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A Wolk

Publications and source records attributed to A Wolk.

At least 37 records · Page 2Linked to original sources
PubMed2001

Fruit, vegetables, dietary fiber, and risk of colorectal cancer.

BACKGROUND: Several recent large prospective cohort studies have failed to demonstrate the presumed protective effect of fruit, vegetable, and dietary fiber consumption on colorectal cancer risk. To further explore this issue, we have examined these associations in a population that consumes relatively low amounts of fruit and vegetables and high amounts of cereals. METHODS: We examined data obtained from a food-frequency questionnaire used in a population-based prospective mammography screening study of women in central Sweden. Women with colorectal cancer diagnosed through December 31, 1998, were identified by linkage to regional cancer registries. Cox proportional hazards models were used to estimate relative risks. All statistical tests were two-sided. RESULTS: During an average 9.6 years of follow-up of 61 463 women, we observed 460 incident cases of colorectal cancer (291 colon cancers, 159 rectal cancers, and 10 cancers at both sites). In the entire study population, total fruit and vegetable consumption was inversely associated with colorectal cancer risk. Subanalyses showed that this association was due largely to fruit consumption. The association was stronger, however, and the dose-response effect was more evident among individuals who consumed the lowest amounts of fruit and vegetables. Individuals who consumed less than 1.5 servings of fruit and vegetables per day had a relative risk for developing colorectal cancer of 1.65 (95% confidence interval = 1.23 to 2.20; P(trend) =.001) compared with individuals who consumed more than 2.5 servings. We observed no association between colorectal cancer risk and the consumption of cereal fiber, even at amounts substantially greater than previously examined, or of non-cereal fiber. CONCLUSIONS: Individuals who consume very low amounts of fruit and vegetables have the greatest risk of colorectal cancer. Relatively high consumption of cereal fiber does not appear to lower the risk of colorectal cancer.

Colorectal Neoplasms↗
PubMed2001

Physical activity and risk of renal cell cancer.

The relation between physical activity and renal cell cancer is unclear. High occupational physical activity has been associated with a decreased risk of renal cell cancer among men-but not among women-in two previous studies, while no association has been found for leisure time physical activity. Our aim was to investigate the association between occupational and leisure time physical activity in a prospective cohort of 17,241 Swedish twins. Information on physical activity and a wide range of potential confounding factors was obtained through a mailed questionnaire. During follow-up from 1967 through 1997 we identified 102 cases of renal cell cancer. We found no evidence of an inverse association between either occupational or leisure time physical activity and risk of renal cell cancer in this prospective cohort.

Aged↗
PubMed2001

Dietary antioxidant vitamins, retinol, and breast cancer incidence in a cohort of Swedish women.

Dietary antioxidant vitamins and retinol have been proposed to be protective against breast cancer on the basis of their ability to reduce oxidative DNA damage and their role in cell differentiation. Epidemiologic studies have not been convincing in supporting this hypothesis, but women with high exposure to free radicals and oxidative processes have not been specifically considered. We explored these issues in the Swedish Mammography Screening Cohort, a large population-based prospective cohort study in Sweden that comprised 59,036 women, 40-76 years of age, who were free of cancer at baseline and who had answered a validated 67-item food frequency questionnaire. During 508,267 person-years of follow-up, 1,271 cases of invasive breast cancer were diagnosed. Cox proportional hazards models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). There was no overall association between intake of ascorbic acid, beta-carotene, retinol or vitamin E and breast cancer incidence. High intake of ascorbic acid was inversely related to breast cancer incidence among overweight women (HR=0.61; 95% CI 0.45-0.82, for highest quintile of intake among women with body mass index>25 kg/m(2)) and women with high consumption of linoleic acid (HR=0.72; 95% CI 0.52-1.02, for highest quintile of ascorbic acid intake and average consumption of more than 6 grams of linoleic acid per day). Among women with a body mass index of 25 or below, the hazard ratio for breast cancer incidence was 1.27 (95% CI 0.99-1.63), comparing the highest to the lowest quintile of ascorbic acid intake. Consumption of foods high in ascorbic acid may convey protection from breast cancer among women who are overweight and/or have a high intake of linoleic acid.

