MID-LIFE WORK-RELATED STRESS INCREASES DEMENTIA RISK IN LATE-LIFE: THE CAIDE 30-YEAR STUDY

Abstract

Background: The associations between work-related stress and various health outcomes in mid-life are well documented, yet less is known about the effects on late-life cognitive process and dementia. The current study investigated the associations between work-related stress in mid-life and the development of cognitive impairment and Alzheimer’s disease in late-life. Methods: The data was derived from the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) study; a prospective cohort study. Participants were randomly selected from four independent population-based samples that completed cardiovascular surveys. First baseline examinations occurred when participants were 50 years old on average, in 1972, 1977, 1982, or 1987. A random sample of 2,000 individ- uals was selected for re-examinations (carried out in 1998 and 2005-2008), where 1,511 subjects participated in at least one re-examination. The re- examinations included an extensive neuropsychological and cognitive assessment. Follow-up time was on average 28 (S.E.M. 1⁄4 0.17) years. Work-related stress comprised the total score of two questions adminis- tered in mid-life. The questions asked participants to rate their stress related to meeting demands at work, and constant hurry at work. Groups were categorized so that those with high or medium levels of stress were compared to those with low levels or no work-related stress. Results: High levels of work-related stress in mid-life were associated with higherrisk of cognitive impairment (where participants with cognitive impair- ment and dementia were compared to the group with no cognitive impair- ment) [odds ratio (OR), 1.5; 95% confidence interval (CI), 1.1-2.1], and Alzheimer’s disease [OR, 2.1; CI, 1.1-3.9], when assessed at the first or second follow-up. Results remained significant after adjusting for age, ed- ucation, marital status, chronic health conditions, apolipoprotein E e 4 allele (APOE e 4), measures of hopelessness and loneliness. Conclusions: High levels of mid-life work-related stress predict the risk of developing dementia in late-life. The evidence suggests that individuals experiencing high levels of work-related stress form an important at-risk population. Preventive interventions are needed for this population in order to post- pone or prevent the development of cognitive impairment and Alzheimer’s disease.