摘要:

AbstractEvidence from epidemiological studies suggests that dietary fiber, as well as fat, has the potential for affecting breast cancer risk. Fiber may have a protective role because of its influence on estrogen metabolism and excretion or because of the endocrine effects of the lignans, a family of compounds formed in the intestine from fiber‐associated precursors. Future research should include additional mechanistic studies and dietary intervention trials in groups of women that have a high risk of breast cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514040

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe associations between colorectal cancer and body weight (expressed as body mass index) and between colorectal cancer and physical activity were examined in 715 histologically confirmed cases of colorectal adenocaircinoma and 727 age‐and sex‐matched controls. The data were obtained from a large, population‐based study, The Melbourne Colorectal Cancer Study, which was conducted in Melbourne, Australia. There was a statistically significant increase in the risk of rectal cancer but not of colon cancer in overweight and obese males but not in females. This association for males remained statistically significant after adjustment was made for dietary risk factors previously established for this study (Nutr Cancer 9, 21–42, 1987), with the exception of sodium intake, which produced a downward modification of the relative risk close to unity. The increased risk of rectal cancer in overweight and obese males was modified by beer intake, which was previously found to be a risk for rectal cancer in males in this study. Various levels of physical activity were not statistically significantly associated with the risk of colorectal cancer in either males or females. Also, the colorectal cancer risks associated with the body mass index were not significantly altered by adjustment for the physical activity level.

ISSN:0163-5581    

DOI:10.1080/01635589009514041

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractWe examined the nutritional epidemiology of gastric cancer in 293 cases and neighborhood‐, age‐, and sex‐matched controls in communities throughout the counties of Niagara, Monroe, and Erie in western New York. The interview was highly detailed, requiring two and one‐half hours to complete; it attempted to provide an estimate of total calories ingested as well as of macro‐and micronutrients and behaviors that could affect alimentary exposures, such as the use of refrigeration. We found that risk was enhanced by sodium, fat, and retinol. Substantial reductions in risk were associated with ingestion of carotene, especially raw vegetables (including celery, cucumbers, carrots, green peppers, tomatoes, and onions), as well as with increased use of low‐temperature food storage. Both refrigeration and carotene could inhibit oxidation products that could act as carcinogens in the stomach.

ISSN:0163-5581    

DOI:10.1080/01635589009514042

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractIn the absence of complete dietary information on a cohort of 472 early‐stage breast cancer patients a caloric prediction technique was developed. Deriving an accurate caloric denominator would enable examination of individual nutrient effects by controlling for potential confounding by calories. Surrogate measures of mean daily caloric intake were generated from estimates of basal metabolic rate (BMR) predicted from age, height, weight, and physical activity. A validation study was undertaken to test the relationship between the BMR proxy terms and mean daily energy intake obtained from four‐day food diaries for 51 subjects. Pearson correlation coefficients between the diary‐derived and predicted values of caloric intake were computed (r = 0.43, p = 0.001). The results are in the range of what many researchers found when comparing self‐reports of total caloric intake in validation and reliability studies of various dietary assessment tools. Because of the large heterogeneity of results across the ages represented in this study (25–77 yrs), it is recommended that small validation studies of this type be carried out in the subpopulations of interest.

ISSN:0163-5581    

DOI:10.1080/01635589009514043

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractColon cancer is the second most common type of cancer in the United States. Bile acids have been implicated in the etiology of this disease. In a previous study, we showed that bile acids can damage DNA in vitro. In this study, we report that this damage is largely prevented when the bile acids are pretreated with cellulose fiber. Preliminary data show that cellulose may act as a catalyst to promote polyesterification of bile acid to a biologically inactive form.

ISSN:0163-5581    

DOI:10.1080/01635589009514044

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractA case‐control study for stomach cancer was conducted in a high‐risk population in Nariño, Colombia to determine the risk of gastric precancerous lesions associated with salt intake measured by sodium‐to‐creatinine ratio of a single urine sample. Gastric biopsies and urine samples were collected from 263 individuals. Urinary sodium‐to‐creatinine ratios were studied in relation to histological data from the biopsies. Significantly high odds ratios for precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) were associated with higher sodium‐to‐creatinine ratios. Adjusted odds ratios (OR) of 2.50 for chronic atrophic gastritis and 7.24 for dysplasia were found. The association with intestinal metaplasia was weaker and not significant (OR = 1.57). Furthermore, an excess risk associated with adding salt to food at the table was found among patients with precancerous lesions (OR = 1.80). These findings support the two‐step involvement of salt in the process of gastric precancerous lesions.