Adult↗
PubMed2001

Long-term tobacco smoking and colorectal cancer in a prospective cohort study.

Tobacco smoking has consistently been associated with colorectal adenomas, precursors of cancer, but the association with colorectal cancer itself has not been consistent. If colorectal cancer emerges only after a 35-year induction period, an association would unlikely be detected in studies where exposure assessment is of shorter duration. Most previous studies do not examine smoking of such duration and therefore do not account for the hypothesized 35-year induction period. By using the Cox proportional hazards models to estimate relative risks, we studied the association of long-term smoking and colorectal cancer risk in a population-based prospective cohort of 17,118 Swedish twins with up to 30 years of follow-up and information on smoking habits prior to baseline exposure assessment. Long-term heavy smoking was associated with a statistically significant 3-fold increased risk of colorectal cancer compared with never smoking (relative risk 3.1, 95% CI 1.4- 7.1). Examining colorectal cancer sub-sites separately, a non-significant 60% increased risk of colon cancer was observed only for heavy smokers and a statistically significant 5-fold increased risk was observed for rectal cancer. Our data lend some support to the hypothesis that heavy long-term cigarette smoking is associated with increased risk of colorectal cancer. Further elucidation of this association would be valuable from both etiologic and public health perspectives.

Adult↗
PubMed2001

Intake of fruits and vegetables and risk of breast cancer: a pooled analysis of cohort studies.

CONTEXT: Some epidemiologic studies suggest that elevated fruit and vegetable consumption is associated with a reduced risk of breast cancer. However, most have been case-control studies in which recall and selection bias may influence the results. Additionally, publication bias may have influenced the literature on associations for specific fruit and vegetable subgroups. OBJECTIVE: To examine the association between breast cancer and total and specific fruit and vegetable group intakes using standardized exposure definitions. DATA SOURCES/STUDY SELECTION: Eight prospective studies that had at least 200 incident breast cancer cases, assessed usual dietary intake, and completed a validation study of the diet assessment method or a closely related instrument were included in these analyses. DATA EXTRACTION: Using the primary data from each of the studies, we calculated study-specific relative risks (RRs) that were combined using a random-effects model. DATA SYNTHESIS: The studies included 7377 incident invasive breast cancer cases occurring among 351 825 women whose diet was analyzed at baseline. For comparisons of the highest vs lowest quartiles of intake, weak, nonsignificant associations were observed for total fruits (pooled multivariate RR, 0.93; 95% confidence interval [CI], 0.86-1.00; P for trend =.08), total vegetables (RR, 0.96; 95% CI, 0.89-1.04; P for trend =.54), and total fruits and vegetables (RR, 0.93; 95% CI, 0.86-1.00; P for trend =.12). No additional benefit was apparent in comparisons of the highest and lowest deciles of intake. No associations were observed for green leafy vegetables, 8 botanical groups, and 17 specific fruits and vegetables. CONCLUSION: These results suggest that fruit and vegetable consumption during adulthood is not significantly associated with reduced breast cancer risk.

Adult↗
PubMed2001

Overweight as an avoidable cause of cancer in Europe.

There is growing evidence that excess body weight increases the risk of cancer at several sites, including kidney, endometrium, colon, prostate, gallbladder and breast in post-menopausal women. The proportion of all cancers attributable to overweight has, however, never been systematically estimated. We reviewed the epidemiological literature and quantitatively summarised, by meta-analysis, the relationship between excess weight and the risk of developing cancer at the 6 sites listed above. Estimates were then combined with sex-specific estimates of the prevalence of overweight [body mass index (BMI) 25-29 kg/m(2)] and obesity (BMI > or = 30 kg/m(2)) in each country in the European Union to obtain the proportion of cancers attributable to excess weight. Overall, excess body mass accounts for 5% of all cancers in the European Union, 3% in men and 6% in women, corresponding to 27,000 male and 45,000 female cancer cases yearly. The attributable proportion varied, in men, between 2.1% for Greece and 4.9% for Germany and, in women, between 3.9% for Denmark and 8.8% for Spain. The highest attributable proportions were obtained for cancers of the endometrium (39%), kidney (25% in both sexes) and gallbladder (25% in men and 24% in women). The largest number of attributable cases was for colon cancer (21,500 annual cases), followed by endometrium (14,000 cases) and breast (12,800 cases). Some 36,000 cases could be avoided by halving the prevalence of overweight and obese people in Europe.

