Lonely adults during midlife were associated with higher symptoms of depression 12 years later. These findings, from a longitudinal study, were published in the Lancet Psychiatry.
Individuals (N=4211) aged 50 years or older were recruited in 2004 for an ongoing study of health, social, and economic characteristics of the English population. Participants were surveyed every 2 years until 2016 or 2017. At each follow-up participants were assessed by the Centre for Epidemiologic Studies Depression Scale (CES-D) and the University of California, Los Angeles Loneliness Scale (R-UCLA).
At follow-up, participants were 55% women, aged mean 65.1 (standard deviation [SD], 8.9) years, 70% were married, 54% had intermediate school qualifications, 66% were unemployed or retired, 25% were in the wealthiest quantile and 12% in the lowest, 55% had a long-term physical illness, and 55% had mobility impairment.
At baseline the mean loneliness score was 4.12 (SD, 1.50) and 17% had a depression severity ³2. Depression and loneliness were correlated (Pearson’s correlation coefficient, 0.49).
Participants who were lonely (score ³6) were older, more were women, unemployed, had lower education, lower wealth, more physical illness, were mobility impaired, experienced more pain, had symptoms of depression, and had smaller social networks compared with participants who were not lonely (score <6).
For every 1-point increase of their loneliness score, symptoms of depression were increased by 0.38 (95% CI, 0.35-0.41; P <.0001) points. The association between loneliness and depression remained significant for all models. After adjusting for covariates (time, social experiences, polygenic risk, sociodemographic features, health status, and baseline depression), the associated increase in depression score with every 1-point increase in loneliness was 0.16 (95% CI, 0.13-0.19; P <.0001) points.
The magnitude of the association between loneliness and depression decreased over time (interaction coefficient, -0.01; 95% CI, -0.019 to -0.009; P =.031). The association between loneliness and depression was 23% (95% CI, 17%-28%) at the first follow-up and 16% (95% CI, 8%-22%) and the final follow-up.
Age (P =.33) or gender (P =.24) were not significant factors for the association between loneliness and depression.
This study may have been limited by treating physical health problems and baseline depressive symptoms as confounders of this correlation, however, these features may be mediators between loneliness and depression instead.
The study authors concluded loneliness among middle aged adults was associated with increased depression severity over time. This association was independent from aspects of social and physical health, indicating targeted interventions of social support may help to reduce loneliness and subsequent depression.
Lee SL, Pearce E, Ajnakina O, et al. The association between loneliness and depressive symptoms among adults aged 50 years and older: A 12-year population-based cohort study. Lancet Psychiatry. 2021;8(1):48-57. doi:10.1016/S2215-0366(20)30383-7