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Serum C‐peptide levels and breast cancer risk: Results from the European prospective investigation into cancer and nutrition (EPIC)
Author(s) -
Verheus Martijn,
Peeters Petra H.M.,
Rinaldi Sabina,
Dossus Laure,
Biessy Carine,
Olsen Anja,
Tjønneland Anne,
Overvad Kim,
Jeppesen Majbritt,
ClavelChapelon Françoise,
Téhard Bertrand,
Nagel Gabriele,
Linseisen Jakob,
Boeing Heiner,
Lahmann Petra H.,
Arvaniti Athina,
Psaltopoulou Theodora,
Trichopoulou Antonia,
Palli Domenico,
Tumino Rosario,
Panico Salvatore,
Sacerdote Carlotta,
Sieri Sabina,
van Gils Carla H.,
BuenodeMesquita Bas H.,
González Carlos A.,
Ardanaz Eva,
Larranaga Nera,
Garcia Carmen Martinez,
Navarro Carmen,
Quirós J. Ramón,
Key Tim,
Allen Naomi,
Bingham Sheila,
Khaw KayTee,
Slimani Nadia,
Riboli Elio,
Kaaks Rudolf
Publication year - 2006
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.21861
Subject(s) - hyperinsulinemia , breast cancer , sex hormone binding globulin , european prospective investigation into cancer and nutrition , medicine , endocrinology , odds ratio , prospective cohort study , cancer , c peptide , testosterone (patch) , oncology , physiology , hormone , insulin , insulin resistance , androgen
It has been hypothesized that chronic hyperinsulinemia, a major metabolic consequence of physical inactivity and excess weight, might increase breast cancer risk by direct effects on breast tissue or indirectly by increasing bioavailable levels of testosterone and estradiol. Within the European Prospective Investigation into Cancer and Nutrition (EPIC), we measured serum levels of C‐peptide—a marker for pancreatic insulin secretion—in a total of 1,141 incident cases of breast cancer and 2,204 matched control subjects. Additional measurements were made of serum sex hormone binding globulin (SHBG) and sex steroids. Conditional logistic regression models were used to estimate breast cancer risk for different levels of C‐peptide. C‐peptide was inversely correlated with SHBG and hence directly correlated with free testosterone among both pre and postmenopausal women. C‐peptide and free estradiol also correlated positively, but only among postmenopausal women. Elevated serum C‐peptide levels were associated with a nonsignificant reduced risk of breast cancer diagnosed up to the age of 50 years [odds ratio (OR) = 0.70, (95% confidence interval (CI), 0.39–1.24); p trend = 0.05]. By contrast, higher levels of C‐peptide were associated with an increase of breast cancer risk among women above 60 years of age, however only among those women who had provided a blood sample under nonfasting conditions [OR = 2.03, (95% CI, 1.20–3.43); p trend = 0.01]. Our results do not support the hypothesis that chronic hyperinsulinemia generally increases breast cancer risk, independently of age. Nevertheless, among older, postmenopausal women, hyperinsulinemia might contribute to increasing breast cancer risk. © 2006 Wiley‐Liss, Inc.