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Biomedical subjects

A Wolk

Publications and source records attributed to A Wolk.

At least 73 records · Page 4Linked to original sources
PubMed1999

Smoking, antioxidant vitamins, and the risk of hip fracture.

Smoking increases the concentrations of free radicals, which have been suggested to be involved in bone resorption. We examined whether the dietary intake of antioxidant vitamins may modify the increased hip fracture risk associated with smoking. We prospectively studied 66,651 women who were 40-76 years of age. Forty-four of the cohort members who sustained a first hip fracture within 2-64 months of follow-up (n = 247) and 93 out of 873 age-matched controls were current smokers. Information on diet was obtained by a validated food-frequency questionnaire. The relative risk of hip fracture for current versus never smokers was analyzed in relation to the dietary intake of antioxidant vitamins stratified into two categories (low/high), where median intakes among the controls were used as cut-off points. After adjustment for major osteoporosis risk factors, the odds ratio (OR) for hip fracture among current smokers with a low intake of vitamin E was 3.0 (95% confidence interval 1.6-5.4) and of vitamin C 3.0 (1.6-5.6). In contrast, the OR decreased to 1.1 (0.5-2.4) and 1.4 (0.7-3.0) with high intakes of vitamin E and C, respectively. This effect was not seen for beta-carotene, selenium, calcium, or vitamin B6. In current smokers with a low intake of both vitamins E and C, the OR increased to 4.9 (2.2-11.0). The influence of the intake of these two antioxidant vitamins on hip fracture risk was less pronounced in former smokers. Our results suggest a role for oxidant stress in the adverse effects on the skeleton of smoking, and that an insufficient dietary intake of vitamin E and C may substantially increase the risk of hip fracture in current smokers, whereas a more adequate intake seems to be protective.

Adult↗
PubMed1999

Beta-carotene intake and risk of postmenopausal breast cancer.

We assessed the relation between beta-carotene consumption at various times in life and breast cancer risk by conducting a case-control study nested within a population-based cohort of women screened for breast cancer in Sweden. We conducted a telephone interview with 273 incident breast cancer cases and 371 controls about their diet at various ages throughout their lifetime. Controls were frequency matched to cases on age, month and year of mammography, and county of residence. We used unconditional logistic regression to measure the association between beta-carotene intake and breast cancer risk while adjusting for total energy intake, recency of intake, and the matching variables. Women were at lower risk with increasing levels of reported intake of beta-carotene. This pattern of association between breast cancer and beta-carotene intake was similar at various times before screening. These findings indicate that although diets high in beta-carotene may be associated with lower breast cancer risk, there does not seem to be evidence of a critical time period during which such diets are more relevant.

Breast Neoplasms↗
PubMed1998

Excessive dietary intake of vitamin A is associated with reduced bone mineral density and increased risk for hip fracture.

BACKGROUND: The highest incidence of osteoporotic fractures is found in northern Europe, where dietary intake of vitamin A (retinol) is unusually high. In animals, the most common adverse effect of toxic doses of retinol is spontaneous fracture. OBJECTIVE: To investigate whether excessive dietary intake of vitamin A is associated with decreased bone mineral density and increased risk for hip fracture. DESIGN: A cross-sectional study and a nested case-control study. SETTING: Two counties in central Sweden. PARTICIPANTS: For the cross-sectional study, 175 women 28 to 74 years of age were randomly selected. For the nested case-control study, 247 women who had a first hip fracture within 2 to 64 months after enrollment and 873 age-matched controls were selected from a mammography study cohort of 66,651 women 40 to 76 years of age. MEASUREMENTS: Retinol intake was estimated from dietary records and a food-frequency questionnaire. Bone mineral density was measured with dual-energy x-ray absorptiometry. Hip fracture was identified by using hospital discharge records and was confirmed by record review. RESULTS: In multivariate analysis, retinol intake was negatively associated with bone mineral density. For every 1-mg increase in daily intake of retinol, risk for hip fracture increased by 68% (95% CI, 18% to 140%; P for trend, 0.006). For intake greater than 1.5 mg/d compared with intake less than 0.5 mg/d, bone mineral density was reduced by 10% at the femoral neck (P = 0.05), 14% at the lumbar spine (P = 0.001), and 6% for the total body (P = 0.009) and risk for hip fracture was doubled (odds ratio, 2.1 [CI, 1.1 to 4.0]). CONCLUSION: High dietary intake of retinol seems to be associated with osteoporosis.

