Background: Indicators of social isolation or support such as living alone, loneliness, being married, and life satisfaction are possible psychosocial risk and protective factors for dementia.
Objective: We investigate the associations of these overlapping psychosocial factors with incident MCI-dementia (neurocognitive disorder) in a population cohort.
Methods: Using data from 1601 participants of the Singapore Longitudinal Ageing Study (SLAS) who were free of MCI or dementia at baseline and followed up to 8 years, we estimated hazards ratio (HR) of association of living alone, loneliness, being married, and high life satisfaction with incident MCI-dementia.
Results: In univariate analyses, individual HRs of association with incident MCI-dementia for living alone was 1.86 [1.18 - 2.95], (p = 0.008), loneliness was 1.26 [0.86 - 1.84], (p = 0.23), being married was 0.54 [0.39 - 0.75] (p < 0.0001), and being very satisfied with life was 0.59 [0.38-0.91]), (p = 0.017). Adjusted mutually for other psychosocial variables, and for age, sex, education, ethnicity, smoking, alcohol, dyslipidemia, hypertension, diabetes, central obesity, history of stroke or heart disease, APOE-ɛ4, depression, physical, social, and productive activities, only being married (0.68 [0.47-0.99], p = 0.044), and being very satisfied with life (0.61 [0.39 - 0.96], p = 0.034) remained significant variables associated with lower risks of developing MCI-dementia.
Conclusion: Individuals who were married and those who were very satisfied with life are protected against the risk of developing MCI and dementia. Controlling for the adverse effects of being without spousal support and low life satisfaction, living alone or a feeling of loneliness were not associated with increased risk of MCI-dementia.
Keywords: Dementia; epidemiology; living alone; protective factors; risk factors.