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G A Colditz

Publications and source records attributed to G A Colditz.

At least 361 records · Page 20Linked to original sources
PubMed1994

The cost of obesity: the US perspective.

Obesity is associated with an increased risk of many major chronic diseases. We estimated the economic costs of obesity-associated non-insulin-dependent diabetes mellitus, cardiovascular disease, gallbladder disease, cancer, and musculoskeletal disorders in 1990 US dollars, using a prevalence-based approach to cost-of-illness. In addition to direct costs, indirect costs were also estimated. The indirect cost of morbidity was estimated by calculating the costs associated with work days lost, and mortality costs were estimated on the basis of lifetime earnings lost. In 1990, the direct cost of obesity-associated disease in the US was $US45.8 billion, and the indirect cost of obesity was estimated to be $US23.0 billion. Therefore the total economic cost of obesity was estimated to be $US68.8 billion in 1990.

Cardiovascular Diseases↗
PubMed1994

Obesity, fat distribution, and weight gain as risk factors for clinical diabetes in men.

OBJECTIVE: To investigate the relation between obesity, fat distribution, and weight gain through adulthood and the risk of non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: We analyzed data from a cohort of 51,529 U.S. male health professionals, 40-75 years of age in 1986, who completed biennial questionnaires sent out in 1986, 1988, 1990, and 1992. During 5 years of follow-up (1987-1992), 272 cases of NIDDM were diagnosed among men without a history of diabetes, heart disease, and cancer in 1986 and who provided complete health information. Relative risks (RRs) associated with different anthropometric measures were calculated controlling for age, and multivariate RRs were calculated controlling for smoking, family history of diabetes, and age. RESULTS: We found a strong positive association between overall obesity as measured by body mass index (BMI) and risk of diabetes. Men with a BMI of > or = 35 kg/m2 had a multivariate RR of 42.1 (95% confidence interval [CI] 22.0-80.6) compared with men with a BMI < 23.0 kg/m2. BMI at age 21 and absolute weight gain throughout adulthood were also significant independent risk factors for diabetes. Fat distribution, measured by waist-to-hip ratio (WHR), was a good predictor of diabetes only among the top 5%, while waist circumference was positively associated with the risk of diabetes among the top 20% of the cohort. CONCLUSIONS: These data suggest that waist circumference may be a better indicator than WHR of the relationship between abdominal adiposity and risk of diabetes. Although early obesity, absolute weight gain throughout adulthood, and waist circumference were good predictors of diabetes, attained BMI was the dominant risk factor for NIDDM; even men of average relative weight had significantly elevated RRs.

Adult↗
PubMed1994

A prospective study of symptomatic gallstones in women: relation with oral contraceptives and other risk factors.

OBJECTIVE: To examine the relation between oral contraceptives (OCs), body mass index (BMI), weight change, alcohol use, parity, smoking, and symptomatic gallstones in women less than 45 years of age. METHODS: In this prospective study, associations between the various self-reported exposures and symptomatic gallstones were assessed in 96,211 female United States nurses with 425 cases of gallstones, using multiple logistic regression. RESULTS: We found little relation between ever-use of OCs and symptomatic gallstones (relative risk [RR] 1.2, 95% confidence interval [CI] 0.9-1.6), although there was a modest elevation in risk for long-term use (RR 1.5, 95% CI 1.0-2.2 for 10-14 years; RR 1.6, 95% CI 1.0-2.4 for 15 or more years). There was also an increased risk in current users of OCs (RR 1.6, 95% CI 1.1-2.4). The risk of symptomatic gallstones increased with increasing BMI and weight gain since age 18. Women with four or more births had an elevated risk of symptomatic gallstones (RR 2.0, 95% CI 1.3-3.2), and current cigarette smokers had a slightly higher risk than never-smokers (RR 1.3, 95% CI 1.0-1.7). The risk decreased with increasing alcohol intake. CONCLUSION: We found no substantial increase in the risk of symptomatic gallstones among ever-OC users, although current and long-term users had somewhat elevated risks. Body mass index remains the strongest predictor of symptomatic gallstones among young women.

Adult↗
PubMed1994

Postmenopausal hormone use and cholecystectomy in a large prospective study.

