The associations between exposure to green and blue spaces with multimorbidity: observational analyses of UK Biobank cohort

Green and blue spaces can protect and promote mental and physical health by
mitigating harm, restoring capacities, and promoting physical activity. However, little
is still known about the ways different types of green and blue spaces affect the risk
of having complex health states, such as multimorbidity.
To fill this gap, this thesis examined the relationships between exposure to several
types of green and blue spaces with multimorbidity. First, a systematic literature
review of longitudinal, observational studies on the relationships between green and
blue spaces with long-term mental health conditions and non-communicable
diseases (NCDs) was conducted. Results from the systematic review showed there
is currently a lack of high-quality, comparative research on different types of green
and blue spaces and how they affect the risk of developing long-term mental health
conditions and NCDs. A data integration study with European Urban Atlas and UK
Biobank was conducted to compute individual-level exposure data on availability of
total green space, street trees, inland water bodies, and accessibility to parks.
Finally, the cross-sectional associations between these green and blue space
exposures with simple, complex, cardio-metabolic, respiratory, and mental
multimorbidity were assessed. Results showed that only inland blue spaces
moderately reduced the odds of having mental and complex multimorbidity, and that
income and physical activity were not strong moderators in these relationships.
Although less commonly studied, inland blue spaces, such as rivers, canals and
lakes, could offer opportunities for relaxation and mental restoration in all individuals,
irrespective of income. Future research should aim to analyse these causal
relationships by seeking to understand the underlying biological, social, and
behavioural mechanisms. This can inform policy and public health practice.
Incorporating blue natural environments into preventative care for multimorbidity can
reduce the burden of multimorbidity on health systems and allow individuals to have
higher quality of life.