Prevalence of hypercalcaemia in a health screening in Stockholm.

A free health check, offered to 21417 20-63-year-old employees of the Stockholm City and County Council in 1971-73, was accepted by 15903 persons. The examination included a multichannel chemical analysis of a single blood sample. Serum calcium levels greater than or equal to 11.0 mg/100 ml (2.75 mmol/l) and greater than or equal to 11.1 mg/100 ml (2.78 mmol/l) were encountered in 3.9% and 1.1% of the population, respectively. Among subjects below 50 years of age, the calcium concentration was significantly higher in males than in females. This difference disappeared in older subjects, essentially because the calcium level decreased with advancing age in the men. To a further investigation were invited 178 subjects with a single serum calcium registration greater than or equal to 11.1 mg/100 ml (2.78 mmol/l). Of this group, 95 persons (53.4%) exhibited hypercalcaemia (HC) on repeated testing. Twelve had been operated on prior to the actural follow-up and found to have parathyroid adenomata. Twenty subjects were on continuous treatment with diuretics of the thiazide type and seven had diseases that might induce HC (two had hyperthyroidism, two hypothyroidism, one sarcoidosis, one hypernephroma and one mammary carcinoma). In 56 patients the laboratory and physical examinations did not reveal any obvious cause for the HC except possible hyperparathyoidism (HPT). Eighty (84.2%) of the 95 HC subjects were women, mostly over 50 years. The 95 persons constituted 6% of the total number of health-screened persons. The highest prevalence, 13%, was recorded for women aged 60-63. The prevalence of HPT in the total material was 3.6%, which is higher than that found in several other studies. This is based on surgical findings to date.