A Swedish study, published in the August 2013 online issue of BMJ Open indicates that a higher number of psychosocial stressors in middle-aged women were associated with increased risk of dementia and Alzheimer’s disease (AD) decades later in life. This is perhaps the first population study on the relationship between midlife stressors and increased risk of dementia in late life.
Stress in adulthood is known to influence mental health later in life, and prolonged exposure to stress and increased levels of glucocorticoids are linked with poorer memory performance and hippocampal atrophy, and an increased production of proinflammatory cytokines in the brain. Stress may lead to a cumulative burden to the brain with dysregulation in neuroendocrine systems. For instance, a study among Holocaust survivors found that higher levels of stress hormones remained decades after the traumatic experience.
Previous research indicates that lifelong work-related stress such as low job control and high work strain (Wang HX et al., Alzheimers Dement, 2012; 8:114) and anxiety and vulnerability to stress contribute to the development of dementia. Also, both physiological (restraint) and psychological stress (social isolation) have been shown to increase brain expression of amyloid-beta and hyperphosphorylated tau (Bissette G., J Alzheimers Dis, 2009; 18:371).
In the BMJ Open study Lena Johansson and colleagues from the Sahlgrenska Academy at Gothenburg University, the Karolinska Institute in Stockholm, Sweden, and the Utah State University in the US, used a prospective longitudinal population study to examine whether common psychosocial stressors in midlife were related to distress, late-life dementia and AD in 800 women, systematically selected for a psychiatric examination in 1968 and followed over 38 years.
The study shows that number of common psychosocial stressors in midlife may have severe and long-standing consequences such as an increased risk of dementia and AD in late life. The authors also report that number of psychosocial stressors in 1968 was related to increased level of distress at every examination conducted between 1968 and 2005.
These results may suggest that further studies investigating the link between midlife stress, dementia and AD are warranted, and that stress management and behavioral therapy might be required in individuals with history of psychosocial stressors.