Few studies have studied the metabolic syndrome as an entity and the risk of cancer. The Norwegian Institute of Public Health has participated in an international project to find out more.
In the part of the project led by Norway, various women’s cancers associated with the metabolic syndrome were studied. The cohort consisted of 290,000 women who were followed for an average of 10 years. The average age at baseline was 44 years, and the age at cancer diagnosis was around 60 years.
There was an increased risk of uterine cancer among women with the metabolic syndrome. This risk was confined to the heaviest women. There was also an increased risk of uterine cancer among women who were overweight / obese, had high blood pressure, and had increased blood levels of glucose and triglycerides.
There was increased breast cancer mortality among women over 60 years with the metabolic syndrome. The strongest association was seen with increased glucose concentrations. However, there was a reduced risk of breast cancer among women with the metabolic syndrome before the age of 50, while there was no effect among women over 60 years. This reduced risk was also seen for the individual factors other than glucose. The risk was lowest among the heaviest women.
There was no overall association between the metabolic syndrome and ovarian cancer. However, among women with high blood pressure and among women with elevated cholesterol levels, there was an increased risk for certain subtypes of ovarian cancer. There was increased mortality from ovarian cancer among women under 50 years with the metabolic syndrome. There was also increased mortality for higher levels of body mass index among women over 50 years of age.
What is metabolic syndrome?
Metabolic syndrome is a group of risk factors for cardiovascular disease and diabetes type 2. The factors used to define the syndrome are abdominal obesity, high blood pressure, an unfavourable profile of fats in the blood (low HDL-cholesterol and increased triglycerides) and insulin resistance. These factors often occur together, but are only moderately associated with each other. These risk factors have been individually associated with various cancers, but few studies have looked at the syndrome as an entity and the risk of cancer.
About the Me-Can project
In 2006, seven cohorts from Norway, Austria and Sweden were included in the Metabolic Syndrome and Cancer project (Me-Can project).
From Norway, data from the Norwegian County Studies, the Cohort of Norway (CONOR), the Age 40 programme and the Oslo Study I were used. All participants in these cohorts have taken part in one or more health studies in the period 1974-2005, and we have information about height / weight, blood pressure, and levels of glucose, cholesterol and triglycerides. We also have information about smoking, and for the Norwegian health studies we have parity, age at childbirth and physical activity. These cohorts are linked to the cancer and cause of death registries in the respective countries.
The strength of the data set is that it is large and contains almost complete exposure information from all the cohorts. We have access to repeated measurements from some of the participants, and have the opportunity to correct for some random errors. The outcome data are also of high-quality. The weaknesses are that we do not have detailed data on possible sources of error, tumour characteristics and treatment. In addition, the range of measurement methods for a number of exposure factors varies between the different cohorts.
The Me-Can project received financial support from the World Cancer Research Fund.
- Bjørge T, Stocks T, Lukanova A, Tretli S, Selmer R, Manjer J, Rapp K, Ulmer H, Almquist M, Concin H, Hallmans G, Jonsson H, Stattin P, Engeland A. Metabolic syndrome and endometrial carcinoma. Am J Epidemiol 2010; 171: 892-902.
- Bjørge T, Lukanova A, Jonsson H, Tretli S, Ulmer H, Manjer J, Stocks T, Selmer R, Nagel G, Almquist M, Concin H, Hallmans G, Häggström C, Stattin P, Engeland A. Metabolic syndrome and breast cancer in the Me-Can (Metabolic Syndrome and Cancer) project. Cancer Epidemiol Biomarkers Prev 2010; 19: 1737-1745.
- Bjørge T, Lukanova A, Tretli S, Manjer J, Ulmer H, Stocks T, Selmer R, Nagel G, Almquist M, Concin H, Hallmans G, Jonsson H, Häggström C, Stattin P, Engeland A. Metabolic risk factors and ovarian cancer in the Metabolic Syndrome and Cancer project. Int J Epidemiol 2011; 40:1667-77.
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