Système de surveillance de la mortalité causée par le cancer

Cet article traite de la mise sur pied et du fonctionnement d’un système de surveillance de la mortalité par cancer, appliqué à un échantillon d’environ 10 pour cent de la population active du Canada. Un couplage informatisé des enregistrements a été utilisé en conjonction avec la base de données sur la mortalité établie par Statistique Canada, afin de connaître l’expérience de mortalité de la cohorte entre 1965 et 1979. Les résultats présentés tendent à montrer que certains types de cancer sont associés à l’occupation, et d’autres aux habitudes de vie, comme le tabagisme et le régime alimentaire. La mortalité par cancer est également analysée selon la classe sociale.This paper reports the establishment of a system for monitoring cancer mortality of individuals forming approximately a 10 percent sample of the Canadian labour force. Computerized record linkage was used in conjunction with the Canadian mortality data base maintained by Statistics Canada to determine the mortality experience of the cohort between 1965 and 1979. Selected results are presented, some of which appear to indicate associations between the occupation and cause of death, and others of which seem likely to indicate the influence of lifestyle factors such as smoking and diet. Cancer mortality is also presented by social class.Este artículo trata del establecimiento y funcionamiento de un sistema de vigilancia de la mortalidad causada por el cancer, aplicado a una muestra de alrededor de 10% de la población activa de Canadá. A fin de conocer la experiencia de mortalidad de la cohorte entre 1965 e 1969, los datos registrados fueron utilizados conjuntamente con informaciones compiladas por Estadística Canada. Los resultados presentados tienden a demostrar que algunos tipos de cancer están asociados al empleo, y otros a las costumbres de vida, como el tabaquismo y la alimentación. La mortalidad producida por el cancer está igualmente analizada segun la clase social

Energy balance and breast cancer risk: a prospective cohort study

While there is evidence that breast cancer risk is positively associated with body mass index (in postmenopausal women) and energy intake and inversely associated with physical activity, few studies have examined breast cancer risk in association with energy balance, the balance between energy intake and expenditure. Therefore, in the cohort study reported here, we studied the independent and combined associations of vigorous physical activity, energy consumption, and body mass index (BMI), with breast cancer risk. The investigation was conducted in 49,613 Canadian women who were participants in the National Breast Screening Study (NBSS) and who completed self- administered lifestyle and food frequency questionnaires between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. During a mean 16.4 years of follow-up, we observed 2545 incident breast cancer cases. Due to exclusions for various reasons, the analyses were based on 40,318 subjects amongst whom there were 1673 incident cases of breast cancer. Participation in vigorous physical activity and body mass index were not independently associated with breast cancer risk in the total cohort. A statistically significant positive trend was observed, however, between energy intake and breast cancer risk (Ptrend = 0.01). Although there was some variation in risk associated with vigorous physical activity, and BMI when the analyses were stratified by menopausal status, these interactions were not statistically significant. The interaction between menopausal status and energy intake, however, was of borderline statistical significance (Pinteraction = 0.06), with a statistically significant increased risk of breast cancer associated with highest versus lowest quartile of energy intake among premenopausal women (Hazard Ratio [HR] = 1.45, 95% confidence interval [CI] = 1.13– 1.85, Ptrend = 0.001). There was evidence of an increased risk of breast cancer associated with a relatively high body mass index among postmenopausal women in the highest quartile level of energy intake (Hazard Ratio [HR] = 1.72, 95% confidence interval [CI] = 1.01– 2.93, Ptrend = 0.05). In addition, there was evidence of an increased risk of breast cancer among premenopausal, physically inactive, overweight/obese women who consumed ‡1972 kcal/day compared to physically active normal weight women who consumed \u3c1972 kcal/day (HR = 1.60, 95% CI = 1.08–2.37). Our data suggest that obese premenopausal women with relatively high energy intake may be at increased risk of breast cancer. In addition, energy imbalance, represented by a relatively high energy intake, lack of participation in vigorous physical activity, and a relatively high body mass index, may be associated with increased breast cancer risk, particularly among premenopausal women

