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BACKGROUND: Because people frequently encounter information about the probability of health risks, there is a need for research to help identify the best formats for presenting these probabilities. METHODS: Three waves of participants were recruited from visitors to a cancer-related Internet site. Participants were presented with a hypothetical scenario that required them to perform 2 mathematical operations of the types that might be encountered in discussions of risk. Each wave encountered different operations. The operations used were compare, halve, triple, add, sequence, and tradeoff. Three numeric formats for communicating risk likelihoods were tested: percentages (e.g., 12%), frequencies (e.g., 12 in 100), and 1 in n (e.g., 1 in 8), and many levels of risk magnitude were crossed with the 3 formats. RESULTS: The total sample of 16,133 individuals represented an overall participation rate of 36.1%. Although the relative performance of the formats varied by operation, aggregated across operations, the percentage and frequency formats had higher overall accuracy rates than the 1-in-n format (57% and 55% v. 45%, respectively). Participants with less education, African Americans, Hispanics, and women had more difficulty with the mathematical operations. DISCUSSION: Percentage and frequency formats facilitate performance of simple operations on risk probabilities compared with the 1-in-n format, which should usually be avoided. [ABSTRACT FROM AUTHOR]

The relationship between postmenopausal hormone use (PMH) and ovarian cancer risk is unclear, particularly for specific hormone formulations, but recent studies suggest that there is a positive association. We conducted a prospective observational study with 82,905 postmenopausal women, including 389 ovarian cancers, in the Nurses' Health Study from 1976 to 2002. Compared with never users of PMH, both current and past users of > or =5 years had a significantly elevated risk of ovarian cancer (RR=1.41, 95% confidence interval (CI) 1.07-1.86 and relative risk (RR)=1.52, 95% CI 1.01-2.27, respectively). Examined by hormone type in continuous years, use of unopposed estrogen was associated with a significant increase in the risk of epithelial ovarian cancer (P for trend <0.001; RR for 5-year increment of use=1.25, 95% CI 1.12-1.38). Use of estrogen plus progestin (RR for 5-year increment of use=1.04, 95% CI 0.82-1.32) was not significantly associated with ovarian cancer risk. Generally, results were similar for serous tumours (RR for 5-year increment of unopposed estrogen use=1.23, 95% CI 1.07-1.40) and slightly stronger for endometrioid tumours (RR for 5-year increment of unopposed estrogen use=1.53, 95% CI 1.20-1.94). Recency of use was not significantly associated with ovarian cancer risk, but statistical power was limited here. [ABSTRACT FROM AUTHOR]

Most cases of breast and prostate cancer are not associated with mutations in known high-penetrance genes, indicating the involvement of multiple low-penetrance risk alleles. Studies that have attempted to identify these genes have met with limited success. The National Cancer Institute Breast and Prostate Cancer Cohort Consortium--a pooled analysis of multiple large cohort studies with a total of more than 5,000 cases of breast cancer and 8,000 cases of prostate cancer--was therefore initiated. The goal of this consortium is to characterize variations in approximately 50 genes that mediate two pathways that are associated with these cancers--the steroid-hormone metabolism pathway and the insulin-like growth factor signalling pathway--and to associate these variations with cancer risk. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although smoking is the primary cause of lung cancer, much is unknown about lung cancer etiology, including risk determinants for nonsmokers and modifying factors for smokers. OBJECTIVE: We hypothesized that alcohol consumption contributes to lung cancer risk. DESIGN: We conducted a pooled analysis using standardized exposure and covariate data from 7 prospective studies with 399 767 participants and 3137 lung cancer cases. Study-specific relative risks (RRs) and CIs were estimated and then combined to calculate pooled multivariate RRs by using a random-effects model. RESULTS: We found a slightly greater risk for the consumption of >/=30 g alcohol/d than for that of 0 g alcohol/d in men (RR: 1.21; 95% CI: 0.91, 1.61; P for trend = 0.03) and in women (RR: 1.16; 95% CI: 0.94, 1.43; P for trend = 0.03). In male never smokers, the RR for consumption of >/=15 g alcohol/d rather than 0 g alcohol/d was 6.38 (95% CI: 2.74, 14.9; P for trend < 0.001). In women, there were few never-smoking cases and no evidence of greater risk (RR: 1.35; 95% CI: 0.64, 2.87). Because of possible residual confounding by smoking, we performed sensitivity analyses by reclassifying the never smokers in the highest drinking category as former smokers. Resulting associations for alcohol consumption were somewhat attenuated, but P for trend = 0.05 for men, which was near the original P = 0.03. CONCLUSIONS: A slightly greater risk of lung cancer was associated with the consumption of >/=30 g alcohol/d than with no alcohol consumption. Alcohol consumption was strongly associated with greater risk in male never smokers. Residual confounding by smoking may explain part of the observed relation. Copyright © 2005 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

