title: Hyperparathyroidism and subsequent incidence of breast cancer.
abstract: Preliminary data are available on the coexistence of primary hyperparathyroidism and breast carcinoma. To further understand the association between hyperparathyroidism and breast cancer, we conducted a record-linkage study in Sweden using the Swedish Cancer Registry from 1958-1997. A total of 9,835 women who underwent surgery for primary parathyroid adenoma were followed to evaluate the hypothesis that a history of primary hyperparathyroidism increases the risk of subsequent breast cancer. During 99,929 person-years of follow-up, 331 cases of newly diagnosed breast cancer were reported. The number of expected breast cancers in this population was 260.0. This resulted in a standardized incidence ratio of 1.27 (95% confidence interval [CI] = 1.14-1.41). The relation persisted over time after the surgical removal of the parathyroid adenoma. Possible explanations for the observed association are a shared etiology including genetic and environmental factors such as early life radiation, and hypercalcemia after the overproduction of parathyroid hormone, which may increase breast cancer incidence.
authors.affiliation: Obstetrics and Gynecology Epidemiology Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. kmichels@rics.bwh.harvard.edu
authors.forename: Karin B
authors.initials: KB
authors.lastname: Michels
authors.forename: Fei
authors.initials: F
authors.lastname: Xue
authors.forename: Lena
authors.initials: L
authors.lastname: Brandt
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000601:surgery; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006961:Hyperparathyroidism / Q000453:epidemiology*; D015994:Incidence; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000453:epidemiology / Q000601:surgery; D012042:Registries