33, 95% CI: 1.03, 1.73). If the association is causal, an estimated 22.7% of erectile dysfunction cases (11.8 million cases) among Chinese men are attributable to cigarette smoking. This 2000-2001 study of Chinese men documented an independent and dose-response relation between cigarette smoking and risk of erectile dysfunction.     

Smoking cessation and lung cancer mortality in a cohort of middle-aged Canadian women

PURPOSE: To determine the impact of smoking cessation on lung cancer mortality among women. METHODS: Survival analysis is used to assess the effect of smoking cessation on lung cancer death in the dietary cohort of 49,165 women aged 40 to 59 years enrolled in the Canadian National Breast Screening Study. RESULTS: During an average of 10.3 years of follow-up, 106 women died of lung cancer. The risk of lung cancer mortality among women who quit before age 50 (HR=0.26; 95% CI, 0.13-0.55 among women who quit at ages 40-49) or quit in the previous 10 years (HR=0.39; 95% CI, 0.22-0.69) is substantially lower than the risk among current smokers. Women who quit after age 40 or have quit for less than 20 years are at substantially higher risk of lung cancer mortality compared with never smokers. Both duration of smoking cessation and age at quitting have independent effects on lung cancer mortality, after controlling for number of cigarettes smoked per day and number of years smoked, as well as other potential confounding variables. CONCLUSION: These findings suggest that programs and policies to promote early cessation of smoking and prevention of relapse should be a public health priority.     

Correlates of smoking in pregnant women in six Brazilian cities

OBJECTIVE: To evaluate sociodemographic and lifestyle correlates of smoking in pregnant women sampled from hospitals. METHODS: A cross-sectional study was conducted in 5,539 pregnant women aged 20 or more who sought medical attention in prenatal clinics of affiliate hospitals of the Brazilian National Health System in the cities of Manaus, Fortaleza, Salvador, Rio de Janeiro, S?o Paulo, and Porto Alegre from 1991 to 1995. Interviews were conducted using a standardized questionnaire that covered sociodemographics and smoking habits before and during pregnancy. Current smoking was defined as smoking at least one cigarette/day, former smoking as reporting having smoked at least one cigarette/day but having quit, and never smoking as never having smoked one cigarette/day. RESULTS: Smoking during pregnancy was associated with lower education (OR=2.13; CI 95%: 1.76-2.57) and greater parity (OR=1.84; CI 95%: 1.53-2.21). Positive associations were also found with increased gestational age and alcohol consumption. No significant association was found with skin color or occupation status. A protective effect was observed for women married or living with a partner (OR=0.55 CI 95%: 0.42-0.72). Having Manaus' women as a reference, Porto Alegre's women showed the greatest risk for smoking in pregnancy (OR=5.00; CI 95%: 3.35-7.38), followed by S?o Paulo's (OR=3.42; CI 95%: 2.25-5.20), Rio de Janeiro (OR=2.53; CI 95%: 1.65-3.88) and Fortaleza's (OR=2.56; CI 95%: 1.74-3.78). CONCLUSIONS: The study findings are similar to those described in the literature regarding education, parity, and marital status. However, no association with skin color was seen in the multivariate analysis. Former smokers had sociodemographic characteristics more similar to non-smokers than former smokers.     

Maternal Exposures to Cigarette Smoke,Alcohol, and Street Drugs and Neural Tube Defect Occurrence in Offspring

Objectives Cigarettes, alcoholic beverages, and street drugs contain substances potentially toxic to the developing embryo. We investigated whether maternal cigarette smoking, secondhand smoke exposure, and alcohol or street drug use contributed to neural tube defect (NTD) occurrence in offspring. Methods We conducted a population-based case-control study among Mexican American women who were residents of the 14 Texas counties bordering Mexico. Case women had an NTD-affected pregnancy and delivered during 1995–2000. Control women were those who delivered live born infants in the same study area, without an apparent congenital malformation, randomly selected by year and facility. We interviewed women in person, 1–3 months postpartum, to solicit relevant information. Results Nonsmoking mothers exposed to secondhand smoke during the first trimester had an NTD odds ratio (OR) of 2.6 (95% confidence interval (CI) = 1.6, 4.0) compared to those who neither smoked nor were exposed to secondhand smoke. Compared to the referent, the OR among women who smoked less than half a pack a day during the first trimester was 2.2 (95% CI = 1.0, 4.8) and 3.4 (95% CI = 1.2, 10.0) among those who smoked a half pack or more. Adjustment for maternal age, education, body mass index, and folate intake had a negligible effect on results. Alcohol and street drug use had no relation to NTD risk when adjusted for cigarette smoking. Conclusions This study suggests that cigarette smoke including secondhand exposure is not only hazardous to the mother but may also interfere with neural tube closure in the developing embryo.     

