The association between social isolation and cognitive function in older adults in urban, fringe and rural regions of Lebanon: A secondary data analysis of two national cross-sectional studies

The rectangularization of the global age structure signals that one out of four persons will be 65+ by 2050. Cognitive function and social status are significant determinants of health in this population. This study examines the association between social isolation and cognitive decline in Lebanese older adults from different geographical areas. Secondary data were derived from two national cross-sectional surveys across Lebanon's urban, fringe, and rural areas. Social isolation and cognitive decline were measured via a 5-item index and the A-IQCODE, respectively. Multivariable analysis evaluated the association between social isolation and cognitive decline across strata of area of residence. The prevalence of cognitive decline and social isolation among 728 older adults was 21 % and 19 %, respectively. After adjustment, the social isolation index score was significantly associated with cognitive decline (aOR 1.45, 95 % CI 1.17–1.81). Only employment (aOR 3.04, 95 % CI 1.19–7.75) and social participation (aOR 1.85, 95 % CI 1.07–3.20) showed a significant association with cognitive decline. We observed no effect modification by area of residence. Upon stratification, the social isolation index score was significantly associated with cognitive decline in urban (p 0.03) and rural (p 0.02) areas but not in the fringe (p 0.31). Our findings reveal a notably high prevalence of informant-rated cognitive decline and social isolation, as well as a significant differential association across geographical regions. Thus, our study is the first to describe these two burdening public health issues in a large cohort of older adults in Lebanon. • The ‘fringe' offers a nuanced understanding of socio-environmental contexts influencing social isolation and cognitive decline. • Links between social isolation and cognitive decline differ across regions in Lebanon, highlighting role of local context. • Unemployment, poor social networking, and infrequent social participation are linked to cognitive decline and are intervention targets. • Reducing social isolation could improve cognitive health among older Lebanese adults amid socio-economic challenges. • This study highlights socio-ecological disparitis shapring social isolation and cognitive decline across regions in Lebanon.