Alzheimer's disease increased in women by common psychosocial stressors
Alzheimer's disease and other types of dementia are afflicting an increasing percentage of the population. According to the National Center for Health Statistics (CDC) and the journal Alzheimer's & Dementia...
"AD is the sixth leading cause of death in the United States and the fifth leading cause of death for people aged 65 years and over."
As study just published in BMJ Open (British Medical Journal) identifies common psychosocial stress as a significant contributor to the development of Alzheimer's disease and other kinds of dementia.
"The aim of this study was to examine whether common psychosocial stressors in midlife were related to distress, late-life dementia and AD, in women followed over 38 years. We further aimed to examine whether experiences of psychosocial stressors modify the previously reported association between long-standing midlife distress and AD."
A baseline psychiatric examination was conducted on 800 women in 1968 and repeated in 1974, 1980, 1992, 2000 and 2005...
"18 psychosocial stressors (eg, divorce, widowhood, work problems and illness in relative) were obtained at baseline. Symptoms of distress were measured according to a standardised question at each study wave. Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria based on information from neuropsychiatric examinations, informant interviews, hospital records, and registry data, and measured through the whole study period."
Common midlife psychosocial stress significantly increased the risk of Alzheimer's disease and dementia:
"During the 37 years of follow-up, 153 women developed dementia (104 of those had Alzheimer's disease (AD)). Number of psychosocial stressors in 1968 was associated with higher incidence of dementia and AD (1.20) between 1968 and 2005, in multivariate Cox regressions. Number of psychosocial stressors in 1968 was also associated with distress in 1968 (1.48), 1974 (1.31), 1980 (1.27), 2000 (1.39) and 2005 (1.35), in multivariate logistic regressions. Number of psychosocial stressors (HR 1.17) and long-standing distress (1968–1974–1980) (HR 1.58) were independently associated with AD."
That is, there was a 21% higher risk of developing AD and a 15% higher risk of developing dementia during the follow-up period. Moreover, the authors point out that psychosocial stress appeared to increase the risk for Alzheimer's disease and dementia even when subjects were not subjective aware of the being distressed:
"We have previously reported that long-standing distress in midlife increase risk of AD and structural brain changes. 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. One reason for this is that individuals respond differently to psychosocial stressors. Thus, biological responses may develop as a reaction to psychosocial stressors also in individuals who do not experience or report increased distress in association to the stressor."
Regarding biological mechanisms they state:
"Stress may cause a number of physiological reactions in the central nervous, endocrine, immune and cardiovascular systems. Thus, psychological stress has been reported to increase the activity of the hypothalamic–pituitary–adrenal axis and the levels of glucocorticoid hormones, cause structural and functional damage to the hippocampus, influence learning and memory processes, increase the production of proinflammatory cytokines in the brain, increase the deposition of β-amyloid peptid and τ-protein in the brain and increase the frequency of cardiovascular disease and hypertension. All these factors have been linked to dementia."
The hippocampus regulates adrenal function and is the brain 'center' for short-term memory. The authors conclude:
"...psychosocial stressors in midlife were associated with incidence of AD and long-standing distress, over several decades. This suggests that common psychosocial stressors may have severe and long-standing physiological and psychological consequences."
Clinical note: practitioners should evaluate and manage the trends toward inflammation, endocrine dysregulation and cardiometabolic decline associated with Alzheimer's disease, dementia and other poor aging phenotypes, while being attentive to the role of psychosocial stress even when the patient is not aware of being distressed.