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1.
In observational studies, estrogen replacement therapy is associated with decreased cardiovascular disease rates and increased breast cancer rates. Recent evidence suggests that the impact of estrogen use on disease outcomes may vary by body mass. In a prospective study of 290,827 postmenopausal US women with no history of cancer or cardiovascular disease at enrollment in 1982, the authors examined the association between postmenopausal estrogen use and all-cause, coronary heart disease, stroke, all-cancer, and breast cancer death rates and whether these associations differed by body mass. After 12 years of follow-up, results from Cox proportional hazards models showed that all-cause death rates were lower among baseline estrogen users than never users (rate ratio (RR) = 0.82, 95% confidence interval (CI): 0.78, 0.87). The lowest relative risk was found for coronary heart disease (RR = 0.66, 95% CI: 0.58, 0.77). The inverse association between estrogen use and coronary heart disease mortality was strongest for thin women (body mass index <22 kg/m2) (RR = 0.49, p for interaction = 0.02). Breast cancer mortality did not increase with estrogen use overall, and no increased risk was observed for thin or heavy women. In this population, the reduction in coronary heart disease mortality among estrogen users was greatest for thinner women. Additional studies are needed to confirm or refute these results.  相似文献   

2.
Two case-control studies of Canadian women aged 40-59 years are reported investigating the relation of cigarette smoking with initial visit (prevalent) and subsequent visit (incident) breast cancer detection, respectively, within the Canadian National Breast Screening Study. The analysis of prevalent breast cancer (1982-1985), which involved 254 cases and 762 controls, showed no evidence of an elevated risk for women with a history of cigarette smoking, with odds ratios of 0.9 (95% confidence interval (Cl) 0.6-1.5) and 1.2 (95% Cl 0.8-1.8) in premenopausal and postmenopausal subjects, respectively. Similarly, in the incident breast cancer analysis (1981-1987) based on 317 cases and 951 controls, women with a history of cigarette smoking had odds ratios of 1.2 (95% Cl 0.8-2.0) and 1.2 (95% Cl 0.9-1.7) in the premenopausal and postmenopausal categories, respectively. No evidence of dose response or of elevated risk in ex-smokers or current smokers was found in either study. These results persisted despite adjustment for several important variables. The present data demonstrate no association between smoking and prevalent or incident breast cancer in either menopausal category, contradicting the authors' previous finding of a positive association with premenopausal prevalent disease earlier in this screening study. The relation of smoking and breast cancer remains controversial. Further study is required to determine whether an association truly does not exist or whether smoking might have both protective and harmful effects that are mediated through different pathways, thus accounting for the paradoxical findings in the literature to date.  相似文献   

3.
PURPOSE: The association between active and passive cigarette smoking before breast cancer diagnosis and survival was investigated among a cohort of invasive breast cancer cases (n = 1273) participating in a population-based case-control study. METHODS: Participants diagnosed with a first primary breast cancer between August 1, 1996, and July 31, 1997, were followed-up until December 31, 2002, for all-cause mortality (n = 188 deaths), including breast cancer-specific mortality (n = 111), as reported to the National Death Index. RESULTS: In Cox models, the adjusted hazards ratios (HRs) for all-cause mortality were slightly higher among current and former active smokers, compared with never smokers (HR, 1.23; 95% confidence interval [95% CI], 0.83-1.84) and 1.19 (95% CI, 0.85-1.66), respectively). No association was found between active or passive smoking and breast cancer-specific mortality. All-cause and breast cancer-specific mortality was higher among active smokers who were postmenopausal (HR, 1.64; 95% CI, 1.03-2.60 and HR, 1.45; 95% CI, 0.78-2.70, respectively) or obese at diagnosis (HR, 2.10; 95% CI, 1.03-4.27 and HR, 1.97; 95% CI, 0.89-4.36, respectively). Associations between smoking and all-cause and breast cancer-specific mortality did not differ by cancer treatment. CONCLUSIONS: These data do not provide strong evidence for an association between smoking and all-cause or breast cancer-specific mortality, although smokers who are postmenopausal or obese at diagnosis may be at higher risk.  相似文献   