Body Weight↗
PubMed2001

A prospective study of obesity and cancer risk (Sweden).

OBJECTIVE: [corrected] We evaluated the relation between obesity and the risks for various forms of cancer. METHODS: In a population-based cohort of 28,129 hospital patients (8165 men, 19,964 women) with any discharge diagnosis of obesity (9557 only diagnosis, 5266 primary, 13,306 secondary) during 1965-1993, cancer incidence was ascertained through 1993 by record linkage to the nationwide Swedish Cancer Registry. Cancer risk was estimated using the standardized incidence ratio (SIR, with 95% confidence interval), which is the ratio of the observed number of cancers to that expected. RESULTS: Overall, a 33% excess incidence of cancer was seen in obese persons, 25% in men and 37% in women. Significant risk elevations were observed for cancers of the small intestine (SIR = 2.8; 95% CI 1.6-4.5), colon (1.3; 1.1-1.5), gallbladder (1.6; 1.1-2.3), pancreas (1.5; 1.1-1.9), larynx (2.1; 1.1-3.5), renal parenchyma (2.3; 1.8-2.8), bladder (1.2; 1.0-1.6), cervix uteri (1.4; 1.1-1.9), endometrium (2.9; 2.5-3.4), ovary (1.2; 1.1-1.5), brain (1.5; 1.2-1.9), and connective tissue (1.9; 1.1-3.0), and for lymphomas (1.4; 1.0-1.7), with higher risk observed for Hodgkin's disease only in men (3.3; 1.4-6.5) and for non-Hodgkin's lymphoma only in women (1.6; 1.2-2.1). The association of obesity with risk of breast, prostate and pancreas cancers was modified by age. CONCLUSIONS: Obesity is associated with more forms of cancer than previously reported.

Adolescent↗
PubMed2001

Sociodemographic and health behaviour factors among dietary supplement and natural remedy users.

OBJECTIVE: To investigate which subgroups of the Swedish adult population use dietary supplements and natural remedies, taking into account sociodemographic and health behaviour factors. DESIGN: A cross-sectional survey conducted in 1996/1997 by Statistics Sweden was used for the analyses. In face-to-face interviews participants reported consumption of dietary supplements and natural remedies during the previous 2 weeks. SETTING: Sweden SUBJECTS: A nationally representative sample of 11 422 adults (5596 men, 5826 women) aged 16-84 y. The response rate was 78%. RESULTS: Overall, 33% of Swedish women and 22% of Swedish men reported use of dietary supplements; prevalence of natural remedy users was 14 and 7%, respectively. The best predictors for use of dietary supplements and natural remedies were age, sex and subjective health. Women and older individuals were more likely to be dietary supplement and/or natural remedy users. Obese men and women were less likely to use dietary supplements than underweight ones. Among men subjective health was significantly related to use of these preparations. Men who reported excellent health ate less than men reporting poor health. This association was weaker among women. Exercise was another important factor. Both men and women (except female dietary supplement users) who reported moderate or heavy exercise were significantly more frequent users of these preparations than those who reported practically no exercise. CONCLUSION: Use of dietary supplements and natural remedies is associated with several sociodemographic and health behaviour factors. SPONSORSHIP: Karolinska Institutet Research Fund.

Adolescent↗
PubMed2001

Validity and reproducibility of self-reported total physical activity--differences by relative weight.

