Sense of Coherence and Incident Dementia in Older Japanese Adults: The Japan Gerontological Evaluation Study

Abstract

ObjectivesThe sense of coherence refers to effectively using available resources to manage stress and promote overall health. Previous studies have linked it to various health outcomes; however, evidence regarding its association with the risk of incident dementia is limited. Hence, this study aimed to fill this research gap using data from a large-scale population survey. DesignProspective cohort study. Setting and ParticipantsThis study included 31,556 participants aged 65 years and older who were free from dementia and disabilities. The participants were enrolled in the 2010 baseline survey of the Japan Gerontological Evaluation Study, and were followed up until the end of 2019. MethodsThe sense of coherence was assessed using a 6-item short-version questionnaire. Incident dementia cases were ascertained through the public long-term care insurance database in Japan. ResultsDuring a median follow-up of 8.3 years, 4326 incident dementia cases were identified. After adjusting for conventional risk factors, the hazard ratios (95% CIs) for each quintile compared to the lowest quintile of the sense of coherence were 0.82 (0.75-0.90), 0.75 (0.68-0.83), 0.76 (0.68-0.84), and 0.78 (0.70-0.87), respectively. The multivariable hazard ratio (95% CI) per 1-SD increment was 0.91 (0.88-0.95). These inverse associations did not exhibit any gender differences (P for gender interaction = .11) and were further confirmed after excluding early incident cases. Similar associations were found for its components; the corresponding multivariable hazard ratios (95% CIs) per 1-SD increment were 0.94 (0.91-0.97) for comprehensibility, 0.92 (0.89-0.95) for manageability, and 0.93 (0.90-0.97) for meaningfulness. Conclusions and ImplicationsModerate and above sense of coherence was associated with the lower risk of dementia among the older population, suggesting a beneficial role of stress management in maintaining the cognitive health of older adults.