A FOLLOW-UP COMPARISON OF STUDY PARTICIPANTS AND REFUSERS WITHIN A RURAL ELDERLY POPULATION

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. F or instance, it is possible that older adults with dementia would be l ess likely to participate in a study of dementing disorders. Methods. A random sample of a rural U.S. population aged 65+ years yielded 1,42 2 participants and 912 refusers in addition to others who were ineligi ble, inaccessible, or untestable. Participants and refusers were compa red on age, sex, 5-year mortality, and causes of death suggestive of d ementia as listed on death certificates. Results. Compared to particip ants, refusers were significantly older and more likely to be women, w ith 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. Conclus ions. In this population, those who refused to participate in a dement ia survey were not more likely to be ill or demented than those who di d participate.