Social isolation and loneliness with risk of cardiometabolic multimorbidity: a prospective cohort study from UK Biobank (Preprint)
Authors: Xiao Zhilin , Li Jing , Luo Yi , Yang Liu , Zhang Guogang , Cheng Xunjie , Bai Yongping 
Published: February 2023

BACKGROUND

The pandemic of the coronavirus disease 2019 (COVID-19) resulted in an increased prevalence of social isolation and loneliness in recent years. Although there is increasing evidence of an association between social isolation/loneliness and mortality in general, the role of social isolation and loneliness in the risk of single and multiple cardiometabolic diseases (CMD) remains controversial or even unknown.

OBJECTIVE

Here we aimed to determine whether social isolation and loneliness are associated with risk of CMD and cardiometabolic multimorbidity (CMM).

METHODS

343,425 individuals with no CMD at baseline (stage I) and 35,209 individuals with only one CMD at baseline (stage II) were included. The exposures were self-reported isolation (including three levels, based on living alone, few contact with family or friends, and disengagement in group activities) and loneliness (including three levels, based on feeling lonely and able to confide). The main outcomes were CMD and CMM which was defined as the coexistence of at least two CMDs: diabetes mellitus (DM), coronary heart disease (CHD), and stroke. Cox proportional hazards models were performed to estimate hazard ratios (HRs) and their 95% CIs.

RESULTS

Both in stage I and stage II, social isolation and loneliness were associated with the incidence of CMD and CMM. In the multivariable adjusted models, compared with the least isolated, the most isolated had higher risks of incident CMD (HR 1.07, 95% CI 1.03 to 1.11) and CMM (HR 1.24, 95% CI 1.12 to 1.36) in stage I, and higher risk of incident CMM in stage II (HR 1.14, 95% CI 1.05 to 1.23). Compared with the least loneliness, those who were most loneliness had about 20% increased risk of CMD and 29% increased risk of CMM in stage I. The most loneliness was also significantly associated with increased CMM risk (HR 1.30, 95% CI 1.19 to 1.42) in stage II. Results of stratified analysis showed that living alone and feeling lonely, in particularly the latter, were much more strongly associated with higher risk of single CMD and CMM. Interestingly, social isolation has little direct effect on the risk of developing CHD, less social contact, as one of the high-risk social isolation factors, indeed increases the risk of incident CHD (HR, 1.05; 95% CI, 1.00-1.11).Moreover,poor diet strengthened the unfavorable association with cardiometabolic outcomes among the most isolated and the loneliest.

CONCLUSIONS

This study revealed the different risk associations of social isolation and loneliness with individual CMD and CMM. Identifying high-risk populations through the level of social participation and loneliness could help to prevent CMD and CMM. Health policies improving the state of living alone, less social contact and feeling lonely might be applicable for the precise prevention and treatment of these conditions. Moreover, ideal healthy diet promotion might substantially attenuate the risks for CMM and CMD among the isolated and lonely people.