Showing papers by "Alicja Wolk published in 2008"

Long-term dietary cadmium intake and postmenopausal endometrial cancer incidence: a population-based prospective cohort study.

Abstract: Environmental pollutants mimicking the effects of estrogen are suggested to contribute to the high incidence of hormone-related cancers, but supporting data are sparse. A potent estrogen-like activity of the pollutant cadmium, mediated via the estrogen receptor-alpha, has been shown in vivo. We prospectively examined the association between cadmium exposure and incidence of postmenopausal endometrial cancer. The Swedish Mammography Cohort is a population-based prospective cohort of 30,210 postmenopausal women free of cancer diagnose at baseline (1987) and who completed a food frequency questionnaire at baseline and in 1997. We estimated the dietary cadmium intake based on the questionnaire data and the cadmium content in all foods. During 16.0 years (484,274 person-years) of follow-up between the baseline and mid-2006, we ascertained 378 incident cases of endometrioid adenocarcinoma. The average estimated dietary cadmium intake was 15 mug/day (80% from cereals and vegetables). Cadmium intake was statistically significantly associated with increased risk of endometrial cancer in all women; the multivariate relative risk (RR) was 1.39 [95% confidence interval (CI), 1.04-1.86; P(trend) = 0.019], comparing highest tertile versus lowest. Among never-smoking women with body mass index (BMI) of <27 kg/m(2), the RR was 1.86 (95% CI, 1.13-3.08; P(trend) = 0.009). We observed a 2.9-fold increased risk (95% CI, 1.05-7.79) associated with long-term cadmium intake consistently above the median at both baseline 1987 and in 1997 in never-smoking women with low bioavailable estrogen (BMI of <27 kg/m(2) and nonusers of postmenopausal hormones). Our results support the hypothesis that cadmium may exert estrogenic effects and thereby increase the risk of hormone-related cancers.

Overweight and obesity and incidence of leukemia: a meta-analysis of cohort studies.

Abstract: We conducted a meta-analysis to summarize the available evidence from cohort studies on the association between excess body weight and incidence of leukemia. Studies were identified by searching the MEDLINE and EMBASE databases (1966-July 2007) and by examining the references of retrieved articles. A random-effects model was used to combine the results from individual studies. We identified 9 cohort studies with data on body mass index (BMI) or obesity in relation to incidence of leukemia. Compared with nonoverweight individuals (BMI or= 30 kg/m(2)) individuals. On a continuous scale, a 5 kg/m(2) increase in BMI was associated with a 13% increased risk of leukemia (RR, 1.13; 95% CI, 1.07-1.19). In a meta-analysis of 4 studies reporting results on subtypes of leukemia, the summary RRs associated with obesity were 1.25 (95% CI, 1.11-1.41) for chronic lymphocytic leukemia, 1.65 (95% CI, 1.16-2.35) for acute lymphocytic leukemia, 1.52 (95% CI, 1.19-1.95) for acute myeloid leukemia and 1.26 (95% CI, 1.09-1.46) for chronic myeloid leukemia. This meta-analysis indicates that excess body weight is associated with an increased risk of developing leukemia.

Height, body mass index, and ovarian cancer: a pooled analysis of 12 cohort studies.

Abstract: Background: Although many studies have investigated the association between anthropometry and ovarian cancer risk, results have been inconsistent. Methods: The associations of height, body mass index (BMI), and ovarian cancer risk were examined in a pooled analysis of primary data from 12 prospective cohort studies from North America and Europe. The study population consisted of 531,583 women among whom 2,036 epithelial ovarian cancer cases were identified. To summarize associations, study-specific relative risks (RR) were estimated using the Cox proportional hazards model and then combined using a random- effects model. Results: Women with height ≥1.70 m had a pooled multivariate RR of 1.38 [95% confidence interval (95% CI), 1.16-1.65] compared with those with height <1.60 m. For the same comparison, multivariate RRs were 1.79 (95% CI, 1.07-3.00) for premenopausal and 1.25 (95% CI, 1.04-1.49) for postmenopausal ovarian cancer (Pinteraction = 0.14). The multivariate RR for women with a BMI ≥30 kg/m2 was 1.03 (95% CI, 0.86-1.22) compared with women with a BMI from 18.5 to 23 kg/m2. For the same comparison, multivariate RRs were 1.72 (95% CI, 1.02-2.89) for premenopausal and 1.07 (95% CI, 0.87-1.33) for postmenopausal women (Pinteraction = 0.07). There was no statistically significant heterogeneity between studies with respect to height or BMI. BMI in early adulthood was not associated with ovarian cancer risk. Conclusion: Height was associated with an increased ovarian cancer risk, especially in premenopausal women. BMI was not associated with ovarian cancer risk in postmenopausal women but was positively associated with risk in premenopausal women. Copyright © 2008 American Association for Cancer Research.