BACKGROUND: Although increased consumption of dietary fiber and grain products is widely recommended to maintain healthy body weight, little is known about the relation of whole grains to body weight and long-term weight changes. OBJECTIVE: We examined the associations between the intakes of dietary fiber and whole- or refined-grain products and weight gain over time. DESIGN: In a prospective cohort study, 74,091 US female nurses, aged 38-63 y in 1984 and free of known cardiovascular disease, cancer, and diabetes at baseline, were followed from 1984 to 1996; their dietary habits were assessed in 1984, 1986, 1990, and 1994 with validated food-frequency questionnaires. Using multiple models to adjust for covariates, we calculated average weight, body mass index (BMI; in kg/m(2)), long-term weight changes, and the odds ratio of developing obesity (BMI > or = 30) according to change in dietary intake. RESULTS: Women who consumed more whole grains consistently weighed less than did women who consumed less whole grains (P for trend < 0.0001). Over 12 y, those with the greatest increase in intake of dietary fiber gained an average of 1.52 kg less than did those with the smallest increase in intake of dietary fiber (P for trend < 0.0001) independent of body weight at baseline, age, and changes in covariate status. Women in the highest quintile of dietary fiber intake had a 49% lower risk of major weight gain than did women in the highest quintile (OR = 0.51; 95% CI: 0.39, 0.67; P < 0.0001 for trend). CONCLUSION: Weight gain was inversely associated with the intake of high-fiber, whole-grain foods but positively related to the intake of refined-grain foods, which indicated the importance of distinguishing whole-grain products from refined-grain products to aid in weight control. Copyright © 2003 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

BACKGROUND: Although it is known that abdominal obesity increases the risk of chronic diseases, prospective data examining the relation between lifestyle factors and the accumulation of abdominal adipose tissue are sparse. OBJECTIVE: The objective of the study was to determine the associations of changes in diet, physical activity, alcohol consumption, and smoking with 9-y waist gain among US men. DESIGN: A prospective cohort comprised 16 587 US men aged 40-75 y at baseline in 1986. Data on lifestyle factors were provided periodically with the use of self-reported questionnaires, and participants measured and reported their waist circumference in 1987 and 1996. RESULTS: In multivariate analyses, a 2% increment in energy intake from trans fats that were isocalorically substituted for either polyunsaturated fats or carbohydrates was significantly associated with a 0.77-cm waist gain over 9 y (P < 0.001 for each comparison). An increase of 12 g total fiber/d was associated with a 0.63-cm decrease in waist circumference (P < 0.001), whereas smoking cessation and a 20-h/wk increase in television watching were associated with a 1.98-cm and 0.59-cm waist gain, respectively (P < 0.001). Increases of 25 metabolic equivalent tasks (METs) * h/wk in vigorous physical activity and of >/= 0.5 h/wk in weight training were associated with 0.38-cm and 0.91-cm decreases in waist circumference, respectively (P < 0.001 for each comparison). These associations remained significant after further adjustment for concurrent change in body mass index. Changes in total fat and alcohol consumption and in walking volume were not significantly related to waist gain. CONCLUSIONS: Waist gain may be modulated by changes in trans fat and fiber consumption, smoking cessation, and physical activity. Copyright © 2003 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

