Types of advance notification in reminder letters and response rates.
Explore the source record for details and available documents.
Adolescent↗
Biomedical subjects
T E Rohan
Publications and source records attributed to T E Rohan.
Risk factors for breast cancer mortality among the National Breast Screening Study of Canada participants.
We studied the relationship between risk factor information and breast cancer mortality by means of a case control study, nested within the population of the National Breast Screening Study of Canada (NBSS). The characteristics of women aged 40-59 years, identified at the initial screen, who subsequently died of breast cancer up to 7 years from the initial screen, were compared with those of controls drawn from the same population. Among the factors evaluated in this study, number of live births and presence of symptoms in the breast revealed on direct questioning were found to be significantly related to breast cancer mortality. The results suggest a decrease in risk of dying of breast cancer associated with one or more live births (OR: 0.79, 95% CI: 0.68, 0.93), and an increase in risk of dying of breast cancer associated with symptoms in the breast revealed on direct questioning at the initial screen (OR: 2.01, 95% CI: 1.20, 3.37).
Adult↗
Dietary fiber and risk of benign proliferative epithelial disorders of the breast.
Following a recent finding, from a case-control study in Adelaide, South Australia, of a reduced risk of breast cancer among women consuming diets rich in fiber, the fiber densities in the diets of 354 women with incident benign proliferative epithelial disorders of the breast (BPED) were compared with the fiber densities of the diets of 354 matched community controls and with those of 189 unmatched controls having breast conditions for which there was no evidence of BPED at biopsy. Fiber intakes were estimated by means of a self-administered quantitative food-frequency questionnaire, and the risk of BPED was estimated for each quintile of fiber density (grams of fiber/megaJoule of total energy intake) relative to an arbitrarily assigned risk of one for the lowest quintile. For women with the highest dietary fiber densities the estimated risk was 0.64 (95% CI 0.34, 1.19) when cases were compared with community controls, and 0.45 (95% CI 0.24, 0.82) when cases were compared with biopsy-negative controls. Similar trends in risk were observed for the intakes of other major fiber components, the association being stronger when the comparison was made with biopsy-negative as opposed to community controls. If these findings can be substantiated, they may open the way to dietary intervention strategies for reducing the incidence of breast cancer.
Adult↗
Dietary factors and risk of prostate cancer: a case-control study in Ontario, Canada.
The relationship between risk of prostate cancer and dietary intake of energy, fat, vitamin A, and other nutrients was investigated in a case-control study conducted in Ontario, Canada. Cases were men with a recent, histologically confirmed diagnosis of adenocarcinoma of the prostate notified to the Ontario Cancer Registry between April 1990 and April 1992. Controls were selected randomly from assessment lists maintained by the Ontario Ministry of Revenue, and were frequency-matched to the cases on age. The study included 207 cases (51.4 percent of those eligible) and 207 controls (39.4 percent of those eligible), and information on dietary intake was collected from them by means of a quantitative diet history. There was a positive association between energy intake and risk of prostate cancer, such that men at the uppermost quartile level of energy intake had a 75 percent increase in risk. In contrast, there was no clear association between the non-energy effects of total fat and monounsaturated fat intake and prostate cancer risk. There was some evidence for an inverse association with saturated fat intake, although the dose-response pattern was irregular. There was a weak (statistically nonsignificant) positive association between polyunsaturated fat intake and risk of prostate cancer. Relatively high levels of retinol intake were associated with reduced risk, but there was essentially no association between dietary beta-carotene intake and risk. There was no alteration in risk in association with dietary fiber, cholesterol, and vitamins C and E. Although these patterns were evident both overall and within age-strata, and persisted after adjustment for a number of potential confounding factors, they could reflect (in particular) the effect of nonrespondent bias.
Adenocarcinoma↗
Familial risk, abortion and their interactive effect on the risk of breast cancer--a combined analysis of six case-control studies.
In a previous study in France, we reported that the relative risk of breast cancer associated with a family history of breast cancer was higher in those subjects with a history of abortions. The present study was undertaken to check the existence of this interaction in other studies and to investigate whether the interaction is modified by the time at which abortions occur. Data were obtained from six case-control studies in France, Australia and Russia, with information on family history of breast cancer and abortion for 2693 breast cancer cases and 3493 controls. The interaction effect was estimated in each study separately, then combined using a multivariate weighted average. The relative risk conferred by a family history of breast cancer increased with the number of abortions (1.8 for no abortion, 1.9 for one abortion, 2.8 for two or more). There was a significant interaction between total number of abortions and family history (P = 0.04), but this was no longer significant when adjusted for other risk factors. The familial risk was highest for those who had had an abortion before first childbirth (1.9 for abortion after first childbirth, 2.7 for abortion before first childbirth). The adjusted risk associated with family history was significantly higher in those with an abortion before first childbirth (P = 0.04). Our findings suggest a synergism between familial factors and abortion. The interaction was not substantially modified by the type of abortion (spontaneous or induced) but was modified by the time at which it occurred in relation to first childbirth. This suggests an effect of abortion itself rather than predisposition to abortion. Further studies of breast cancer cases, particularly among BRCA1 gene carriers and their families, could improve our understanding of this effect.
