['To study if parathyroid surgery reduced fracture risk in patients with primary hyperparathyroidism.', 'Controlled cohort study.', 'All subjects diagnosed with primary hyperparathyroidism (ICD8 codes: 252.00, 252.01, 252.03, 252.04, 252.05, 252.08, 252.09, and ICD10 codes: E21.0, E21.2, E21.3) between 1980 and 1999 in Denmark were retrieved from the National Hospital Discharge System.', 'A total of 3213 subjects (mean age at diagnosis 60.9 +/- 16.3 years) were identified of whom 1934 (60%) had parathyroid surgery whilst 1279 (40%) did not. Total follow-up time after diagnosis was 19.565 (median 6.1) years.', 'Fracture occurrence after diagnosis was identified from the National Hospital Discharge System.', 'Conservatively treated patients were older than surgically treated at diagnosis (64.2 +/- 17.4 years vs. 58.3 +/- 15.2 years, P < 0.01). The mean serum calcium was 2.95 mmol L-1 in surgically treated and 2.74 in conservatively treated in a subgroup from one centre, n = 687). At the time of diagnosis, 172 (9%) of the subsequently surgically treated had had any fracture whilst the same was the case for 176 (14%) of the conservatively treated (P < 0.05). Parathyroid surgery reduced the risk of hip (HR = 0.44, 95% CI: 0.32-0.62) and upper arm (HR = 0.44, 95% CI: 0.27-0.72) fractures after diagnosis whilst the occurrence of other fracture types remained unchanged.'] Is parathyroid surgery associated with a decreased risk of hip and upper arm fractures in primary hyperparathyroidism : a controlled cohort study?