Fruit and vegetable consumption in the prevention of cancer: an update: REVIEW: FRUIT, VEGETABLES AND CANCER

Abstract: Abstract. Terry P, Terry JB, Wolk A (The Karolinska Institute, Stockholm, Sweden; Albert Einstein College of Medicine, Bronx, NY, USA; and National Food Administration, Uppsala, Sweden). Fruit and vegetable consumption in the prevention of cancer: an update (Review). J Intern Med 2001; 250: 280–290.

A tool for deterministic and probabilistic sensitivity analysis of epidemiologic studies

Abstract: Classification errors, selection bias, and uncontrolled confounders are likely to be present in most epidemiologic studies, but the uncertainty introduced by these types of biases is seldom quantif...

Validity of self-reported total physical activity questionnaire among older women

Abstract: Aim of this study was to assess the validity of a short self-administered physical activity questionnaire, intended to measure past year total daily physical activity, by comparison with activity records and accelerometers. Over a 1-year period, data from a questionnaire, 7-day activity records and accelerometers were obtained from a subset of 116 women between the ages of 56 and 75 years from the population-based Swedish Mammography Cohort. We estimated concordance correlations as measure of validity, deattenuated for intraindividual variation in the reference method. Deattenuated concordance correlations comparing total daily activity measured by the questionnaire with the accelerometers and the records were 0.38 (95% CI: 0.22-0.54) and 0.64 (95% CI: 0.45-0.83), respectively. Validity of leisure-time activity (walking/bicycling and exercise) and inactivity (watching TV/reading) estimates comparing the records with the questionnaire were 0.42 (95% CI: 0.22-0.62) and 0.52 (95% CI: 0.36-0.69), respectively. These data indicate that the average past year total physical activity, leisure-time activity and inactivity can be estimated with a reasonable validity using our short self-administered questionnaire.

Adiponectin receptor expression is elevated in colorectal carcinomas but not in gastrointestinal stromal tumors.

Abstract: Circulating adiponectin is inversely associated with colorectal carcinoma. However, adiponectin receptor expression has not been examined in normal gastrointestinal tissue, colorectal malignancies, or gastrointestinal stromal tumors (GISTs). We collected 40 colorectal carcinomas and 12 non-tumor colorectal tissue specimens from patients with colorectal cancer, as well as 45 tumor and 13 non-tumor specimens from patients with GIST. Expression and localization of adiponectin receptors (AdipoR1 and AdipoR2) were assessed using immunohistochemistry. We also confirmed expression of adiponectin receptors using rtPCR in matched normal and colorectal cancer specimens obtained from five patients. Finally, we detected adiponectin receptors and assessed adiponectin signaling in three colon cancer cell lines. Adiponectin receptor expression, assessed by either rtPCR or immunohistochemistry, was present in normal tissue and was significantly lower than in colorectal carcinomas. Among carcinomas, 95% displayed positive or strongly positive expression of AdipoR1 and 88% of AdipoR2, versus 8% and 0%, respectively, for non-tumor specimens (P<0.0001). AdipoR1 expression assessed by rtPCR was 1.6-fold higher in tumor than in non-tumor tissue (P<0.05). In addition, we found that adiponectin at physiological concentrations can activate in vitro intracellular signaling pathways in three colon cancer cell lines, expressing both adiponectin receptors 1 and 2. No significant differences in expression of adiponectin receptors in tumor versus non-tumor GI specimens were detected among patients with GIST. Colon cancer cell lines express adiponectin receptors, through which adiponectin activates in vitro intracellular signaling pathways. Adiponectin receptors are also detected in normal GI tissue and their expression is elevated in colorectal carcinomas, but not in GIST.

