Re: "Nutritional epidemiology of postmenopausal breast cancer in western New York".
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Breast Neoplasms↗
Biomedical subjects
G R Howe
Publications and source records attributed to G R Howe.
Dietary fiber, vitamins A, C, and E, and risk of breast cancer: a cohort study.
Risk of breast cancer was examined in relation to intake of dietary fiber and vitamins A, C, and E, and food groups which are sources of these dietary constituents, in a cohort of 56,837 women enrolled in the Canadian National Breast Screening Study. Between 1982 and 1987, 519 incident, histologically confirmed cases of breast cancer were identified among women who previously had completed self-administered dietary questionnaires. Their nutrient and food intake was compared with that of 1,182 women who had not developed breast cancer during the follow-up period. Women at the uppermost quintile level of dietary fiber intake had a 30 percent reduction in risk of breast cancer relative to that for women at the lowest quintile level (adjusted odds ratio = 0.68, 95 percent confidence interval = 0.46-1.00), and the reduction in risk persisted after adjustment (separately) for total vitamin A, beta-carotene, vitamin C, and alpha-tocopherol. Inverse associations of similar magnitude were observed in association with consumption of pasta, cereals (the trend for which was statistically significant), and vegetables rich in vitamins A and C. Smaller, statistically nonsignificant reductions in risk were observed with increasing intake of dietary retinol, beta-carotene, and vitamin C, but the magnitude of these associations was reduced after adjustment for other dietary factors. Vitamin E intake was not associated with altered risk of breast cancer.
Ascorbic Acid↗
Recall bias in the association of micronutrient intake and breast cancer.
A nested case-control study within the Canadian National Breast Screening Study was conducted to examine whether there was evidence for recall bias in the reporting of past micronutrient intake. Dietary data collected upon enrollment between 1982 and 1985 from 325 breast cancer cases and 628 matched controls were compared with data collected in 1988 after disease diagnosis. The retrospective estimates of mean micronutrient intakes from food sources were found to be very similar to the prospective estimates for cases and controls. Errors of omission and commission for the reporting of previous supplementary vitamin use were identical for both subject groups. The odds ratios estimated for the association of micronutrient intake and breast cancer for the prospective and retrospective data were similar in magnitude and the 95% confidence intervals overlapped considerably. There was no evidence for recall bias in the estimation of past micronutrient intake by breast cancer cases as compared to controls.
Bias↗
Cancer mortality (1956-1985) among male employees of Atomic Energy of Canada Limited with respect to occupational exposure to external low-linear-energy-transfer ionizing radiation.
The mortality experience between 1956 and 1985 of 8977 males employed by Atomic Energy of Canada Limited is reported. A total of 4260 men, 47% of the cohort, were exposed to low doses of external ionizing radiation at low dose rates, with a mean cumulative equivalent dose of 52.1 mSv. For cancers as a whole the excess relative risk, based on 227 deaths, was 0.36% per 10 mSv (90% confidence bounds -0.46, 2.45). This is quite comparable to the corresponding estimate based on the atomic bomb survivors study. There was a positive association between radiation dose and death from leukemia (excluding chronic lymphatic leukemia) P = 0.058. However, this was based on only four deaths and hence cannot sensibly be compared to estimates based on high-dose studies. The present results suggest that, for cancer as a whole, risk estimates based on high-dose studies are unlikely to underestimate risks substantially for low-dose and low-dose-rate exposures.
Canada↗
The Canadian Labour Force Ten Percent Sample Study. Cancer mortality among men, 1965-1979.
The mortality experience of 415,309 men enrolled in the Canadian Labour Force 10% Sample Study has been updated to the end of 1979. The occupation and industry in which these men were employed between 1965 and 1969 were available, and these records were matched to the Canadian National Mortality Data Base by computerized record linkage. A total of 9,739 deaths from cancer between 1965 and 1979 were identified. Analyses were conducted with respect to men employed in 274 occupations and 294 industries with respect to mortality from 33 different types of cancer resulting in 243 associations in which the 90% lower confidence bound for the relative risk compared to the whole cohort had a value of 1.0 or greater. Based on the criteria of strength of association, dose-response, and consistency, 23 associations were identified as being of particular interest. Of these associations, four (waiters, bartenders and breweries with cancer of the buccal cavity and pharynx, and bartenders with lung cancer) seem most likely to be caused by excess smoking and/or alcohol consumption, and could provide a useful guide for intervention strategies focused on those employed in these occupations. A further seven (carpenters and stomach cancer, clerical occupations and colon cancer, truck drivers, plumbers and pipefitters, sheet metal workers, shipbuilding and repair, and asbestos products manufacturers with lung cancer) have support in terms of biological plausibility and/or other studies in the literature and appear to warrant more intensive study. The third group of associations, although demonstrating strength of association, a dose-response effect, and/or consistency, may well have arisen by chance given the many comparisons made in this study.
Adult↗
Dietary intake of fiber and decreased risk of cancers of the colon and rectum: evidence from the combined analysis of 13 case-control studies.
