# Associations among green spaces, ambient temperature, air pollution, and body mass index: a nationwide study in South Korea from 2008 to 2021

## TL;DR

This study examines how green spaces, temperature, and air pollution in South Korea relate to BMI trends from 2008 to 2021.

## Contribution

It provides new insights into how environmental factors interact with obesity in a nationwide South Korean population.

## Key findings

- Green space showed a negative correlation with BMI in normal weight individuals but not in overweight or obese groups.
- Ambient temperature had a positive correlation with BMI in normal weight and some obese groups.
- Air pollution and temperature had a negative correlation, contradicting prior studies.

## Abstract

In this study, we explored the associations among green space, ambient temperature, and air pollution from 2008 to 2021, with the aim to provide insights into the trends and relationships among built and natural environments factors and their impact on obesity in South Korean adults.

A total of 674,962 subjects from the Community Health Survey were analyzed. Descriptive statistics, Pearson correlation, and robust regression were used to help understand the changes in trend and the correlations between variables.

The mean age of the study subjects did not differ significantly based on body mass index (BMI); however, the obesity class 3 group had the lowest mean age. Exploration of green space and BMI showed a generally negative correlation in the normal weight group, but no such correlation was found in the overweight or obesity class 3 group. A positive correlation was observed between ambient temperature and BMI in the normal weight, overweight, and obesity class 1 groups. No strong association was found between air pollution and BM. While supporting evidence was found for the relationship between green space and ambient temperature, no such relationship was found between green space and air pollution. Lastly, air pollution and ambient temperature showed negative correlations, which contradicts the findings of prior studies.

Further exploration is needed to identify potential mechanisms and develop policies and neighborhood-level interventions aimed at addressing the built and natural environments factors contributing to obesity in urbanized settings.

The study design and data analysis protocol were reviewed and approved by the Institutional Review Board of the National Medical Center (IRB No. 202306069 IRB examination exemption approval 20230622).