ORDET Cohort Research Articles

Adherence to Diet Quality Indices and Breast Cancer Risk in the Italian ORDET Cohort.

Breast cancer (BC) is the most common cancer in women, with 2.3 million diagnoses in 2020. There is growing evidence that lifestyle factors, including dietary factors, particularly the complex interactions and synergies between different foods and nutrients (and not a single nutrient or food), may be associated with a higher risk of BC. The aim of this work was to evaluate how the Italian Mediterranean Index (IMI), the Greek Mediterranean Index, the DASH score, and the EAT-Lancet score can help lower the risk of BC, and analyze if chronic low-grade inflammation may be one of the possible mechanisms through which dietary patterns influence breast cancer risk. We evaluated the effect of adherence to these four dietary quality indices in the 9144 women of the ORDET cohort who completed a dietary questionnaire. The effect of adherence to dietary patterns on chronic inflammation biomarkers was evaluated on a subsample of 552 participants. Hazard ratios (HRs) with 95% confidence intervals (CIs) for BC risk in relation to the index score categories used were estimated using multivariable Cox models adjusted for potential confounders. Regression coefficients (β), with 95% CI for C-reactive protein (CRP), TNF-α, IL-6, leptin, and adiponectin levels in relation to adherence to dietary patterns were evaluated with the linear regression model adjusted for potential confounders. IMI was inversely associated with BC in all women (HR: 0.76, 95% CI: 0.60-0.97, P trend = 0.04), particularly among postmenopausal women (HR: 0.64, 95% CI: 0.42-0.98, P trend = 0.11). None of the other dietary patterns was associated with BC risk. Higher IMI and Greek Mediterranean Index scores were inversely associated with circulating CRP (β: -0.10, 95% CI: -0.18, -0.02, and β: -0.13, 95% CI: -0.21, -0.04). The higher score of the EAT-Lancet Index was instead associated with a higher concentration of circulating levels of CRP (β: 0.10, 95% CI: 0.02, 0.18). In conclusion, these results suggest that adherence to a typical Italian Mediterranean diet protects against BC development, especially among postmenopausal women, possibly through modulation of chronic low-grade inflammation.

Prediagnostic Levels of Copper and Zinc and Breast Cancer Risk in the ORDET Cohort.

Case-control studies show that copper (Cu) is high and zinc (Zn) low in blood and urine of women with breast cancer compared with controls. To assess whether prediagnostic Cu and Zn are associated with breast cancer risk, OR of breast cancer according to Cu, Zn, and Cu/Zn ratio in plasma and urine was estimated in a nested case-control study within the ORDET cohort, using conditional logistic regression adjusted for multiple variables: First 496 breast cancer cases and matched controls, diagnosed ≥2 years after recruitment (to eliminate reverse causation) were analyzed. Then all eligible cases/controls were analyzed with stratification into years from recruitment to diagnosis. For women diagnosed ≥2 years, compared with lowest tertiles, breast cancer risk was higher in the highest tertile of plasma Cu/Zn ratio (OR, 1.75; 95% CI, 1.21-2.54) and the highest tertile of both plasma and urine Cu/Zn ratio (OR, 2.37; 95% CI, 1.32-4.25). Risk did not vary with ER/PR/HER2 status. For women diagnosed <2 years, high Cu/Zn ratio was strongly associated with breast cancer risk. Our prospective findings suggest that increased Cu/Zn ratio in plasma and urine may be both an early marker of, and a risk factor for, breast cancer development. Further studies are justified to confirm or otherwise our results and to investigate mechanisms. Our finding that prediagnostic Cu/Zn ratio is a strong risk factor for breast cancer development deserves further investigation and, if confirmed, might open the way to interventions to reduce breast cancer risk in women with disrupted Cu/Zn homeostasis.

Micronutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer Subtypes.