BACKGROUND: Colorectal cancer is a major public health problem in both North America and western Europe, and incidence and mortality rates are rapidly increasing in many previously low-risk countries. It has been hypothesized that increased intakes of fiber, vitamin C, and beta carotene could decrease the risk of colorectal cancer. PURPOSE: The objective of this study was to examine the effects of fiber, vitamin C, and beta-carotene intakes on colorectal cancer risk in a combined analysis of data from 13 case-control studies previously conducted in populations with differing colorectal cancer rates and dietary practices. The study was designed to estimate risks in the pooled data, to test the consistency of the associations across the studies, and to examine interactions of the effects of the nutrients with cancer site, sex, and age. METHODS: Original data records for 5287 case subjects with colorectal cancer and 10,470 control subjects without disease were combined. Logistic regression analysis was used to estimate relative risks and confidence intervals for intakes of fiber, vitamin C, and beta carotene, with the effects of study, sex, and age group being adjusted by stratification. RESULTS: Risk decreased as fiber intake increased; relative risks were 0.79, 0.69, 0.63, and 0.53 for the four highest quintiles of intake compared with the lowest quintile (trend, P < .0001). The inverse association with fiber is seen in 12 of the 13 studies and is similar in magnitude for left- and right-sided colon and rectal cancers, for men and for women, and for different age groups. In contrast, after adjustment for fiber intake, only weak inverse associations are seen for the intakes of vitamin C and beta carotene. CONCLUSION: This analysis provides substantive evidence that intake of fiber-rich foods is inversely related to risk of cancers of both the colon and rectum. IMPLICATIONS: If causality is assumed, we estimate that risk of colorectal cancer in the U.S. population could be reduced about 31% (50,000 cases annually) by an average increase in fiber intake from food sources of about 13 g/d, corresponding to an average increase of about 70%.
Adolescent↗
Leukemia and other cancers around UK nuclear installations.
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Air Pollution, Radioactive↗
High-fat diets and breast cancer risk. The epidemiologic evidence.
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Bias↗
Colon cancer in Argentina. II: Risk from fibre, fat and nutrients.
A case-control study has been conducted to investigate the relationship between total energy intake, fibre and nutrients and colon cancer in Argentina. Cases are 110 newly diagnosed patients from 10 hospitals between 1985 and 1986. Two neighbourhood controls per case were matched on age, sex and place of residence. The intake of calories, fibre and nutrients was estimated from the information collected on food consumption during the 5-year period up to 6 months prior to interview of subjects, based on a pilot study and standard portion sizes in Argentina. In conditional regression models, dietary fibre is highly protective (odds ratio (OR) = 0.07 per 19.02 g/day; 95% confidence interval (CI): 0.02 to 0.25) and total energy intake increases risk (RR = 1.82 per 1000 kcal/day; 95% CI: 1.20 to 2.77), each with adjustment for the other. Analysis of caloric components (fat, protein and carbohydrates) reveals that carbohydrates are the most important factor driving the total energy effect. Other nutrients make little apparent contribution to risk.
Adult↗
A collaborative case-control study of nutrient intake and pancreatic cancer within the search programme.
Case-control studies of pancreatic cancer were conducted in 5 populations with moderate to high rates and differing dietary practices, using a common protocol and questionnaire. Comprehensive diet histories were completed for a total of 802 cases and 1669 controls identified in Adelaide (Australia), Montreal and Toronto (Canada), Utrecht (The Netherlands) and Opole (Poland). Positive associations were observed with intake of carbohydrates and cholesterol, and inverse associations with dietary fiber and vitamin C. These relationships were generally consistent among the 5 studies, and showed statistically significant and generally monotonic dose-response relationships. The relative risks for highest vs. lowest quintile of intake were estimated for carbohydrates to be 2.57 (95% confidence interval 1.64-4.03), cholesterol 2.68 (1.72-4.17), dietary fiber 0.45 (0.30-0.63), and vitamin C 0.53 (0.38-0.76). The consistency, strength, and specificity of these associations provides evidence for the hypothesis that some or all of these dietary factors may alter the risk of pancreatic cancer.
Adult↗
Risk factors for fibroadenoma: a case-control study in Australia.
Risk factors for fibroadenoma were examined in a case-control study involving 117 fibroadenoma cases ascertained by a major private pathology laboratory in Adelaide, Australia, between January 1983 and October 1985. For each case a population control was randomly selected from the electoral roll in Adelaide and matched to the corresponding case by sex, age, and socioeconomic grading of area of residence. Another 189 women whose first biopsy for benign breast disease was examined in the same laboratory during the same time period as those of the cases, but did not show evidence of epithelial proliferation, were also included in the study as a biopsy control group. Risk of fibroadenoma was associated inversely with the Quetelet index, but there was no evidence of an association with age at menarche or menopausal status. The risk of fibroadenoma decreased with an increasing number of full-term pregnancies and was increased in association with use of oral contraceptives at an early age (under 20 years); however, these two associations were observed only when cases were compared with the population controls. Alcohol consumption and dietary fat intake were found not to be associated with altered risk of fibroadenoma, while in multivariate analyses, duration of cigarette smoking and daily vitamin C intake were both shown to have inverse associations with risk of fibroadenoma. Although fibroadenoma does share some risk factors with breast cancer, there is insufficient evidence to suggest that it represents a precursor state.
