Serum calcium levels are elevated among women with untreated postmenopausal breast cancer

Erica Martin, Megan Miller, Lacey Krebsbach, James R. Beal, Gary G. Schwartz, Abe E. Sahmoun

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Objective Reports of an association between primary hyperparathyroidism in women and risk of breast cancer suggest an etiologic role for high serum calcium. However, data on the association between serum calcium levels and breast cancer in women without clinical hyperparathyroidism are limited. Methods We conducted a hospital-based case-control study among postmenopausal women in Fargo, ND. Cases were women aged 65 and older with newly diagnosed, histologically confirmed breast cancer. Controls were aged 65 and older without clinical cancer who were seen at the same hospital. Results We obtained data on 190 white cases and 172 white controls. Primary hyperparathyroidism (an abnormally high calcium level confirmed by an abnormally high serum PTH) was found in 3/190 cases and in 0/172 controls (p = 0.25). After excluding the women with primary hyperparathyroidism, the mean calcium levels among cases was 9.6 mg/dL (range, 7.5-11.0, SD = 0.47) vs. 9.4 mg/dL (7.7-10.5, 0.43) among the controls (p < 0.0001). Comparing women in the top with women in the bottom fertile of serum calcium, the multivariable-adjusted odds ratio (OR) for breast cancer was 5.21 (95% CI: 2.59-10.48). There was no relationship between serum calcium and tumor size or stage. Conclusion The distribution of serum calcium levels among postmenopausal women with incident breast cancer was shifted significantly toward the right. These findings are consistent with an effect of early breast tumors on calcium homeostasis. However, the lack of association between serum calcium levels and tumor size or stage supports the hypothesis that subclinical hyperparathyroidism may increase the risk for breast cancer.

Original languageEnglish (US)
Pages (from-to)251-257
Number of pages7
JournalCancer Causes and Control
Issue number2
StatePublished - Feb 2010
Externally publishedYes


  • Breast cancer
  • Epidemiology
  • Postmenopausal
  • Primary hyperparathyroidism
  • Serum calcium

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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