4.
Smoking habits and risk of benign breast disease   总被引:1,自引:0,他引:1  
The relationship between smoking habits and the risk of benign breast disease (BBD) was analyzed using data from a case-control study conducted between 1981 and 1983 in the greater Milan area, Northern Italy. Cases (n = 288) were women with histologically confirmed BBD (203 dysplasia, 85 benign tumours) referred to the National Cancer Institute of Milan for biopsies. Controls were women (n = 291) seen on selected days for a cytological smear for cervical cancer in outpatient clinics of the same Institute. No consistent association emerged between various indicators of smoking habits (smoking status, number of cigarettes smoked per day, duration of smoking) and the risk of BBD. Compared with never smokers the relative risk (RR) of all BBD combined was 0.7 (95% confidence interval, Cl: 0.4-1.3) in exsmokers, 1.4 (95% Cl: 0.8-2.5) in smokers of less than 10 cigarettes per day, and 1.1 (95% Cl: 0.7-1.7) in smokers of 10 or more cigarettes per day. There was some suggestion that the risk may be below unity post-menopause, but the relative risks for smokers were not statistically different in pre- (RR = 1.2; 95% Cl: 0.8-1.8) and post-menopausal (RR = 0.6; 95% Cl: 0.2-1.7) women. The risk of benign tumours (chiefly fibradenoma) was higher in current smokers, but this finding was not statistically significant (RR = 1.5; 95% Cl: 0.9-2.6) and the highest risks were observed in the strata of lighter smokers and those with shorter duration of smoking. Overall these results fail to support a negative association between smoking habits and benign breast disease.  相似文献   

5.
Recent studies have found that the risk of death continues to increase among female smokers, as compared with women who have never smoked. We wanted to examine the effect of smoking on all-cause and cause-specific mortality and calculate the corresponding population attributable fraction (PAF) of mortality in the Norwegian women and cancer study; a nationally representative prospective cohort study. We followed 85,320 women, aged 31–70 years, who completed a questionnaire in 1991–1997, through linkages to national registries through December 2008. Questionnaire data included information on lifestyle factors, including lifetime history of smoking. Poisson regression models were fitted to estimate relative risks (RRs) with 95 % confidence intervals (CIs) adjusting for age, birth cohort, education, postmenopausal status, alcohol consumption and body mass index, all at enrollment. During a mean follow-up time of 14 years 2,842 deaths occurred. Compared with that of never smokers, current smokers had a mortality rate that was double (RR = 2.34; 95 % CI 2.13–2.62) from deaths overall, triple (RR = 3.30; 95 % CI 2.21–4.82) from cerebrovascular disease and myocardial infarction (RR = 3.65; 95 % CI 2.18–6.15), 12 times (RR = 12.16; 95 % CI 7.80–19.00) from lung cancer and seventeen times (RR = 17.00; 95 % CI 5.90–48.78) from chronic obstructive pulmonary diseases. The PAF of mortality due to smoking was 34 % (CI 30–39). In summary, one in three deaths among middle aged women in Norway could have been prevented if the women did not smoke. More middle-aged women, than ever before, are dying prematurely due to smoking in Norway.  相似文献   

6.
As part of a prospective study begun in 1981, we evaluated 8,600 postmenopausal women and 5,049 men residing in a southern California retirement community for risk factors for hip fracture. Incidence rates were twice as high in women as in men, but in both sexes the rates nearly doubled every 5 years between 70 and 90 years. Active exercise was strongly and negatively associated with hip fracture risk in both sexes; the age-adjusted relative risk was 0.6 and 0.5 for females and males, respectively, for 1 or more hours of exercise per day compared with less than 1/2 hour of exercise. A high body mass index (upper tertile of weight divided by height squared) was associated with a strong reduction in hip fracture risk for females (RR = 0.5). Current cigarette smokers had a significantly increased risk (RR = 1.8 and RR = 2.2 for females and males, respectively) compared with never-smokers, but the risk for past smokers was not different from that of lifetime nonsmokers. Other factors related to reduced hip fracture risk in women were high parity, late age at menarche, and long menstrual cycle length. These age-adjusted relative risk estimates did not change materially in multivariate analysis when adjusted simultaneously for age, active exercise, body mass, smoking, and, for women, age at menarche and number of children. Among estrogen users, the lowest risk of hip fracture was observed for recent users (RR = 0.8), while users who had stopped estrogen use 15 or more years ago had a relative risk of 1.1, suggesting that the protective effect of estrogen dissipates after many years since cessation of estrogen therapy.  相似文献   

