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.


CONCLUSIONS
Lifestyle interventions as recommended for cardiovascular disease prevention may be of value to prevent breast cancer mortality in postmenopausal women.
Bjørge
Tone
T
Department of Public Health and Primary Health Care, University of Bergen, N-5018 Bergen, Norway. tone.bjorge@isf.uib.no
Lukanova
Annekatrin
A
Jonsson
Håkan
H
Tretli
Steinar
S
Ulmer
Hanno
H
Manjer
Jonas
J
Stocks
Tanja
T
Selmer
Randi
R
Nagel
Gabriele
G
Almquist
Martin
M
Concin
Hans
H
Hallmans
Göran
G
Häggström
Christel
C
Stattin
Pär
P
Engeland
Anders
A
D000328:Adult; D000367:Age Factors; D000368:Aged; D001317:Austria / Q000453:epidemiology; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D024821:Metabolic Syndrome / Q000150:complications / Q000453:epidemiology*; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology