DEMENTIA AND BORDERLINE DEMENTIA IN BRITAIN - 8-YEAR INCIDENCE AND POST-SCREENING OUTCOMES

Survivors from a nationally representative sample of elderly people or iginally screened in 1985 were reassessed in 1989 and again in 1993. O n each occasion respondents were rated as cognitively impaired, border line impaired or unimpaired (using a brief information/orientation sca le), with the validity of these ratings assessed in subsequent clinica l interviews. Where follow-up screening was not possible, information was derived from death certificates and hospital case-notes. Over 8 ye ars (1985-93) the overall incidence rate per person-year at risk was 1 . 58%, giving age-specific rates of 0 . 72, 1 . 32, 1 . 63, 3 . 46, 2 . 55 and 1 . 41% for the age groups 65-69, 70-74, 75-79, 80-84, 85-89 and greater than or equal to 90 respectively. Of 43 individuals class ified at screening as borderline impaired in 1985 and 1989, 19 were di agnosed as demented at clinical interviews conducted within 16 weeks o f screening. Four-year follow-ups among the remaining 24 showed that 1 5 had died, while 6 showed a worsened cognitive status. Controlling fo r both age and sex, aggregated 4-year mortality was significantly high er among those defined at screening in 1985 and 1989 as either impaire d or borderline, when compared with the unimpaired.