Are social isolation, lack of social support or loneliness risk factors for cardiovascular disease in Australia and New Zealand? A systematic review and meta-analysis.

Background: An international systematic review concluded that individuals with poor social health (social isolation, lack of social support or loneliness) are 30% more likely to develop coronary heart disease (CHD) and stroke. Notably, the two included Australian papers reported no association between social health and CHD or stroke.

Objective: We undertook a systematic review and meta-analysis to investigate the association between social isolation, lack of social support and loneliness and cardiovascular disease (CVD) incidence among people living in Australia and New Zealand.

Methods: Four electronic databases were systematically searched for longitudinal studies published until June 2020. Two reviewers undertook title/abstract screen and one reviewer undertook full-text screen and data extraction. Quality was assessed using the Newcastle - Ottawa Quality Assessment Scale.

Results: Of the 725 unique records retrieved, five papers met our inclusion criteria. These papers reported data from three Australian longitudinal datasets, with a total of 2137 CHD and 590 stroke events recorded over follow-up periods ranging from 3 to 16 years. Reports of two CHD and two stroke outcomes were suitable for meta-analysis. The included papers reported no association between social health and incidence of CVD in all fully adjusted models and most unadjusted models.

Conclusions: Our systematic review is inconclusive as it identified only a few studies, which relied heavily on self-reported CVD. Further studies using medical diagnosis of CVD, and assessing the potential influence of residential remoteness, are needed to better understand the relationship between social health and CVD incidence in Australia and New Zealand.