BackgroundVitamins involved in one-carbon metabolism are hypothesized to influence breast cancer (BC) risk. However, epidemiologic studies that examined associations between B vitamin intake and BC risk have provided inconsistent results. We prospectively examined, in the Italian ORDET cohort, whether B vitamin consumption was associated with risk of BC and BC subtypes.MethodsAfter a mean follow-up of 16.5 years, 391 BCs were diagnosed among 10,786 cohort women. B vitamin intakes were estimated from food frequency questionnaires. Cox proportional hazard models adjusted for energy intake and confounders, estimated hazard ratios (HR) with 95% confidence intervals (CIs) for BC according to intake.ResultsRRs were 0.61 (95% CI 0.38–0.97 highest vs. lowest quartile; P trend 0.025) for thiamine; 0.48 (95% CI 0.32–0.71; P trend <0.001) for riboflavin; 0.59 (95% CI 0.39–0.90; P trend 0.008) for vitamin B6, and 0.65 (95% CI 0.44–0.95; P trend 0.021) for folate. As regards risk of BC subtypes, high riboflavin and folate were significantly associated with lower risk of estrogen receptor positive (ER+) and progesterone receptor positive (PR+) cancers, and high thiamine was associated with lower risk of ER-PR- cancers. High riboflavin was associated with lower risk of both HER2+ and HER2- cancers, high folate with lower risk of HER2- disease, and high thiamine with HER2+ disease.ConclusionsThese findings support protective effects of thiamine and one-carbon metabolism vitamins (folate, riboflavin, and vitamin B6) against BC in general; while folate may also protect against ER+PR+ and HER2- disease; and thiamine against ER-PR-, and HER2+ disease.

Toenail selenium and risk of type 2 diabetes: the ORDET cohort study

Epidemiologic studies, particularly randomized controlled trials, have shown a direct relation between dietary and environmental exposure to the metalloid selenium and risk of type 2 diabetes. We investigated the association between baseline toenail selenium levels and diabetes occurrence in a case–control study nested in ORDET, a population-based female cohort in Northern Italy. After a median follow-up of 16 years, we identified 226 cases of type 2 diabetes cases and 395 age-matched control women with available toenail samples at baseline. The multivariate odds ratios of diabetes in increasing a priori defined categories of toenail selenium exposure were 1.09 (95% confidence interval 0.61, 1.96), 0.71 (0.38, 1.34) and 1.14 (0.46, 2.80) compared with the lowest category. The results were not substantially altered when quartile distribution of toenail selenium in controls was used to define exposure categories. Spline regression analysis did not show homogeneous risk trends. Overall, we did not find an association between toenail selenium and subsequent development of diabetes. Since the diabetogenic activity of selenium is strongly supported by experimental studies and some observational investigations, our null results might be explained by the limitations of overall selenium toenail content to assess environmental exposure to selenium species of etiologic relevance in the study population.

Endogenous sex steroids in premenopausal women and risk of breast cancer: the ORDET cohort

IntroductionPrevious studies showed that higher testosterone levels are associated with greater risk of breast cancer in premenopausal women, but the literature is scant and inconsistent.MethodsIn a prospective nested case-control study of 104 premenopausal women with incident breast cancer and 225 matched controls, all characterized by regular menstrual cycles throughout their lifetime, we measured the concentration of estradiol, total and free testosterone (FT), progesterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in blood samples collected on days 20 through 24 of their cycles.ResultsIn logistic regression models, the multivariate odds ratios (ORs) of invasive breast cancer for women in the highest tertile of circulating FT compared with the lowest was 2.43 (95% confidence interval (95% CI), 1.15 to 5.10; Ptrend = 0.03), whereas for total testosterone, the association had the same direction but was not statistically significant (OR, 1.27; 95% CI, 0.62 to 2.61; Ptrend = 0.51). Endogenous progesterone was not statistically associated with breast cancer (OR, 1.16; 95% CI, 0.60 to 2.27; Ptrend = 0.75), nor were the other considered hormones.ConclusionsConsistent with previous prospective studies in premenopausal women and our own earlier investigation, we observed that higher levels of FT are positively associated with breast cancer risk in women with regular menstrual cycles throughout their lifetimes. No evidence of risk was found associated with the other endogenous sex steroids.

Prospective study on the role of glucose metabolism in breast cancer occurrence

High circulating glucose, insulin resistance and obesity appear to be associated with increased risk of breast cancer (BC). We sought further insight into the relation of these variables to BC. We assessed associations of BC risk with serum fasting glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) index and sex-binding hormone globulin (SHBG) in women recruited to the ORDET cohort who gave blood samples in 1987-1992. After a median 13.5 years of follow-up, 356 women developed BC. Four matched controls per case were selected by incidence density sampling, and rate ratios (RR) were estimated by conditional logistic regression. Women in the highest glucose quartile had a significantly greater risk of BC than those in the lowest glucose quartile (RR 1.63; 95% CI: 1.14-2.32; p for trend of 0.003). The association was significant in pre and post menopausal women separately and in women diagnosed after 55 years. Women in the highest HOMA-IR quartile had higher BC risk than the lowest quartile (RR 1.44; 95% CI: 1.03-2.02). Significantly increased BC risk in women diagnosed after 55 years was also present in the highest HOMA-IR quartile; in the same group decreased BC risk was significantly associated with high SHBG. The results of this study add to the existing epidemiological evidence that hyperglycemia and insulin resistance increase BC risk.

