In 2022, one in 11 people globally have type 2 diabetes mellitus (T2DM); by 2045, it will be one in eight (International Diabetes Federation et al., 2021). A sedentary lifestyle, an unhealthy diet, and being overweight or obese are promoters of the development of diabetes (Zheng et al., 2018). Hence, interventions and formulation of multilevel prevention strategies focused on modifying lifestyle are necessary to decrease the disease burden.

On one hand, industrial development and urbanization have brought many benefits to the population, such as access to advanced technology and improved healthcare resources. However, this progress has also had negative impacts on the environment. As cities expand and industrial activity increases, access to natural areas is increasingly limited. This can have serious consequences for ecosystems and wildlife, as well as potentially exposing people to higher levels of pollution and noise pollution. (Manisalidis et al., 2020; World Health Organization. Regional Office for Europe, 2017).

In recent years, studies have investigated the effects of green spaces (any land with vegetation) on health (Sallis et al., 2006, 2016; Van Holle et al., 2012). Systematic reviews have found that exposure to green spaces improves mental health (Gianfredi et al., 2021; Zhang et al., 2021), lower the prevalence/risk of high blood pressure, overweight, or obesity (Zhao et al., 2022), and lower the risk of all-cause mortality (Rojas-Rueda et al., 2019). The potential ways in which green spaces may contribute to improved health outcomes include the promotion of healthy lifestyles through increased physical activity, improved air quality, increased opportunities for social engagement, and reductions in stress levels(Coombes et al., 2010; Nieuwenhuijsen et al., 2017; Petraviciene et al., 2018; Putrik et al., 2015).

Previous systematic reviews have suggested that exposure to green spaces may have a protective effect on T2DM (De la Fuente et al., 2020; den Braver et al., 2018; Dendup et al., 2018). However, their estimates are based on combining results from cross-sectional, longitudinal, and ecological studies (De la Fuente et al., 2020; den Braver et al., 2018; Dendup et al., 2018). The combination of these studies reduces the strength of evidence and the understanding of a potential causal effect between green spaces and T2DM. Therefore, this systematic review aims to summarize the epidemiological evidence on exposure to green space and the incidence of T2DM from longitudinal studies.