Adult↗
PubMed1998

Independent regulatory elements in the upstream region of the Drosophila beta 3 tubulin gene (beta Tub60D) guide expression in the dorsal vessel and the somatic muscles.

The beta 3 tubulin gene (beta Tub60D) is a structural gene expressed during mesoderm development from the extended germ band stage onward. Expression within the individual mesodermal derivatives is guided by different control elements. The upstream regions allow expression in the dorsal vessel and the somatic mesoderm while enhancers localized in the first intron guide expression in the visceral mesoderm. Deletion analysis carried out in transgenic flies revealed independent regulatory elements for the dorsal vessel and the somatic mesoderm. For expression in the somatic mesoderm, a 279-bp region is absolutely essential. This region contains a binding site for the Drosophila myocyte-specific enhancer binding factor 2 (D-MEF2), a MADS-box transcription factor known to be essential for mesoderm development. Deletion or mutation of this D-MEF2 binding site strongly reduces transcription. This pattern is consistent with the strongly reduced expression of beta 3 tubulin in D-mef2 mutant embryos. This analysis furthermore reveals that the D-MEF2 binding site acts in concert with nearby cis regulatory elements. These data show that the upstream control region of the beta 3 tubulin gene is an early target of the D-MEF2 transcriptional activator.

Animals↗
PubMed1998

Insulin-like growth factor 1 and prostate cancer risk: a population-based, case-control study.

BACKGROUND: Recent epidemiologic investigations have suggested an association between increased blood levels of insulin-like growth factor 1 (IGF-1) and increased risk of prostate cancer. Our goal was to determine whether an association exists between serum levels of IGF-1 and one of its binding proteins, insulin-like growth factor-binding protein 3 (IGFBP-3), and prostate cancer risk. METHODS: An immunoradiometric assay was used to quantify IGF-1 levels and IGFBP-3 levels in serum samples as part of a population-based, case-control study in Sweden. The study population comprised 210 patients with newly diagnosed, untreated prostate cancer and 224 frequency-matched control subjects. Data were analyzed by use of unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Reported P values are two-sided. RESULTS: The mean serum IGF-1 level for case patients (158.4 ng/mL) was significantly higher than that for control subjects (147.4 ng/mL) (P = .02); corresponding mean serum IGFBP-3 levels were not significantly different between case patients (2668 ng/mL) and control subjects (2518 ng/mL) (P =.09). We found a moderately strong and statistically significant (P = .04) positive association between serum levels of IGF-1 levels and risk of prostate cancer (OR = 1.51; 95% CI = 1.0-2.26 per 100 ng/mL increment); the association was particularly strong for men younger than 70 years of age (OR = 2.93; 95% CI = 1.43-5.97). No association was found between serum IGF-1 levels and disease stage. Serum IGFBP-3 levels were not significantly associated with increased risk of disease, and adjustment for IGFBP-3 had little effect on the association between IGF-1 levels and risk of prostate cancer. CONCLUSION: Elevated serum IGF-1 levels may be an important predictor of risk for prostate cancer. However, our results do not support an important role for serum IGFBP-3 as a predictor of risk for this disease.

Aged↗
PubMed1998

Risk for endometrial cancer in relation to occupational physical activity: a nationwide cohort study in Sweden.

