Prevalence of dementia in diabetics: a community-based case-control study

Abstract

Objective To determine prevalence of dementia in diabetics and non-diabetics, and in different age and gender groups. Methods A case-control study was conducted among participants aged 50 and over in Jing' an temple community in Shanghai. Subjects in diabetics group were matched to non-diabetics groups for age and sex with 1:1 matching. Personal information and case history were collected through questionnaire. The subjects were screened for dementia using the Mini Mental State Examination (MMSE). Subjects that screened positively (indicated by an MMSE score below 19, 21 and 24 among those with illiteracy, elementary school and above junior middle school education, respectively) were subsequently examined by a series of neuropsychological tests. Based on all available information, a diagnosis of dementia was defined according to the Diagnostic and Statistical Manual of Mental Disorders ( DSM )-Ⅳ criteria Results Prevalence of dementia of 4. 75% (23/484, 95% CI: 3. 03%-7.04%) in diabetics was higher than that of 2. 24% (11/490,95% CI: 1.13% -3.98%) in non-diabetics (X~2 = 4.54, P=0.03).Prevalence of dementia among diabetics in age groups of 60-69, 70-79 and 80 and above was 1.94% (2/103), 4. 43 % (9/203) and 14.12% (12/85, trend X~2 =18.04, P <0.01), and in non-diabetics was 1.43% (2/140), 2. 86% (6/210) and 5.00% (3/60, trend X~2 = 4.58, P=0.03), respectively.Prevalence of dementia among female and male in diabetics was 6.55% (19/299) and 2.06% (4/194) (X~2 = 5.18, P = 0.02), respectively, and in non-diabetics was 3.01% (9/299) and 1.05% (2/191).Conclusions Prevalence of dementia is significantly higher in diabetics than in non-diabetics, higher in women than men, and increases as age rises. Key words: Diabetes mellitus; Dementia; Prevalence