Green space, neighborhood walkability and cardiometabolic health in early pregnancy: The Healthy Start study

Abstract

BACKGROUND AND AIM: Green space and neighborhood walkability have been associated with cardiometabolic health, but relationships with cardiometabolic markers during pregnancy are unclear. We estimated associations of residential green space and neighborhood walkability with cardiometabolic health in early pregnancy. METHODS: We included 1208 pregnant women enrolled in the Colorado-based Healthy Start study (2009-2014). During a study visit in early pregnancy (median 17 weeks of gestation), we measured systolic and diastolic blood pressure and collected fasting blood samples. We measured serum glucose and insulin and calculated the Homeostatic Model for Assessment of Insulin Resistance (HOMA-IR). We used the average Normalized Difference Vegetation Index (NDVI) in circular buffers of 250m, 500m and 1000m surrounding the participants’ homes to estimate exposure to green space. The walkability of the Census block group of the maternal residence was assessed by the National Walkability Index of 2010. Associations of green space and neighborhood walkability with cardiometabolic markers in early pregnancy were assessed by linear regression, adjusting for covariates. RESULTS:A higher average NDVI in all buffer sizes was associated with a lower diastolic blood pressure and (non-significantly) lower systolic blood pressure in early pregnancy. For example, women in the highest tertile of green space in a buffer of 500m (NDVI ≥0.21) had a 1.21mmHg [95%CI -2.23, -0.20] lower diastolic blood pressure than women in the lowest tertile. Additionally, pregnant women who lived in the most walkable neighborhoods had a 3.41mmHg [95%CI -5.31, -1.51] lower systolic and 2.18mmHg [95%CI -3.73, -0.63] lower diastolic blood pressure than women residing in the least walkable neighborhoods. We found no associations of green space or neighborhood walkability with glucose, insulin or HOMA-IR. CONCLUSIONS:In this racially and ethnically diverse population, higher exposure to residential green space and higher neighborhood walkability were associated with lower systolic and diastolic blood pressure in early pregnancy. KEYWORDS: Green space, Walkability, Female, Obesity and metabolic disorders