Selection of elderly controls using random digit dialing.
The experience of identifying and soliciting elderly male controls, using a nonclustered random digit dialing procedure in a case-control study, is presented. For elderly controls (ages 65-84) 3.5 times more residential telephone numbers were required than for controls encompassing a much broader age range (ages 40-84). This is a function of the proportion of elderly in the population and their lower response to telephone identification. Elderly controls, age 70 and older, also had lower participation rates.
Olsen
G W
GW
Epidemiology Department, Dow Chemical Company, Midland, MI 48674.
Mandel
J S
JS
D000368:Aged; D000369:Aged, 80 and over; D004032:Diet; D004034:Diet Surveys; D004812:Epidemiologic Methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D009749:Nutrition Surveys; D010190:Pancreatic Neoplasms / Q000209:etiology; D011897:Random Allocation; D013689:Telephone