OBJECTIVE: To examine the association between postmenopausal hormone use and cholecystectomy. METHODS: A prospective cohort study was performed, with follow-up every 2 years. Participants were 54,845 postmenopausal United States nurses, who reported both hormone use and cholecystectomy on mailed questionnaires. RESULTS: Cholecystectomy was reported by 1750 women during 8 years of follow-up. After adjusting for confounding factors, women currently using postmenopausal hormones were at an increased risk of cholecystectomy (relative risk [RR] 2.1, 95% confidence interval [CI] 1.9-2.4) compared to never-users. For current users, the risk of cholecystectomy increased with increasing duration of hormone use (RR 2.6, 95% CI 2.2-3.1 for 10 years or more) and higher doses of estrogen (RR 2.4, 95% CI 2.0-2.9 for users of 1.25 mg or more). Although the risk for past hormone users decreased substantially in women who had discontinued use 1-2.9 years ago (RR 1.6, 95% CI 1.2-2.0), a small risk persisted for women who had stopped taking hormones 5 or more years previously (RR 1.3, 95% CI 1.1-1.6). However, after controlling for time since last use, duration of past use had little or no effect on the risk of cholecystectomy (RR 1.4 and RR 1.7 for past users of less than 2 years and 10 or more years' duration, respectively). CONCLUSION: Women using postmenopausal hormones are at an increased risk of cholecystectomy. Women and their physicians should consider the spectrum of risks and benefits when deciding whether to take hormones.

Cholecystectomy↗
PubMed1993

Tubal ligation, hysterectomy, and risk of ovarian cancer. A prospective study.

OBJECTIVE: To assess whether tubal ligation and hysterectomy affect subsequent risk of ovarian cancer. DESIGN: Prospective cohort study with 12 years of follow-up. SETTING: United States, multistate. PARTICIPANTS: A total of 121,700 female registered nurses who were 30 to 55 years of age in 1976; the follow-up rate was 90% as of 1988. MAIN OUTCOME MEASURE: Ovarian cancer of epithelial origin confirmed by medical record review. RESULTS: We observed a strong inverse association between tubal ligation and ovarian cancer, which persisted after adjustment for age, oral contraceptive use, parity, and other ovarian cancer risk factors (multivariate relative risk [RR], 0.33; 95% confidence interval [CI], 0.16 to 0.64). The association was similar when we assessed tubal ligation status at the baseline questionnaire and excluded cases in the first 4 years to eliminate any possible short-term decrease in risk due to screening of the ovaries during ligation surgery. We noted a weaker inverse association between simple hysterectomy and ovarian cancer (RR, 0.67; 95% CI, 0.45 to 1.00). Neither vasectomy nor condom use by a partner was associated with risk of ovarian cancer. CONCLUSIONS: These data indicate that tubal ligation, and perhaps hysterectomy, may substantially reduce risk of epithelial ovarian cancer.

Adult↗
PubMed1993

Smoking cessation in relation to total mortality rates in women. A prospective cohort study.

OBJECTIVE: To examine the temporal relationship between stopping smoking and total mortality rates among middle-aged women. DESIGN: Prospective cohort study with 12 years of follow-up. SETTING: Registered nurses residing in the United States. PARTICIPANTS: 117,001 female registered nurses, ages 30 to 55 years, who were free of manifest coronary heart disease, stroke, and cancer (except nonmelanoma skin cancer) in 1976. MAIN OUTCOME MEASURES: Total mortality, further categorized into deaths from cardiovascular diseases, cancers, and violent deaths. RESULTS: A total of 2847 deaths (933 among "never smokers," 799 among former smokers, and 1115 among current smokers) occurred during 1.37 million person-years of follow-up. The multivariate relative risks for total mortality compared with never smokers were 1.87 (95% CI, 1.65 to 2.13) for current smokers and 1.29 (CI, 1.14 to 1.46) for former smokers. Participants who started smoking before the age of 15 years had the highest risks for total mortality (multivariate relative risk, 3.15; CI, 2.16 to 4.59), cardiovascular disease mortality (relative risk, 9.94; CI, 5.15 to 19.19), and deaths from external causes of injury (relative risk, 5.39; CI, 1.84 to 15.78). Compared with continuing smokers, former smokers had a 24% reduction in risk for cardiovascular disease mortality within 2 years of quitting. The excess risks for total mortality and both cardiovascular disease and total cancer mortality among former smokers approached the level of that for never smokers after 10 to 14 years of abstinence. The health benefits of cessation were clearly present regardless of the age at starting and daily number of cigarettes smoked. CONCLUSIONS: The risk of cigarette smoking on total mortality among former smokers decreases nearly to that of never smokers 10 to 14 years after cessation.

