Martin Almquist

Metabolic Syndrome and Breast Cancer in the Me-Can (Metabolic Syndrome and Cancer) Project

Background: Few studies have assessed the metabolic syndrome (MetS) as an entity in relation to breast cancer risk, and results have been inconsistent. We aimed to examine the association between MetS factors (individually and combined) and risk of breast cancer incidence and mortality. Methods: Two hundred ninety thousand women from Austria, Norway, and Sweden were enrolled during 1974-2005, with measurements of height, weight, blood pressure, and levels of glucose, cholesterol, and triglycerides. Relative risks (RR) of breast cancer were estimated using Cox proportional hazards regression for each MetS factor in quintiles and for standardized levels (z-scores) and for a composite z-score for the MetS. Results: There were 4,862 incident cases of breast cancer and 633 deaths from breast cancer identified. In women below age 50, there was a decreased risk of incident cancer for the MetS (per 1-unit increment of z-score; RR, 0.83; 95% confidence interval, 0.76-0.90) as well as for the individual factors (except for glucose). The lowest risks were seen among the heaviest women. In women above age 60, there was an increased risk of breast cancer mortality for the MetS (RR, 1.23; 95% confidence interval, 1.04-1.45) and for blood pressure and glucose. The strongest association with mortality was seen for increased glucose concentrations. Conclusions: The MetS was associated with a decreased risk of incident breast cancer in women below age 50 with high body mass index, and with an increased risk of breast cancer mortality in women above 60. Impact: Lifestyle interventions as recommended for cardiovascular disease prevention may be of value to prevent breast cancer mortality in postmenopausal women. Cancer Epidemiol Biomarkers Prev; 19(7); 1737–45. ©2010 AACR.

Serum levels of vitamin D, PTH and calcium and breast cancer risk-a prospective nested case-control study.

Previous studies indicate that calcium and its regulating hormones, i.e., parathyroid hormone (PTH) and vitamin D, might affect breast cancer risk. Evidence also suggests that this relationship could be influenced by menopausal status and BMI. We examined breast cancer risk related to prediagnostic serum levels of vitamin D (25OHD2 and 25OHD3), PTH and calcium using a nested case–control design within the Malmö Diet and Cancer Study. There were 764 incident breast cancer cases, and 764 controls were selected by incidence density matching, using age as the underlying time scale, matching on calendar time at inclusion, menopausal status and age at inclusion. Using logistic regression analysis, odds ratios (OR) with 95% confidence intervals were calculated for breast cancer risk in different quartiles of the analyzed factors. All analyses were adjusted for risk factors for breast cancer, and for levels of albumin, creatinine and phosphate. Analyses were repeated stratified for BMI and menopausal status, and for low vs. high levels of 25OHD3, PTH and calcium. There was a weak, nonsignificant inverse association between breast cancer risk and 25OHD3, and the OR for the 2nd, 3rd and 4th quartiles, as compared to the first, were 0.84 (0.60–1.15), 0.84 (0.60–1.17) and 0.93 (0.66–1.33). Serum calcium was positively associated with breast cancer in premenopausal women (OR for the 4th quartile = 3.10:1.33–7.22 and p for quartile trend = 0.04), and in women with BMI > 25 (OR for the 4th quartile = 1.94:1.12–3.37 and p for trend < 0.01). There was no association between baseline serum PTH and breast cancer risk.

Impact of Cigarette Smoking on Cancer Risk in the European Prospective Investigation into Cancer and Nutrition Study.

PURPOSE Our aim was to assess the impact of cigarette smoking on the risk of the tumors classified by the International Agency for Research on Cancer as causally associated with smoking, referred to as tobacco-related cancers (TRC). METHODS The study population included 441,211 participants (133,018 men and 308,193 women) from the European Prospective Investigation Into Cancer and Nutrition. We investigated 14,563 participants who developed a TRC during an average follow-up of 11 years. The impact of smoking cigarettes on cancer risk was assessed by the population attributable fraction (AF(p)), calculated using the adjusted hazard ratios and 95% CI for current and former smokers, plus either the prevalence of smoking among cancer cases or estimates from surveys in representative samples of the population in each country. RESULTS The proportion of all TRC attributable to cigarette smoking was 34.9% (95% CI, 32.5 to 37.4) using the smoking prevalence among cases and 36.2% (95% CI, 33.7 to 38.6) using the smoking prevalence from the population. The AF(p) were above 80% for cancers of the lung and larynx, between 20% and 50% for most respiratory and digestive cancers and tumors from the lower urinary tract, and below 20% for the remaining TRC. CONCLUSION Using data on cancer incidence for 2008 and our AF(p) estimates, about 270,000 new cancer diagnoses per year can be considered attributable to cigarette smoking in the eight European countries with available data for both men and women (Italy, Spain, United Kingdom, the Netherlands, Greece, Germany, Sweden, Denmark).