A prospective study of dietary selenium intake and risk of type 2 diabetes

BackgroundGrowing evidence raises concern about possible associations of high selenium exposure with diabetes in selenium-replete populations such as the US. In countries with lower selenium status, such as Italy, there is little epidemiological evidence on the association between selenium and diabetes. This study examined the prospective association between dietary selenium intake and risk of type 2 diabetes.MethodsThe ORDET cohort study comprised a large sample of women from Northern Italy (n = 7,182). Incident type 2 diabetes was defined as a self-report of a physician diagnosis, use of antidiabetic medication, or a hospitalization discharge. Dietary selenium intake was measured by a semi-quantitative food-frequency questionnaire at the baseline examination (1987-1992). Participants were divided in quintiles based on their baseline dietary selenium intake.ResultsAverage selenium intake at baseline was 55.7 μg/day. After a median follow-up of 16 years, 253 women developed diabetes. In multivariate logistic regression analyses, the odds ratio for diabetes comparing the highest to the lowest quintile of selenium intake was 2.39, (95% CI: 1.32, 4.32; P for linear trend = 0.005). The odds ratio for diabetes associated with a 10 μg/d increase in selenium intake was 1.29 (95% CI: 1.10, 1.52).ConclusionsIn this population, increased dietary selenium intake was associated with an increased risk of type 2 diabetes. These findings raise additional concerns about the association of selenium intake above the Recommended Dietary Allowance (55 μg/day) with diabetes risk.

Urinary 6-Sulphatoxymelatonin Levels and Risk of Breast Cancer in Premenopausal Women: The ORDET Cohort

Lower urinary melatonin levels are associated with a higher risk of breast cancer in postmenopausal women. Literature for premenopausal women is scant and inconsistent. In a prospective case-control study, we measured the concentration of 6-sulphatoxymelatonin (aMT6s) in the 12-hour overnight urine of 180 premenopausal women with incident breast cancer and 683 matched controls. In logistic regression models, the multivariate odds ratio (OR) of invasive breast cancer for women in the highest quartile of total overnight aMT6s output compared with the lowest was 1.43 [95% confidence interval (CI), 0.83-2.45; P(trend) = 0.03]. Among current nonsmokers, no association was existent (OR, 1.00; 95% CI, 0.52-1.94; P(trend) = 0.29). We observed an OR of 0.68 between overnight urinary aMT6s level and breast cancer risk in women with invasive breast cancer diagnosed >2 years after urine collection and a significant inverse association in women with a breast cancer diagnosis >8 years after urine collection (OR, 0.17; 95% CI, 0.04-0.71; P(trend) = 0.01). There were no important variations in ORs by tumor stage or hormone receptor status of breast tumors. Overall, we observed a positive association between aMT6s and risk of breast cancer. However, there was some evidence to suggest that this might be driven by the influence of subclinical disease on melatonin levels, with a possible inverse association among women diagnosed further from recruitment. Thus, the influence of lag time on the association between melatonin and breast cancer risk needs to be evaluated in further studies.

Metabolic syndrome and postmenopausal breast cancer in the ORDET cohort: A nested case–control study

Background and aimsThe increase in breast cancer incidence over recent decades has been accompanied by an increase in the frequency of metabolic syndrome. Several studies suggest that breast cancer risk is associated with the components of metabolic syndrome (high serum glucose and triglycerides, low HDL-cholesterol, high blood pressure, and abdominal obesity), but no prospective study has investigated risk in relation to the presence of explicitly defined metabolic syndrome. We investigated associations between metabolic syndrome, its components, and breast cancer risk in a nested case–control study on postmenopausal women of the ORDET cohort. Methods and resultsAfter a median follow-up of 13.5 years, 163 women developed breast cancer; metabolic syndrome was present in 29.8%. Four matched controls per case were selected by incidence density sampling, and rate ratios were estimated by conditional logistic regression. Metabolic syndrome (i.e. presence of three or more metabolic syndrome components) was significantly associated with breast cancer risk (rate ratio 1.58 [95% confidence interval 1.07–2.33]), with a significant risk increase for increasing number of components (P for trend 0.004). Among individual metabolic syndrome components, only low serum HDL-cholesterol and high triglycerides were significantly associated with increased risk. ConclusionsThis prospective study indicates that metabolic syndrome is an important risk factor for breast cancer in postmenopausal women. Although serum HDL-cholesterol and triglycerides had the strongest association with breast cancer, all components may contribute to increased risk by multiple interacting mechanisms. Prevention or reversal of metabolic syndrome by life-style changes may be effective in preventing breast cancer in postmenopausal women.

