Cumulative Loneliness May Accelerate Memory Decline Among Older Adults

Accelerated memory aging may be related with cumulative loneliness, according to the results of a study published in Alzheimer’s & Dementia.

Investigators at the University of Michigan School of Public Health sourced data for this study from the US Health and Retirement Study (HRS) which was a population-based longitudinal survey conducted between 1996 and 2016. Participants (N=9032) were evaluated for the number of time points between 1996 and 2004 they expressed loneliness and compared their cumulative loneliness with risk for accelerated memory aging evaluated between 2004 and 2016.

The study population comprised 37.49% men, median age of 62 (range, 50-95) years, 84.53% were White, 73.14% were partnered, 53.11% were working for pay, 23.43% had less than a high school education, 15.16% were in the poorest household wealth quintile, mean objective social isolation index score was 2.20 (SD, 1.07), Center for Epidemiologic Studies-Depression (CES-D) score was 1.02 (SD, 1.57), and Activities of Daily Living (ADL) score was 0.17 (SD, 0.59).

Stratified by duration of loneliness all baseline characteristics differed between groups (all P <.001).

Compared with individuals who were never lonely, loneliness at 2 (β, -0.040; P =.024) and 3 or more (β, -0.075; P <.001) time points were significantly related with memory function and rate of decline after adjusting for all cofounders with a significant year-by-loneliness trend (P <.001).

These values indicated that for every year, individuals who were never lonely had a memory z-score decline of 0.087 SD units, those who were lonely at 1 time point had an additional 0.014 SD units, 2 time points had 0.028 SD units, and the most lonely had 0.035 SD units of additional decline.

Among individuals aged 50 to 64 years at baseline (n=5761), the effect of loneliness on memory was less strong (P =.042) compared with the older cohort (≥65 years; n=3271; P <.001).

Stratified by gender, a significant year-by-loneliness-by-gender interaction was observed (P =.002), in which memory decline was similar among nonlonely women and men. The effect of loneliness at 3 or more time points was stronger among women, with a 0.040 additional SD unit decline compared with 0.016 SD units among similarly lonely men.

The results of the sensitivity analyses supported the main findings of this study.

This study was limited by relying on a single item to measure loneliness.

Study authors concluded, “In this population-based cohort study of middle-aged and older adults in the United States, cumulative duration of loneliness in mid- to-late life may be a salient risk factor for accelerated memory aging, especially among women aged 65 and over. Further research from diverse populations to investigate underlying biological mechanisms is warranted.”