The Relationship between Late-Onset Depression and Alzheimer's Disease

Kim, Bo Ra; Kim, Young Kee; Lee, Byung Ook; Park, Sang Jin

Abstract

OBJECTIVES
With the elderly population rising sharply, there is a rising interest in dementia, and recently researches on risk factors for dementia, particularly of Alzheimer's disease have been actively conducted. The purpose of this research is to examine the effect of the late-onset depression as a risk factor for Alzheimer's disease.
METHODS
The subjects were divided into the group of the patients who were diagnosed with depression in the National Health Insurance Corporation Ilsan Hospital from March 1, 2000 to December 31, 2009 and the corresponding control group, which was the group of the patients who were diagnosed with osteoarthritis for the same period. Of the above patients, the following cases were excluded from the final analysis. The excluded cases were those who were first diagnosed with either of the two diseases at the age of less than 50, and those who were diagnosed with major psychiatric disorder or neurologic disorder. As a result, a total of 5,347 people, made up of 1,697 depression patients and 3,650 osteoarthritis patients, were selected. Two groups were compared through survival analysis.
RESULTS
Form the Log-Rank tests, it could be confirmed that there were significant differences (p<0.01) among the two groups. Even when many confounding factors including age and gender were controlled, the degree of occurrence of Alzheimer's disease was found to be higher in the group of late-onset depression patients than in the group of osteoarthritis patients (HR : 2.53-2.80).
CONCLUSION
The late-onset depression can become independently the risk factor for Alzheimer's disease. Therefore it can be expected that the rate of occurrence of Alzheimer's disease may be reduced through active medical treatment of depression.