Notwithstanding its biologic plausibility, the association between physical activity and endometrial cancer has been analyzed in only a few epidemiological studies. Retrospective assessment of exposure and small sample size often hampers interpretation of published data. We studied risk for endometrial cancer in relation to physical activity at work in a large cohort of Swedish women identified in the nationwide censuses in 1960 and 1970, with jobs that could be consistently classified into one of 4 levels of physical demands. Follow-up from 1971 through 1989 was accomplished through record linkages. Multivariate Poisson regression models were used to estimate relative risk. The risk for endometrial cancer increased regularly with decreasing level of occupational physical activity (p for trend < 0.001), and was associated more strongly with activity in 1970 than in 1960. In multivariate analyses, adjusted for age at follow-up, place of residence, calendar year of follow-up, and social class, the relative risk among women with the same physical activity level in 1960 and in 1970 was 30% higher for sedentary as compared with high/very high activity level; (p for trend=0.04). The protective effect of physical activity appeared to be confined to women aged 50 to 69, among whom sedentary work was associated with a 60% higher risk than that observed among women estimated to be physically most active. The excess seemed to disappear within 10 years after a change in physical activity level. Although confounding cannot be ruled out in our data, occupational physical activity appears to reduce the risk for endometrial cancer.

Adult↗
PubMed1998

Body size in different periods of life and breast cancer risk in post-menopausal women.

Adult obesity has been associated with an increased risk of post-menopausal breast cancer, but it is unclear whether this relationship reflects a causal role of obesity during childhood and adolescence, of weight gain during adult life or of adult obesity per se. In a population-based case-control study in all of Sweden, we included 3,345 (84% of all eligible) women aged 50-74 years with invasive breast cancer, and 3,454 (82% of all selected) controls of similar age. Mailed questionnaires and telephone interviews were used to collect detailed information on anthropometric measures. Odds ratios were estimated through multiple logistic regression. Women with the leanest somatotype at age 7 had about a 3-fold higher risk of breast cancer than the most obese (P for trend 0.0009). A suggested protective effect of a high body mass at age 18 and a detrimental influence of body mass 1 year prior to data collection largely reflected the effect of weight gain after age 18, a strong predictor of breast cancer risk. Among women at least 20 years post menopause, those who had gained 30 kg or more since age 18 had an odds ratio of 2.04 (95% confidence interval 1.20-3.48) of breast cancer compared with those who had maintained their weight unchanged. The effect of weight gain was unequivocal among non-users but not among users of hormone replacement therapy. Our findings have important implications, suggesting weight preservation as a means for prevention of post-menopausal breast cancer as well as a causal role of childhood body build in breast cancer etiology.

Age Factors↗
PubMed1998

Alcohol and breast cancer in women: a pooled analysis of cohort studies.

OBJECTIVE: To assess the risk of invasive breast cancer associated with total and beverage-specific alcohol consumption and to evaluate whether dietary and nondietary factors modify the association. DATA SOURCES: We included in these analyses 6 prospective studies that had at least 200 incident breast cancer cases, assessed long-term intake of food and nutrients, and used a validated diet assessment instrument. The studies were conducted in Canada, the Netherlands, Sweden, and the United States. Alcohol intake was estimated by food frequency questionnaires in each study. The studies included a total of 322647 women evaluated for up to 11 years, including 4335 participants with a diagnosis of incident invasive breast cancer. DATA EXTRACTION: Pooled analysis of primary data using analyses consistent with each study's original design and the random-effects model for the overall pooled analyses. DATA SYNTHESIS: For alcohol intakes less than 60 g/d (reported by >99% of participants), risk increased linearly with increasing intake; the pooled multivariate relative risk for an increment of 10 g/d of alcohol (about 0.75-1 drink) was 1.09 (95% confidence interval [CI], 1.04-1.13; P for heterogeneity among studies, .71). The multivariate-adjusted relative risk for total alcohol intakes of 30 to less than 60 g/d (about 2-5 drinks) vs nondrinkers was 1.41 (95% CI, 1.18-1.69). Limited data suggested that alcohol intakes of at least 60 g/d were not associated with further increased risk. The specific type of alcoholic beverage did not strongly influence risk estimates. The association between alcohol intake and breast cancer was not modified by other factors. CONCLUSIONS: Alcohol consumption is associated with a linear increase in breast cancer incidence in women over the range of consumption reported by most women. Among women who consume alcohol regularly, reducing alcohol consumption is a potential means to reduce breast cancer risk.