OBJECTIVE: Physical activity is hypothesized to reduce the risk of obesity and several other chronic diseases and enhance longevity. However, most of the questionnaires used measure only part of total physical activity, occupational and/or leisure-time activity, which might lead to misclassification of total physical activity level and to dilution of risk estimates. We evaluated the validity and reproducibility of a short self-administered physical activity questionnaire, intended to measure long-term total daily 24 h physical activity. METHOD: The questionnaire included questions on level of physical activity at work, hours per day of walking/bicycling, home/household work, leisure-time activity/inactivity and sleeping and was sent twice during one year (winter/spring and late summer). Two 7-day activity records, performed 6 months apart, were used as the reference method. One-hundred and eleven men, aged 44-78, completed the questionnaire and one or two activity records. The physical activity levels were measured as metabolic equivalents (MET)xh/day. RESULTS: Spearman correlation coefficient between total daily activity score estimated from the first questionnaire and the records (validity) was 0.56 (deattenuated) and between the first and the second questionnaire (reproducibility) 0.65. Significantly higher validity correlations were observed in men with self-reported body mass index below 26 kg/m(2) than in heavier men (r=0.73 vs r=0.39). CONCLUSIONS: This study indicates that the average total daily physical activity scores can be estimated satisfactorily in men using this simple self-administered questionnaire.

Adult↗
PubMed2001

Use of dietary supplements and natural remedies increased dramatically during the 1990s.

OBJECTIVES: To estimate the prevalence and trends in dietary supplement and natural remedy use in Sweden during the 1980s and 1990s. DESIGN: Three nationally representative, cross-sectional surveys conducted in 1980-81, 1988-89 and 1996-97 were used for analysis. In face-to-face interviews participants reported consumption of dietary supplements and natural remedies during the previous 2 weeks. SETTING: Sweden. SUBJECTS: The samples consisted totally of 38 594 adults aged 16-84 years (14 642 in the 1980-81 survey, 12 391 in the 1988-89 survey and 11 561 in the 1996-97 survey). Main outcome measures. Changes in prevalence of dietary supplement and natural remedy users between 1980 and 1997. RESULTS: The 70% increase in the prevalence of dietary supplement users amongst both men and women [odds ratio (OR), 1.7; 95% confidence interval (CI), 1.6-1.9, OR, 1.7; 95% CI, 1.5-1.8, respectively] occurred mainly between 1988-89 and 1996-97. The increase in the prevalence of natural remedy users was even more dramatic - more than threefold in men (OR, 3.3; 95% CI, 2.9-4.0) and almost threefold in women (OR, 2.6; 95% CI, 2.3-2.9) - and the systematic increase started already in the 1980s. The increase was observed in all age groups and in all socio-economic groups, except for farmers. In 1996-97 the prevalence of dietary supplement users was 22% amongst men and 33% amongst women, and of natural remedies 7 and 14%, respectively. CONCLUSIONS: During the last two decades, the use of dietary supplements and natural remedies amongst the adult Swedish population has dramatically increased.

Adolescent↗
PubMed2001

Fruit and vegetable consumption in the prevention of cancer: an update.

Fruit and vegetables are considered to be important means of preventing cancer through diet. However, several recent large prospective cohort studies and clinical trials have found no associations regarding several major cancers, including cancers of the colon, breast and stomach. Although these results are disconcerting, especially for health-conscious individuals, there is also mounting evidence that people who avoid fruit and vegetables completely, or consume very little, are indeed at increased risk of these cancers. These individuals in particular should be identified, with the goal of helping them find ways to include more fruit and vegetables in their diets.

Feeding Behavior↗
PubMed2001

Birth weight and risk of renal cell cancer.

BACKGROUND: The prenatal period has been suggested to be important for future cancer risk. Conditions in utero are also important for the development of the kidney, and birth weight, a marker of fetal nutrition and growth, is linearly correlated with the number of nephrons and the structural and functional unit of the kidney. An association between birth weight and renal cell cancer, the major form of kidney cancer, is biologically plausible, but has never been studied. METHODS: We conducted a population-based, case-controlled study in Sweden of men and women aged 20 to 79 years. We collected self-reported information on categories of birth weight from 648 patients with newly diagnosed renal cell cancer and from 900 frequency-matched control subjects. We used unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) as estimates of the relative risks. RESULTS: An increased risk of renal cell cancer was observed among men with a birth weight of > or =3500 g (adjusted OR = 1.3, 95% CI, 1.0 to 1.8) compared with men with a birth weight between 3000 and 3499 g, especially in the subgroup without hypertension or diabetes (adjusted OR = 1.8, 95% CI, 1.2 to 2.6). No clear association among men with a birth weight <3000 g or among women was found. CONCLUSIONS: Our study shows that conditions in utero, reflected by birth weight, might affect the risk of renal cell cancer in adulthood. It is unclear why no association was found among women. Further studies, based on weight from birth certificates, are needed to clarify this relationship.