7.
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.  相似文献   

8.
Objectives To evaluate the impacts of health examinations (HE) and smoking on disease mortality risk in Japan. Methods By using the large cohort database of a Japanese life insurance company, 720,611 subjects aged 20 to 80 years, who had contracted for life insurance between April 1, 1995 and March 31, 1998, were followed up until September 30, 1999. Cox’s proportional hazard model was used to estimate age-adjusted relative risk (RR) for disease death. Results After adjusting for age, disease mortality in smokers was significantly higher than that in non-smokers (men, RR 1.51, 95% CI: 1.25–1.81; women, RR 1.54, 95% CI: 1.12–2.11). Meanwhile, disease mortality in HEees (those who had got HE within the past 2 years) was significantly lower than that in non-HEees (men, RR 0.70, 95% CI: 0.56–0.88; women, RR 0.71, 95% CI: 0.54–0.92). The magnitude of the impact of HE on disease mortality risk varied according to smoking status. Non-smokers showed a significantly lower risk associated with HE, whereas smokers did not. Conclusions HE may allow an appreciable reduction in disease mortality, however, the reduction effect may be limited to non-smokers. Smoking cessation may be essential to improve the preventive effects of HE.  相似文献   

9.
PURPOSE: To examine associations between elevated white blood cell count (WBC) and cerebrovascular disease (CeVD) mortality independent of cigarette smoking and by gender. METHODS: We used Cox regression analyses of data from 8459 adults (3982 men; 4477 women) aged 30 to 75 years in the NHANES II Mortality Study (1976-1992) to estimate the relative risk of death from CeVD across quartiles of WBC. RESULTS: During 17 years of follow-up, there were 192 deaths from CeVD (93 men; 99 women). Compared with those with WBC (cells/mm(3))<5700, adults with WBC>8200 were at increased risk of CeVD mortality (relative risk [RR], 2.1; 95% confidence interval [CI], 1.2-3.7) after adjustment for smoking and other cardiovascular disease risk factors. Similar results were observed among never smokers (RR, 2.0; 95% CI, 1.0-3.8). The adjusted relative risk of CeVD mortality comparing those with WBC>8200 to those with WBC<5700 was 1.5 (95% CI, 0.7-3.5) among men and 2.7 (95% CI, 1.4-5.0) among women. CONCLUSIONS: Elevated WBC may predict CeVD mortality even after considering the effects of smoking and other cardiovascular disease risk factors.  相似文献   

10.
目的 探讨军队老年男性不同吸烟状态与烟草相关死亡的关系.方法 选择队列设计,采用多元Cox比例风险模型计算RR值和95%CI.研究对象为西安市22个军队干休所的全部男性离休干部,共计1 268人.观察终点指标为全死因和烟草相关死亡.结果 截止2005年6月30日,共观察18 766.28人·a,平均随访14.80人·a.死亡491人,748人存活,29人失访.多元Cox模型分析显示,既往吸烟者与不吸烟者比较,相对危险度(95%CI)分别为总死亡1.24(1.01~1.53)、慢性阻塞性肺病1.91(1.06~3.46)、肺癌2.91(1.36~6.23)、冠心病1.15(0.68~1.93).与吸烟者比较,戒烟者总死亡和肺癌死亡的危险性分别下降66.67%和14.98%.结论 吸烟为该队列老年男性死亡的主要危险因素,戒烟可以降低总死亡和肺癌死亡的危险性.  相似文献   

11.
Caffeine consumption is associated with a reduced risk of Parkinson's disease in men but not in women. This gender difference may be due to an interaction between caffeine and use of postmenopausal estrogens. The authors prospectively assessed the relation between coffee consumption and Parkinson's disease mortality among participants in the Cancer Prevention Study II, a cohort of over 1 million people enrolled in 1982. Causes of deaths were ascertained through death certificates from January 1, 1989, through 1998. Parkinson's disease was listed as a cause of death in 909 men and 340 women. After adjustment for age, smoking, and alcohol intake, coffee consumption was inversely associated with Parkinson's disease mortality in men (p(trend) = 0.01) but not in women (p = 0.6). In women, this association was dependent on postmenopausal estrogen use; the relative risk for women drinking 4 or more cups (600 ml) of coffee per day compared with nondrinkers was 0.47 (95% confidence interval: 0.27, 0.80; p = 0.006) among never users and 1.31 (95% confidence interval: 0.75, 2.30; p = 0.34) among users. These results suggest that caffeine reduces the risk of Parkinson's disease but that this hypothetical beneficial effect may be prevented by use of estrogen replacement therapy.  相似文献   