Alcohol Drinking↗
PubMed1998

Calcium and fructose intake in relation to risk of prostate cancer.

Laboratory and clinical data indicate an antitumor effect of 1,25(OH)2 vitamin D (1,25(OH)2D) on prostate cancer. High calcium intake suppresses formation of 1,25(OH)2D from 25(OH)D, thereby decreasing the 1,25(OH)2D level. Ingestion of fructose reduces plasma phosphate transiently, and hypophosphatemia stimulates 1,25(OH)2D production. We thus conducted a prospective study among 47,781 men of the Health Professionals Follow-Up Study free of cancer in 1986 to examine whether calcium and fructose intake influenced risk of prostate cancer. Between 1986 and 1994, 1369 non-stage A1 and 423 advanced (extraprostatic) cases of prostate cancer were diagnosed. Higher consumption of calcium was related to advanced prostate cancer [multivariate relative risk (RR), 2.97; 95% confidence interval (CI), 1.61-5.50 for intakes > or = 2000 mg/day versus < 500 mg/day; P, trend, 0.002] and metastatic prostate cancer (RR, 4.57; CI, 1.88-11.1; P, trend, <0.001). Calcium from food sources and from supplements independently increased risk. High fructose intake was related to a lower risk of advanced prostate cancer (multivariate RR, 0.51; CI, 0.33-0.80, for intakes > 70 versus < or = 40 g/day; P, trend, 0.007). Fruit intake was inversely associated with risk of advanced prostate cancer (RR, 0.63; 95% CI, 0.43-0.93; for > 5 versus < or = 1 serving per day), and this association was accounted for by fructose intake. Non-fruit sources of fructose similarly predicted lower risk of advanced prostate cancer. A moderate positive association between energy-adjusted fat intake and advanced prostate cancer was attenuated and no longer statistically significant when controlled for calcium and fructose. Our findings provide indirect evidence for a protective influence of high 1,25(OH)2D levels on prostate cancer and support increased fruit consumption and avoidance of high calcium intake to reduce the risk of advanced prostate cancer.

Adult↗
PubMed1998

A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer.

BACKGROUND: Animal studies suggest that monounsaturated and polyunsaturated fat may have opposite effects on the risk of breast cancer. METHODS: We performed a population-based prospective cohort study, including 61,471 women aged 40 to 76 years from 2 counties in central Sweden who did not have any previous diagnosis of cancer; 674 cases of invasive breast cancer occurred during an average follow-up of 4.2 years. All subjects answered a validated 67-item food frequency questionnaire at baseline. Cox proportional hazards models were used to obtain adjusted rate ratio (RR) estimates with 95% confidence intervals (CIs). RESULTS: After mutual adjustment of different types of fat, an inverse association with monounsaturated fat and a positive association with polyunsaturated fat were found. The RR for each 10-g increment in daily intake of monounsaturated fat was 0.45 (95% CI, 0.22-0.95), whereas the RR for a 5-g increment of polyunsaturated fat was 1.69 (95% CI, 1.02-2.78); the increments correspond to approximately 2 SDs of intake in the population. Comparing the highest quartile of intake with the lowest, we found an RR of 0.8 (95% CI, 0.5-1.2) for monounsaturated fat and 1.2 (95% CI, 0.9-1.6) for polyunsaturated fat. Saturated fat was not associated with the risk of breast cancer. CONCLUSIONS: Our results indicate that various types of fat may have specific opposite effects on the risk of breast cancer that closely resemble the corresponding effects in experimental animals. Research investigations and health policy considerations should take into account the emerging evidence that monounsaturated fat might be protective for risk of breast cancer.

