Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 53, Issue 6 M465-M470, Copyright © 1998 by The Gerontological Society of America
A follow-up comparison of study participants and refusers within a rural elderly population
M Ganguli, A Mendelsohn, M Lytle and H Dodge
Department of Psychiatry, University of Pittsburgh School of Medicine, USA. gangulim@msx.upmc.edu
BACKGROUND: Survey rates are known to decline with age. Survey results can
be affected by response bias if nonresponders are more, or less, likely
than participants to suffer from the condition being studied. For instance,
it is possible that older adults with dementia would be less likely to
participate in a study of dementing disorders. METHODS: A random sample of
a rural U.S. population aged 65+ years yielded 1,422 participants and 912
refusers in addition to others who were ineligible, inaccessible, or
untestable. Participants and refusers were compared on age, sex, 5-year
mortality, and causes of death suggestive of dementia as listed on death
certificates. RESULTS: Compared to participants, refusers were
significantly older and more likely to be women, with mortality similar to
that of participants at approximately 5-year follow-up. Death certificate
data revealed no significant differences in reported causes of death
indicating or suggesting dementia. CONCLUSIONS: In this population, those
who refused to participate in a dementia survey were not more likely to be
ill or demented than those who did participate.
