Though most people experience a great deal of stress at some point in their lives, a new Swedish study finds that for middle-aged women, high amounts of stress may increase their risk of developing Alzheimer's disease, the Guardian reports.
Researchers from Gothenburg University studied 800 middle-aged women in 1968 and followed up with them at regular intervals for 38 years until 2005, taking note of how often they experienced irritability, sleep problems, fear and other symptoms of distress.
Published in the journal BMJ Open, the study found that high levels of stress for middle-aged women increased their risk of developing Alzheimer's by 21 percent and developing dementia in any form by 15 percent.
"Our study shows that common psychosocial stressors may have severe and longstanding physiological and psychological consequences", co-authors, led by Dr. Lena Johansson of the neuropsychiatric epidemiology unit at Gothenburg University, told the Guardian.
Highly stressful life events for middle-aged women include mental illness, alcoholism and widowhood. Of the 800 women involved in the study, 425 died during the course of the research, while 153 (19 percent) developed dementia at the average age of 78, according to the Guardian. Other common stressors experienced by participants included unemployment and social isolation.
"We all go through stressful events at some stage in our lives," said Doug Brown, director of research and development at the Alzheimer's Society. "Understanding how these events may become a risk factor for the development of Alzheimer's disease is key to helping us find ways of preventing or treating the condition."
While the link between high levels of stress in middle age and dementia may not be definitive, the casual link is significant enough for the researchers to note a pattern, as "stress may cause a number of physiological reactions in the central nervous, endocrine, immune and cardiovascular systems," they write.
"From this study it is hard to know whether stress contributes directly to the development of dementia, whether it is purely an indicator of another underlying risk factor in this population of women, or whether the link is due to an entirely different factor," Simon Ridley, head of research at Alzheimer's Research UK, told the Guardian.
