Whenever I give a presentation about the signs and symptoms of Alzheimer’s disease and discuss the known risk factors for the disease, I am asked this question . . . ( 90% of the time by the women audience members) . . . “Dr. A, is stress a risk factor for Alzheimer’s disease?”
Well, based on research findings from a variety of studies, the short answer is “Yes.” Let’s consider the latest finding from a study that revealed that stress in middle-aged women could lead to the development of dementia later on in life.
This research is based on a 35-year-study of 1,415 women from the Prospective Population Study of Women in Gothenburg, Sweden. The women were initially examined in 1968 (ages ranged from 38 years to 60 years), and then re-examined in the following cycles: 1974, 1980, 1992 and 2000. In addition to neuropsychiatric tests and questions on activities of daily living, the following question was asked by a physician to measure the level of stress in the first three cycles of data collection: “Have you experienced any period of stress (one month or longer) in relation to circumstances or everyday life, such as work, health or family situations?”
The measure of “stress” was defined as a sense of irritation, tension, nervousness, anxiety, fear or sleeping problems. Participants were asked to choose “0″ if they never experienced stress, “1″ if they have experienced stress more than five years ago, “2″ if have experienced one period of stress during the last five years, “3″ if they have experienced several periods of stress during the last five years, “4″ if they have constant stress during the last year, or “5″ if they have experienced constant stress during the last five years.
In addition, data was collected on a variety of factors (i.e. confounders) that may affect the association of stress to dementia, such as lifestyle factors (smoking and wine consumption), coronary heart disease, blood pressure and use of antihypertensive medication.
Participants were classified as having dementia at each cycle if they fulfilled the criteria put forth by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). The diagnosis of Alzheimer’s disease was based on criteria put forth by National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association. The diagnosis of vascular dementia was based on the criteria proposed by the National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et 1″Enseignement en Neurosciences.
Of the women initially assessed in 1968, 161 developed dementia during the follow-up period of 35 years (105 diagnosed with Alzheimer’s disease, 40 diagnosed with vascular dementia, 16 with another type of dementia). The average age of dementia onset was 76 years. Stress that was rated as “frequent/constant” at the baseline and follow up cycles (1968, 1974 and 1980) was related to increased risk of developing dementia and these associations did not change when adjusted for potential confounding variables.
In addition, among women who participated in all three examinations, the risk of dementia increased with the number of examinations when stress was reported. Compared to a woman who never reported stress, if a woman reported stress at one examination cycle her risk for dementia was 1.10, if she reported stress at two examination cycles her risk was 1.73, and if she reported stress at three examination cycles the risk of dementia rose to 2.51.
These findings suggest that long standing psychological stress in middle-aged females is related to the development of dementia later in life. How the present findings could result in a better understanding of the risk factors for dementia and Alzheimer’s disease will need to be confirmed in studies that aim to study the potential neurobiological mechanisms for these associations.
Here are three articles you can refer to, to learn about this particular study or research in the area of Stress and dementia.
Johansson L, Guo X, Waern M et al. Midlife psychological stress and risk of dementia: a 35 year longitudinal population study. Brain,2010.
Hange D, Bengtsson C, Sundh V et al. The natural history of psychosomatic symptoms and their association with psychological symptoms: observations from the Population Study of Women in Gothenburg. Eur J Gen Pract 2007.
Wilson RS, Evans DA, Bienias JL et al. Proneness to psychological distress is associated with risk of Alzheimer’s disease. Neurology 2003.
Thanks for reading.
Neelum T. Aggarwal, M.D.
Steering Committee Member, ADCS
This post originally appeared in Alzheimer’s Insights, an ADCS Blog.