Social Inequalities and Mortality in Europe - Results from a Large Multi-National Cohort

Background Socio-economic inequalities in mortality are observed at the country level in both North America and Europe. The purpose of this work is to investigate the contribution of specific risk factors to social inequalities in cause-specific mortality using a large multi-country cohort of Europeans. Methods A total of 3,456,689 person/years follow-up of the European Prospective Investigation into Cancer and Nutrition (EPIC) was analysed. Educational level of subjects coming from 9 European countries was recorded as proxy for socio-economic status (SES). Cox proportional hazard models with a step-wise inclusion of explanatory variables were used to explore the association between SES and mortality; a Relative Index of Inequality (RII) was calculated as measure of relative inequality. Results Total mortality among men with the highest education level is reduced by 43% compared to men with the lowest (HR 0.57, 95% C.I. 0.52–0.61); among women by 29% (HR 0.71, 95% C.I. 0.64–0.78). The risk reduction was attenuated by 7% in men and 3% in women by the introduction of smoking and to a lesser extent (2% in men and 3% in women) by introducing body mass index and additional explanatory variables (alcohol consumption, leisure physical activity, fruit and vegetable intake) (3% in men and 5% in women). Social inequalities were highly statistically significant for all causes of death examined in men. In women, social inequalities were less strong, but statistically significant for all causes of death except for cancer-related mortality and injuries. Discussion In this European study, substantial social inequalities in mortality among European men and women which cannot be fully explained away by accounting for known common risk factors for chronic diseases are reported.

Metabolic factors and the risk of pancreatic cancer: a prospective analysis of almost 580,000 men and women in the Metabolic Syndrome and Cancer Project.

Background: The aim of this study was to investigate the association between factors in metabolic syndrome (MetS; single and combined) and the risk of pancreatic cancer. Methods: The Metabolic Syndrome and Cancer Project is a pooled cohort containing data on body mass index, blood pressure, and blood levels of glucose, cholesterol, and triglycerides. During follow-up, 862 individuals were diagnosed with pancreatic cancer. Cox proportional hazards analysis was used to calculate relative risks (RR) with 95% confidence intervals using the abovementioned factors categorized into quintiles and transformed into z-scores. All z-scores were summarized and a second z-transformation creating a composite z-score for MetS was done. All risk estimates were calibrated to correct for a regression dilution bias. Results: The trend over quintiles was positively associated with the risk of pancreatic cancer for mid-blood pressure (mid-BP) and glucose in men and for body mass index, mid-BP, and glucose in women. The z-score for the adjusted mid-BP (RR, 1.10; 1.01-1.20) and the calibrated z-score for glucose (RR, 1.37; 1.14-1.34) were positively associated with pancreatic cancer in men. In women, a positive association was found for calibrated z-scores for mid-BP (RR, 1.34; 1.08-1.66), for the calibrated z-score for glucose (RR, 1.98; 1.41-2.76), and for the composite z-score for MetS (RR, 1.58; 1.34-1.87). Conclusion: Our study adds further evidence to a possible link between abnormal glucose metabolism and risk of pancreatic cancer. Impact: To our knowledge, this is the first study on MetS and pancreatic cancer using prediagnostic measurements of the examined factors. Cancer Epidemiol Biomarkers Prev; 19(9); 2307–17. ©2010 AACR.

Metabolic Syndrome and Endometrial Carcinoma

The authors examined the association between the metabolic syndrome and risk of incident endometrial and fatal uterine corpus cancer within a large prospective cohort study. Approximately 290,000 women from Austria, Norway, and Sweden were enrolled during 1974-2005, with measurements of height, weight, systolic and diastolic blood pressure, and circulating levels of glucose, total cholesterol, and triglycerides. Relative risks were estimated using Cox proportional hazards regression. The metabolic syndrome was assessed as a composite z score, as the standardized sum of z scores for body mass index, blood pressure, glucose, cholesterol, and triglycerides. A total of 917 endometrial carcinomas and 129 fatal cancers were identified. Increased risks of incident endometrial carcinoma and fatal uterine corpus cancer were seen for the metabolic syndrome factors combined, as well as for individual factors (except for cholesterol). The relative risk of endometrial carcinoma for the metabolic syndrome was 1.37 (95% confidence interval: 1.28, 1.46) per 1-unit increment of z score. The positive associations between metabolic syndrome factors (both individually and combined) and endometrial carcinoma were confined to the heaviest women. The association between the metabolic syndrome and endometrial carcinoma risk seems to go beyond the risk conferred by obesity alone, particularly in women with a high body mass index.

Body size and risk of differentiated thyroid carcinomas: findings from the EPIC study.

