A log-linear relationship between reported impairments and age: implications for the multistage hypothesis.
The relationship of mortality rates with age can be represented by a log-linear (Gompertz-type) plot and also, slightly less satisfactorily, by a log-log plot. Similar relationships are observed for incidence rates for a number of specific diseases. For a case where the log-log plot seems preferable, a multistage model is often invoked to explain this relationship. This study investigated the relationship between rates of various impairments and age. Both log-linear and log-log plots of data from the HALS study are compared. Because impairment rates are essentially prevalence rates, models explaining linearity in these plots are different from those used for incidence rates; however, a multistage model with independent events occurring simultaneously may apply.
Forbes
W F
WF
Program in Gerontology, University of Waterloo, Ontario, Canada.
Thompson
M E
ME
Agwani
N
N
Hayward
L M
LM
D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002908:Chronic Disease / Q000453:epidemiology; D004813:Epidemiology; D005260:Female; D006311:Hearing Disorders / Q000453:epidemiology; D006801:Humans; D016014:Linear Models; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology; D008875:Middle Aged; D009026:Mortality; D009069:Movement Disorders / Q000453:epidemiology; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D014786:Vision Disorders / Q000453:epidemiology