Jinqi Wang of Capital Medical University in Beijing and colleagues from Australia, China, and the United States conducted a longitudinal cohort study and found that childhood loneliness is associated with accelerated cognitive decline and dementia later in life. The study used data from nearly 13,600 individuals (mean age 58.34 years; 52.8 percent women) from the nationally representative CHARLS cohort. Childhood loneliness was defined as subjective frequent feelings of loneliness and lack of close friends before age 17. Cognitive function was measured using episodic memory and executive function measures, and dementia was identified based on cognitive and functional impairment or physician diagnosis. The analysis was conducted using linear mixed-effects models and Cox proportional hazards models. The article was published in JAMA Network Open.
4.2 percent of participants experienced loneliness in childhood, and another 48 percent were likely to experience it. Compared with those who did not experience loneliness, both those who did and those who did not experience it experienced accelerated cognitive decline in middle and old age (β -0.03 and -0.02 standard deviations per year, respectively). Childhood loneliness was also associated with an increased likelihood of developing dementia (odds ratio 1.47). These patterns persisted when adjusting for loneliness in adulthood and restricting the analysis to those who did not experience it. Adult loneliness mediated 8.5 percent of the association between childhood loneliness and cognitive decline and 17.2 percent of the association with dementia, but did not modify these associations.
