Midlife Stress May Trigger Dementia, Alzheimer's in Women

Deborah Brauser

October 02, 2013

Common psychosocial stressors experienced by women during midlife may lead to a higher risk of developing dementia and Alzheimer's disease (AD), new research suggests.

The population study included 800 women from Sweden who were first examined in 1968 and then followed up periodically for 38 years.

Results showed that the number of stressors, such as workplace problems, serious illness, divorce, and widowhood, experienced at baseline was associated with a 21% higher risk of developing AD and a 15% higher risk of developing dementia during the follow-up period. It was also associated with significantly increased later-life distress.

The findings show that accumulated stress from common events "may have severe and long-standing physiological and psychological consequences," write Lena Johansson, PhD, RN, from the Neuropsychiatric Epidemiology Unit at the Institute of Neuroscience and Physiology at Gothenburg University in Mölndal, Sweden, and colleagues.

They add that these physiologic consequences can include adverse reactions in the central nervous, cardiovascular, endocrine, and immune systems.

However, the investigators point out that more studies are now needed for replication and to investigate whether interventions such as stress management and behavioral therapy should be started in patients who are experiencing these stressors.

The study was published online September 30 in BMJ Open.

Impact of Common Stressors

Although previous research has shown that severe stressors such as combat and natural disasters can influence both physical and mental health throughout the life course, the long-term impact of more common stressors is unclear.

In the current analysis, the researchers assessed 800 participants in the larger Prospective Population Study of Women in Gothenburg, Sweden. It began in 1968, when the women were in their late 30s, mid 40s, or 50s.

Follow-up assessments were conducted in 1974, 1980, 1992, 2000, and 2005.

At baseline, the women were asked whether they had experienced any of 18 specific stressors, which included death of a child, unemployment for themselves or a partner, or alcoholism or mental illness in a close family member.

They were also asked at baseline and at each follow-up point about having ever experienced symptoms of distress (such as sleep disturbances, irritability, and fear) lasting for at least 1 month or longer.

A psychiatric examination, including tests and a neuropsychiatric assessment, was also given at all times of measurement, and medical records for all of the women were collected.

Biological Response

Results showed that 25% of the women reported at baseline having experienced at least 1 of the listed stressful events, and 16% reported having experienced 4 or more of the events.

Interestingly, the most commonly reported stressors were mental illness in a sibling (31.9%) and mental illness in a mother (26.5%).

During the follow-up period, 19.1% of all participants developed dementia; the average age at time of diagnosis was 78 years. A total of 68% of the women who developed dementia went on to develop AD.

"The mean time from the baseline examination in 1968 to dementia onset was 29 years," report the investigators.

The number of stressful events reported at baseline was associated with a higher incidence of the development of AD (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.08 - 1.36) or all- type dementia (HR, 1.15; 95% CI, 1.05 - 1.27) at some point during follow-up, as well as having symptoms of distress at each time of measurement.

"We have previously reported that long-standing distress in midlife increase risk of AD and structural brain changes," write the researchers.

"These findings are now extended by showing that number of psychosocial stressors and report of distress independently predicted AD, that is, increased distress could not completely explain the association between midlife stressors and dementia," they write.

They note that this may be because of the different ways individuals respond to stressors.

"Thus, biological responses may develop as a reaction to psychosocial stressors."

The study was funded by several organization, which are listed in the original article. The study authors have disclosed no relevant financial relationships.

BMJ Open. Published online September 3, 2013. Abstract


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