Is loneliness associated with mild cognitive impairment in low- and middle-income countries?

Background: Loneliness may be a risk factor for mild cognitive impairment but studies on this topic are scarce, particularly from low- and middle-income countries (LMICs). Therefore, the aim of the present study was to investigate the association between loneliness and mild cognitive impairment (MCI) in six LMICs (China, Ghana, India, Mexico, Russia and South Africa). Methods: Cross-sectional, community-based, nationally representative data from the WHO Study on global AGEing and adult health (SAGE) were analyzed. The definition of MCI was based on the National Institute on Ageing-Alzheimer's Association criteria. Multivariable logistic regression analysis and meta-analysis were conducted to assess associations. Results: The final analytical sample consisted of 19,092 and 13,623 individuals aged 50-64 years (middle-aged adults) and >= 65 years (older adults), respectively. Among the middle-aged, overall, loneliness was associated with a non-significant 1.43 (95% confidence interval [CI] = 0.93-2.21) times higher odds for MCI although significant associations were observed in China (OR = 1.51; 95%CI = 1.08-2.09) and South Africa (OR = 3.87; 95%CI = 1.72-8.71). As for older adults, overall, there was a significant association between loneliness and MCI (OR = 1.52; 95%CI = 1.12-2.07). Conclusion: In this large representative sample of middle-aged and older adults from multiple LMICs, findings suggest that loneliness is associated with MCI. It may be prudent to consider reducing loneliness in low-economic settings to aid in the prevention of MCI and ultimately dementia.