Decrease in the relative heterogeneity of health with age: a cross-national comparison.
Using data from seven studies from Canada, Australia and the United States we were able to evaluate the heterogeneity of health status for 34,095 people aged 60 years and older. We found that relative heterogeneity (measured by the coefficient of variation) decreased with age. The coefficient of variation also decreased as a function of deficit accumulation (i.e. was lower when people demonstrated more deficits) displaying a power-law relationship. The exponent was close to 0.5, and therefore belongs to the dynamic universality class, which is typical for complex dynamical networks. We interpret this as showing that decline in relative heterogeneity is a robust finding, and represents, at the group level, increased vulnerability amongst elderly people.
Mitnitski
Arnold
A
Department of Medicine, Division of Geriatric Medicine, Dalhousie University, 1421-5955 Veterans Memorial Lane, Halifax, Nova Scotia, Canada B3H 1C6.
Rockwood
Kenneth
K
D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002170:Canada; D006304:Health Status; D006801:Humans; D008875:Middle Aged