Showing papers by "Arthur Schatzkin published in 2000"

Lack of Effect of a Low-Fat, High-Fiber Diet on the Recurrence of Colorectal Adenomas

Abstract: Background We tested the hypothesis that dietary intervention can inhibit the development of recurrent colorectal adenomas, which are precursors of most large-bowel cancers. Methods We randomly assigned 2079 men and women who were 35 years of age or older and who had had one or more histologically confirmed colorectal adenomas removed within six months before randomization to one of two groups: an intervention group given intensive counseling and assigned to follow a diet that was low in fat (20 percent of total calories) and high in fiber (18 g of dietary fiber per 1000 kcal) and fruits and vegetables (3.5 servings per 1000 kcal), and a control group given a standard brochure on healthy eating and assigned to follow their usual diet. Subjects entered the study after undergoing complete colonoscopy and removal of adenomatous polyps; they remained in the study for approximately four years, undergoing colonoscopy one and four years after randomization. Results A total of 1905 of the randomized subjects (91....

A prospective study of diet quality and mortality in women.

Abstract: Results There were 2065 deaths due to all causes in the cohort. The RFS was inversely associated with all-cause mortality. Compared with those in the lowest quartile, subjects in the upper quartiles of the RFS had relative risks for all-cause mortality of 0.82 (95% confidence interval [CI], 0.73-0.92) for quartile 2, 0.71 (95% CI, 0.620.81) for quartile 3, and 0.69 (95% CI, 0.61-0.78) for quartile 4 adjusted for education, ethnicity, age, body mass index, smoking status, alcohol use, level of physical activity, menopausal hormone use, and history of disease (x 2 1 for trend=35.64, P,.001

Evaluation of Alternative Approaches to Assign Nutrient Values to Food Groups in Food Frequency Questionnaires

Abstract: Although every food frequency questionnaire (FFQ) requires a nutrient database to produce nutrient intake estimates, it is often unclear how a particular database has been generated. Moreover, alternative methods for constructing a database have not been rigorously evaluated. Using 24-hour recalls from the 1994-1996 Continuing Survey of Food Intake by Individuals, the authors categorized 5,261 individual foods reported by 10,019 adults into 170 food groups consistent with line items on an FFQ. These food groups were used to generate 10 potential nutrient databases for a FFQ that varied by whether the authors 1) used means or medians, 2) did or did not consider age, 3) incorporated collapsing strategies for small age-gender-portion size cells, 4) excluded outliers in a regression, and 5) used weighted median nutrient density x age-gender-portion size-specific median gram weights (Block method). Mean error, mean squared error, and mean absolute error were calculated and compared across methods, with error being the difference in total observed (from recalls for each individual) and total estimated intake (from each of the 10 methods) for seven nutrients. Mean methods for assigning nutrients to food groups were superior to median approaches for all measurements. Among the mean methods, no single variation was consistently better.

Dietary fat, fat subtypes, and breast cancer in postmenopausal women: a prospective cohort study.

Abstract: Background: The intake of total dietary fat and of certain fat subtypes has been shown to be strongly associated with breast cancer in international comparisons and in animal experiments. However, observational epidemiologic studies have generally reported either weak positive or no associations. To extend the prospective epidemiologic evidence on this question, we examined the association between adult dietary intake of fat, fat subtypes, and breast cancer in a large, prospective cohort of postmenopausal women. Methods: Participants were selected from a national breast cancer mammography screening program conducted from 1973 through 1981 at 29 centers throughout the United States. From 1987 through 1989, 40022 postmenopausal women satisfactorily completed a mailed, self-administered questionnaire that included a 60-item National Cancer Institute/Block food-frequency questionnaire. Women were then followed for an average of 5.3 years; 996 women developed breast cancer. Risk was assessed by use of Cox proportional hazard regression, with age as the underlying time metric. All statistical tests were two-sided. Results: Compared with women in the lowest quintile (Q1) of percentage of energy from total fat, the adjusted risk ratio (RR) and 95% confidence interval (CI) for women in the highest quintile (Q5) was 1.07 (95% CI = 0.86-1.32). In analyses stratified by history of benign breast disease (BBD), a positive association was observed among only women with no history of BBD (RR Q5 versus Q1 = 2.20; 95% CI = 1.41-3.42; test for trend, P = .0003). The increased risk in these women appeared to be attributable to unsaturated fat intake and oleic acid in particular. Conclusions: In this study, there was no overall association between fat intake during adulthood and breast cancer risk; however, among women with no history of BBD, there appeared to be a positive association between total and unsaturated fat intake and breast cancer risk.

Intermediate markers as surrogate endpoints in cancer research.

Abstract: This article addresses theoretical and practical problems in using surrogate endpoints in experimental and observational studies of cancer.