Showing papers by "Alicja Wolk published in 2003"

Obesity and hormone-dependent tumors: Cohort and co-twin control studies based on the Swedish Twin Registry

Abstract: Obesity increases the risk of certain cancer types, e.g., cancer of the endometrium, colon and gallbladder. For some other cancer forms, e.g., prostate cancer, the association is less clear. We examined the association between body mass index (BMI) and hormone-dependent tumors, utilizing a cohort of 21,884 Swedish twins born during 1886-1925. Information about BMI at different ages and potential confounding factors was collected prospectively. The Swedish Cancer Registry was used to identify cases of cancer in the prostate (n = 666), breast (n = 607), corpus uteri (n = 150) and ovary (n = 118) during 1969-1997. The material was analyzed as a traditional cohort and with co-twin control analyses that allow for control of genetic influences. Obesity (BMI >/=30 kg/m(2)) at baseline was positively associated with cancer in the corpus uteri [relative risk (RR) = 3.03, 95% confidence interval (CI) 1.82-5.03], as was BMI at age 25, independently of BMI at baseline. Increased risk was also found for breast cancer but only in older women (>/=70 years). Overweight at age 25 was associated with decreased risk of breast cancer (RR = 0.51, 95% CI 0.33-0.78). No association was found for prostate cancer. We conclude that age is an important effect modifier of cancer risk associated with obesity and that obesity and overweight in young adult life may affect cancer risk also later in life.

Common and Country-Specific Dietary Patterns in Four European Cohort Studies

Abstract: The association between diet and cancer, predominantly investigated univariately, has often been inconsistent, possibly because of the large number of candidate risk factors and their high intercorrelations. Analysis of dietary patterns is expected to give more insight than analysis of single nutrients or foods. This study aimed to develop and apply a common methodological approach to determine dietary patterns in four cohort studies originating in Finland, the Netherlands, Sweden and Italy. Food items on each of the food frequency questionnaires were aggregated into 51 food groups, defined on the basis of their position in the diet pattern and possible relevance to cancer etiology. Exploratory factor analysis was used to analyze dietary patterns. Using a standardized approach, 3-5 stable dietary patterns were identified, explaining 20-29% of total variance in consumption of the food groups. Two dietary patterns, which explained most of the variance, were consistent across the studies. The first pattern was characterized by high consumption of (salad) vegetables, the second by high consumption of pork, processed meat and potatoes. In addition, a few specifically national food patterns were identified. Sensitivity analyses showed that the identified patterns were robust for number of factors extracted, distribution of input variables and energy adjustment. Our findings suggest that some important eating patterns are shared by the four populations under study, whereas other eating patterns are population specific.

Age and temporal trends of total physical activity in Swedish men.

Abstract: Purpose: Few epidemiological studies have been conducted among middle-aged women on long-term total and specific physical activity (PA) trends. We studied in a cross-sectional setting the relationship of self-reported total daily PA with age and calendar time. Methods: In a population-based cohort of 38,988 women aged 49-83 yr in central Sweden, information was collected on physical activity, such as work or occupation, household work, walking or bicycling, exercise, watching TV or reading, and other lifestyle factors through a self-administered questionnaire. Total and specific daily PA levels at ages 15, 30, and 50 yr were recalled retrospectively and measured as metabolic equivalents (MET[middle dot]h[middle dot]d-1). Results: Total PA level linearly decreased with calendar time in all three age groups (slope for 5-yr change in calendar time among those 15 yr of age = -0.82; 95% confidence interval (CI), -0.86 to -0.78; among those 30 yr of age=-0.42; 95% CI, -0.45 to -0.38; and among those 50 yr of age = -0.62; 95% CI, -0.66 to -0.58). High-intensity activities such as walking or bicycling decreased by 0.21 MET[middle dot]h[middle dot]d-1 (95% CI, -0.22 to -0.20) every 5-calendar-year change among adolescents between the 1930s and 1960s. Total activity level decreased in all age groups by an average of approximately 3MET[middle dot]h-1[middle dot]d-1, corresponding to approximately 45 min of brisk walking. Conclusions: Our results suggest that intervention efforts aimed at engaging in healthful amounts of physical activity are needed throughout the life cycle.

Multivitamin Supplements Are Inversely Associated with Risk of Myocardial Infarction in Men and Women—Stockholm Heart Epidemiology Program (SHEEP)

Abstract: Epidemiologic data relating multivitamin supplement use to the risk of cardiovascular disease are sparse and inconsistent. We examined the association between self-selected use of low dose multivitamin supplements and the risk of myocardial infarction (MI). Our results are based on data from a large population-based, case-control study of subjects aged 45-70 y residing in Sweden, a country in which consumption of fruits and vegetables is relatively low and foods are not fortified with folic acid. The study included 1296 cases (910 men, 386 women) with a first nonfatal MI and 1685 controls (1143 men, 542 women) frequency-matched to the cases by sex, age and hospital catchment area. Odds ratios (OR) and 95% CI were calculated from unconditional logistic regression models. Among controls, 57% of the women and 35% of the men used dietary supplements; corresponding figures for the cases were 42 and 27%, respectively. Of those taking supplements, 80% used multivitamin preparations. After adjustment for major cardiovascular risk factors, the OR of MI comparing regular users of supplements with nonusers were 0.79 (95% CI 0.63-0.98) for men and 0.66 (95% CI 0.48-0.91) for women. This inverse association was not modified by such healthy lifestyle habits as consumption of fruits and vegetables, intake of dietary fiber, smoking habits and level of physical activity, although never smoking appeared to outweigh the association in women. Findings from this study indicate that use of low dose multivitamin supplements may aid in the primary prevention of MI.

Dietary intake of heterocyclic amines and cancers of the esophagus and gastric cardia.

Abstract: The results of two epidemiological studies suggest that high intake of heterocyclic amines, which are formed on the surface of meats cooked at high temperatures, might be associated with increased risk of esophageal or cardia cancers. Our aim was to further investigate heterocyclic amine intake and risk of these cancers. We examined data from a nationwide, population-based, case-control study of risk factors for adenocarcinoma of the esophagus and gastric cardia and squamous cell carcinoma of the esophagus in Sweden, with 185, 258, and 165 cases, respectively, and 815 controls. Heterocyclic amine intake was estimated based on the frequency of consumption and degree of surface browning of commonly fried meats, and the consumption of pan juices. Statistically nonsignificant 50-70% higher risks of esophageal squamous cell carcinoma were observed among individuals in the highest quartile levels of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-1methyl-6-phenylimidazo[4,5-b]pyridine relative to those in the lowest. Dose-risk trends were evident. Subjects reporting high intake of all three heterocyclic amines had an odds ratio of 2.4 (95% confidence interval, 1.2-4.8) relative to those with low intake of all three substances. In contrast, no association was found with risk of adenocarcinoma of the esophagus or gastric cardia. Heterocyclic amine intake might be associated with an increase in risk of squamous cell carcinoma of the esophagus. Given the dearth of epidemiological data regarding these cancers and the lack of established biological mechanisms, confirmatory data are needed.