Adult↗
PubMed2001

Inverse association between intake of cereal fiber and risk of gastric cardia cancer.

BACKGROUND & AIMS: Recent data show that salivary nitrites form carcinogenic nitrosamines, especially at the gastric cardia. Wheat fiber has been shown to neutralize such mutagen formation. Our aim was to evaluate the association between dietary fiber and cancers of the esophageal and gastric cardia. METHODS: We examined data from a large-scale population-based case-control study of risk factors for adenocarcinoma of the gastric cardia and esophagus and squamous cell carcinoma of the esophagus. RESULTS: We found a strong dose-dependent inverse association between total dietary fiber intake and risk of gastric cardia adenocarcinoma, which was driven mainly by intake of cereal fiber. The odds ratio among individuals in the highest quartile of cereal fiber intake compared with the lowest was 0.3 (95% confidence interval, 0.2-0.5; P trend < 0.0001). High intake of cereal fiber was also associated with a moderately decreased risk of esophageal adenocarcinoma, but no linear dose-risk trend was observed. There was no association between dietary fiber and esophageal squamous cell carcinoma. CONCLUSIONS: High intake of cereal fiber may significantly lower the risk of gastric cardia cancer.

Adenocarcinoma↗
PubMed2001

Fatty acid composition of adipose tissue and serum lipids are valid biological markers of dairy fat intake in men.

The fatty acid intake is in part reflected by the fatty acid composition of adipose tissue and serum lipids. We evaluated whether the proportions of myristic (14:0), pentadecanoic (15:0) and heptadecanoic (17:0) fatty acids in the adipose tissue triacylglycerols and serum cholesterol esters and phospholipids reflect long-term dairy fat consumption in free-living men. In 114 healthy men aged 40-76 y, we compared the relative content of 14:0, 15:0 and 17:0 in subcutaneous adipose tissue and in serum lipids with relative intake (g/100 g of total fat) assessed by two 1-wk weighed food records made 6 mo apart and assessed by fourteen 24-h dietary recall interviews equally distributed during 1 y. According to food records, the mean +/- SD dairy fat intake was 24.9 +/- 13.1 g/d (29.6 +/- 10.5 g/100 g total fat); intake of 14:0, 15:0 and 17:0 was 4.6, 0.23 and 0.16 g/100 g total fat, and the content in adipose tissue was 3.6, 0.36 and 0.25 g/100 g fatty acids, respectively. Pearson correlation coefficients between intake of dairy fat (based on 24-h recalls) and fatty acid composition of adipose tissue were 0.64 (P: < 0.001) for 14:0, 0.74 (P: < 0.001) for 15:0 and 0.60 (P: < 0.001) for 15:0 + 17:0. Corresponding correlations with serum cholesterol esters were 0.34 (P: < 0.001) (14:0), 0.45 (P: < 0.001) (15:0) and 0.56 (P: < 0.001) (15:0 + 17:0), and with serum phospholipids the values were 0.30 (P: < 0.01) (14:0), 0.50 (P: < 0.001) (15:0) and 0.50 (P: < 0.001) (15:0 plus 17:0). In our study population, the relative content of 15:0 or 14:0 in adipose tissue is a valid biomarker for long-term dairy fat intake in free-living individuals. When adipose tissue is not available, 15:0 content in serum cholesterol esters or phospholipids might be used. Intake data based on repeated 24-h recalls are equally informative and may be an equivalent choice in nutritional studies.

