Green Space and Depression during Pregnancy: Results from the Growing Up in New Zealand Study

Abstract

Background: Antenatal depression is an important contributor to poor maternal health experienced by some women. This study aimed to determine whether exposure to green space during pregnancy is associated with less depression, and whether this association is moderated by relevant factors, such as age, education, self-identified ethnicity, physical activity, residential rurality, and socioeconomic status. Methods: Health data were sourced from the cohort study "Growing Up in New Zealand" comprised of 6772 participants. Green space was estimated based on the proportion of green space within the Census Area Unit. Adjusted logistic mixed effect models were used to investigate the association between green space and antenatal depression after controlling for confounding variables. Results: Maternal exposure to green space were not associated with lower odds of antenatal depression. Indications of effect modifications due to relevant factors were not observed. Conclusions: This study did not determine an association between access to green space (measured based on the distance to the nearest green space) and antenatal depression. Therefore, a link between green space and antenatal depression was not established. For that reason, ensuring residential areas contain adequate green space may or may not be helpful in preventing antenatal depression and adverse health outcomes associated with this depression. More studies focusing on pregnant women in a range of social contexts, and considering both exposure and access to green space, are warranted to determine the relationships between green space and antenatal depression.

The Influence of Socio-economic and Socio-demographic Factors in the Association Between Urban Green Space and Health

“…Mukherjee et al (2017) showed that park size was significantly negatively associated with depression even when models were adjusted for confounders such as income, education or employment status, but also for age, gender, marital status and household composition. Similarly, Calogiuri et al (2016) and Nichani et al (2017) found that socio-economic inequality in mental well-being was significantly lower among respondents reporting good access to a green space compared with those who had less access. Other studies, however, could not find any relationship between health outcome and socio-economic or socio-demographic confounders (Calogiuri et al 2016;Nichani et al 2017) or showed that significant associations between green space and health outcome became non-significant after models were adjusted for confounders (Cusack et al 2017;Richardson et al 2017a).…”

“…Similarly, Calogiuri et al (2016) and Nichani et al (2017) found that socio-economic inequality in mental well-being was significantly lower among respondents reporting good access to a green space compared with those who had less access. Other studies, however, could not find any relationship between health outcome and socio-economic or socio-demographic confounders (Calogiuri et al 2016;Nichani et al 2017) or showed that significant associations between green space and health outcome became non-significant after models were adjusted for confounders (Cusack et al 2017;Richardson et al 2017a). For example, Padilla et al (2016) showed that the significant association between green space and stress disappeared when models were adjusted for socioeconomic confounders.…”

“…The size of the park might be one quality criteria that particularly relates to physical activity and mental health outcomes. It has been argued that larger parks in particular are related to a lower risk of cardiometabolic diseases and greater levels of physical activity, whereas studies that only focus on accessibility distance measures without considering any quality aspect could often not find any significant relationship between health outcomes and urban green space (Michael et al 2014;Nichani et al 2017). Mukherjee et al (2017) found an inverse association between park size and depression.…”

A Systematic Review and Meta-Analysis of Associations between Green and Blue Spaces and Birth Outcomes

“…We examined the effect sizes corresponding to 300 m or the closest buffer size reported, since it captures residential greenness, and also it allowed comparability between studies. A study [37] that measured green space percentage in census unit and did not define buffer distances was also included. Effect estimates based on continuous NDVI were included when other types of exposure (e.g., Q4 vs. Q1) were also reported [10,38].…”

“…Some studies considered the distance to major green spaces in the neighbourhood, either by calculating the linear distance [38,[49][50][51][52][53] or by using street network buffer based on walkable distances [40,49,50,54]. Some studies [27,37,[44][45][46][55][56][57][58][59] used the proportion of green/natural spaces in the total area of census block or zip code as a surrogate for greenness exposure. A number of studies [27,45,51,56] considered public green spaces, while one [46] also included private greenness (e.g., private gardens) in the analysis.…”