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Thomas E Rohan

Publications and source records attributed to Thomas E Rohan.

64 records · Page 4Linked to original sources
PubMed2002

A cohort study of dietary carotenoids and lung cancer risk in women (Canada).

OBJECTIVE: To investigate the association between dietary carotenoid intake and lung cancer risk in women. METHODS: A case-cohort study was undertaken in the Canadian National Breast Screening Study dietary cohort, which consists of 56,837 women who completed a self-administered dietary questionnaire. The cohort was recruited between 1980 and 1985, and during follow-up to the end of 1993 a total of 196 cohort members were diagnosed with incident lung cancer. For analysis, a subcohort consisting of a random sample of 5681 women was selected from the full dietary cohort. After exclusions for various reasons, the analyses were based on 155 cases and 5,361 non-cases. RESULTS: When compared to those in the lowest quartile level of intake, the adjusted incidence rate ratios (95% confidence intervals) for those in the highest quartile levels of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein intake were 0.90 (0.51-1.58). 1.40 (0.76-2.59), 0.66 (0.33-1.32), 1.04 (0.61-1.76), and 1.26 (0.70-2.24), respectively; none of the associated tests for trend was statistically significant. CONCLUSION: These results suggest that there is no association between dietary carotenoid intake and lung cancer risk. at least for the range of intakes observed here.

Adult↗
PubMed2002

A cohort study of dietary fibre intake and menarche.

OBJECTIVE: To evaluate the influence of dietary fibre on menarche in a cohort of pre-menarcheal girls. DESIGN: Prospective cohort study. SETTING: Ontario, Canada. SUBJECTS: Free-living pre-menarcheal girls (n = 637), 6 to 14 years of age. METHODOLOGY: Information on dietary intake, physical activity and date of menarche was collected at baseline and was updated annually by self-administered questionnaires for three years. Cox proportional hazards models were used to evaluate the association between dietary fibre and menarche, adjusting for age at entry to the study and potential confounders. RESULTS: A higher intake of energy-adjusted dietary fibre was associated with a lower risk of (i.e. a later age at) menarche (relative hazard 0.54, 95% confidence interval (CI) 0.31-0.94 for highest vs. lowest quartile, P for trend = 0.027). At the fibre component level, a higher intake of energy-adjusted cellulose was associated with a lower risk of menarche (relative hazard 0.45, 95% CI 0.26-0.76, P for trend = 0.009). CONCLUSIONS: The findings are consistent with the hypothesis that pre-menarcheal dietary intake can influence menarche.

Adolescent↗
PubMed2002

Dietary carotenoids and risk of breast cancer.

BACKGROUND: Many studies of fruit and vegetable consumption showed inverse associations with breast cancer risk, suggesting the potential importance of carotenoids (and other phytochemicals) contained in these foods. To date, however, only one prospective cohort study has examined dietary carotenoids other than beta-carotene in relation to breast cancer risk. OBJECTIVE: Our aim was to examine the relations between dietary intakes of beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, and lutein + zeaxanthin and breast cancer risk in a large cohort study of Canadian women. DESIGN: A case-cohort analysis was undertaken in a cohort of 56 837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993 a total of 1589 women were diagnosed with biopsy-confirmed incident breast cancer. For comparison, a subcohort of 5681 women was randomly selected. After exclusions for various reasons, the analyses were based on 1452 cases and 5239 noncases. RESULTS: We found no clear association between intakes of any of the studied carotenoids and breast cancer risk in the study population as a whole or in subgroups defined by smoking status; relative body weight (assessed by body mass index); intakes of total fat, energy, alcohol, or folic acid; family history of breast cancer; or menopausal status. CONCLUSIONS: Our data do not support any association between dietary intakes of the studied carotenoids and breast cancer risk. However, prospective cohort studies of carotenoids in relation to breast cancer are scarce and further studies are warranted.

Breast Neoplasms↗
PubMed2002

Meat and dairy food consumption and breast cancer: a pooled analysis of cohort studies.

BACKGROUND: More than 20 studies have investigated the relation between meat and dairy food consumption and breast cancer risk with conflicting results. Our objective was to evaluate the risk of breast cancer associated with meat and dairy food consumption and to assess whether non-dietary risk factors modify the relation. METHODS: We combined the primary data from eight prospective cohort studies from North America and Western Europe with at least 200 incident breast cancer cases, assessment of usual food and nutrient intakes, and a validation study of the dietary assessment instrument. The pooled database included 351,041 women, 7379 of whom were diagnosed with invasive breast cancer during up to 15 years of follow-up. RESULTS: We found no significant association between intakes of total meat, red meat, white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categorical analyses suggested a J-shaped association for egg consumption where, compared to women who did not eat eggs, breast cancer risk was slightly decreased among women who consumed < 2 eggs per week but slightly increased among women who consumed > or = 1 egg per day. CONCLUSIONS: We found no significant associations between intake of meat or dairy products and risk of breast cancer. An inconsistent relation between egg consumption and risk of breast cancer merits further investigation.

Animals↗
PubMed2002

Dietary carotenoid intake and colorectal cancer risk.

