title: Influence of age on plasma osmolality: a community study.
abstract: We have shown an age-associated increase in plasma osmolality (p less than 0.001) in 152 randomly selected subjects, living in the community. In the old [mean age 78.0 (7.5) years] the plasma osmolality was 302.2 (300.6-303.8) mOsmol/kg compared with 291.2 (290.0-292.3) mOsmol/kg in the young [39.2 (11.2) years] (p less than 0.0001). In a further group of 20 screened, health status defined, elderly subjects the plasma osmolality was 298.1 (295.9-300.3) mOsmol/kg, which was significantly higher than the young group (p less than 0.0001) but lower than the unscreened old subjects (p = 0.005). The variance was also significantly lower (p = 0.03). The results may reflect a loosening of homoeostatic control and highlight the need for care in subject selection in studies of ageing.
authors.affiliation: Department of Geriatric Medicine, University Hospital of South Manchester.
authors.forename: K A
authors.initials: KA
authors.lastname: McLean
authors.forename: P A
authors.initials: PA
authors.lastname: O'Neill
authors.forename: I
authors.initials: I
authors.lastname: Davies
authors.forename: J
authors.initials: J
authors.lastname: Morris
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D014882:Water-Electrolyte Balance / Q000502:physiology*