Lifelong depression may increase risk of vascular dementia

OAKLAND, Calif., May 7, 2012 – Depressive symptoms that occur in both midlife and late life are associated with an increased risk of developing vascular dementia, while symptoms that occur in late life only are more likely to be early signs of Alzheimer's disease, according to University of California at San Francisco and Kaiser Permanente researchers.

The study, which appears in the current issue of the Archives of General Psychiatry, is the first to examine whether midlife or late-life depression is more likely to lead to either Alzheimer's disease or vascular dementia in the long term. The researchers explain that vascular dementia, the second most common type of dementia, develops when impaired blood flow to parts of the brain deprives cells of nutrients and oxygen.

"People who had depressive symptoms in both midlife and late life were much more likely to develop vascular dementia, while those who had depressive symptoms in late life only were more likely to develop Alzheimer's disease," said the study's lead author Deborah E. Barnes, PhD, MPH, with the UCSF Departments of Psychiatry and Epidemiology & Biostatistics and the San Francisco Veterans Affairs Medical Center.

"The findings have important public health implications because they raise hope that adequate treatment of depression in midlife may reduce dementia risk, particularly vascular dementia, later in life," added Rachel Whitmer, PhD, a research scientist at the Kaiser Permanente Northern California Division of Research and the principal investigator of the study.

UCSF and Kaiser Permanente investigators examined the association between depressive symptoms and dementia over the course of 45 years in a longitudinal study of more than 13,000 long-term members of the Kaiser Permanente Northern California integrated care delivery system. The study population consisted of members who participated in a voluntary health examination called the Multiphasic Health Checkup in San Francisco and Oakland during 1964-1973 when they were 40-55 years old.

Participants were evaluated for depressive symptoms in midlife as part of the Multiphasic Health Checkup and again in late life between 1994-2000. Between 2003-2009, 3,129 participants were diagnosed with dementia.

Though more research is needed, the findings suggest that depression that begins in late life may be an early symptom of Alzheimer's disease, while chronic depression over the life course may reflect a long-term process of changes to blood flow in the brain associated with increased risk of vascular dementia.

Additional authors on the paper include: Kristin Yaffe, MD, UCSF Departments of Psychiatry, Neurology and Epidemiology & Biostatistics and San Francisco Veterans Affairs Medical Center; Amy L. Byers, PhD, MPH, UCSF Department of Psychiatry and San Francisco Veterans Affairs Medical Center; Mark McCormick, MD, Kaiser Permanente Santa Clara Medical Center Department of Psychiatry; and Catherine Schaefer, PhD, Kaiser Permanente Division of Research.

The study was funded by the Brain and Behavior Research Foundation (formerly the National Alliance for Research on Schizophrenia and Depression), the National Institutes of Health and Kaiser Permanente Community Benefit.

The San Francisco Veterans Affairs Medical Center has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF. UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.

The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR's 500-plus staff is working on more than 250 epidemiological and health services research projects. For more information, go to: www.dor.kaiser.org.

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America's leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services to improve the health of our members and the communities we serve. We currently serve 8.9 million members in nine states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: www.kp.org/newscenter.