Adipose Tissue↗
PubMed2001

Fruit and vegetable consumption in the prevention of oesophageal and cardia cancers.

The incidence of adenocarcinoma of the oesophagus has increased rapidly in recent decades. In order to appreciate the potential for prevention by means of dietary modification, we estimated the aetiological fractions and the increments in absolute risk attributable to low intake of fruit and vegetables for adenocarcinoma and squamous cell carcinoma of the oesophagus and for adenocarcinoma of the gastroesophageal junction. We conducted a nationwide population-based case-control study in Sweden, with participation of 608 cases and 815 controls. We used unconditional logistic regression to estimate relative risks, from which we calculated aetiological fractions. Individuals in the highest exposure quartile (median 4.8 servings/day) versus the lowest (median 1.5 servings/day) showed approximately 50% lower risk of oesophageal adenocarcinoma and 40% lower risk of oesophageal squamous cell carcinoma, but no risk reduction for gastric cardia adenocarcinoma. Approximately 20% of oesophageal adenocarcinoma, and likewise squamous cell carcinoma, in Sweden was attributed to consuming less than three servings of fruit and vegetables per day. A very large number of individuals (over 25,000) would need to increase their fruit and vegetable consumption moderately in order to prevent one oesophageal cancer per year. Moderate relative risk reductions translate into weak absolute risk reductions for oesophageal cancers in Sweden.

Adenocarcinoma↗
PubMed2001

Coffee consumption and risk of colorectal cancer in a population based prospective cohort of Swedish women.

BACKGROUND: The presumed protective effect of coffee consumption on colorectal cancer, which is supported by case control studies, has not been confirmed in prospective cohort studies. Cohort studies are few in number however and often suffer from a small number of cases, limited attention to confounding variables, and a low percentage of heavy coffee drinkers. METHODS: We examined data from a large population based cohort of Swedish women who were free from cancer at the start of follow up, with a wide range of coffee consumption, information on many potentially confounding variables, and a larger number of cases than any previous cohort study of coffee consumption and colorectal cancer. RESULTS: During an average of 9.6 years of follow up of 61 463 women aged 40-74 years, we observed 460 incident cases of colorectal cancer (291 with colon cancer, 159 with rectal cancer, 10 with cancer at both sites). We found no association between coffee consumption and colorectal cancer risk. The risk ratio for drinking four or more cups per day compared with none was 1.04 (95% confidence interval 0.63-1.69; p for trend 0.84). The findings were similar for cancers of the distal and proximal colon and rectum. CONCLUSIONS: The recently published affirmative conclusions regarding the protective effect of coffee consumption may be premature. For patients seeking advice about coffee consumption, the evidence suggests that moderate or even high consumption will probably not influence the risk of colorectal cancer.

Adult↗
PubMed2001

Tea consumption and the risk of colorectal cancer in Sweden.

The association between tea drinking and colorectal cancer risk remains unclear. The evidence for black tea is sparse but may indicate an increased risk with regular use. Because black tea is a common beverage in many populations, the significant twofold increased risk of colon cancer recently reported from a large prospective cohort of male Finnish smokers is disconcerting. Using Cox proportional hazards models to estimate relative risks, we examined this association in a large, population-based prospective cohort study in Sweden. During an average 9.6 years of follow-up of our cohort of 61,463 women (588,270 person-yr), we observed 460 incident cases of colorectal cancer (291 colon, 159 rectal, and 10 with both colon and rectal cancer). We observed no association between tea consumption and combined colorectal cancers in age- or multivariate-adjusted models. With the use of collapsed exposure categories, the multivariate-adjusted relative risk for the highest exposure (> or = cups/day) compared with the lowest (never or seldom) was 0.97 (95% confidence interval = 0.63-1.48, p for trend = 0.34). Examining the association by cancer subsite, we observed no association between tea consumption and proximal, distal, or combined colon cancers. We did, however, observe a nonsignificant positive association with rectal cancers, which became stronger and statistically significant among women > or = 65 years of age at baseline. Our data do not support the strong, dose-dependent positive association with colon cancer found in the Finnish study.

Age Factors↗