Adult↗
PubMed1993

A prospective study of dietary fat and risk of prostate cancer.

BACKGROUND: The strong correlation between national consumption of fat and national rate of mortality from prostate cancer has raised the hypothesis that dietary fat increases the risk of this malignancy. Case-control and cohort studies have not consistently supported this hypothesis. PURPOSE: We examined prospectively the relationship between prostate cancer and dietary fat, including specific fatty acids and dietary sources of fat. We examined the relationship of fat consumption to the incidence of advanced prostate cancer (stages C, D, or fatal cases) and to the total incidence of prostate cancer. METHODS: We used data from the Health Professionals Follow-up Study, which is a prospective cohort of 51529 U.S. men, aged 40 through 75, who completed a validated food-frequency questionnaire in 1986. We sent follow-up questionnaires to the entire cohort in 1988 and 1990 to document new cases of a variety of diseases and to update exposure information. As of January 31, 1990, 300 new cases of prostate cancer, including 126 advanced cases, were documented in 47855 participants initially free of diagnosed cancer. The Mantel-Haenszel summary estimator was used to adjust for age and other potentially confounding variables. Multiple logistic regression was used to estimate relative risks (RRs) when controlling simultaneously for more than two covariates. RESULTS: Total fat consumption was directly related to risk of advanced prostate cancer (age- and energy-adjusted RR = 1.79, with 95% confidence interval [CI] = 1.04-3.07, for high versus low quintile of intake; P [trend] = .06). This association was due primarily to animal fat (RR = 1.63; 95% CI = 0.95-2.78; P [trend] = .08), but not vegetable fat. Red meat represented the food group with the strongest positive association with advanced cancer (RR = 2.64; 95% CI = 1.21-5.77; P = .02). Fat from dairy products (with the exception of butter) or fish was unrelated to risk. Saturated fat, monounsaturated fat, and alpha-linolenic acid, but not linoleic acid, were associated with advanced prostate cancer risk; only the association with alpha-linolenic acid persisted when saturated fat, monounsaturated fat, linoleic acid, and alpha-linolenic acid were modeled simultaneously (multivariate RR = 3.43; 95% CI = 1.67-7.04; P [trend] = .002). CONCLUSION: The results support the hypothesis that animal fat, especially fat from red meat, is associated with an elevated risk of advanced prostate cancer. IMPLICATIONS: These findings support recommendations to lower intake of meat to reduce the risk of prostate cancer. The potential roles of carcinogens formed in cooking animal fat and of alpha-linolenic acid in the progression of prostate cancer need to be explored.

Adult↗
PubMed1993

A prospective study of the intake of vitamins C, E, and A and the risk of breast cancer.

BACKGROUND: Although it has been hypothesized that large intakes of the antioxidant vitamins C, E, and A reduce the risk of breast cancer, few prospective data are available. METHODS: We prospectively studied 89,494 women who were 34 to 59 years old in 1980 and who did not have cancer. Their intakes of vitamins C, E, and A from foods and supplements were assessed at base line and in 1984 with the use of a validated semiquantitative food-frequency questionnaire. RESULTS: Breast cancer was diagnosed in 1439 women during eight years of follow-up. After multivariate adjustment for known risk factors, the relative risk among women in the highest quintile group for intake of vitamin C as compared with the risk among those in the lowest quintile group was 1.03 (95 percent confidence interval, 0.87 to 1.21); for vitamin E, after vitamin A intake had been controlled for, the relative risk was 0.99 (95 percent confidence interval, 0.83 to 1.19). In contrast, among women in the highest quintile group for intake of total vitamin A the relative risk was 0.84 (95 percent confidence interval, 0.71 to 0.98; P for trend = 0.001). Among women in the lowest quintile group for intake of vitamin A from food, consumption of vitamin A from supplements was associated with a reduced risk (P = 0.03). The significant inverse association of vitamin A intake with the risk of breast cancer was also found on study of data based on the 1984 questionnaire and four years of follow-up. CONCLUSIONS: Large intakes of vitamin C or E did not protect women in our study from breast cancer. A low intake of vitamin A may increase the risk of this disease; any benefit of vitamin A supplements may be limited to women with diets low in vitamin A.