Smoking and lung cancer: risk as a function of cigarette tar content

The hypothesis of reduction in lung cancer risk associated with the adoption of low-tar cigarettes was examined in a subset of subjects from a population-based, case-control study of incident primary lung cancer among New Jersey white men. Risk was related to time-weighted average tar levels of cigarettes smoked in 1973-1980. Unadjusted estimates of risk were significantly low for the lowest tar (less than 14 mg/cig) smokers [odds ratio = 0.53 (0.29,0.97)] compared with the highest (21.1-28 mg/cig). However, adjustment by age and total pack-years rendered the risk reduction insignificant. Of note was the finding that cases who smoked low-tar cigarettes compensated for reducing tar by increasing the number of cigarettes they smoked by almost half a pack per day from the years 1963-1972 to 1973-1980, while in the same period controls and high-tar cigarette smoking cases did not increase the numbers smoked.     

Smoking and subsequent human papillomavirus infection: a mediation analysis

PurposeSmoking is an established risk factor for a human papillomavirus (HPV) infection advancing to cervical precancer and cancer, but its role earlier in the natural history is less clear. Smoking is inversely associated with possessing HPV antibodies from a past infection suggesting that smoking may influence acquiring subsequent infections.MethodsIn a cohort of 1976 U.S. women, we evaluate whether reduced antibodies to HPV-16 is a mechanism for smoking's role on acquiring a subsequent HPV-16 infection, through the analytic technique of causal mediation analysis. We posit a causal model and estimate two counterfactually defined effects: a smoking impaired antibody-mediated indirect effect and a nonmediated direct effect representing all other potential mechanisms of smoking.ResultsCompared to never smokers, current smokers had increased odds of HPV-16 infection by the antibody-mediated indirect effect (odds ratio [OR] = 1.29; 95% confidence interval [CI]: 1.11, 1.73); the estimated direct effect was very imprecise (OR = 0.57; 95% CI, 0.26–1.13). We observed a stronger estimated indirect effect among women who smoked at least half a pack of cigarettes daily (OR = 1.61, 95% CI, 1.27–2.15) than among women who smoked less than that threshold (OR = 1.09; 95% CI, 0.94–1.44).ConclusionsThis is the first study to directly test the mechanism underlying smoking as an HPV cofactor. The results support current smoking as a risk factor earlier in the natural history of HPV and are consistent with the hypothesis that smoking increases the risk of a subsequent infection by reducing immunity.     

Cigarette smoking and completed suicide among middle-aged men: a population-based cohort study in Japan

PURPOSE: To clarify whether cigarette smoking was associated with completed suicide in a cohort of middle-aged Japanese men. METHODS: A total of 45,209 out of 57,714 men, aged 40 to 69 years, in nine public health centers across Japan responded to a self-administered questionnaire that included questions regarding their smoking history. The questionnaire was distributed in 1990 (Cohort I) and in 1993 and 1994 (Cohort II). By the end of 2000, 173 suicides were identified by death certificates. RESULTS: After adjusting for potential confounders, current smokers had a marginally higher risk of suicide than never smokers. Current smokers with more than 60 pack-years of cigarette smoking had a more than two-fold higher risk of suicide than never smokers (pooled multivariate relative risk=2.1; 95% confidence interval, 1.1, 4.0), but a significant dose-response relationship between pack-years of smoking and suicide was not found. The risk of suicide increased significantly with increasing numbers of cigarettes smoked per day (p for trend=0.036). Smoking status, duration of quitting, duration of smoking, and age at the start of smoking were not significantly associated with suicide risk. CONCLUSION: Our results suggest that heavy smoking, particularly a large number of cigarettes per day at baseline was associated with an increased risk of suicide independent of several potential confounders.     

Cigarette smoking and risk of breast carcinoma in situ

BACKGROUND: Although the associations with cigarette smoking have been explored extensively for invasive breast cancer, the relation to in situ cancer has not previously been examined in depth. METHODS: We analyzed data from a population-based case-control study of women living in Wisconsin, Massachusetts, and New Hampshire. Eligible cases of incident breast carcinoma in situ were reported to statewide registries in 1997-2001 (n = 1878); similarly aged controls (n = 8041) were randomly selected from population lists. Smoking history and other risk factor information were collected through structured telephone interviews. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated from logistic regression models adjusting for potential confounders. RESULTS: In multivariate models, the OR for breast carcinoma in situ among current smokers was 0.8, compared with never-smokers (95% CI = 0.7-1.0). Risk estimates increased towards the null with greater time since smoking cessation. Odds ratios were also less than 1.0 among women who initiated smoking in adolescence (OR = 0.8) or after a full-term birth (OR = 0.7), relative to women who never smoked. The reduced odds ratios associated with current smoking were strongest among women with annual screening mammograms (OR = 0.7; 95% CI = 0.6-0.9). Odds ratios were not less than 1.0 among current smokers without a recent screening mammogram (1.3; 0.9-2.0). CONCLUSIONS: Our findings suggest an inverse association between current smoking and risk of breast carcinoma in situ among women undergoing breast cancer screening.