Adenofibroma↗
Occupational exposure to sulfuric acid in southern Ontario, Canada, in association with laryngeal cancer.
A case-referent study, designed to test associations between asbestos, nickel, and the development of laryngeal cancer, was conducted in southern Ontario in 1977-1979. The cases were individually matched to neighborhood referents for gender and age. This constituted the primary study. Personal interviews had secured tobacco, alcohol, and detailed work histories. To 183 of the male pairs was added retrospective assessments of sulfuric acid exposure for each job, blind of disease status; this constituted the data base for an augmented secondary analysis. Logistic regression revealed statistically significant odds ratios when tobacco and alcohol were controlled. Exposure-response gradients were strongly positive with odds ratios in the range of 1.97 [95% confidence interval (95% CI) 0.63-6.13] for short duration-low level exposure through 6.91 [95% CI 2.20-21.74] for long duration-higher level exposure employing progressively more specific definitions of exposure. Asbestos as a confounder and the interaction terms examined were nonsignificant. These findings are corroborative of those of other studies.
Adult↗
Using dead controls to adjust for confounders in case-control studies.
The use of dead controls in a case-control study, the primary purpose of which is to control for confounding, leads to consistent relative risk estimates within stratum of the confounder, even if the causes of death of controls are associated with that confounder. Dead controls may be more comparable to dead cases in terms of data quality, and therefore, under these circumstances, the use of dead controls may be advantageous.
Case-Control Studies↗
Nutritional factors and pancreatic cancer: a case-control study from south-west Poland.
A population-based case-control study of diet and pancreatic cancer has been conducted in the Opole Voivodeship region in Poland, using 110 cases and 195 controls. A full diet history was used to estimate the daily intake of calories, fat, protein, carbohydrate, cholesterol, retinol, vitamin C, and fibre. There is a strong positive association with the intake of cholesterol with relative risks of 1.90, 3.77, and 4.31 for the 3 upper quartiles compared with the lowest (p, trend = less than 0.01). An inverse association was seen with vitamin C intake, with corresponding relative risks of 1.10, 0.30, and 0.37 (p, trend = less than 0.01). Weak inverse associations were seen with the intake of retinol and fibre. There is evidence of an inverse association with fat intake, particularly unsaturated fats, and of a positive association with the intake of carbohydrate and to a lesser extent, protein. These results further support the potential importance of dietary factors in the aetiology of cancer of the pancreas.
Case-Control Studies↗
Risk of cancer mortality in populations living near nuclear facilities.
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Humans↗
A cohort study of fat intake and risk of breast cancer.
Between 1982 and 1987, 519 newly incident, histologically confirmed cases of breast cancer were identified in a cohort of 56,837 women enrolled in the Canadian National Breast Screening Study. These women had completed a dietary questionnaire before the occurrence of their breast cancer, and this has been used to estimate their intake of dietary fat and several other nutrients. There is evidence of a positive association between breast cancer and total fat intake, with a relative risk of 1.35 (95% confidence interval, 1.00-1.82) per 77 g per day, and some evidence of a dose-response relationship (P = .052).
Adult↗
Cigarette smoking and cancer of the pancreas: evidence from a population-based case-control study in Toronto, Canada.
Results are reported with respect to smoking data from a population-based case-control study of pancreatic cancer conducted in Toronto, Canada, between 1983 and 1986. Lifetime smoking histories were obtained for 249 cases and 505 controls. A statistically highly significant positive association was observed between lifetime cigarette consumption and risk of pancreatic cancer. There was a rapid decrease in risk with time for those who quit cigarette smoking, the risk for ex-smokers being the same as for lifetime non-smokers between 10 and 15 years after quitting. Limiting exposure to the 15 years prior to diagnosis considerably strengthens the association and leads to a much more clearly defined dose-response relationship with relative risks of 1.88, 4.61, and 6.52 for tertiles of consumption for current cigarette smokers compared with lifetime non-smokers (p trend less than 10(-5)). We conclude that the current data, together with those from previous studies, strongly support a causal relationship between cigarette smoking and risk of pancreatic cancer, and indicate that cessation of smoking is likely to prove a rapidly effective preventive measure for this major type of cancer.
Adult↗
Coffee and alcohol as determinants of risk of pancreas cancer: a case-control study from Toronto.
Results are reported from a population-based study of 249 cases of pancreas cancer and 505 controls carried out in Toronto, Canada, between 1983 and 1986. Lifetime consumption of coffee and alcohol and medical histories were assessed by personal interviews. No evidence of any association was found with different types of coffee or alcohol after adjusting for smoking, calories and fibre intake. There was a significant increased risk associated with a history of diabetes mellitus within 5 years of cancer development. A protective effect of a history of some allergic conditions, hay fever, eczema and asthma, was observed, although the relative risks were not significant (p value greater than 0.10).
Adult↗