Jinqi Wang from Capital Medical University in Beijing and colleagues from Australia, China and the United States conducted a longitudinal cohort study and found that loneliness in childhood is associated with accelerated cognitive decline and dementia in later life. The study used data from almost 13,600 people (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 by episodic memory and executive function, and dementia was identified by cognitive and functional impairment or a doctor's diagnosis. The analysis was conducted using linear mixed-effects models and Cox proportional hazards models. The article was published in JAMA Network Open.
Loneliness was experienced in childhood by 4.2 percent of participants, and was possible for another 48 percent. Compared with those who did not experience loneliness, both those who did and those who did experience loneliness experienced accelerated cognitive decline in midlife 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 loneliness. 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.
