Decline in the Incidence of All-Cause and Alzheimer's Disease Dementia: a 12-Year-Later Rural Cohort Study in Korea

BACKGROUND: There has been no study on the time trends of dementia incidence in Korea. We report the 5-year incidence and its correlates of all-cause and Alzheimer's disease (AD) dementia, and compared our results with those of a 12-year-prior cohort study conducted in the same area. METHODS: A total of 751 community-dwelling older adults were followed up for a mean duration of 5.4 years. The age-, gender-, and educational attainment-specific incidence of all-cause and AD dementia were reported as cases per 1,000 person-years. We performed univariate and multivariate cox proportional hazard regression analyses to determine whether baseline sociodemographic, lifestyle, and clinical variables were associated with the risk of all-cause and AD dementia. A 12-year-prior cohort study was used for descriptive comparison to indicate the time trends of dementia incidence. RESULTS: The incidence rates were 16.2 and 13.0 cases per 1,000 person-years for all-cause and AD dementia, respectively. The baseline diagnosis of mild cognitive impairment increased the 5-year incidence of all-cause dementia by more than 4-fold. Old age and low baseline global cognitive function were noted as risk factors for both all-cause and AD dementia. CONCLUSION: Upon comparing the results with those from the earlier cohort study in Yeoncheon, the incidence of all-cause and AD dementia decreased by approximately 40% over 12 years; it has been mainly driven by the increase in the educational level of older adults. The declining time trends of incidence should be taken into account for estimating the future prevalence of dementia in Korea.

Differences between One-Person and Multi-Person Households on Socioeconomic Status, Health Behavior, and Metabolic Syndrome Across Gender and Age Groups

BACKGROUND: The rising popularity of one-person households makes the health hazards they are prone to, highly relevant in epidemiological studies. This study aimed at comparing health-related characteristics like the socioeconomic status, health behavior, and metabolic syndrome of one-person households, to multi-person households in Korea.METHODS: The participants required for this study included 9,423 Koreans aged 19 and above, who took the Sixth Korean National Health and Nutrition Examination Survey. The household types were classified into “one-person” and “multi-person.” The differences between the two, based on their annual socioeconomic status, health behavior, anthropometric variables, and blood test results were analyzed.RESULTS: The percentage of men and women in one-person households was 7.2% and 10.5%, respectively. Such households had a lower annual income and education than multi-person households. The odds ratios (OR) for alcohol consumption (OR, 1.69; 95% confidence interval [CI], 1.16–2.46) and smoking (OR, 3.24; 95% CI, 1.77–5.95) were significantly higher for one-person households of women, aged 60 and above, compared to multiperson households. The OR for metabolic syndrome was considerably higher in one-person households of middle-aged people in contrast to multiperson households for both men (OR, 1.84; 95% CI, 1.14–2.95) and women (OR, 1.90; 95% CI, 1.21–2.99).CONCLUSION: The socioeconomic status was lower, and the health behaviors were worse in one-person households as compared to multi-person households. Considering the growing popularity of one-person households, it is suggested that medical plans be customized to suit the characteristics of the specific group.