Several studies have found inverse associations between fruit and vegetable consumption and colorectal cancer risk, suggesting the potential etiological importance of carotenoids (and other phytochemicals) contained in these foods. However, only one study (a case-control study) has examined the association between dietary carotenoids other than beta-carotene and colorectal cancer risk. In the study reported here, we examined the relationships between dietary intakes of beta-carotene, alpha-carotene, lycopene, lutein, and beta-cryptoxanthin and colorectal cancer risk in a large cohort study of Canadian women. A case-cohort analysis was undertaken within the cohort of 56,837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993, a total of 388 women were diagnosed with colorectal cancer. For comparative purposes, a subcohort of 5,681 women was randomly selected. After exclusions for various reasons, the analyses were based on 295 cases and 5,334 noncases. We did not find any clear association between intake of any of the studied carotenoids and colorectal cancer risk in the study population as a whole or in subgroups defined by smoking status, relative body weight (body mass index), intakes of total fat, energy, alcohol, and folic acid, or menopausal status. Our data do not support any association between dietary intakes of the studied carotenoids and colorectal cancer risk. However, given that this is the first prospective cohort study of carotenoids in relation to colorectal cancer, further studies are warranted.

Adult↗
PubMed2002

Fish consumption and breast cancer risk.

The omega-3 fatty acids, especially long-chain eicosapentaenoic acid (20:5n-3) and docosahexaenoic (22:6n-3) contained in "fatty" fish, have consistently been shown to retard the growth of breast cancer in vitro and in animal experiments. In contrast, studies of the association between fish consumption and breast cancer risk in human populations have not consistently shown inverse associations. However, previous studies have not considered the specific types of fish consumed. Using data from a large, nationwide case-control study conducted in Sweden, we examined the association between consumption of fatty and lean fish and breast cancer risk. Odds ratios (OR) and 95% confidence intervals were computed from unconditional logistic regression models. High consumption of fish was weakly associated with reduced breast cancer risk, and the association was not statistically significant. With multivariate adjustment, the OR for women with the highest consumption (> or =3.5 servings/wk) compared with women with the lowest (virtually none) was 0.88 (95% confidence interval = 0.60-1.29, P for trend = 0.15). When type of fish was examined separately, the association was similar for fatty and lean fish.

Aged↗
PubMed2002

Cigarette smoking and the risk of breast cancer in women: a review of the literature.

Animal experiments and in vitro studies have shown that compounds found in tobacco smoke, such as polycyclic hydrocarbons, aromatic amines, and N-nitrosamines, may induce mammary tumors. The findings of smoking-specific DNA adducts and p53 gene mutations in the breast tissue of smokers also support the biological plausibility of a positive association between cigarette smoking and breast cancer, as does the detection of carcinogenic activity in breast fluid. However, epidemiological studies conducted over the past few decades have variably shown positive, inverse, or null associations. To help reconcile the discrepant findings, epidemiologists have paid increasing attention to measures of exposure to tobacco smoke that might be of the greatest etiological importance, to aspects of the smoker that might modify the association between smoking and breast cancer risk, and to the potentially different associations that might exist with different types of breast tumors, such as those with and without estrogen or progesterone receptors. Overall, the results of these studies suggest that smoking probably does not decrease the risk and indeed suggest that there may be an increased breast cancer risk with smoking of long duration, smoking before a first full-term pregnancy, and passive smoking. These findings require confirmation in future studies, as do suggestions of increased risk among women with certain genotypes.

Age Factors↗
PubMed2002

Dietary fat and risk of lung cancer in a pooled analysis of prospective studies.

Lung cancer rates are highest in countries with the greatest fat intakes. In several case-control studies, positive associations have been observed between lung cancer and intakes of total and saturated fat, particularly among nonsmokers. We analyzed the association between fat and cholesterol intakes and lung cancer risk in eight prospective cohort studies that met predefined criteria. Among the 280,419 female and 149,862 male participants who were followed for up to 6-16 years, 3,188 lung cancer cases were documented. Using the Cox proportional hazards model, we calculated study-specific relative risks that were adjusted for smoking history and other potential risk factors. Pooled relative risks were computed using a random effects model. Fat intake was not associated with lung cancer risk. For an increment of 5% of energy from fat, the pooled multivariate relative risks were 1.01 [95% confidence interval (CI), 0.98-1.05] for total, 1.03 (95% CI, 0.96-1.11) for saturated, 1.01 (95% CI, 0.93-1.10) for monounsaturated, and 0.99 (95% CI, 0.90-1.10) for polyunsaturated fat. No associations were observed between intakes of total or specific types of fat and lung cancer risk among never, past, or current smokers. Dietary cholesterol was not associated with lung cancer incidence [for a 100-mg/day increment, the pooled multivariate relative risk was 1.01 (95% CI, 0.97-1.05)]. There was no statistically significant heterogeneity among studies or by sex. These data do not support an important relation between fat or cholesterol intakes and lung cancer risk. The means to prevent this important disease remains avoidance of smoking.

Case-Control Studies↗
PubMedDate not supplied

Insulin-like growth factors and coronary heart disease.

Insulin-like growth factor-1 (IGF-I), the primary mediator of growth hormone (GH) effects, is an important regulator of cell growth, differentiation, and apoptosis. GH and IGF-I deficiency is known to be associated with premature atherosclerosis and elevated cardiovascular disease mortality. Recent evidence suggests that cardiovascular disease risk may also be elevated among apparently healthy individuals who have serum IGF-I levels in the low-normal range. In this review, we appraise the epidemiologic and clinical studies implicating low IGF-I level as a risk factor for incident myocardial infarction and other manifestations of coronary heart disease. Potential mechanisms that may underlie this association include beneficial effects of IGF-I on myocyte survival after ischemia, stability of atherosclerotic lesions, and endothelial function. We conclude that additional confirmatory data from prospective studies are needed to confirm low IGF-I level as an independent cardiovascular risk factor. However, if this finding is confirmed, this would support the rationale for intervention trials aimed at reducing cardiovascular disease morbidity and mortality among older adults by targeting the GH/IGF-I pathway.

Acute Disease↗