12.
Nonspecific inflammatory bowel disease and smoking   总被引:4,自引:0,他引:4  
The authors assessed the relation between cigarette smoking and nonspecific inflammatory bowel disease in a case-control study of 124 cases of ulcerative colitis, 109 cases of Crohn's disease, and 250 age- and sex-matched control subjects in hospital for acute nongastric or intestinal conditions unrelated to smoking. For ulcerative colitis, the risk for current smoking compared with never smoking was 0.5, with a 95% confidence interval (Cl) of 0.3-1.0. They observed decreasing risk with increasing number of cigarettes smoked. The risk for ex-smokers, however, was greater than that for never smokers (relative risk = 2.7; 95% Cl = 1.5-4.9). The elevated risk of ulcerative colitis in ex-smoking in the presence of an overall lack of association with ever-smoking may plausibly be attributed to either 1) brief induction time of a protective effect of smoking on ulcerative colitis or 2) selective cessation of smoking due perhaps to very early symptoms of the disease. If time at first onset of bowel symptoms, instead of clinical diagnosis, is considered as the index date, the negative association between ulcerative colitis and current smoking would have weakened in men and disappeared in the overall series. There was clear evidence of a positive association between cigarette smoking and Crohn's disease (relative risk for ever smokers vs. never smokers = 4.0; 95% Cl = 2.2-7.3). The risk estimates increased with the number of cigarettes smoked per day and duration of habit. The association between current smoking and Crohn's disease was even stronger when age at first onset of bowel symptoms was considered as the index date, but the risk for ex-smokers fell below unity.  相似文献   

13.
BACKGROUND: Both smoking and obesity have been linked to increased mortality, but evaluating the joint effect has been limited. This nationwide, prospective mortality study of U.S. radiologic technologists was designed to evaluate the combined mortality risks of obesity and smoking. METHODS: Mortality risk was investigated in 64,120 women and 18,760 men who completed a baseline questionnaire (1983 to 1989). Body mass index (BMI) (weight adjusted for height, or kilograms divided by meters squared) was calculated from self-reported weight and height at baseline, with five categories: less than 18.5 (underweight), 18.5 to 24.9 (normal), 25.0 to 29.9 (overweight), 30.0 to 34.9 (moderately obese), and 35.0 and higher (very obese). Participants were followed from the questionnaire until the date of death or through 2002, whichever occurred first. The combined association among BMI and smoking and all-cause, cancer, and circulatory disease mortality by gender and attained age (less than 65 years, 65 years and older) was examined using Cox proportional hazards regression analyses (conducted in 2005). Person-years at risk averaged 16 years (women aged less than 65), 6 years (women aged 65 and older), 15 years (men aged less than 65), and 7 years (men aged 65 and older), totaling 1.35 million person-years. RESULTS: In all gender/age groups, both obesity and smoking, particularly current smoking, contributed substantially to all-cause mortality, with 3.5- to 5-fold risks for very obese, current smokers compared to normal weight, never smokers. Current smoking was the predominant risk factor for cancer mortality. Combining obesity with current smoking increased circulatory disease mortality by 6- to 11-fold for people aged less than 65 years, compared to normal weight, never smokers. Obese former smokers (less than 65 years) had notably lower risks. CONCLUSIONS: Obese smokers (aged less than 65 years) had strikingly high mortality risks, particularly from circulatory disease mortality.  相似文献   

14.
Body weight and mortality among adults who never smoked   总被引:5,自引:0,他引:5  
In a 12-year prospective study, the authors examined the relation between body mass index (BMI) and mortality among the 20,346 middle-aged (25-54 years) and older (55-84 years) non-Hispanic white cohort members of the Adventist Health Study (California, 1976-1988) who had never smoked cigarettes and had no history of coronary heart disease, cancer, or stroke. In analyses that accounted for putative indicators (weight change relative to 17 years before baseline, death during early follow-up) of pre-existing illness, the authors found a direct positive relation between BMI and all-cause mortality among middle-aged men (minimum risk at BMI (kg/m2) 15-22.3, older men (minimum risk at BMI 13.5-22.3), middle-aged women (minimum risk at BMI 13.9-20.6), and older women who had undergone postmenopausal hormone replacement (minimum risk at BMI 13.4-20.6). Among older women who had not undergone postmenopausal hormone replacement, the authors found a J-shaped relation (minimum risk at BMI 20.7-27.4) in which BMI <20.7 was associated with a twofold increase in mortality risk (hazard ratio (HR) = 2.2, 95% confidence interval (CI) 1.3, 3.5) that was primarily due to cardiovascular and respiratory disease. These findings not only identify adiposity as a risk factor among adults, but also raise the possibility that very lean older women can experience an increased mortality risk that may be due to their lower levels of adipose tissue-derived estrogen.  相似文献   

