Cognitive impairment and eight-year mortality in the Kangwha cohort of the older people

Abstract

연구대상은 강화지역의 1599명의 여성과 1150명의 남성으로 총 2749명이었다. 기초조사는 1994년에 이루어졌으며 2002년까지 8년 추적조사되었다. 사망과의 관계와 함께 인지능력과 혈압과의 관련성도 분석하였다. 인지능력 이상에 대해서는 30점 만점의 Mini-Mental State Examination(MMSE)를 이용하였다. 그 점수가 24-30점 이면 인지능력 정상, 18-23점이면 중등도 인지능력이상, 17점 이하이면 고도 인지능력이상으로 구분하였다. 통계분석은 생존분석을 이용하였다.

인지능력이상이 있는 사람은 정상인 사람들에 비하여서 평균연령이 높았고, 경제수준과 교육수준이 낮았으며, 혈압이 더 높았다. 인지능력이 있는 남자의 사망위험은 정상인 사람에 비하여서 1.5(95% CI, 1.10-2.04)배 더 높았고 여성의 사망위험은 1.3(95% CI, 1.02-1.65)배 더 높았다. 연령과 자가평가건강수준도 사망위험 증가와 관련이 있었다. 또한, 수축기 혈압과 이완기 혈압 모두 인지능력이상과 관련성이 있었다. 이러한 결과들을 통해서 노년의 수명연장을 위해서는 인지능력 이상의 조기발견을 통한 예방이 필요함을 제시한다.

[영문]The relationship between cognitive impairment and mortality was examined in a community residents population sample of 1,599 women and 1,150 men aged 65 years or over in Kangwha County, Korea in 1994-2002. In addition, we separately examined the relationship between high blood pressure and cognitive impairment. The cognitive function of 2,749 respondents was assessed by using the 30-point Mini-Mental State Examination (MMSE) in 1994. No cognitive impairment was defined as a score of 24-30 points on the Mini-Mental State Examination, mild cognitive impairment was defined as a score of 18-23 points, and severe impairment was defined as a score of 0-17 points.

Cox proportional hazards models were conducted to examine the association between cognitive impairment and increased risk for mortality. When compared with cognitively unimpaired subjects, those cognitively impaired subjects were older, had poorer functional status, elevated blood pressure and were not as well educated.

After control for multiple potential confounders, in both men and women severe impairment remained predictor of increased mortality; the relative risk was 1.5(CI 1.10-2.04) and 1.3 (1.02-1.65) for men and women, respectively. Among men mild impaired remained significantly; the relative risk was 1.3 (CI 1.02-1.60).

In multiple logistic regression analyses, high systolic blood pressure was related to cognitive impairment among women and high diastolic blood pressure was marginally related to cognitive impairment in both men and women.

We found that cognitive impairment is a significant predictor of mortality as well. Early detection of impaired cognition and attention to associated health problems could improve the quality of life of these older adults and perhaps extend their survival.