Marital status, life satisfaction affect dementia risk in Asians
Individuals who are married or report being very satisfied with life have a lower risk of developing mild cognitive impairment (MCI) and dementia, according to results from the Singapore Longitudinal Ageing Study (SLAS).
After adjusting for factors such as age, sex, education, ethnicity, apolipoprotein E (APOE-Ɛ4), comorbidities (hypertension, dyslipidemia, diabetes, obesity, depression, history of stroke or heart disease), and smoking and alcohol intake, individuals who were married and those who reported being very satisfied with life had a lower likelihood of developing MCI/dementia (hazard ratio [HR], 0.66, 95 percent confidence interval [CI], 0.46–0.94; p=0.019 and HR, 0.63, 95 percent CI, 0.40–0.99; p=0.044, respectively). [J Alzheimers Dis 2017;doi:10.3233/JAD-160862]
This association remained after adjusting for psychosocial variables, such as marital status and loneliness, in addition to the abovementioned factors (HR, 0.68, 95 percent CI, 0.47–0.99; p=0.044 and HR, 0.61, 95 percent CI, 0.39–0.96; p=0.034 for those who were married and very satisfied with life, respectively).
However, upon adjusting for lifestyle, behavioural, and vascular risk factors, as well as psychosocial variables, being married was no longer associated with a reduced risk of cognitive decline (odds ratio [OR], 0.95, 95 percent CI, 0.71–2.27; p=0.70), though the association remained for individuals who were very satisfied with life (OR, 0.69, 95 percent CI, 0.52–0.92; p=0.011).
“Life satisfaction thus appears to be the most robust psychosocial factor that predicts a lower likelihood of cognitive decline and neurocognitive disorder, independently of marital status, living arrangement, and loneliness,” said the researchers, who recommended further study into identifying factors that “influence social connectedness and quality of relationships and its associations with cognitive and health outcomes”.
After adjusting for demographic, lifestyle, and vascular risk factors, individuals who lived alone had an elevated risk of developing MCI/dementia (HR, 1.64, 95 percent CI, 1.02–2.63; p=0.041). However, after adjusting for psychosocial variables, living alone was no longer associated with increased MCI/dementia risk.
“Living arrangement is not a consistent surrogate measure of social isolation across different populations. Older persons who live alone may be more likely to be a self-selected population of those who are in good health and independent in their daily living activities,” said the researchers.
Subjects were 1,601 individuals (median age, 64.9 years, 64.5 percent female, 94.9 percent Chinese) with no MCI or dementia at baseline who participated in the SLAS conducted between September 2003 and December 2005, of whom 163 developed MCI/dementia (3.01 per 100 person-years). Individuals were followed up for up to 8 years. Seventy-five percent of subjects (n=1,197) were married and 24 percent (n=379) reported being very satisfied with life.
“Our results underline the need to be cognizant of the role of psychosocial factors in cognitive health, and proactive preventive actions should address psychosocial factors as assiduously as lifestyle and vascular risk factors,” said the researchers.