Glycaemic index, glycaemic load and ovarian cancer risk: a prospective cohort

Background There is some evidence that plasma insulin levels might influence ovarian cancer risk. Glyacemic index (GI) and glycaemic load (GL) are measures that allow the carbohydrate content of individual foods to be classified according to their postprandial glycaemic effects and hence their effects on circulating insulin levels. Therefore, we examined ovarian cancer risk in association with GI and GL, and intake of dietary carbohydrate and sugar. Methods The study was conducted in a prospective cohort of 49 613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food-frequency questionnaire (FFQ) between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the FFQ were used to estimate overall GI and GL, and Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between energy-adjusted quartile levels of GL, overall GI, total carbohydrates, total sugar and ovarian cancer risk. Results During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. GI and total carbohydrate and sugar intakes were not associated with ovarian cancer risk in the total cohort. GL was positively associated with a 72% increase in risk of ovarian cancer (HR = 1.72, 95% CI = 1.13–2.62, Ptrend = 0.01) and the magnitude of the association was slightly greater among postmenopausal (HR = 1.89, 95% CI = 0.98–3.65, Ptrend = 0.03) than among premenopausal women (HR = 1.64, 95% CI = 0.95–2.88, Ptrend = 0.07). Conclusions Our data suggest that consumption of diets with high GL values may be associated with increased risk of ovarian cancer

Dietary fiber intake and ovarian cancer risk: a prospective cohort study

There is some evidence from case–control studies that dietary fiber intake might be inversely associated with ovarian cancer risk, but there are limited prospective data. Therefore, we examined ovarian cancer risk in association with intake of dietary fiber in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS), who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate intake of total dietary fiber, of fiber fractions, and of fiber from various sources. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between energy-adjusted quartile levels of fiber intake and ovarian cancer risk. During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. Total dietary fiber and fiber fractions were not associated with ovarian cancer risk in this study population

Dietary carbohydrates and breast cancer risk: A prospective study of the roles of overall glycemic index and glycemic load

We examined breast cancer risk in association with an overall glycemic index (GI), glycemic load (GL), and dietary carbohydrate and sugar intake in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. During a mean follow-up of 16.6 years, we observed 1,461 incident breast cancer cases. GI, GL, total carbohydrate, and total sugar intake were not associated with breast cancer risk in the total cohort. However, there was evidence of effect modification of the association between GI and breast cancer risk by menopausal status (p = 0.01), the hazard ratio for the highest versus the lowest quintile level of GI being 0.78 (95% CI = 0.52–1.16; p trend = 0.12) in premenopausal women and 1.87 (95% CI = 1.18–2.97; p trend = 0.01) in postmenopausal women. The associations between GI and GL were not modified by body mass index (BMI) or by vigorous physical activity among pre- or postmenopausal women. Similarly, the associations between GI/GL and risk in postmenopausal women were not modified by BMI, vigorous physical activity, or ever use of hormone replacement therapy (HRT), although the associations were slightly stronger among those who reported no vigorous physical activity (p trend = 0.02), among those who reported ever using HRT (p trend = 0.02) and among normal-weight women (BMI \u3c 25 kg/m2; p trend = 0.03). Our data suggest that consumption of diets with high GI values may be associated with increased risk of breast cancer among postmenopausal women, possibly more so among subgroups defined by participation in vigorous physical activity, ever use of HRT, and those who are not overweight

Intake of Coffee and Tea and Risk of Ovarian Cancer: A Prospective Cohort Study

There is some evidence from case-control studies that coffee consumption might be positively associated with ovarian cancer risk, whereas the epidemiologic evidence regarding tea consumption and ovarian cancer is inconsistent. To date, there have been few prospective studies of these associations. Therefore, we examined ovarian cancer risk in association with both coffee and tea intake in a prospective cohort study of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate the daily intake of coffee and tea. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between categories of coffee and tea intake and ovarian cancer risk. During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. Tea intake was not associated with ovarian cancer risk in our study population. In contrast, a borderline positive association was observed among women who drank \u3e 4 cups of coffee/day compared to women who did not drink coffee (HR = 1.62, 95% CI = 0.95–2.75, P trend = 0.06). Given the pervasive use of these beverages, the associations between coffee and tea consumption and ovarian cancer risk warrant investigation in further prospective studies

Glycaemic index, glycaemic load and ovarian cancer risk: a prospective cohort study

Background There is some evidence that plasma insulin levels might influence ovarian cancer risk. The glycaemic index (GI) and glycaemic load (GL) are measures that allow the carbohydrate content of individual foods to be classified according to their postprandial glycaemic effects and hence their effects on circulating insulin levels. Therefore, we examined ovarian cancer risk in association with GI and GL, and intake of dietary carbohydrate and sugar. Methods The study was conducted in a prospective cohort of 49 613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food-frequency questionnaire (FFQ) between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the FFQ were used to estimate overall GI and GL, and Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between energy-adjusted quartile levels of GL, overall GI, total carbohydrates, total sugar, and ovarian cancer risk. Results During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. GI and total carbohydrate and sugar intakes were not associated with ovarian cancer risk in the total cohort. GL was positively associated with a 72% increase in risk of ovarian cancer (HR=1.72, 95% CI=1.13-2.62, Ptrend=0.01) and the magnitude of the association was slightly greater among postmenopausal (HR=1.89, 95% CI=0.98-3.65, Ptrend=0.03) than among premenopausal women (HR=1.64, 95% CI=0.95-2.88, Ptrend=0.07). Conclusions Our data suggest that consumption of diets with high GL values may be associated with an increased risk of ovarian cancer

