JMIR Publications

ABSTRACT

Background:

Health benefits of urban green space have been widely reported in literature, but the biological mechanisms remain unexplored and a causal relationship cannot be established between green space exposure and cardiorespiratory health.

Objective:

We conducted a panel study using personal tracking devices to continuously collect the individual exposure data in healthy Chinese adults aged 50 to 64 years living in Hong Kong.

Methods:

A panel of cardiorespiratory biomarkers were tested each week for a period of consecutive five weeks. Weekly exposure to green space, air pollution and physical activities of individual participants was collected by personal tracking devices. The effects of green space exposure measured by the Normalized Difference Vegetation Index (NDVI) at the buffer zones of 100-, 250- and 500-meters were estimated by a generalized linear mixed-effects model, with adjustment for confounding variables of sociodemographic characteristics, exposure to air pollutants and noise, exercises and nutrient intakes.

Results:

A total of 39 participants (mean age 56.4 years, range 50-63 years) were recruited and followed up for five consecutive weeks. After adjustment for sex, income, occupation, physical activities, dietary intake, noise and air pollution, significant negative associations with the 100m-, 250m- and 500m-buffer NDVI were found in total cholesterol, low-density lipoprotein (LDL-C), glucose and high-sensitivity C-reactive protein (hs-CRP). But the effect estimates of glucose and hs-CRP were not significant after adjustment for multiple testing.

Conclusions:

Health benefits of green space can be found in some metabolic and inflammatory biomarkers. Further studies are warranted to establish the causal relationship of green space and cardiorespiratory health.