Childhood loneliness and deficit-accumulation frailty progression in mid-to-late life.

BACKGROUND

Adult loneliness has been linked to various age-related conditions, yet the long-term consequences of childhood loneliness remain poorly understood. This study examined the association between childhood loneliness and frailty progression in mid-to-late adulthood.

METHODS

We analyzed data from 13,643 participants in the China Health and Retirement Longitudinal Study from 2011 through 2018. Childhood loneliness was defined based on self-reported frequent feelings of loneliness and the absence of close friendships before the age of 17. Frailty, defined using a 40-item deficit-accumulation frailty index (FI), was repeatedly measured. Linear mixed-effect models were used to evaluate the associations between childhood loneliness and frailty progression.

RESULTS

Of 13,643 participants (mean [SD] age, 58.48 [9.42] years; 6445 [47.2%] male), 561 (4.1%) reported definite childhood loneliness, while 6580 (48.2%) reported possible childhood loneliness. Compared with people without childhood loneliness, those with definite loneliness had higher baseline FI (β = 1.740; 95% CI: 0.903 to 2.576) and faster frailty progression (β = 0.289; 95% CI: 0.145 to 0.433). Possible childhood loneliness was also associated with accelerated frailty progression (β = 0.153; 95% CI: 0.095 to 0.210). These associations persisted after adjusting for adult loneliness, and no significant interaction between childhood and adult loneliness was observed. Childhood loneliness remained significantly associated with faster FI progression among individuals without adult loneliness

CONCLUSIONS

In this national cohort, childhood loneliness was associated with accelerated frailty progression in adulthood, independent of adult loneliness. These findings underscore the enduring impact of childhood loneliness on frailty and healthy aging across the life course.