Adult↗
PubMed1993

Family history, age, and risk of breast cancer. Prospective data from the Nurses' Health Study.

OBJECTIVE: To examine prospectively the risk of breast cancer as influenced by a maternal history of breast cancer, the mother's age at diagnosis, or a sister's history of breast cancer. DESIGN: Prospective cohort study with biennial follow-up. SETTING/PARTICIPANTS: 117,988 women in the Nurses' Health Study aged 30 to 55 years in 1976, followed up through 1988 (1.3 million person-years of follow-up). RESULTS: We identified 2389 incident cases of invasive breast cancer. Compared with women without a maternal history of breast cancer, the age-adjusted relative risk (RR) of breast cancer was highest among women whose mother was diagnosed before the age of 40 years (RR, 2.1 [95% confidence interval, 1.6 to 2.8]). The RR decreased with advancing maternal age at time of diagnosis to 1.5 (95% confidence interval, 1.1 to 2.2) for maternal diagnosis after the age of 70 years. Having a sister with a history of breast cancer also was related to increased risk; for women with one sister with breast cancer compared with those with one sister without such a history, the age-adjusted RR was 2.3 (95% confidence interval, 1.6 to 3.4). Women whose mother and sister both had a history of breast cancer had an RR of 2.5 (95% confidence interval, 1.5 to 4.2) compared with those without a family history. These associations did not differ appreciably when stratified by age; menopausal status; history of benign breast disease; body mass index; age at menarche; or parity or age at first birth of the women at risk. The results remained unchanged when we controlled for these risk factors in multivariate models. Despite slightly greater mammography surveillance and earlier detection of tumors among women with a family history of breast cancer, detection bias is unlikely to account for more than a small part of the observed association. CONCLUSIONS: Risk of breast cancer is approximately doubled among women whose mother had breast cancer diagnosed before the age of 40 years or who have a sister with breast cancer, and remains elevated even for those whose mothers were diagnosed with breast cancer at the age of 70 years or older. However, the risk associated with a mother or sister history of breast cancer is smaller than suggested by earlier retrospective studies. Overall, within this population of middle-aged women, only 2.5% of breast cancer cases are attributable to a positive family history.

Adult↗
PubMed1993

Folate, methionine, and alcohol intake and risk of colorectal adenoma.

BACKGROUND: Reduced methylation of DNA may contribute to loss of the normal controls on proto-oncogene expression. In humans, hypomethylation of DNA has been observed in colorectal cancers and in their adenomatous polyp precursors. Accumulation of DNA methylation abnormalities, observed during progression of human colorectal neoplasia, may be influenced by certain dietary factors. The apparent protective effect of fresh fruits and vegetables, the major folate sources, on colorectal cancer incidence suggests that a methyl-deficient diet contributes to occurrence of this malignancy. Low dietary folate and methionine and high intake of alcohol may reduce levels of S-adenosylmethionine, which is required for DNA methylation. PURPOSE: To determine if dietary factors that may influence methyl availability are related to colorectal adenomas, we prospectively examined the association of folate, methionine, and alcohol intakes and risk of colorectal adenoma. METHODS: We assessed dietary intake for a 1-year period for women of the Nurses' Health Study, started in 1976, and for men of the Health Professionals Follow-up Study, started in 1986--using a semiquantitative food frequency questionnaire. Adenomatous polyps of the left colon or rectum were diagnosed in 564 of 15,984 women who had had an endoscopy between 1980 and 1990 and in 331 of 9490 men who had undergone an endoscopy between 1986 and 1990. RESULTS: High dietary folate was inversely associated with risk of colorectal adenoma in women (multivariate relative risk [RR] = 0.66; 95% confidence interval [CI] = 0.46-0.95 between high and low quintiles of intake) and in men (RR = 0.63; 95% CI = 0.41-0.98) after adjusting for age, family history, indications for endoscopy, history of previous endoscopy, total energy intake, saturated fat intake, dietary fiber, and body mass index. Relative to nondrinkers, drinkers of more than 30 g of alcohol daily (about two drinks) had an elevated risk of adenoma (in women, RR = 1.84, 95% CI = 1.19-2.86; in men, RR = 1.64, 95% CI = 0.92-2.93). Methionine intake was inversely associated with risk of adenomas 1 cm or larger (RR = 0.62; 95% CI = 0.46-0.85, combining men and women). CONCLUSIONS: Folate, alcohol, and methionine could influence methyl group availability, and a methyl-deficient diet may be linked to early stages of colorectal neoplasia. A dietary pattern that increases methyl availability could reduce incidence of colorectal cancer. IMPLICATIONS: These data support efforts to increase dietary folate in segments of the population having diets with low intakes of this nutrient.