Fat, Protein, and Meat Consumption and Renal Cell Cancer Risk: A Pooled Analysis of 13 Prospective Studies

Abstract: Background Results of several case-control studies suggest that high consumption of meat (all meat, red meat, or processed meat) is associated with an increased risk of renal cell cancer, but only a few prospective studies have examined the associations of intakes of meat, fat, and protein with renal cell cancer. Methods We conducted a pooled analysis of 13 prospective studies that included 530,469 women and 244,483 men and had follow-up times of up to 7-20 years to examine associations between meat, fat, and protein intakes and the risk of renal cell cancer. All participants had completed a validated food frequency questionnaire at study entry. Using the primary data from each study, we calculated the study-specific relative risks (RRs) for renal cell cancer by using Cox proportional hazards models and then pooled these RRs by using a random-effects model. All statistical tests were two-sided. Results A total of 1,478 incident cases of renal cell cancer were identified (709 in women and 769 in men). We observed statistically significant positive associations or trends in pooled age-adjusted models for intakes of total fat, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, total protein, and animal protein. However, these associations were attenuated and no longer statistically significant after adjusting for body mass index, fruit and vegetable intake, and alcohol intake. For example, the pooled age-adjusted RR of renal cell cancer for the highest vs the lowest quintile of intake for total fat was 1.30 (95% confidence interval [CI] = 1.08 to 1.56; P(trend) = .001) and for total protein was 1.17 (95% CI = 0.99 to 1.38; P(trend) = .02). By comparison, the pooled multivariable RR for the highest vs the lowest quintile of total fat intake was 1.10 (95% CI = 0.92 to 1.32; P(trend) = .31) and of total protein intake was 1.06 (95% CI = 0.89 to 1.26; P(trend) = .37). Intakes of red meat, processed meat, poultry, or seafood were not associated with the risk of renal cell cancer. Conclusions Intakes of fat and protein or their subtypes, red meat, processed meat, poultry, and seafood are not associated with risk of renal cell cancer.

Dietary fiber intake and risk of postmenopausal breast cancer defined by estrogen and progesterone receptor status--a prospective cohort study among Swedish women.

Abstract: There is few data on the association between dietary fiber intake and estrogen receptor (ER)/progesterone receptor (PR)-defined breast cancer risk. We evaluated the association between dietary fiber and ER/PR-defined breast cancer risk stratified by postmenopausal hormone use, alcohol intake, and family history of breast cancer in the population-based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Fiber intake was measured by food-frequency questionnaire collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratio derived from Cox proportional hazard regression models. During an average of 8.3-year follow-up, 1,188 breast cancer cases with known ER/PR status were diagnosed. When comparing the highest to the lowest quintile, we observed non-significant inverse associations between total fiber intake and the risk of all tumor subtypes; the multivariate-adjusted RRs were 0.85 (95% CI: 0.69-1.05) for overall, 0.85 (0.64-1.13) for ER+PR+, 0.83 (0.52-1.31) for ER+PR- and 0.94 (0.49-1.80) for ER-PR-. For specific fiber, we observed statistically significant risk reductions for overall (34%) and for ER+PR+ (38%) for the highest versus lowest quintile of fruit fiber, and non-significant inverse associations for other subtypes of cancer and types of fiber. Among ever-users of postmenopausal hormone (PMH), total fiber intake and especially cereal fiber were statistically significantly associated with approximately 50% reduced risk for overall and ER+PR+ tumors when comparing the highest to the lowest quartile, but no association was observed among PMH never users. Our results suggest that dietary fiber intake from fruit and cereal may play a role in reducing breast cancer risk.

Association of physical activity with cancer incidence, mortality, and survival: a population-based study of men

Abstract: Within a population-based cohort study, 40,708 men aged 45-79 years followed from 1998 to 2004. After adjusting for potential confounders, we observed a strong inverse linear association between total daily physical activity (PA) and death from cancer (n=1153). For each increment of 4 metabolic equivalent (MET)-h day(-1) of total PA (approximately 1 h daily of moderate effort) cancer incidence (n=3714) tended to be decreased by 2% and cancer mortality decreased significantly by 12% (95% confidence interval=6-18%). The 5-year survival after cancer among those men in the top quartile of total PA (77%) was significantly higher compared to the lowest quartile (69%). Compared to those men who hardly ever walked or biked, walking or bicycling an average of 30 min day(-1) was associated with a 34% (18-47%) lower rate of cancer death and with improved cancer survival by 33% (14-47%). Incidence of cancer was 16% (2-28%) lower among those who walked or biked at least 60 min day(-1). Our results suggest that higher levels of PA and the main component of active living, walking or bicycling are associated with reduced cancer incidence and mortality, as well as higher cancer survival.