15.
Estrogen use and myocardial infarction risk: a case-control study   总被引:1,自引:0,他引:1  
A case-control study was conducted to examine the relationship of estrogen use to myocardial infarction in postmenopausal white women. After exclusion of proxy responses and of controls with discharge diagnoses of gynecologic or gallbladder diseases, there remained 39 matched sets (33 pairs and 6 triplets). The unadjusted relative odds ratio (RO) for past estrogen use was found to be 0.83. However, after simultaneous adjustment for cardiovascular diseases, smoking, education, and type of menopause, the net RO was 0.61. Type of menopause was found to interact with estrogen use, in that the protective effect was seen mainly in surgical menopause women, in whom the net RO for estrogen use was 0.37. Although none of the results reached statistical significance, they are consistent with recent results indicating a protective effect for estrogen therapy in regard to coronary heart disease, mainly among women undergoing surgical menopause.  相似文献   

16.
Menthol cigarette smoking and oesophageal cancer   总被引:3,自引:0,他引:3  
Oesophageal cancer incidence and mortality among American blacks is over three times the rate for whites. Between 1950 and 1977 the age-adjusted oesophageal cancer mortality rate approximately doubled in non-whites while remaining virtually unchanged in whites. Between World War II and the 1970s menthol cigarette sales dramatically increased, roughly paralleling the increase in oesophageal cancer among blacks. The present study uses existing data from a large hospital-based case-control study to test whether menthol cigarette smoking is related to oesophageal cancer. Oesophageal cancer cases were current smokers. Controls were matched to the cases on age (+/- 5 years) and sex, had conditions thought not to be related to tobacco use, and were also current smokers. Tabular analyses showed no change in risk for males ever-smoking menthol versus those never smoking menthol cigarettes. For women, however, there was an increased risk. Results of logistic regression analyses performed to account for potential confounding factors showed a marginally significant (P = 0.08) decrease in risk among male short term (less than 10 years) menthol smokers versus male never-menthol smokers (OR = 0.50, 95% Cl: 0.23-1.07) but no increased risk for menthol smoking of longer duration. Duration of menthol smoking fitted as a continuous variable showed no increased risk (P = 0.9) after accounting for non-menthol cigarette smoking duration (about 2% per year increase, P = 0.02). For females, the logistic analysis produced a marginally significant (P = 0.07) increased risk for longer menthol use (OR = 2.30, 95% Cl: 0.93-5.72).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
目的分析中国成年人饮茶与全因死亡和死因别死亡风险间的关联。方法本研究分析基于中国慢性病前瞻性研究项目。饮茶信息为基线自报。死亡信息主要通过链接死亡监测系统获取。使用Cox比例风险回归模型计算风险比(HR)及其95%CI。结果纳入分析的438 443例研究对象随访11.1年共发生死亡34 661例。与从不饮茶者相比, 当前非每日饮茶者和每日饮茶者全因死亡HR值(95%CI)依次为0.89(0.86~0.91)和0.92(0.88~0.95)。分性别分析显示, 饮茶对全因死亡风险的保护作用主要见于男性(交互P<0.05)。与从不饮茶者相比, 当前每日饮茶者死于缺血性心脏病、缺血性脑卒中、出血性脑卒中、恶性肿瘤、呼吸系统疾病及其他死因的HR值(95%CI)依次为0.83(0.76~0.92)、0.82(0.69~0.97)、0.86(0.78~0.94)、1.03(0.97~1.09)、1.00(0.87~1.16)、0.84(0.78~0.90)。在不吸烟且不过量饮酒者中, 每日饮茶与恶性肿瘤死亡风险间不存在有统计学显著性的关联, 但在吸烟或过量饮酒者中, 每日饮茶者死于恶性肿瘤的风...  相似文献   