Sex Hormone Levels, Breast Cancer Risk, and Cancer Receptor Status in Postmenopausal Women: the ORDET Cohort

Endogenous sex hormone levels have been associated with increased breast cancer risk in postmenopausal women in several prospective studies. However, it remains unclear to what extent serum hormone-breast cancer associations differ with receptor status. Associations between serum sex hormone levels and breast cancer risk were assessed in a nested case-control study on postmenopausal women of the ORDET cohort. After a median follow-up of 13.5 years, 165 women developed breast cancer. Relative risks of developing breast cancer were estimated by conditional logistic regression. Total and free testosterone levels were directly associated with breast cancer risk [relative risk, 3.28 (95% confidence interval, 1.93-5.55) and 2.86 (95% confidence interval, 1.66-4.94), respectively, for highest versus lowest quartile]. When relations between hormone level and risk of breast cancer expressing various receptor combinations were assessed, high total testosterone was significantly associated with increased risk of estrogen receptor-positive cancers, irrespective of progesterone receptor status. High total testosterone was also associated with increased risk of both human epidermal growth factor receptor 2 (HER2)-negative (HER2(-)) and HER2(+) cancers. High estradiol tended to be associated with increased risk of HER2(-) cancer and inversely associated with HER2(+) cancer, with significant (P = 0.027) heterogeneity between HER2(+) and HER2(-) cancers. However, there were relatively few HER2(+) cases. This study provides further evidence that high levels of circulating testosterone increase the risk of developing breast cancer in postmenopausal women. The cancers that develop are mainly estrogen receptor positive. Although HER2(+) and HER2(-) breast cancers were both associated with high total testosterone, they showed opposing associations with estrogen.

Reliability of Urinary 6-sulfatoxymelatonin as a Biomarker in Breast Cancer

The objective of this study is to evaluate the effect of cryopreservation at different storage temperatures on urinary 6-sulfatoxymelatonin (aMT6s) concentration. Overnight urine from 28 postmenopausal women participating in the ORDET cohort study was filtered and separated into 6 mL aliquots. Urine samples were stored at -80 degrees C and at -30 degrees C for an average of 14 years. Urinary aMT6s concentration was assessed using a competitive immunoassay. Mean aMT6s values of samples stored at -30 degrees C were systematically lower than those of samples stored at -80 degrees C (10.7 ng/mL versus 15.8 ng/mL, p<0.001). Bland Altman plots showed disagreement between determinations at different storage temperatures at the highest levels of the metabolite concentration. The degree of agreement evaluated in terms of intraclass correlation coefficient was 0.68 (95% CI 0.41-0.84, p<0.0001). Pearson's correlation coefficient between aMT6s values of the two differently stored samples was 0.93 (p<0.001), while the Kendal tau coefficient for rank distribution was 0.73 (p<0.001). Our data suggest that storage temperatures might affect degradation of aMT6s during storage. However, individual characterization by melatonin levels does not seem to be affected by cryopreservation conditions.

Erythrocyte Membrane Phospholipid Composition as a Biomarker of Dietary Fat

Background/Aims: In a cross-sectional study, we investigated the relationship between erythrocyte membrane phospholipid fatty acid composition and dietary fat; we also investigated roles of menopausal status, age, body mass index (BMI) and waist-to-hip ratio (WHR) in interindividual variation of the biomarker. Methods: Study participants were 204 women, aged 39–65 years, drawn from the ORDET cohort and selected as controls in a study of breast cancer. Membrane composition was assessed using capillary gas chromatography. Dietary fat composition was evaluated using a food frequency questionnaire. Results: In pre- and postmenopausal women, erythrocyte membrane phospholipid levels of linoleic acid, oleic acid, and mono-unsaturated fatty acids were significantly associated with corresponding dietary measures (partial correlation coefficients: 0.23 and 0.39; 0.45 and 0.47; 0.40 and 0.48; respectively, in pre- and postmenopausal women). Among postmenopausal women, membrane poly-unsaturated fatty acids were correlated with the corresponding dietary measure (r = 0.39, p < 0.001). Membrane eicosapentanoic and docosahexanoic acid levels were significantly correlated with intake of fish/shell fish : r = 0.21 and r = 0.43 (premenopausal), and r = 0.41 and r = 0.44 (postmenopausal). Age, BMI and WHR had independent effects on membrane lipid composition. Age was associated with delta-6 desaturase activity in postmenopausal women (r = 0.25, p < 0.05). BMI was negatively associated with delta-9 desaturase activity in both pre- and postmenopausal women (r = –0.29, p = 0.01 and r = –0.22, p < 0.01, respectively). WHR was negatively associated with delta-5 desaturase activity in pre-menopausal women (r = –024, p < 0.05). Conclusions: Erythrocyte membrane levels of some specific fatty acids can be used as biomarkers of these fatty acids as proportions of dietary fat.