Adenoma↗
PubMed1993

Vitamin E consumption and the risk of coronary disease in women.

BACKGROUND: Interest in the antioxidant vitamin E as a possible protective nutrient against coronary disease has intensified with the recognition that oxidized low-density lipoprotein may be involved in atherogenesis. METHODS: In 1980, 87,245 female nurses 34 to 59 years of age who were free of diagnosed cardiovascular disease and cancer completed dietary questionnaires that assessed their consumption of a wide range of nutrients, including vitamin E. During follow-up of up to eight years (679,485 person-years) that was 97 percent complete, we documented 552 cases of major coronary disease (437 nonfatal myocardial infarctions and 115 deaths due to coronary disease). RESULTS: As compared with women in the lowest fifth of the cohort with respect to vitamin E intake, those in the top fifth had a relative risk of major coronary disease of 0.66 (95 percent confidence interval, 0.50 to 0.87) after adjustment for age and smoking. Further adjustment for a variety of other coronary risk factors and nutrients, including other antioxidants, had little effect on the results. Most of the variability in intake and reduction in risk was attributable to vitamin E consumed as supplements. Women who took vitamin E supplements for short periods had little apparent benefit, but those who took them for more than two years had a relative risk of major coronary disease of 0.59 (95 percent confidence interval, 0.38 to 0.91) after adjustment for age, smoking status, risk factors for coronary disease, and use of other antioxidant nutrients (including multi-vitamins). CONCLUSIONS: Although these prospective data do not prove a cause-and-effect relation, they suggest that among middle-aged women the use of vitamin E supplements is associated with a reduced risk of coronary heart disease. Randomized trials of vitamin E in the primary and secondary prevention of coronary disease are being conducted; public policy recommendations about the widespread use of vitamin E should await the results of these trials.

Adult↗
PubMed1993

Vitamin E consumption and the risk of coronary heart disease in men.

BACKGROUND: The oxidative modification of low-density lipoproteins increases their incorporation into the arterial intima, an essential step in atherogenesis. Although dietary antioxidants, such as vitamin C, carotene, and vitamin E, have been hypothesized to prevent coronary heart disease, prospective epidemiologic data are sparse. METHODS: In 1986, 39,910 U.S. male health professionals 40 to 75 years of age who were free of diagnosed coronary heart disease, diabetes, and hypercholesterolemia completed detailed dietary questionnaires that assessed their usual intake of vitamin C, carotene, and vitamin E in addition to other nutrients. During four years of follow-up, we documented 667 cases of coronary disease. RESULTS: After controlling for age and several coronary risk factors, we observed a lower risk of coronary disease among men with higher intakes of vitamin E (P for trend = 0.003). For men consuming more than 60 IU per day of vitamin E, the multivariate relative risk was 0.64 (95 percent confidence interval, 0.49 to 0.83) as compared with those consuming less than 7.5 IU per day. As compared with men who did not take vitamin E supplements, men who took at least 100 IU per day for at least two years had a multivariate relative risk of coronary disease of 0.63 (95 percent confidence interval, 0.47 to 0.84). Carotene intake was not associated with a lower risk of coronary disease among those who had never smoked, but it was inversely associated with the risk among current smokers (relative risk, 0.30; 95 percent confidence interval, 0.11 to 0.82) and former smokers (relative risk, 0.60; 95 percent confidence interval, 0.38 to 0.94). In contrast, a high intake of vitamin C was not associated with a lower risk of coronary disease. CONCLUSIONS: These data do not prove a causal relation, but they provide evidence of an association between a high intake of vitamin E and a lower risk of coronary heart disease in men. Public policy recommendations with regard to the use of vitamin E supplements should await the results of additional studies.