Abortion, Induced↗
A review of physical activity and breast cancer.
Breast cancer risk is influenced by endogenous hormones. Physical activity may offer one means for the primary prevention of breast cancer through its influence on ovarian hormones. This influence is manifested by changes in age at menarche and the number and nature of ovulatory menstrual cycles, factors that themselves are related to breast cancer risk. Animal experimental studies show that breast cancer risk is decreased by exercise at the time of tumor initiation but not necessarily by exercise during tumor promotion. Epidemiologic studies indicate, overall, a decreased risk of breast cancer among those women who are more physically active, whereas experimental studies of the effects of exercise in women have shown that exercise can influence characteristics of the menstrual cycle. Nevertheless, the experimental studies in women and epidemiologic studies of physical activity and breast cancer risk have been hampered by a number of methodologic limitations. The major problems in the epidemiologic studies include crude and incomplete measurements of physical activity over a woman's lifetime and inadequate control for potential confounding factors. Experimental studies of the effects of physical activity on menstrual activity in women have not adequately quantified the intensity of activity and the resultant effects on menstrual cycle changes.
Animals↗
Printed signatures and response rates.
Explore the source record for details and available documents.
Adolescent↗
Physical activity and risk of breast cancer.
The association between recreational physical activity and breast cancer risk was examined in a population-based case-control study in Adelaide, Australia between 1982 and 1984. There were 451 incident, histologically confirmed cases of breast cancer, identified through the South Australian Central Cancer Registry, which were each age-matched to one control selected at random from the electoral register. These women, aged 20-74 years at diagnosis, reported their level of weekly recreational physical activity in a self-administered questionnaire. The questionnaire reports of light, moderate and vigorous physical activity were converted into total kilocalories per week of energy expenditure. A decrease in risk of breast cancer was found with increasing levels of total recreational physical activity (P (trend) = 0.09). The adjusted odds ratio for those women who expended more than 4,000 kcal/week was 0.73 (95% confidence interval (CI) 0.51-1.05) compared with women who undertook no physical activity. The reduction in risk with recreational physical activity was most evident for women who undertook any vigorous activity. These results provide some support for the hypothesis that physical activity may decrease the risk of developing breast cancer.
Adult↗
Physical activity and survival from breast cancer.
The association between recreational physical activity and survival from breast cancer was investigated in a population-based cohort of breast cancer patients in Adelaide, South Australia. These patients, aged 20-74 years at diagnosis, had been recruited between 1982 and 1984 into a case-control study of diet, hormones and breast cancer. Of the 451 patients with breast cancer originally enrolled, 412 were followed for a median interval of 5.5 years. The study participants reported their weekly levels of light, moderate and vigorous recreational physical activity, which were then converted into estimates of kilocalories per week of energy expenditure. Despite some fluctuation in the hazard ratios by level of physical activity, there was little evidence for an association between total recreational physical activity and risk of death from breast cancer overall, or within menopausal strata. Similarly, there was little evidence for associations between individual types of recreational physical activity and risk of death from breast cancer.
Adult↗
Design and analysis considerations in a cohort study involving repeated measurement of both exposure and outcome: the association between genital papillomavirus infection and risk of cervical intraepithelial neoplasia.
Cohort studies commonly involve a single determination of exposure, and one or more assessments of whether or not the outcome of interest has occurred. This approach is appropriate when the exposure does not change with time, and when one can readily determine the time of outcome (for example, mortality). If either of these conditions is not met, however, we may introduce bias into the estimate of effect, since we may misclassify individual members of the cohort with respect to exposure, outcome or both. We can reduce this bias by measuring exposure and outcome on more than one occasion. In this paper, we illustrate the design and analysis issues that arise in such circumstances, by reference to an ongoing prospective study of the relationship between genital papillomavirus infection and risk of cervical intraepithelial neoplasia. This study entails annual assessments of the status of the study subjects with respect to both conditions. In particular, we examine the implications that use of this design has on the statistical power of the study.
Adult↗
High-fiber diets and reduced risk of breast cancer.
In a case-control study of 451 women with breast cancer and 451 population-based controls from metropolitan Adelaide, Australia, the risk of breast cancer was studied in relation to intake of dietary fiber and various fiber components. Intakes were estimated by means of a self-administered quantitative food-frequency questionnaire, and risks of breast cancer were estimated for each quintile of fiber density (intake/megaJoule of total energy intake) relative to an arbitrarily assigned risk of unity for women in the lowest quintile of fiber density. There were highly significant reductions in relative risk associated with increasing intake of a number of components of total dietary fiber. In women with the highest 20% estimated dietary densities of total non-starch polysaccharides (NSP), the relative risk of breast cancer was 0.46, and a test for trend across the quintiles was significant at p < 0.001. Separate risk estimations for various fiber components defined by the Englyst method of analysis revealed highest risk reductions associated with high densities of mannose from insoluble NSP and of glucose from soluble NSP. For many fiber components the point estimates of relative risk were quite similar both for pre- and for post-menopausal women, although results for the latter (who comprised over two thirds of all cases) were statistically more significant. The study provides strong support for recent conjecture that foods rich in dietary fiber may be protective against breast cancer.
