Metabolically defined body size and body shape phenotypes and risk of postmenopausal breast cancer in the European Prospective Investigation into Cancer and Nutrition

In a new research study, scientists from the International Agency for Research on Cancer (IARC) and partner institutions investigate the associations of metabolically defined body size and body shape phenotypes with the risk of postmenopausal breast cancer in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The results were published in the journal Cancer Medicine.

Excess body fatness and high insulin levels are both associated with an increased risk of postmenopausal breast cancer. However, it is not well documented whether women with high body fatness who have normal insulin sensitivity (a low level of circulating insulin or low C-peptide levels) or women with normal body fatness who have elevated levels of insulin are at increased risk of breast cancer.

The study investigated data of 610 cases of postmenopausal breast cancer and 1130 matched controls within the EPIC cohort. Concentrations of C-peptide – a marker for insulin secretion – in the control participants were used to define metabolically healthy and metabolically unhealthy status. Women classified as metabolically unhealthy and overweight or obese had an elevated risk of postmenopausal breast cancer compared with women who were metabolically healthy and of normal weight. Conversely, women who were metabolically healthy and overweight or obese and women who were metabolically unhealthy and of normal weight were not at statistically significant elevated risk of postmenopausal breast cancer compared with women who were metabolically healthy and of normal weight.

Overall, although additional studies with detailed information on both anthropometric measures and metabolic parameters are needed, these findings are consistent with those from previous studies suggesting that being overweight or obese and metabolically unhealthy increases the risk of postmenopausal breast cancer, whereas women who are overweight or obese and have normal insulin levels are not at higher risk. These findings also highlight the importance of assessing the effects of anthropometric measures in conjunction with metabolic parameters to identify women at higher risk of breast cancer.

Mahamat-Saleh Y, Rinaldi S, Kaaks R, Biessy C, Gonzalez-Gil EM, Murphy N, et al.
Metabolically defined body size and body shape phenotypes and risk of postmenopausal breast cancer in the European Prospective Investigation into Cancer and Nutrition
Cancer Med, Published online 25 April 2023;
https://doi.org/10.1002/cam4.5896

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