Adult↗
PubMed1998

Dairy products, calcium, phosphorous, vitamin D, and risk of prostate cancer (Sweden)

OBJECTIVES: Dairy products consistently have been associated with an increased risk of prostate cancer, yet the mechanism of this relationship remains unknown. Recent hypotheses propose that 1,25 dihydroxyvitamin D (1,25 D) is protective for prostate cancer. One study in the United States found that calcium consumption, which can lower circulating 1,25 D, was associated with higher risk of advanced prostate cancer, and we sought to address this hypothesis in a distinct population. METHODS: We analyzed data from a population-based case-control study of prostate cancer conducted in Orebro, Sweden, with 526 cases and 536 controls. Using unconditional logistic regression models, we examined the relationship of dairy products, dietary calcium, phosphorous, and vitamin D with risk of total, extraprostatic, and metastatic prostate cancer. RESULTS: Calcium intake was an independent predictor of prostate cancer (relative risk (RR) = 1.91, 95 percent confidence interval (CI) 1.23-2.97 for intake > or = 1183 vs. < 825 mg/day), especially for metastatic tumors (RR = 2.64, 95 percent CI 1.24-5.61), controlling for age, family history of prostate cancer, smoking, and total energy and phosphorous intakes. High consumption of dairy products was associated with a 50 percent increased risk of prostate cancer. CONCLUSIONS: Our results support the hypothesis that high calcium intake may increase risk of prostate cancer, and this relation may underlie previously observed associations between dairy products and prostate cancer.

Adult↗
PubMed1998

Effect of additional questions about fat on the validity of fat estimates from a food frequency questionnaire. Study Group of MRS SWEA.

OBJECTIVE: We studied whether the validity of fat estimates from food frequency questionnaires (FFQ) can be increased by using in nutrient calculation an additional qualitative information about the type of fat and reduced consumption of visible fat and skin. DESIGN: A random sample of women answered an 88-item self-administered FFQ and performed 4 x 1-week weighed dietary records (DR). SETTING: Uppsala County in central Sweden. SUBJECTS: One hundred and eighty-four women aged 30-77 y, with FFQ and complete DR; 73 women with subcutaneous adipose tissue (AT) samples. METHODS: Fat intake from the FFQ was calculated with/without use of qualitative information and compared to DR and fat composition of AT. MAIN OUTCOME MEASURES: Estimates of long-time intake of total fat, saturated, monounsaturated, polyunsaturated fat and ten specific fatty acids based on FFQ, DR and composition of AT. RESULTS: Mean absolute fat intake estimates based on FFQ (without vs with use of additional fat information) were 21.2 vs 20.2 g/d for saturated, 17.1 vs 16.0 g/d for monounsaturated and 7.3 vs 7.3 g/d for polyunsaturated fat. The Pearson correlation coefficient between the FFQ and AT for polyunsaturated fat was 0.65 vs 0.67. Corresponding correlation between the FFQ and DR was 0.40 vs 0.41; adjustment for energy intake increased this correlation from 0.40 to 0.52. CONCLUSIONS: The increase in the validity of fat estimates due to use of qualitative information about fat was negligible; energy adjustment had greater impact than asking additional questions.

Adipose Tissue↗
PubMed1998

Evaluation of a biological marker of dairy fat intake.

