Associations between residential greenness and blood lipids in Chinese elderly population

Abstract

Objective: Previous studies on residential green space were inconsistent with blood lipid levels and hyperlipidemia. Thus, our study aims to explore the relationship between urban residential greenness and the blood lipid level and hyperlipidemia of the Chinese elderly population.

Methods: A total of 59,865 older adults were collected from the Shenzhen healthy aging Research (SHARE). Blood lipid levels [total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)] were measured. Participants' exposure to residential greenness was measured by the satellite-based normalized difference vegetation index (NDVI). Generalized linear mixed models (GLMMs) and logistic regression were performed to assess the associations of residential greenness with lipid levels and dyslipidemia (high TG, high TC, low HDL-C, and high LDL-C).

Results: Each per 1 standard deviation (SD) increase in NDVI_250-m was associated with a higher HDL-C level (β = 0.003, 95% (confidence interval, CI):0.001-0.005) and lower TG level (β = - 0.005, 95% CI - 0.141-0.121), after fully adjusting for covariates. Each increment in per interquartile range (IQR)-unit increase in NDVI_250-m was associated with lower odds of high TG (odds ratio, OR 0.94, 95% CI 0.91-0.97) and low HDL-C (OR 0.96, 95% CI 0.94-0.99). The NDVI_250-m has the highest protective effect on the incidence of high TG and low HDL-C, followed by NDVI_500-m and NDVI_1250-m. Stratified analyses showed that association between residential greenness and hyperlipidemia was modified by sex, age, BMI, household registration, and physical activity.

Conclusion: Higher greenness exposure was beneficially associated with lipid levels and dyslipidemia among Chinese city-dwelling older adults.

Keywords: Blood lipid; Cohort study; Elderly population; Hyperlipidemia; Residential greenness.