Community study of dementia in the older Korean rural population

This study aims to estimate the prevalence of all dementias, including Alzheimer's disease (AD) and vascular dementia (VaD) in a population of Korean elderly and to identify possible risk factors which correlated with specific types of dementia.

A two-phase survey, based on a door-to-door survey, was conducted. Initially, the Korean version of the Psychogeriatric Assessment Scale (PAS-K) was administered to all 1037 participants aged 65 years and older. Three hundred and seventy people sampled from the case groups (n = 320) of PAS-K subscales and the non-case group (n = 50) entered the second phase for clinical evaluation. Dementia was defined using the DSM-III-R, NINCDS-ADRDA and NINDS-AIREN criteria.

Among 1037 elderly people aged 65-94 years who completed the interview, 74 cases of dementia were detected, giving an overall age-standardized prevalence (95% CI) of 6.8% (6.1-7.5) (male 6.3%[5.3-7.4]; female 7.1%[6.1-8.0]). The prevalence (95% CI) of AD was 4.2% (3.6-4.7) (male 2.4%[2.0-2.8]; female 5.3%[4.5-6.1]), and it increased with age. The prevalence (95% CI) of VaD was 2.4% (2.0-2.8) (male 3.5%[2.7-4.3]; female 1.6%[1.2-2.1]). Smoking for longer than 30 pack-years significantly increased the risk of VaD (OR = 11.5 [2.8-44,6]).

Long-term smoking, much more prevalent in men, may be closely related to higher risk of cerebrovascular disease that leads to vascular dementia.