Long-term Dietary Acrylamide Intake and Breast Cancer Risk in a Prospective Cohort of Swedish Women

Abstract: The association between dietary acrylamide intake and the incidence of invasive breast cancer was examined among 61,433 Swedish women who were cancer free and completed a food frequency questionnaire in 1987-1990 and again in 1997. During a mean follow-up of 17.4 years, a total of 2,952 incident cases of breast cancer were diagnosed in the cohort. In multivariate analyses controlling for breast cancer risk factors, no statistically significant association was observed between long-term acrylamide intake (assessed at baseline and in 1997) and the risk of breast cancer, overall or by estrogen receptor (ER) and progesterone receptor (PR) status. The multivariate rate ratios comparing extreme quartiles of acrylamide intake were 0.91 (95% confidence interval (CI): 0.80, 1.02) for overall breast cancer, 0.89 (95% CI: 0.74, 1.08) for ER+PR+ tumors, 1.17 (95% CI: 0.84, 1.64) for ER+PR- tumors, and 0.91 (95% CI: 0.61, 1.38) for ER-PR- tumors. The association between acrylamide intake and breast cancer risk did not differ by smoking status. These findings for Swedish women do not support the hypothesis that dietary acrylamide is positively associated with risk of breast cancer, at least not within the ranges of acrylamide consumed by this population.

Folate Intake and Risk of Breast Cancer by Estrogen and Progesterone Receptor Status in a Swedish Cohort

Abstract: Background: Folate is a B vitamin involved in one-carbon metabolism and has been postulated to influence the risk of breast cancer. However, epidemiologic studies of folate intake in relation to breast cancer risk are inconclusive. We examined the association between dietary folate intake and the risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status of the breast tumor in the Swedish Mammography Cohort. Methods: Our study population consisted of 61,433 women who completed a food frequency questionnaire at baseline (1987-1990) and again in 1997. Cox proportional hazards models were used to estimate rate ratios (RR) with 95% confidence intervals (95% CI). Results: During an average of 17.4 years of follow-up, 2,952 incident cases of invasive breast cancer were ascertained. We observed no association between dietary folate intake and risk of total breast cancer or ER+/PR+ or ER-/PR- tumors. The multivariate RR of total breast cancer comparing extreme quintiles of folate intake was 1.01 (95% CI, 0.90-1.13; P trend = 0.84). However, folate intake was inversely associated with risk of ER+/PR- breast cancer ( n = 417 cases; RR for highest versus lowest quintile, 0.79; 95% CI, 0.59-1.07; P trend = 0.01). Results did not vary by alcohol intake or menopausal status. Conclusions: These findings do not support an overall association between folate intake and risk of breast cancer but suggest that folate intake may be inversely associated with ER+/PR− tumors. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3444–9)

Dietary supplement use and mortality in a cohort of Swedish men.

Abstract: The use of dietary supplements has increased substantially in most industrialized countries. The aim of this study was to prospectively examine the association between use of dietary supplements and all-cause mortality, cancer mortality and CVD mortality in men. We used the population-based prospective cohort of 38 994 men from central Sweden, 45-79 years of age, with no cancer or CVD at baseline and who completed a self-administered FFQ including questions on dietary supplement use and life-style factors in 1997. During average 7.7 years of follow-up, 3403 deaths were ascertained; among them, 771 due to cancer and 930 due to CVD (during 5.9 years of follow-up). In multivariate adjusted models including all men there was no association observed between use of any dietary supplement or of multivitamins, vitamin C, vitamin E or fish oil specifically and all-cause mortality, cancer or CVD mortality. Among current smokers, regular use of any supplement was associated with statistically significant increased risk of cancer mortality: relative risk (RR) 1.46 (95 % CI 1.06, 1.99). Among men reporting an inadequate diet at baseline (assessed by Recommended Food Score), there was a statistically significant inverse association between use of any dietary supplement and CVD mortality (RR 0.72; 95 % CI 0.57, 0.91), no associations were observed among men with adequate diets. In conclusion, we cannot exclude that the use of dietary supplements is harmful for smokers. On the other hand, among men with an insufficient diet, the use of supplements might be beneficial in reducing CVD mortality.