Carotenoid, Vitamin A, Vitamin C, and Vitamin E Intake and Risk of Ovarian Cancer: a Prospective Cohort Study

It is thought that oxidative stress resulting to repeated ovulation may increase the risk of ovarian cancer by inducing DNA damage (1). Consumption of antioxidants may, therefore, decrease ovarian cancer risk by counteracting oxidative stress and the resultant DNA damage (2, 3). Currently, the epidemiologic evidence regarding associations between antioxidants and risk of ovarian cancer is mixed (4-12). Of the two prospective studies, Kushi et al. (4) and Fairfield et al. (7) both reported no association between β-carotene and ovarian cancer risk. In addition, Fairfield et al. (7) found no association with any of the other four major carotenoids (α-carotene, β-cryptoxanthin, lycopene, and lutein) or vitamins A or C. However, they did observe a statistically significant increased risk of ovarian cancer associated with relatively high intake of vitamin E from food sources (7). Given the current lack of prospective data regarding these relationships, we examined the association between intake of dietary carotenoids and vitamins A, C, and E and ovarian cancer risk in a cohort of Canadian women

Glycaemic index, glycaemic load and risk of endometrial cancer: a prospective cohort study

Objective High-glycaemic-load diets may increase endometrial cancer risk by increasing circulating insulin levels and, as a consequence, circulating oestrogen levels. Given the paucity of epidemiological data regarding the relationship between the dietary glycaemic index and glycaemic load and endometrial cancer risk, we sought to examine these associations using data from a prospective cohort study. Design, setting, and subjects We examined the association between dietary glycaemic load and endometrial cancer risk in a cohort of 49 613 Canadian women aged between 40 and 59 years at baseline who completed self-administered food-frequency questionnaires between 1982 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Results During a mean of 16.4 years of follow-up, we observed 426 incident cases of endometrial cancer. Hazard ratios for the highest versus the lowest quartile level of overall glycaemic index and glycaemic load were 1.47 (95% confidence interval (CI) = 0.90–2.41; P for trend = 0.14) and 1.36 (95% CI = 1.01–1.84; P for trend = 0.21), respectively. No association was observed between total carbohydrate or total sugar consumption and endometrial cancer risk. Among obese women (body mass index \u3e 30 kg m−2) the hazard ratio for the highest versus the lowest quartile level of the glycaemic load was 1.88 (95% CI = 1.08–3.29; P for trend = 0.54) and there was a 55% increased risk for the highest versus the lowest quartile level of glycaemic load among premenopausal women. There was also evidence to support a positive association between glycaemic load and endometrial cancer risk among postmenopausal women who had used hormone replacement therapy. Conclusions Our data suggest that diets with the high glycaemic index or high glycaemic load may be associated with endometrial cancer risk overall, and particularly among obese women, premenopausal women, and postmenopausal women who use hormone replacement therapy

There is no association between the omega-3 index and depressive symptoms in patients with heart disease who are low fish consumers

Background: Long chain Omega-3 polyunsaturated fatty acids (LCn3PUFAs) may improve cardiovascular health and depression. This study investigated the relationships between erythrocyte membrane LCn3PUFA status, depression and angina symptoms in patients with heart disease.  Methods: We recruited 91 patients (65 males and 26 females, mean age 59.2 ± 10.3 years) with heart disease and depressive symptoms (Center for Epidemiological Studies Depression Scale, CES-D ≥ 16) and low fish/fish oil intakes. The Omega-3 Index (EPA+DHA) of erythrocyte membranes (as a percentage of total fatty acids) was assessed by gas chromatography. Depression status was measured by both self-report and clinician-report scales; CES-D and the Hamilton depression scale (HAM-D). Angina symptoms were measured using the Seattle Angina Questionnaire and the Canadian Cardiovascular Society Classification for Angina Pectoris.  Results: The mean Omega-3 Index was 4.8 ± 1.0% (±SD). Depression scores measured by CES-D and HAM-D were 29.2 ± 8.8 (moderate to severe) and 11.0 ± 5.7 (mild) (arbitrary units) respectively reflecting a different perception of depressive symptoms between patients and clinicians. Angina status was inversely associated with depression scores (r > -0.26, P < 0.03). There were no significant relationships between individual LCn3PUFA or the Omega-3 Index and either the depression scores or the angina symptoms.  Conclusion: Worse angina status was associated with worse depression, but the Omega-3 Index was not associated with symptoms of depression or angina in patients with heart disease