18.
Evidence is growing that secondhand smoke can cause death from several diseases. The association between household exposure to secondhand smoke and disease-specific mortality was examined in two New Zealand cohorts of lifelong nonsmokers ("never smokers") aged 45-77 years. Individual census records from 1981 and 1996 were anonymously and probabilistically linked with mortality records from the 3 years that followed each census. Age- and ethnicity-standardized mortality rates were compared for never smokers with and without home exposure to secondhand smoke (based on the reported smoking behavior of other household members). Relative risk estimates adjusted for age, ethnicity, marital status, and socioeconomic position showed a significantly greater mortality risk for never smokers living in households with smokers, with excess mortality attributed to tobacco-related diseases, particularly ischemic heart disease and cerebrovascular disease, but not lung cancer. Adjusted relative risk estimates for all cardiovascular diseases were 1.19 (95% confidence interval: 1.04, 1.38) for men and 1.01 (95% confidence interval: 0.88, 1.16) for women from the 1981-1984 cohort, and 1.25 (95% confidence interval: 1.06, 1.47) for men and 1.35 (95% confidence interval: 1.11, 1.64) for women from the 1996-1999 cohort. Passive smokers also had nonsignificantly increased mortality from respiratory disease. Sensitivity analyses indicate that these findings are not due to misclassification bias.  相似文献   

19.
Cohort study of all-cause mortality among tobacco users in Mumbai, India   总被引:4,自引:0,他引:4  
INTRODUCTION: Overall mortality rates are higher among cigarette smokers than non-smokers. However, very little is known about the health effects of other forms of tobacco use widely prevalent in India, such as bidi smoking and various forms of smokeless tobacco (e.g. chewing betel-quid). We therefore carried out a cohort study in the city of Mumbai, India, to estimate the relative risks for all-cause mortality among various kinds of tobacco users. METHODS: A baseline survey of all individuals aged > or = 35 years using voters' lists as a selection frame was conducted using a house-to-house approach and face-to-face interviews. RESULTS: Active follow-up of 52,568 individuals in the cohort was undertaken 5-6 years after the baseline study, and 97.6% were traced. A total of 4358 deaths were recorded among these individuals. The annual age-adjusted mortality rates were 18.4 per 1000 for men and 12.4 per 1000 for women. For men the mortality rates for smokers were higher than those of non-users of tobacco across all age groups, with the difference being greater for lower age groups (35-54 years). The relative risk was 1.39 for cigarette smokers and 1.78 for bidi smokers, with an apparent dose-response relationship for frequency of smoking. Women were basically smokeless tobacco users, with the relative risk among such users being 1.35 and a suggestion of a dose-response relationship. DISCUSSION: These findings establish bidi smoking as no less hazardous than cigarette smoking and indicate that smokeless tobacco use may also cause higher mortality. Further studies should be carried out to obtain cause-specific mortality rates and relative risks.  相似文献   

20.
To examine the relation of noncontraceptive estrogen use to the risk of breast cancer among postmenopausal women, the authors conducted a case-control study: 1,686 cases were compared with 2,077 hospital control subjects, of whom 1,120 had non-gynecologic cancers and 957 had nonmalignant (also non-gynecologic) conditions. Data were obtained from 1980 to 1986, by interview of subjects in hospitals in the United States and Canada. The relative risk estimate for any use of replacement estrogens unopposed by progestogens was 1.2 (95% confidence interval (Cl) 1.0-1.4), after adjustment for age and type of menopause; when all known risk factors for breast cancer were taken into account in a multivariate analysis, the estimate was similar. For use of at least 15 years duration, the estimate was 0.9 (95% Cl 0.5-1.9). Most of the unopposed use was of conjugated estrogens: overall, the relative risk (95% Cl) was 1.3 (1.0-1.6); for durations of 15 or more years, it was 0.9 (0.4-1.9); for use of 5 years followed by a latent interval of 15 or more years, it was 1.3 (0.7-2.4); and for current use it was 1.1 (0.7-1.6). There was no evidence of increased breast cancer risk when the conjugated estrogen users were divided according to dose. There was little use of estrogens opposed by progestogens; the relative risk estimate was 1.7 (95% Cl 0.9-3.3). The results of this large study provide no evidence that the use of unopposed conjugated estrogens increases the risk of breast cancer, even after long durations of use or long latent intervals, but the possibility of a modest increase (less than a doubling) could not be excluded. There were insufficient data to evaluate the effects of nonconjugated estrogens and of combined estrogen and progestogen therapy.  相似文献   

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