Adult↗
PubMed1993

Intake of trans fatty acids and risk of coronary heart disease among women.

Trans isomers of fatty acids, formed by the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, increase the ratio of plasma low-density-lipoprotein to high-density-lipoprotein cholesterol, so it is possible that they adversely influence risk of coronary heart disease (CHD). To investigate this possibility, we studied dietary data from participants in the Nurses' Health Study. We calculated intake of trans fatty acids from dietary questionnaires completed by 85,095 women without diagnosed CHD, stroke, diabetes, or hypercholesterolaemia in 1980. During 8 years of follow-up, there were 431 cases of new CHD (non-fatal myocardial infarction or death from CHD). After adjustment for age and total energy intake, intake of trans isomers was directly related to risk of CHD (relative risk for highest vs lowest quintile 1.50 [95% Cl 1.12-2.00], p for trend = 0.001). Additional control for established CHD risk factors, multivitamin use, and intakes of saturated fat, monounsaturated fat, and linoleic acid, dietary cholesterol, vitamins E or C, carotene, or fibre did not change the relative risk substantially. The association was stronger for the 69,181 women whose margarine consumption over the previous 10 years had been stable (1.67 [1.05-2.66], p for trend = 0.002). Intakes of foods that are major sources of trans isomers (margarine, cookies [biscuits], cake, and white bread) were each significantly associated with higher risks of CHD. These findings support the hypothesis that consumption of partially hydrogenated vegetable oils may contribute to occurrence of CHD.

Age Factors↗
PubMed1993

A comparison of prospective and retrospective assessments of diet in the study of breast cancer.

Fat intake was examined in relation to risk of breast cancer using dietary questionnaires administered both before and after the diagnosis of breast cancer. Among the Nurses' Health Study cohort members who completed a food frequency questionnaire and were free of cancer in 1986, 398 were diagnosed with breast cancer during 2 years of follow-up. These cases and 798 age-matched controls (cohort members who also completed a dietary questionnaire in 1986 but did not develop breast cancer) were sent another food frequency questionnaire in 1989 inquiring about their diet in 1985. Three hundred cases and 602 controls responded to the second questionnaire. The age-adjusted analysis using the prospective (1986) questionnaire demonstrated no appreciable associations between breast cancer incidence and intakes of total fat (odds ratio (OR) between highest and lowest quintiles = 0.87; 95% confidence interval (CI) 0.54-1.40) and saturated fat (OR = 0.97; CI 0.64-1.46). The age-adjusted analysis using the retrospective (1989) questionnaire suggested positive associations between breast cancer incidence and intakes of total fat (OR = 1.43; 95% CI 0.90-2.27) and saturated fat (OR = 1.38; 95% CI 0.89-2.13). When nutrients were adjusted for total energy intake, the direction and magnitude of the differences between the prospective and retrospective analyses were similar to the analyses unadjusted for energy intake. These results suggest that case-control studies of diet and breast cancer may yield biased associations between fat intake and the risk of breast cancer.

Adult↗
PubMed1993

A retrospective cohort study of vasectomy and prostate cancer in US men.

OBJECTIVE: To examine the relationship between vasectomy and prostate cancer. DESIGN: Retrospective cohort study. SETTING: Husbands of nurses in 11 large states in the United States. PARTICIPANTS: In questionnaires administered in 1976 and 1978, 14,607 married female participants of the Nurses' Health Study reported vasectomy as the couple's form of contraception. In 1989, we contacted these 14,607 women and 14,607 age-matched participants whose husbands had not had a vasectomy prior to 1978 to ascertain their husband's disease status between 1976 and 1989. MAIN OUTCOME MEASURE: Diagnosis of prostate cancer. RESULTS: During the study period, from 1976 through 1989, 96 new cases of prostate cancer were diagnosed in the cohort. Vasectomy was associated with an increased risk of prostate cancer (age-adjusted relative risk, 1.56; 95% confidence interval, 1.03 to 2.37; P = .04). The relative risk of prostate cancer increased over time since vasectomy. Among men who had their vasectomy 20 or more years in the past, the relative risk of prostate cancer was 1.89 (95% confidence interval, 1.14 to 3.14; P = .005), and after excluding stage A and B cases, the relative risk was 2.06 (95% confidence interval, 0.95 to 4.43; P = .07). This elevated risk of prostate cancer among vasectomized men persisted when we adjusted for smoking, alcohol consumption, educational level, body mass index, and geographical area of residence. CONCLUSIONS: These results support evidence from other epidemiologic studies that vasectomy increases risk of prostate cancer. A biological mechanism whereby vasectomy influences the rate of prostate cancer may be related to a diminished secretory rate of prostatic fluid following vasectomy, or, alternatively, to the postvasectomy immune response to sperm antigens, which may cross-react with tumor-associated antigens and suppress tumor immunosurveillance mechanisms.

