Purpose <p>Increasing evidence supports the existence of an association between social relationships and cardio-cerebrovascular diseases (CCVDs). However, the magnitude of the association between various social relationship factors and CCVDs remains uncertain.</p> Methods <p>Four databases were systematically searched to investigate the associations between social relationship factors and CCVDs in the general population. The retrieved longitudinal cohort studies were independently subjected to eligibility screening, data extraction, and quality assessment using the modified Newcastle–Ottawa scale by two reviewers. Relative risk (RR) with 95% confidence interval (CI) were pooled using random effects models. We conducted a synthesis across social relationship factors to estimate overall effects for the structural and functional aspects.</p> Results <p>Thirty cohort studies were included. The meta-analysis revealed that social support (RR: 1.28, 95% CI: 1.11–1.47), social isolation (RR: 1.14, 95% CI: 1.07–1.22), loneliness (RR: 1.21, 95% CI: 1.07–1.37), social integration (RR: 1.16, 95% CI: 1.05–1.27) and social network (RR: 1.49, 95% CI: 1.02–2.18) were significantly associated with CCVDs. Compared with structural aspects of social relationships, functional aspects were associated with a slightly greater CCVD risk (RR: 1.23, 95% CI: 1.13–1.35 vs. RR: 1.14, 95% CI: 1.09–1.20).</p> Conclusions <p>Our findings confirm that adequate social support, high social integration, and large social networks are associated with a lower CCVD risk, whereas high social isolation and loneliness are associated with a higher risk. Furthermore, functional aspects of social relationships are associated with a slightly greater CCVD risk than structural aspects. This analysis provides evidence that enhancing social relationships may help prevent CCVD.</p>