OBJECTIVES: To describe the association of sunscreen use, sunburning, and tanning bed use by age, sex, residence, and psychosocial variables associated with tan-seeking behaviors, and to compare these findings with sun protection recommendations from federal agencies and cancer organizations. METHODS: A cross-sectional study, from all 50 states, of 10 079 boys and girls 12 to 18 years of age in 1999. Data were collected from self-report questionnaires with the children of the participants from the Nurses Health Study (Growing Up Today Study). RESULTS: The prevalence of sunscreen use was 34.4% with girls more likely to use sunscreen than boys (40.0 vs 26.4, odds ratio: 1.86; 95% confidence interval: 1.70-2.03). Eighty-three percent of respondents had at least 1 sunburn during the previous summer, and 36% had 3 or more sunburns. Nearly 10% of respondents used a tanning bed during the previous year. Girls were far more likely than boys to report tanning bed use (14.4 vs 2.4), and older girls (ages 15-18) were far more likely than younger girls (ages 12-14) to report tanning bed use (24.6% vs 4.7). Tanning bed use increased from 7% among 14-year-old girls to 16% by age 15, and more than doubled again by age 17 (35%; N = 244). Multivariate analysis demonstrated that attitudes associated with tanning, such as the preference for tanned skin, having many friends who were tanned, and belief in the worth of burning to get a tan, were generally associated with sporadic sunscreen use, more frequent sunburns, and increased use of tanning beds. CONCLUSIONS: Our findings suggest that many children are at subsequent risk of skin cancer because of suboptimal sunscreen use, high rates of sunburning, and tanning bed use. Recommendations in the United States for improved sun protection and avoidance of tanning beds and sunburning, which began in the early 1990s, have been primarily unheeded. Nationally coordinated campaigns with strong policy components must be developed and sustained to prevent skin cancer in a new generation of children and adolescents. [ABSTRACT FROM AUTHOR]

Context: The rate of tuberculosis (TB) among US homeless persons may be 20 times that of the general adult population. Studies suggest that the majority of urban homeless TB cases are attributable to ongoing transmission of TB. Optimal TB-control strategies in both chronically and transiently homeless populations are not known.Objective: To examine the effects of TB-control strategies on projected TB cases and deaths in US homeless populations using a computer-based simulation model.Design, Setting, and Population: The US general population and a theoretical population of 2 million homeless individuals in 1995 were divided into 18 clinical states based on the risk for or presence of TB and human immunodeficiency virus (HIV) infection in a semi-Markov model.Main Outcome Measures: Prevalence of transiently and chronically homeless individuals with active TB and deaths from TB as a function of public health measures taken to control and eliminate TB, including improvement of treatment effectiveness, improvement in access to treatment, and vaccination with BCG.Results: A 10% increase in access to treatment among homeless persons with active TB produced larger declines in predicted TB cases and deaths after 10 years (cases and deaths among chronically homeless persons decreased 12.5% and 19.8% and among transiently homeless persons dropped 35.9% and 32.4%, respectively) than improvements in the effectiveness of treatment programs (cases and deaths among chronically homeless persons declined 7.2% and 3.1% and among transiently homeless persons dropped 10.9% and 4.1%, respectively). A 10% increase in access to treatment among homeless persons with latent TB infection led to a 6.7% decline in TB among chronically homeless persons and a 5.7% decline among transiently homeless persons, while a 10% improvement in effectiveness of treatment for latent TB infection was associated with declines of 3.0% and 3.3%, respectively. When treatment for latent TB infection was modeled to be the same in vaccinated and nonvaccinated populations, BCG vaccination led to TB case declines of 15.4% and 21.5% in chronically and transiently homeless populations, respectively.Conclusions: Overcoming barriers faced by homeless individuals in accessing TB treatment programs will be crucial to reducing the burden of TB in this high-risk group. Increased treatment access, improvement in the effectiveness of treatment programs, and BCG vaccination of HIV-negative homeless individuals have the best chance to markedly decrease TB morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background: Increased physical activity has been associated with reduced risk for cardiovascular disease in the general population, but data are limited on its role among persons with type 2 diabetes mellitus.Objective: To determine whether physical activity decreases risk for cardiovascular disease among diabetic women.Design: Prospective cohort study.Setting: The Nurses' Health Study.Patients: 5125 female nurses with diabetes.Measurements: Physical activity was first assessed in 1980 and was updated in 1982, 1986, 1988, and 1992 through validated questionnaires. Average hours of moderate or vigorous exercise and a metabolic equivalent of task (MET) score were computed.Results: During 14 years of follow-up (31 432 person-years), 323 new cases of cardiovascular disease were documented (225 cases of coronary heart disease and 98 cases of stroke). The age-adjusted relative risks according to average hours of moderate or vigorous activity per week (<1, 1 to 1.9, 2 to 3.9, 4 to 6.9, >/=7) were 1.0, 0.93 (95% CI, 0.69 to 1.26), 0.82 (CI, 0.61 to 1.10), 0.54 (CI, 0.39 to 0.76), and 0.52 (CI, 0.25 to 1.09) (P < 0.001 for trend). These figures did not change materially after adjustment for smoking, body mass index, and other cardiovascular risk factors (1.0, 1.02, 0.87, 0.61, and 0.55, respectively; P = 0.001 for trend). In separate analyses, levels of physical activity were inversely associated with coronary heart disease and ischemic stroke. Among women who did not exercise vigorously, the multivariate relative risks for cardiovascular disease across quartiles of MET score for walking were 1.0, 0.85, 0.63, and 0.56 (P = 0.03 for trend). Faster usual walking pace was independently associated with lower risk.Conclusion: Among diabetic women, increased physical activity, including regular walking, is associated with substantially reduced risk for cardiovascular events. [ABSTRACT FROM AUTHOR]

