title: Osteopenia, pathological fractures, and increased urinary calcium excretion in schizophrenic patients with polydipsia.
abstract: Ten male chronic schizophrenic patients with polydipsia and 10 nonpolydipsic controls, matched for gender, diagnosis, duration of illness, age, and race, were studied by dual- and single-photon absorptiometry to estimate bone density of the lumbar spine and radius and by 24-hr urine collections to estimate urinary electrolyte excretion. Bone density was normal in the control group, but was abnormally low in the polydipsic group, which had a markedly increased incidence of fractures. Electrolyte excretion was normal in the control group and in the polydipsic group when water intake was restricted to normal amounts; increased urinary sodium and calcium excretion occurred in proportion to polydipsia. As polydipsia is associated with a number of physiological changes, the cause of the osteopenia is unclear; we suggest that a negative calcium balance caused by increased urinary calcium excretion induced by extracellular space expansion may play an important role in the causation of the skeletal changes.
authors.affiliation: Department of Psychiatry, Queen's University, Kingston, Ontario, Canada.
authors.forename: N J
authors.initials: NJ
authors.lastname: Delva
authors.forename: J L
authors.initials: JL
authors.lastname: Crammer
authors.forename: S V
authors.initials: SV
authors.lastname: Jarzylo
authors.forename: J S
authors.initials: JS
authors.lastname: Lawson
authors.forename: J A
authors.initials: JA
authors.lastname: Owen
authors.forename: M
authors.initials: M
authors.lastname: Sribney
authors.forename: B J
authors.initials: BJ
authors.lastname: Weir
authors.forename: E R
authors.initials: ER
authors.lastname: Yendt
mesh_terms: D000328:Adult; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000503:physiopathology*; D002118:Calcium / Q000652:urine*; D004326:Drinking / Q000502:physiology*; D004573:Electrolytes / Q000652:urine; D005598:Fractures, Spontaneous / Q000503:physiopathology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000293:injuries; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013904:Thoracic Vertebrae / Q000293:injuries; D014869:Water Intoxication / Q000503:physiopathology*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D004573:Electrolytes; D002118:Calcium