Fruit and Vegetable Consumption and Risk of Bladder Cancer: A Prospective Cohort Study

Abstract: Fruit and vegetable consumption has been inconsistently associated with risk of bladder cancer. We used data from a prospective population-based cohort study of 82,002 Swedish women and men to examine the association between fruit and vegetable consumption and bladder cancer incidence. Diet was assessed with a validated food frequency questionnaire. During a mean follow-up of 9.4 years, 485 incident cases of bladder cancer were identified in the Swedish cancer registries. We found no statistically significant association between intakes of total fruits and vegetables, total fruits, or total vegetables and bladder cancer risk after adjustment for age, sex, education, and cigarette smoking. The multivariate rate ratios (95% confidence intervals) comparing the highest with the lowest quartile of intake were 0.80 (0.60-1.05) for total fruits and vegetables, 0.93 (0.69-1.25) for fruits, and 0.89 (0.67-1.19) for vegetables. Likewise, no associations were observed for citrus fruits, cruciferous vegetables, or green leafy vegetables. The associations did not differ by sex or smoking status. In conclusion, findings from this prospective study suggest that fruit and vegetable intakes are not likely to be appreciably associated with the risk of bladder cancer.

Combined effects of obesity and physical activity in predicting mortality among men

Abstract: OBJECTIVE: We evaluated the hypothesis that higher levels of total daily physical activity can eliminate the increased mortality rate associated with overweight and obesity. DESIGN: Population-base ...

Dietary lignans and postmenopausal breast cancer risk by oestrogen receptor status: a prospective cohort study of Swedish women.

Abstract: Among the 51 823 postmenopausal women in the Swedish Mammography Cohort, we investigated breast cancer risk in relation to the FFQ-based estimated lignan intake by oestrogen receptor (ER) and progesterone receptor (PR) subtypes. A significant 17% risk reduction for breast cancer overall in the high lignan quartile was observed, especially among PMH user (Pinteraction<0.010), but no heterogeneity across ER/PR subtypes.

Association between repeat length of exon 1 CAG microsatellite in the androgen receptor and bone density in men is modulated by sex hormone levels.

Abstract: In this study we examined whether the androgen receptor (AR) gene CAG repeat polymorphism and serum androgen levels are associated with bone mineral density (BMD) and changes in BMD during 2-3 years in 229 healthy men 41-76 years old. Microsatellite analysis was performed on an automated sequencer. Indices of bioavailable testosterone (free testosterone [FT] and free androgen index) were calculated. BMD was measured using both dual-energy Xray absorptiometry and quantitative ultrasound. All participants completed a questionnaire regarding major possible osteoporosis risk factors. In linear regression analysis there was a modest positive association, which was independent of age and body mass index (BMI), between AR repeat length and BMD at all sites. Although this association was significant independent of BMI, analyses in the subgroup of obese men (BMI > 30) did not reach significance, while the effect was enhanced when analyzing only nonobese men (BMI < or = 30). There was no association between the AR gene polymorphism and rate of bone loss, FT, and BMD or testosterone and bone loss. Interestingly, the association between AR and BMD was modified by total testosterone. The lowest age- and BMI-adjusted average femoral neck BMD was found among men in the lowest tertile for both AR repeat length and FT, whereas men within the higher categories of these variables displayed the highest BMD. In conclusion, there is a positive association between the AR CAG repeat polymorphism and BMD, which is modified by androgen levels in healthy men.

SHORT REPORT Overweight and obesity and incidence of leukemia: A meta-analysis of cohort studies

Abstract: pared with nonoverweight individuals (BMI < 25 kg/m 2 ), the summary relative risks (RRs) of leukemia were 1.14 [95% confidence interval (CI), 1.03–1.25] for overweight individuals (BMI 25–30 kg/m 2 ) and 1.39 (95% CI, 1.25–1.54) for obese (BMI 30 kg/m 2 ) individuals. On a continuous scale, a 5 kg/m 2 increase in BMI was associated with a 13% increased risk of leukemia (RR, 1.13; 95% CI, 1.07–1.19). In a meta-analysis of 4 studies reporting results on subtypes of leukemia, the summary RRs associated with obesity were 1.25 (95% CI, 1.11–1.41) for chronic lymphocytic leukemia, 1.65 (95% CI, 1.16–2.35) for acute lymphocytic leukemia, 1.52 (95% CI, 1.19–1.95) for acute myeloid leukemia and 1.26 (95% CI, 1.09–1.46) for chronic myeloid leukemia. This meta-analysis indicates that excess body weight is associated with an increased risk of developing leukemia. ' 2007 Wiley-Liss, Inc.

Dietary supplement use and mortality in a cohort of Swedish men – response from Åkesson and Wolk

Abstract: Dr Boucher raises the question of the use of vitamin D supplements in the prospective population-based study of mortality performed among