Background: Infrequent bowel movements and use of laxatives have been hypothesized to increase risk of colorectal neoplasia. However, the few existing epidemiologic studies in humans have been inconclusive.Purpose: To investigate prospectively the associations of bowel movement frequency and laxative use with the occurrence of adenomatous colorectal polyps in women.Methods: A total of 17,400 women 36-61 years of age, without previous diagnosis of cancer or polyps, responded to a mailed questionnaire in 1982 that assessed bowel movement frequency and use of laxatives and had an endoscopy between 1984 and 1996. Between 1984 and 1996, 906 cases of adenomatous polyps (496 classified as small (< 1 cm), 358 classified as large (> or = 1 cm) and 52 unclassified) were documented. Relative risks (RRs) of adenomas and 95% confidence intervals (CIs) were calculated using logistic regression.Results: After controlling for adenoma risk factors, the multivariate RRs associated with having bowel movements every third day or less compared to once daily were 0.9 (95% CI: 0.7-1.2) for total colorectal adenomas, 1.0 (95% CI: 0.7-1.5) for large adenomas and 1.0 (95% CI: 0.7-1.3) for adenomas of the colon only. The multivariate RRs associated with weekly to daily laxative use compared to never use were 0.9 (95% CI: 0.7-1.1) for total colorectal adenomatous polyps, 1.0 (95% CI: 0.7-1.5) for large adenomas and 0.8 (95% CI: 0.6-1.2) for colon adenomatous polyps only.Conclusion: These findings do not support an association between infrequent bowel movement or laxative use and risk of colorectal adenomas. [ABSTRACT FROM AUTHOR]

Background: Diets high in fruits and vegetables have been shown to be associated with a lower risk of lung cancer. beta-Carotene was hypothesized to be largely responsible for the apparent protective effect, but this hypothesis was not supported by clinical trials.Methods: We examined the association between lung cancer risk and fruit and vegetable consumption in 77 283 women in the Nurses' Health Study and 47 778 men in the Health Professionals' Follow-up Study. Diet was assessed with the use of a food-frequency questionnaire that included 15 fruits and 23 vegetables. We used logistic regression models to estimate relative risks (RRs) of lung cancer within each cohort. All statistical tests were two-sided.Results: We documented 519 lung cancer cases among the women and 274 among the men. Total fruit and vegetable consumption was associated with a modestly lower risk of lung cancer among the women but not among the men. The RR for the highest versus lowest quintile of intake was 0.79 (95% confidence interval [CI] = 0.59-1.06) among the women and 1.12 (95% CI = 0.74-1.69) among the men after adjustment for smoking status, quantity of cigarettes smoked per day, time since quitting smoking, and age at initiation of smoking. However, total fruit and vegetable consumption was associated with a lower risk of lung cancer among never smokers in the combined cohorts, although the reduction was not statistically significant (RR = 0.63; 95% CI = 0.35-1.12 in the highest tertile).Conclusion: Higher fruit and vegetable intakes were associated with lower risks of lung cancer in women but not in men. It is possible that the inverse association among the women remained confounded by unmeasured smoking characteristics, although fruits and vegetables were protective in both men and women who never smoked. [ABSTRACT FROM AUTHOR]