ISSN:0163-5581    

DOI:10.1080/01635589009514045

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractGastric nitrite content was studied in relation to precancerous lesions of the stomach in a case‐control study conducted in a high‐risk Colombian population. The proportion of detectable nitrite in gastric juice and the mean pH were significantly higher among those with precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) than among the controls (normal and superficial gastritis); the proportion and mean pH increased with the progression of histological changes from normal to dysplasia. Nitrite was not detectable in gastric juice with a pH less than 5.0. A positive association was found between the proportion of detectable nitrite and the risk of gastric precancerous lesions. Odds ratios of 4.39 for intestinal metaplasia and 24.72 for dysplasia remained significant after controlling for confounders. This finding suggests that nitrite may be a precursor of a mutagen that targets gastric epithelial cells.

ISSN:0163-5581    

DOI:10.1080/01635589009514046

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractAlthough the inhibitory effect of caloric restriction on tumorigenesis is substantial and well known, the pertinent mechanisms remain to be determined. We recently suggested that the risk of cancer may be directly related to the total number of dividing cells within an affected organ. This study evaluates the effects of early caloric restriction on the cellular growth of the colon. The experiment began one day postpartum and ended six weeks later with the killing of all animals. It consisted of two consecutive periods: a) three weeks of suckling and b) three weeks postweaning. Animals whose food was restricted only during the suckling period showed normal colons when killed at six weeks. Caloric restriction (40%) for three weeks postweaning resulted in colons of lower weight with fewer cells (less total DNA) and reduced total DNA synthesis ([3H]thymidine uptake, dpm/colon) when compared with animals fed ad libitum postweaning. Conversely, only rats fed ad libitum from birth through the first three weeks after weaning demonstrated an increase (21%) in the rate of DNA synthesis (dpm/mg DNA) compared with other animals. In addition, the colonic crypts showed no differences in the number of cells or the number of dividing cells, as determined by autoradiography. By contrast, the total number of crypts (and/or the number of mucosal cells between crypts) are reduced, and hence the total number of colonic mucosal cells dividing at any given time are similarly decreased. The reduced number of dividing cells in the colons of these animals (i.e., those restricted postweaning) could explain previous data suggesting that they are resistant to the induction of colon cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514047

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractBoth selenium and calorie restriction are anticarcinogenic in many tumor models, but the mechanisms of action are unknown. This study compared the effects of elevated selenium (Se) intake and calorie restriction on coionic cellular growth. Female weanling rats were divided into four groups: control, 40% calorie restricted, and 4 or 6 mg Se/l H2O as selenate. Control rats and rats given Se consumed the control diet ad libitum. Rats in the 40% calorie‐restricted group were pair fed 40% less than the total intake of control rats with a diet designed to provide equal nutrients except calories from carbohydrate. After three weeks, rats were injected with [3H]thymidine (1μCi/g body wt) and killed one hour later. Se at 4 and 6 mg/l H2O and 40% calorie restriction significantly decreased food intake, weight gain, colon weight, and total colon DNA compared with controls. Total number of cells per crypt was not affected by any treatment, whereas total DNA synthesis was significantly decreased, suggesting that the total number of coionic crypts are reduced by calorie restriction and Se treatment. The rate of cell division was decreased only in rats given 6 mg Se/l H2O. These results indicate that elevated Se intake and caloric restriction decrease coionic mucosal growth by decreasing growth in general, but only very high intakes of Se affect coionic cell turnover.

ISSN:0163-5581    

DOI:10.1080/01635589009514048

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe reported milk consumption habits of 3,334 cancer patients and 1,300 comparable control subjects seen at Roswell Park Memorial Institute were studied. The cancer patient group included persons diagnosed with cancers of the oral cavity, stomach, colon, rectum, lung, breast, uterus, cervix, prostate, or bladder. Data were obtained by means of a standardized admissions questionnaire. As a group, control patients were more likely to report never drinking whole milk; cancer patients more often reported frequent consumption of whole milk. Relative risks of different patterns of milk consumption for specific cancer diagnoses, adjusted for sex, age, smoking history, education, and county of residence, were calculated with multiple logistic regression analysis. Elevated risks for frequent consumption of whole milk relative to not drinking milk were observed for cancers of the oral cavity, stomach, colon, rectum, lung, bladder, breast, and cervix. Reduced risks for frequent consumption of 2% milk relative to not drinking milk were observed for cancers of the oral cavity, stomach, rectum, lung, and cervix. Preference for exclusive consumption of reduced‐fat milk was linked to significant risk reduction for oral and cervical cancers, and drinking only whole milk was linked to significant risk increases for cancers of the oral cavity, stomach, rectum, lung, and breast. Some associations were observed for a computed index of milk fat intake, but the overall pattern of effects was not fully explained by variations in fat content. The effects observed for some sites may be confounded by other dietary or nondietary correlates of risk.

ISSN:0163-5581    

DOI:10.1080/01635589009514049

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor