THE RISK OF HIP-FRACTURES IN PATIENTS WITH PRIMARY HYPERPARATHYROIDISM - A POPULATION-BASED COHORT STUDY WITH A FOLLOW-UP OF 19 YEARS

Objective. To evaluate primary hyperparathyroidism (HPT) as a risk factor for hip fractures. Design. A population-based, record-linked, prospective study with a mean observation time of 17 years (women) and 16.5 years (men). Setting. A cohort obtained from a register of hospital admissions in the Uppsala Health Care Region, Sweden, 1965-1983. Participants. All patients (1373 women and 551 men) who were admitted to hospital with the diagnosis of HPT during the period. Comparisons were made with the entire background population. Measurements. Cohort subjects were followed with regard to a first instance of hip fracture prior to or after the diagnosis of HPT. The observed number of cases was compared with that expected on the basis of person-years of observation and incidence rates in the background population. Analyses were made for cervical and trochanteric fractures, and for patients operated and not operated for HPT. Main results. (i) Women. During 23341 person-years of observation, 67 cases of first hip fractures occurred, yielding a relative risk (RR) of 0.93 (95 % confidence interval [CI] 0.72-1.19). The RR for cervical fractures was 0.77 (CI 0.54-1.06), and for trochanteric fractures 1.33 (CI 0.88-1.93). Operation for HPT did not influence the risk of hip fracture. (ii) Men. The total person-years was 9091. Eleven fractures were observed-compared with the expected 7.90 (RR 1.39; CI 0.69-2.50). Men operated for HPT had an increased risk for cervical hip fractures (RR 2.73; CI 1.18-5.39). Owing to the few fractures in this group (n = 8) the relevance of this is uncertain. Conclusions. This study indicates that HPT is not a risk factor for hip fractures in women.