Background: There is conflicting evidence on whether stress is a risk factor for breast cancer. The present study examined prospectively the relationship between stress at work and risk of breast cancer.Methods: Participants comprised 26 936 postmenopausal women in the Nurses' Health Study ages 46-72 who were in paid employment, and who had no previous history of cancer. Multivariate-adjusted regression analysis was used to examine the relationship between job strain (measured by the Karasek Job Content Questionnaire in 1992) and risk of incident invasive and in situ breast cancer.Results: From 1992 through 1994, 219 women were diagnosed with breast cancer. No evidence was found for a relationship between job stress and risk of breast cancer. Compared with women in low strain jobs, the multivariate-adjusted relative risks of breast cancer were RR = 0.78 (95% CI : 0.52-1.16) for high-strain jobs; RR = 0.76 (95% CI : 0.49-1.17) for active jobs; and RR = 0.94 (95% CI : 0.67-1.34) for passive jobs. Although job strain was related to less breast cancer screening among women in highly demanding jobs, it was not associated with tumour size.Conclusions: Job stress was not related to an increase in the incidence of breast cancer in the present cohort of nurses. [ABSTRACT FROM AUTHOR]

Context: Persuasive evidence has demonstrated that increased physical activity is associated with substantial reduction in risk of coronary heart disease. However, the role of physical activity in the prevention of stroke is less well established.Objective: To examine the association between physical activity and risk of total stroke and stroke subtypes in women.Design and Setting: The Nurses' Health Study, a prospective cohort study of subjects residing in 11 US states.Subjects: A total of 72,488 female nurses aged 40 to 65 years who did not have diagnosed cardiovascular disease or cancer at baseline in 1986 and who completed detailed physical activity questionnaires in 1986, 1988, and 1992.Main Outcome Measure: Incident stroke occurring between baseline and June 1, 1994, compared among quintiles of physical activity level as measured by metabolic equivalent tasks (METs) in hours per week.Results: During 8 years (560,087 person-years) of follow-up, we documented 407 incident cases of stroke (258 ischemic strokes, 67 subarachnoid hemorrhages, 42 intracerebral hemorrhages, and 40 strokes of unknown type). In multivariate analyses controlling for age, body mass index, history of hypertension, and other covariates, increasing physical activity was strongly inversely associated with risk of total stroke. Relative risks (RRs) in the lowest to highest MET quintiles were 1. 00, 0.98, 0.82, 0.74, and 0.66 (P for trend=.005). The inverse gradient was seen primarily for ischemic stroke (RRs across increasing MET quintiles, 1.00, 0.87, 0.83, 0.76, and 0.52; P for trend=.003). Physical activity was not significantly associated with subarachnoid hemorrhage or intracerebral hemorrhage. After multivariate adjustment, walking was associated with reduced risk of total stroke (RRs across increasing walking MET quintiles, 1.00, 0. 76, 0.78, 0.70, and 0.66; P for trend=.01) and ischemic stroke (RRs across increasing walking MET quintiles, 1.00, 0.77, 0.75, 0.69, and 0.60; P for trend=.02). Brisk or striding walking pace was associated with lower risk of total and ischemic stroke compared with average or casual pace.Conclusion: These data indicate that physical activity, including moderate-intensity exercise such as walking, is associated with substantial reduction in risk of total and ischemic stroke in a dose-response manner. JAMA. 2000. [ABSTRACT FROM AUTHOR]