Depression and risk of sarcopenia: a national cohort and Mendelian randomization study. Frontiers in psychiatry Background:Depression and the increased risk of sarcopenia are prevalent among the elderly population. However, the causal associations between these factors remain unclear. To investigate the potential association between depression and the risk of sarcopenia in older adults, this study was performed. Methods:In the baseline survey, a total of 14,258 individuals aged 40 and above from the China Health and Retirement Longitudinal Study (2015) participated. We initially described the baseline prevalence of the disease. Then, logistic regression and restricted cubic spline (RCS) regression were conducted to assess the relationship between depression and sarcopenia. Subgroup analysis was performed to validate the robustness of the findings. Additionally, we conducted Mendelian randomization analysis using the inverse variance weighting estimator to assess the causal relationship between depression and sarcopenia. Furthermore, we adopted six methods, including MR-Egger, simple median, weighted median, maximum likelihood, robust adjusted profile score (RAPS), and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO), for sensitivity analyses. Results:Depression patients exhibited higher risks of sarcopenia in all five models adjusting for different covariates ( < 0.05). The RCS analysis demonstrated a linear relationship between depression and sarcopenia ( < 0.05). In the subgroup analysis, increased risk was observed among participants aged 60-70, married or cohabiting individuals, non-smokers, non-drinkers, those with less than 8 h of sleep, BMI below 24, and individuals with hypertension (all < 0.05). Mendelian randomization results revealed that genetically proxied depression led to a reduction in appendicular skeletal muscle mass (all < 0.05). Conclusion:Our study provides observational and causal evidences that depression can lead to sarcopenia. This finding emphasizes the importance of timely identification and management of depression, as well as implementing targeted educational programs as part of comprehensive strategies to prevent sarcopenia. 10.3389/fpsyt.2023.1263553

Social isolation, loneliness, and incident type 2 diabetes mellitus: results from two large prospective cohorts in Europe and East Asia and Mendelian randomization. EClinicalMedicine Background:Social isolation and loneliness pose significant public health challenges globally. The objective of this study is to investigate the association between social isolation, loneliness, and the risk of type 2 diabetes mellitus (T2DM). Methods:423,503 UK adults from the UK Biobank (UKB) and 13,800 Chinese adults from the China Health and Retirement Longitudinal Study (CHARLS) were analyzed. The exposures of interest were social isolation and loneliness. Social isolation was evaluated based on the number of household members, frequency of social activities, contact with others, and marriage status (CHARLS only). Loneliness was evaluated by the subjective feeling of loneliness and the willingness to confide in others (UKB only). The primary endpoint was incident T2DM. The two-sample Mendelian randomization (MR) analysis was based on the genome-wide association studies of UKB (n = 463,010) and the European Bioinformatics Institute (n = 655,666). Findings:The UKB cohort study documented 15,072 T2DM cases during a mean follow-up of 13.5 years, and the CHARLS cohort study recorded 1,249 T2DM cases during a mean follow-up of 5.8 years. Social isolation and loneliness showed significant associations with an elevated risk of T2DM in both UKB (social isolation [most vs least]: HR 1.17, 95% CI 1.11-1.23; loneliness [yes vs no]: HR 1.21, 95% CI 1.13-1.30) and CHARLS cohorts (social isolation [yes vs no]: HR 1.22, 95% CI 1.06-1.40; loneliness [yes vs no]: HR 1.21, 95% CI 1.07-1.36). These associations remained significant after accounting for baseline glucose status and genetic susceptibility to T2DM. Two-sample MR analyses determined that feeling lonely (OR 1.04, 95% CI 1.02-1.06) and engaging in fewer leisure/social activities (OR 1.03, 95% CI 1.02-1.05) were associated with increased T2DM risk, whereas more contact with friends or family (OR 0.99, 95% CI 0.98-0.99) was associated with reduced T2DM risk. Interpretation:Social isolation and loneliness are each associated with an elevated risk of T2DM, with MR analyses suggesting potential causal links. These associations remain significant after considering genetic susceptibility to T2DM. The findings highlight the importance of promoting initiatives to address social isolation and loneliness as part of T2DM prevention strategies. Funding:CAMS Innovation Fund for Medical Sciences (No. 2021-I2M-1-008) and National Natural Science Foundation of China (No. 72103187). 10.1016/j.eclinm.2023.102236