Results from case‐control and prospective studies suggest a moderate positive association between obesity and height and differentiated thyroid carcinoma (TC). Little is known on the relationship between other measures of adiposity and differentiated TC risk. Here, we present the results of a study on body size and risk of differentiated TC based on a large European prospective study (EPIC). During follow‐up, 508 incident cases of differentiated TC were identified in women, and 58 in men. 78% of cases were papillary TC. Cox proportional hazard models were used to estimate hazard ratios (HRs). In women, differentiated TC risk was significantly associated with body mass index (BMI, kg/m2) (HR highest vs lowest quintile = 1.41, 95% CI: 1.03–1.94); height (HR = 1.61; 95% CI: 1.18–2.20); HR highest vs lowest tertile waist (HR = 1.34, 95% CI: 1.00–1.79) and waist‐to‐hip ratio (HR = 1.42, 95% CI: 1.05–1.91). The association with BMI was somewhat stronger in women below age 50. Corresponding associations for papillary TC were similar to those for all differentiated TC. In men the only body size factors significantly associated with differentiated TC were height (non linear), and leg length (HR highest vs. lowest tertile = 3.03, 95% CI: 1.30–7.07). Our study lends further support to the presence of a moderate positive association between differentiated TC risk and overweight and obesity in women. The risk increase among taller individuals of both sexes suggests that some genetic characteristics or early environmental exposures may also be implicated in the etiology of differentiated TC.

Metabolic Factors and the Risk of Colorectal Cancer in 580,000 Men and Women in the Metabolic Syndrome and Cancer Project (Me-Can)

The metabolic syndrome (MetS) has been related to an increased risk of colorectal cancer, but the modest size of previous studies precluded detailed characterization of the role of individual MetS factors and their interaction on risk.

Total serum cholesterol and cancer incidence in the Metabolic syndrome and Cancer Project (Me-Can).

Objective To investigate the association between total serum cholesterol (TSC) and cancer incidence in the Metabolic syndrome and Cancer project (Me-Can). Methods Me-Can consists of seven cohorts from Norway, Austria, and Sweden including 289,273 male and 288,057 female participants prospectively followed up for cancer incidence (n = 38,978) with a mean follow-up of 11.7 years. Cox regression models with age as the underlying time metric were used to estimate hazard ratios (HR) and their 95% confidence intervals (CI) for quintiles of cholesterol levels and per 1 mmol/l, adjusting for age at first measurement, body mass index (BMI), and smoking status. Estimates were corrected for regression dilution bias. Furthermore, we performed lag time analyses, excluding different times of follow-up, in order to check for reverse causation. Results In men, compared with the 1st quintile, TSC concentrations in the 5th quintile were borderline significantly associated with decreasing risk of total cancer (HR = 0.94; 95%CI: 0.88, 1.00). Significant inverse associations were observed for cancers of the liver/intrahepatic bile duct (HR = 0.14; 95%CI: 0.07, 0.29), pancreas cancer (HR = 0.52, 95% CI: 0.33, 0.81), non-melanoma of skin (HR = 0.67; 95%CI: 0.46, 0.95), and cancers of the lymph−/hematopoietic tissue (HR = 0.68, 95%CI: 0.54, 0.87). In women, hazard ratios for the 5th quintile were associated with decreasing risk of total cancer (HR = 0.86, 95%CI: 0.79, 0.93) and for cancers of the gallbladder (HR = 0.23, 95%CI: 0.08, 0.62), breast (HR = 0.70, 95%CI: 0.61, 0.81), melanoma of skin (HR = 0.61, 95%CI: 0.42, 0.88), and cancers of the lymph−/hematopoietic tissue (HR = 0.61, 95%CI: 0.44, 0.83). Conclusion TSC was negatively associated with risk of cancer overall in females and risk of cancer at several sites in both males and females. In lag time analyses some associations persisted, suggesting that for these cancer sites reverse causation did not apply.

Cigarette smoking and colorectal cancer risk in the European prospective investigation into cancer and nutrition study

BACKGROUND & AIMS There has been consistent evidence for a relationship between smoking and colorectal cancer (CRC), although it is not clear whether the colon or rectum is more sensitive to the effects of smoking. We investigated the relationships between cigarette smoking and risk of CRC and tumor location. METHODS We analyzed data from 465,879 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study; 2741 developed CRC during the follow-up period (mean, 8.7 years). Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS The risk of colon carcinoma was increased among ever smokers (HR, 1.18; 95% CI, 1.06-1.32) and former cigarette smokers (HR, 1.21; 95% CI, 1.08-1.36), compared with never smokers; the increased risk for current smokers was of borderline significance (HR, 1.13; 95% CI, 0.98-1.31). When stratified for tumor location, the risk of proximal colon cancer was increased for former (HR, 1.25; 95% CI, 1.04-1.50) and current smokers (HR, 1.31; 95% CI, 1.06-1.64), but the risks for cancers in the distal colon or rectum were not. Subsite analyses showed a nonsignificant difference between the proximal and distal colon (P = .45) for former smokers and a significant difference for current smokers (P = .02). For smokers who had stopped smoking for at least 20 years, the risk of developing colon cancer was similar to that of never smokers. CONCLUSIONS Ever smokers have an increased risk of colon cancer, which appeared to be more pronounced in the proximal than the distal colon location.