Adult↗
Repeatability of interview-derived information on sexual history: a study in women.
We assessed the repeatability of interview-derived information on age at first sexual intercourse and number of sexual partners in women participating in an ongoing prospective study of genital human papillomavirus infection in Toronto, Canada. Of the 100 study participants invited to attend for re-interview twice during their first year in the study, 74 attended for the first follow-up interview about 5 months after recruitment, and 28 of these 74 subjects attended for a second interview about 4 months later. For both age at first sexual intercourse and number of sexual partners, intraclass correlation coefficients were high, ranging from 0.94 to 0.98. Repeatability differed a little by human papillomavirus status, but not by levels of other relevant factors.
Adolescent↗
Recreational physical activity and risk of benign proliferative epithelial disorders of the breast in women.
The association between recreational physical activity and the risk of benign proliferative epithelial disorders (BPED) of the breast was examined in a case-control study conducted in Adelaide, Australia, between 1983 and 1985. The study included 383 incident, histologically confirmed cases of BPED identified through the major private pathology laboratory, 383 unbiopsied community controls matched to the cases for age and area of residence, and 192 controls whose biopsies did not show any signs of epithelial proliferation. Subjects reported their level of usual weekly physical activity in a self-administered questionnaire. When cases were compared with community controls, there was some evidence for a negative association between risk of BPED and total recreational physical activity. However, the reverse was observed when the cases were compared with biopsy controls. These patterns were essentially the same when examined by intensity of activity and by menopausal status. Despite the lack of an association between physical activity and risk BPED in this study, further investigation is warranted because of the potential benefits for the primary prevention of breast disease.
Adult↗
Do cigarette smokers have diets that increase their risks of coronary heart disease and cancer?
It has been proposed that differences in diet between smokers and nonsmokers may partially explain the positive association between cigarette smoking and diseases such as cancer and coronary heart disease. To investigate the potential for this confounding, the authors studied the relation between cigarette smoking and nutrient intake in a population-based sample of 451 Australian women between 1982 and 1984. Dietary intake was determined by a quantitative food frequency questionnaire. Relations with smoking were assessed by use of analysis of covariance. The mean daily intake of total dietary fiber in current smokers was 4.1 g lower than in never smokers, with a 95% confidence interval for the difference of 1.4-6.8 g. The mean intake of total calories, cholesterol, sucrose, linoleic acid, total fat, and monounsaturated and polyunsaturated fat did not vary significantly by smoking status. However, former smokers were found to have a higher ratio of polyunsaturated to saturated fat as compared with current or never smokers and a lower intake of saturated fat as compared with current smokers. These associations persisted when the effects of total energy intake, age, years of education, and alcohol consumption were considered. The decreased ingestion of fiber by cigarette smokers could contribute to their increased risks of coronary heart disease and cancer compared with those in nonsmokers. The increased ratio of polyunsaturated to saturated fat and decreased ingestion of saturated fat in the diet of former smokers may help to reduce their risks.
Adult↗
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↗
Dietary factors and survival from breast cancer.
The association between self-reported intake of various dietary factors at diagnosis and survival from breast cancer was studied in a population-based cohort of breast cancer patients in Adelaide, South Australia. These patients had been recruited between 1982 and 1984 into a case-control study of diet and incident breast cancer. Of the 451 patients recruited originally, 412 were followed for a median interval of 5.5 years. There were decreases in the risk of death from breast cancer ranging from 25 to 40% at all levels of energy and protein intake above the baseline, whereas for fat intake there was a 40% increase in risk at the uppermost quintile level. There was also some reduction in risk at the upper levels of intake of beta-carotene and vitamin C. However, there were no dose-dependent variations in risk of death by level of intake for any of the dietary factors studied, and most of the variation in risk that was observed was relatively insubstantial.
Adult↗
Oral contraceptives and risk of benign proliferative epithelial disorders of the breast.
In a case-control study conducted in Adelaide, South Australia, we investigated the hypothesis that use of oral contraceptives is associated with increased risk of benign proliferative epithelial disorders (BPED) of the breast, conditions strongly associated with increased risk of breast cancer and thought to have pre-malignant potential. The study was restricted to women with no prior history of breast biopsy, and involved 383 cases of biopsy-confirmed BPED, 192 controls whose biopsy did not show epithelial proliferation, and 383 unbiopsied community controls individually matched to cases by age and socio-economic grading of area of residence. When cases were compared with community controls, the adjusted odds ratio (OR) for the association between ever-use of oral contraceptives and risk of BPED was 1.1 (95% CI 0.7 to 1.7), while when cases were compared with biopsy controls, the adjusted OR was 0.9 (95% CI 0.5 to 1.5). There was little variation in risk of BPED with total duration of use of oral contraceptives, and with duration of use before first pregnancy, while current users had a statistically significant 60% reduction in risk, irrespective of the control group used for comparative purposes. Also, there was little variation in risk with years since first and last use of oral contraceptives, and there was no trend in the association between ever-use of oral contraceptives and risk of BPED by degree of cytological atypia.
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↗