Adult↗
PubMed1993

A prospective cohort study of vasectomy and prostate cancer in US men.

OBJECTIVE: To examine prospectively the relationship between vasectomy and prostate cancer. DESIGN: Cohort study. SETTING: Health professionals (dentists, veterinarians, osteopaths, optometrists, pharmacists, and podiastrists) in the United States. PARTICIPANTS: There were 10,055 male members of the Health Professionals Follow-up Study, aged 40 to 75 years, who had had a vasectomy, and 37,800 members who had not had a vasectomy at the time of study entry in 1986. These participants had provided detailed information on various life-style variables including diet. MAIN OUTCOME MEASURE: Diagnosis of prostate cancer. RESULTS: Between 1986 and 1990, 300 new cases of prostate cancer were diagnosed in participants who were initially free of diagnosed cancer. Vasectomy was associated with an elevated risk of prostate cancer (age-adjusted relative risk, 1.66; 95% confidence interval, 1.25 to 2.21; P = .0004). This elevated risk persisted after excluding 21 stage A1 cases (age-adjusted relative risk, 1.56; 95% confidence interval, 1.15 to 2.11; P = .004). Among men who had their vasectomy at least 22 years in the past (before 1965), the risk of prostate cancer was even higher (relative risk, 1.85; 95% confidence interval, 1.26 to 2.72; P = .002). This elevated risk among men with vasectomy did not appear to be caused by detection bias and persisted when we controlled for diet, level of physical activity, smoking, alcohol consumption, educational level, body mass index, and geographical area of residence. CONCLUSIONS: These results support evidence from other epidemiologic studies that vasectomy increases risk of prostate cancer. The consistency of results among various epidemiologic studies, the increase of risk over time following vasectomy, the apparent lack of confounding or bias, and the existence of physiological changes in the prostate following vasectomy suggest that the association may be causal.

Adult↗
PubMed1993

Epidemiology of breast cancer. Findings from the nurses' health study.

BACKGROUND: The epidemiology of breast cancer was reviewed in the context of hormonal, hereditary, histologic, and dietary risk factors. METHODS: Literature review. RESULTS: Late age at menarche and early age at first birth decrease the risk of breast cancer as does an early age at menopause. These risk factors relate to the lifetime exposure of the breast tissue to ovarian hormones. Although an early first birth is associated with a transient increase in the risk of breast cancer, perhaps as a result of the breast's exposure to high levels of hormones before terminal differentiation, in older women, parity is associated with a decreased risk of breast cancer. Among postmenopausal women, obesity is associated with higher levels of estrogens and an increased risk of breast cancer. Within the strata of breast cancer stages at diagnosis, obesity is associated with increased mortality, again supporting the influence of endogenous estrogens on this disease's incidence, recurrence, and survival rates. Consistent with these relationships, current use of estrogen therapy among postmenopausal women is associated with an increased risk of breast cancer. A family history of breast cancer is associated with approximately a two-fold increase in the risk of breast cancer, and this risk is greater if the diagnosis was made when the woman's mother was young, although even a diagnosis in an older mother is associated with an increased risk in her daughters. The follow-up of women with a history of benign breast biopsy results shows that atypical hyperplasia is associated with a fourfold increase in risk compared with a biopsy specimen without proliferative changes. Atypia doubles the risk. These data support the concept of atypia as a precursor lesion for breast cancer and may warrant its use as a marker in further studies. Consistent data from retrospective and prospective studies show a positive association between moderate alcohol intake and the risk of breast cancer. This may reflect the increase in estrogen levels observed among women who consume alcohol. Data from prospective studies do not support a relationship between dietary fat intake and the risk of breast cancer either in premenopausal or postmenopausal women. CONCLUSIONS: Few of these associations offer the potential for intervention to reduce the breast cancer risk.

Adolescent↗