Reliability of urinary 6-sulfatoxymelatonin as a biomarker in breast cancer

The objective of this study is to evaluate the effect of cryopreservation at different storage temperatures on urinary 6-sulfatoxymelatonin (aMT6s) concentration. Overnight urine from 28 postmenopausal women participating in the ORDET cohort study was filtered and separated into 6 mL aliquots. Urine samples were stored at -80 degrees C and at -30 degrees C for an average of 14 years. Urinary aMT6s concentration was assessed using a competitive immunoassay. Mean aMT6s values of samples stored at -30 degrees C were systematically lower than those of samples stored at -80 degrees C (10.7 ng/mL versus 15.8 ng/mL, p<0.001). Bland Altman plots showed disagreement between determinations at different storage temperatures at the highest levels of the metabolite concentration. The degree of agreement evaluated in terms of intraclass correlation coefficient was 0.68 (95% CI 0.41-0.84, p<0.0001). Pearson's correlation coefficient between aMT6s values of the two differently stored samples was 0.93 (p<0.001), while the Kendal tau coefficient for rank distribution was 0.73 (p<0.001). Our data suggest that storage temperatures might affect degradation of aMT6s during storage. However, individual characterization by melatonin levels does not seem to be affected by cryopreservation conditions.

Dietary Patterns and Risk of Breast Cancer in the ORDET Cohort

Abstract The aim of this study was to evaluate the association between dietary patterns and risk of developing breast cancer in an Italian cohort. Women volunteers were recruited from 1987 to 1992 from residents in Varese province, northern Italy, an area covered by a cancer registry. Participants completed a semiquantitative food frequency questionnaire, and anthropometric and other data were collected systematically. Using nutritional data from 8984 women with an average follow up of 9.5 years and 207 incident cases of breast cancer, we conducted an exploratory factor analysis to identify major dietary patterns. Four dietary patterns, which explained 30% of the variance, emerged: salad vegetables (mainly consisting of raw vegetables and olive oil); western (mainly consisting of potatoes, red meat, eggs and butter); canteen (pasta and tomato sauce); and prudent (cooked vegetables, pulses, and fish, with negative loading on wines and spirits). After adjustment for potential confounders, only the salad vegetables pattern was associated with significantly lower (34–35%) breast cancer incidence (RR = 0.66, CI95% = 0.47±0.95 comparing highest with lowest tertile) with a significant linear trend (P = 0.016). Women with body mass index &amp;lt;25 had an even greater risk reduction in the highest tertile of the salad vegetables pattern (&amp;gt;50% less risk than the lowest tertile, RR = 0.39, CI95% = 0.22–0.69) with a significant trend (P = 0.001); whereas women with body mass index ≥25 had no protective effect for the consumption of salad vegetables. These findings suggest that a diet rich in raw vegetables and olive oil protects against breast cancer.

Fat and Protein Intake and Subsequent Breast Cancer Risk in Postmenopausal Women

The role of diet in the etiology of breast cancer has been extensively evaluated. Case-control studies generally support an association, while cohort studies have produced inconsistent results. This study, carried out on the ORDET cohort, is the first prospective Italian study to address the relation between diet and breast cancer. Female volunteers were recruited from 1987 to 1992 among residents of Varese Province, Northern Italy, an area covered by a cancer registry. A semiquantitative self-administered food questionnaire was completed by participants. After a mean 5.5 yr of follow-up, 56 cases of invasive breast cancer were identified among the 3,367 postmenopausal members; 214 controls were randomly chosen from the cohort, matched to cases for age, menopausal status at recruitment, recruitment center, and recruitment period. The adjusted odds ratios for the highest tertile of intake vs. the lowest were 3.47 [95% confidence interval (CI) = 1.43-8.44] for total fat, 3.78 (95% CI = 0.95-15.0) for animal protein, and 0.42 (95% CI = 0.18-0.95) for total carbohydrates. These findings indicate a significant positive association between total fat and animal protein and risk of breast cancer and an inverse association with carbohydrates and constitute new evidence for a role of diet in the etiology of breast cancer.