We evaluated whether the adipose tissue content of 2 fatty acids of exogenous origin specific for ruminant fat, 15:0 and 17:0, reflect average long-term dairy fat consumption in free-living subjects. In 81 healthy women aged 30-77 y, we compared the relative content of these 2 fatty acids in subcutaneous adipose tissue with relative intake (% of total fat) based on four 1-wk weighed diet records made 3-4 mo apart and on a food-frequency questionnaire reflecting average past year consumption. The mean (+/-SD) daily milk fat intake was 20.0 +/- 9.1 g and fat from ruminant meat was 3.0 +/- 1.5 g according to food records, representing 29.2 +/- 8.9% and 4.6 +/- 2.2% of total fat, respectively. The intake of 15:0 and 17:0, which are 1.05% and 0.61% of milk fat and 0.43% and 0.83% of ruminant meat fat, was 0.22 +/- 0.10 and 0.15 +/- 0.06 g, respectively. Content of 15:0 and 17:0 in adipose tissue was 0.35% and 0.24% and relative dietary intake was 0.33% and 0.22% according to the food records and 0.32% and 0.21%, respectively, according to the food-frequency questionnaire. Correlation coefficients between 15:0 content in adipose tissue and intake from dairy foods only, according to food records, were 0.63 (Pearson) and 0.59 (Spearman); corresponding values for 17:0 were 0.42 and 0.45, respectively. Content of 15:0 and 17:0 in subcutaneous adipose tissue might be a valid biological marker of long-term milk fat intake in free-living individuals in populations with high consumption of dairy products.

Adipose Tissue↗
PubMed1997

Body size and prostate cancer: a 20-year follow-up study among 135006 Swedish construction workers.

BACKGROUND: Obesity is associated with endocrine changes (e.g., increased estrogen and decreased testosterone in the blood) that have been implicated in the cause of prostate cancer and, therefore, an association between body weight and the risk of developing prostate cancer would be expected. However, because of bias or low statistical power in previous epidemiologic studies, associations between anthropometric measurements (height and weight), body mass index (BMI), and the risk of prostate cancer may have been inadvertently overlooked. PURPOSE: We performed a large, retrospective cohort study among Swedish construction workers to evaluate possible associations of adult weight, height, BMI, and lean body mass (LBM) by age at entry in the study with the incidence and mortality rate of prostate cancer. METHODS: We analyzed data that had been compiled in a computerized central register on a cohort of approximately 135000 male construction workers. Information on height and weight had been collected with the use of a comprehensive questionnaire filled out by nurses at the time of enrollment in the cohort, from 1971 through 1975. Complete follow-up was achieved through 1991 by means of record linkage to the Swedish National Cancer Register, the Death Register, and the Migration Register. A total of 2368 incident cases and 708 deaths from prostate cancer occurred in the cohort during a follow-up period averaging 18 years. We used only information obtained at the index visit from 1971 through 1975 to determine age-adjusted rate ratios (RRs) in a Poisson-based multiplicative multivariate model with age and the relevant exposure variable (e.g., weight, height, BMI, and LBM) as independent variables. RESULTS: All anthropometric measurements were positively associated with the risk of prostate cancer and were more strongly related to mortality than to incidence. The excess risk of death from prostate cancer was statistically significant in all BMI categories above the reference category: RR = 1.40 (95% confidence interval [CI] = 1.09-1.81) in the highest category compared with the lowest (P for trend = .04). For height and LBM, the excess risk in the highest compared with the lowest categories was somewhat less pronounced: RR = 1.28 (95% CI = 1.02-1.60) and RR = 1.26 (95% CI = 1.02-1.57), respectively. Statistically significant linear dose-response relationships were also found with the incidence of prostate cancer, with the exception of BMI (P for trend = .10). CONCLUSION: Our large cohort study indicates that various aspects of body size are related to the risk of prostate cancer and that future studies are needed to study the role of body size and prostate cancer.

Adult↗
PubMed1997

A high dietary calcium intake is needed for a positive effect on bone density in Swedish postmenopausal women.

