The impacts of multidimensional urban greenness on incident dyslipidaemia and blood lipid profiles among adults: A 10-year longitudinal cohort study in Hong Kong

Although the health benefits of greener environments are well documented, longitudinal evidence linking multidimensional greenness to blood lipid health, a key risk factor for cardiovascular diseases, remains limited, particularly in high-density urban settings. This 10-year (2008-2017) cohort study investigated the associations between multidimensional greenness and lipid health in Hong Kong. We assessed aerial greenness, street-level visibility (Green View Index), and three-dimensional greenness volume at each participant's addresses. We examined the associations between greenness and blood lipid profiles (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol) and the development of dyslipidaemia among 24,458 adults and 6,239 adults, respectively. Using time-varying Cox regression models and linear mixed-effects models, we found that each interquartile range increase in all greenness metrics was associated with 8–14% reduced risk of the development of dyslipidaemia. All greenness metrics were also associated with healthier levels of lipid profiles. Notably, we identified potential thresholds (1.1 m³) for the health impacts of three-dimensional greenness volume, which require an increase of approximately 37.5% above current average levels in Hong Kong. Mediation analyses revealed that fine particulate matter significantly mediated up to 40.39% of the impact of three-dimensional greenness volume on the development of dyslipidaemia. Non-elderly adults and female participants appeared to derive smaller health benefits from greenness. These findings provide quantitative targets for urban greening, and also a mechanistic justification for using nature-based solutions to build a sustainable healthy city.