Testing direct and indirect effects of green space availability on reproductive outcomes

Abstract

Background/Aim:Adverse reproductive effects can lead to cognitive development problems, medical conditions, morbidity and mortality in future stages of lives. Surrounding residential greenness has a positive effect in reproductive health. Different studies have proposed that this effect could be both direct and indirect. Indirect effects of greenness may happen through the reduction of environmental exposure (air pollution, noise and temperature regulation), the promotion of physical activity and the improvement of psychological health. The aim of the study was to analyze the relationship between surrounding residential greenness and reproductive health, studying the possible role of said mediators.Methods:441 pregnant women (mean age 33.52, SD = 4.88) were recruited in Donostialdea, Basque Country, Spain, during the first ultrasound in the Basque Health Service. After signing the informed consent form, participants were given the study questionnaire and one accelerometer (ActiGraph GT3X-BT) which they used it for one week. In the second trimester of pregnancy they repeated the whole process again. Environmental exposures (NO2 and availability of >5000 m2 green space in 300m) were assigned to all participants. Moderate to Vigorous Physical Activity (MVPA) was determined with the accelerometer. Psychological health was measured with the General Health Questionnaire (GHQ-12). Birth weight, preterm birth, small and large for gestational age (SGA & LGA) were defined as outcome variables and newborn sex, season, deprivation index and parity as covariates. Natural effects models were used to analyze aforementioned direct and indirect effects.Results:Greenness availability had a negative effect on birth weight (-138g; p-value = 0.022). A marginal protective effect of greenness availability on LGA (OR = 0.54; p-value = 0.091) was detected in the model with GHQ as mediator.Conclusions:Greenness availability in 300m had limited effects on reproductive outcomes. Using other measures of greenness may help to understand this question better.