Green areas and vitamin D status:

Analysis with women living in a medium-sized city with a tropical climate

Abstract

Vitamin D deficiency is a global health problem and approaches that consider Nature-Based Solutions (NbS) can bring new perspectives of solution. About 80% of the amount of vitamin D that the body needs is produced endogenously through exposure of the skin to ultraviolet B (UVB) radiation from sunlight. The average UVB exposure in urban areas will depend in part on the local climate and the amount of cover and types of trees. The study analyzed the association between green areas and vitamin D levels. A sample of 101 women aged 35 years and over, living in the city of Araraquara, Brazil, was analyzed. The Normalized Difference Vegetation Index (NDVI) was calculated as an indicator of exposure to green areas, being defined as the surrounding residential vegetation. A logistic regression model was used to analyze the association between residential vegetation index and vitamin D status. A statistically significant positive association was observed between exposure to below-median residential surrounding vegetation index and prevalence of insufficient levels of 25(HO)D (P=0,03). The study shows that lower levels of residential green are associated with a higher prevalence of vitamin D insufficiency. NbS approaches contribute to a better understanding of suitable environments for achieving good levels of vitamin D, avoiding the need for pharmaceutical supplementation of the nutrient.