The importance of dietary calcium for bone health is unclear, partly since most investigations have dealt only with a fairly narrow range of calcium intake. In the present population-based observational study with longitudinal dietary assessment, we investigated women with a mean age of 60 years and with a consistently high (range 1417-2417, mean 1645 mg, n = 40), intermediate (800-1200, mean 1006 mg, n = 35) or low (400-550, mean 465 mg, n = 40) estimated daily consumption of calcium. Measurements of bone mineral density (BMD) of the lumbar spine, femoral neck and total body were performed by dual-energy X-ray absorptiometry, as well as ultrasound of the heel. In a multivariate analysis, with adjustment for energy intake the risk factors for osteoporosis (age, body mass index, physical activity, menopausal age, use of estrogens, smoking and former athletic activity), the group with the highest calcium intake had higher values for BMD than the others at all measured sites. The average mean difference compared with the low and the intermediate calcium group was 11% for the femoral neck, 8-11% for the lumbar spine and 5-6% for total body BMDs. In univariate analyses and multivariate models which did not include energy intake, the differences between the groups were less pronounced. The women in the intermediate calcium group had approximately the same mean BMD values as those in the low calcium group. These findings support the view that only a high calcium intake (3% highest percentiles in the studied population) protects against osteoporosis in Swedish postmenopausal women.

Adult↗
PubMed1997

Diet and the risk of papillary and follicular thyroid carcinoma: a population-based case-control study in Sweden and Norway.

A population-based case-control study was conducted in two regions of Sweden and Norway to investigate the association between dietary habits and the risk of thyroid cancer. The consumption of selected foods was reported in a self-completed food-frequency questionnaire by 246 cases with histologically confirmed papillary (n = 209) and follicular (n = 37) thyroid carcinoma, and 440 age- and gender-matched controls. Odds ratios (OR) and their 95 percent confidence interval (CI) were calculated as estimates of the relative risk using conditional logistic regression. High consumption of butter (OR = 1.6, CI = 1.1-2.5) and cheese (OR = 1.5, CI = 1.0-2.4) was associated with increased risks. Residence in areas of endemic goiter in Sweden was associated with an elevated risk, especially among women (OR = 2.5, CI = 1.3-4.9). High consumption of cruciferous vegetables was associated with increased risk only in persons who ever lived in such areas. A decreased risk was associated with consumption of iodized salt in northern Norway, and with use of iodized salt during adolescence among women (OR = 0.6, CI = 0.6-1.0). The results of this study suggest a role of diet and environment in the risk of thyroid cancer.

Adolescent↗
PubMed1997

Non-dietary factors as risk factors for breast cancer, and as effect modifiers of the association of fat intake and risk of breast cancer.

To assess more precisely the relative risks associated with established risk factors for breast cancer, and whether the association between dietary fat and breast cancer risk varies according to levels of these risk factors, we pooled primary data from six prospective studies in North America and Western Europe in which individual estimates of dietary fat intake had been obtained by validated food-frequency questionnaires. Based on information from 322,647 women among whom 4,827 cases occurred during follow-up: the multivariate-adjusted risk of late menarche (age 15 years or more compared with under 12) was 0.72 (95 percent confidence interval [CI] = 0.62-0.82); of being postmenopausal was 0.82 (CI = 0.69-0.97); of high parity (three or more births compared with none) was 0.72 (CI = 0.61-0.86); of late age at first birth (over 30 years of age compared with 20 or under) was 1.46 (CI = 1.22-1.75); of benign breast disease was 1.53 (CI = 1.41-1.65); of maternal history of breast cancer was 1.38 (CI = 1.14-1.67); and history of a sister with breast cancer was 1.47 (CI = 1.27-1.70). Greater duration of schooling (more than high-school graduation compared with less than high-school graduation) was associated significantly with higher risk in age-adjusted analyses, but was attenuated after controlling for other risk factors. Total fat intake (adjusted for energy consumption) was not associated significantly with breast cancer risk in any strata of these non-dietary risk factors. We observed a marginally significant interaction between total fat intake and risk of breast cancer according to history of benign breast disease; with fat intake being associated nonsignificantly positively with risk among women with a previous history of benign breast disease; no other significant interactions were observed. Risks for reproductive factors were similar to those observed in case-control studies; relative risks for family history of breast cancer were lower. We found no clear evidence in any subgroups of a major relation between total energy-adjusted fat intake and breast cancer risk.

Breast Neoplasms↗