Greenness such as trees, plants, and shrubs may positively influence mental and physical health, but the relationship between greenness and asthma is poorly understood. Because asthma is the most prevalent child respiratory disease internationally, elucidating the role of greenness may substantially benefit public health. The purpose of this systematic review was to synthesize findings related to effects of greenness on asthma in children. Following PRISMA guidelines, six databases were searched for international publication of primary research results relevant to the relationship between greenness and child asthma. Of 82 initial results, seven articles remained after removal of duplicates and applying exclusion criteria. Six reported no direct association between greenness and child asthma, while one found increased greenness protective for asthma. None found a negative direct association between greenness and child asthma. Evidence supported benefits of greenness on child asthma through mediation of factors such as exposure to tobacco smoke, high traffic volume, and difficult family relationships. Even without a direct association, greenness can be considered a public health asset as it may mediate other factors contributing to asthma in children. Public health nurses can use these findings to educate clients and partners while advocating for policies to protect greenness.

Background: While benefits of greenness to health have been reported, findings specific to child respiratory health are inconsistent.Methods: We utilized a prospective birth cohort followed from birth to age 7 years (n = 617). Residential surrounding greenness was quantified via Normalized Difference Vegetation Index (NDVI) within 200, 400, and 800 m distances from geocoded home addresses at birth, age 7 years, and across childhood. Respiratory health outcomes were assessed at age 7 years, including asthma and lung function [percent predicted forced expiratory volume in the first second (%FEV₁), percent predicted forced vital capacity (%FVC), and percent predicted ratio of forced expiratory volume in the first second to forced vital capacity (%FEV₁/FVC)]. We assessed associations using linear and logistic regression models adjusted for community deprivation, household income, and traffic-related air pollution. We tested for effect measure modification by atopic status.Results: We noted evidence of positive confounding as inverse associations were attenuated upon adjustment in the multivariable models. We found evidence of effect measure modification of NDVI and asthma within 400 m at age 7 years by atopic status (p = 0.04), whereby children sensitized to common allergens were more likely to develop asthma as exposure to greenness increased (OR = 1.3, 95% CI: 0.9, 2.0) versus children not sensitized to common allergens (OR = 0.8, 95% CI: 0.5, 1.2). We found consistently positive associations between NDVI and %FEV₁and %FVC which similarly evidenced positive confounding upon adjustment. In the adjusted regression models, NDVI at 7 years of age was associated with %FEV₁(200 m: β = 2.1, 95% CI: 0.1, 3.3; 400 m: β = 1.6, 95% CI: 0.3, 2.9) and %FVC (200 m: β = 1.8, 95% CI: 0.7, 3.0; 400 m: β = 1.6, 95% CI: 0.3, 2.8; 800 m: β = 1.5, 95% CI: 0.1, 2.8). Adjusted results for %FEV₁/FVC were non-significant except exposure at birth in the 400 m buffer (β = 0.81, 95% CI: 0.1, 1.5). We found no evidence of effect measure modification of NDVI by atopic status for objective measures of lung function.Conclusion: Sensitivity to allergens may modify the effect of greenness on risk for asthma in children but greenness is likely beneficial for concurrent lung function regardless of allergic status.

Polybrominated diphenyl ethers (PBDEs) are persistent environmental pollutants used as flame retardants. Gestational PBDE exposure has been associated with a variety of behavior problems in children, but little is known about its impact into adolescence, particularly on social skills, which are important for achieving social competence, establishing identity, and forming lasting relationships. We investigated associations between gestational exposure to PBDEs and social skills and problem behaviors in early adolescence in a longitudinal pregnancy and birth cohort in Cincinnati, Ohio (recruited 2003–2006). We measured maternal serum concentrations of five PBDE congeners during gestation. At age 12, we collected social skills and problem behaviors scores from 243 adolescents and their caregivers using the Social Skills Improvement System (SSiS). We used multivariable linear regression models to estimate associations between maternal PBDE concentrations and SSiS outcomes, controlling for potential covariates. We report associations for the five congeners and a summary exposure variable (∑₅BDE: the sum of BDE- 28, 47, 99, 100, and 153, n=197). We found sex-specific associations of ∑₅BDE concentrations with adolescent-reported Problem Behaviors (∑₅BDE × sex p_int=0.02) and caregiver-reported Social Skills (∑₅BDE × sex p_int=0.02) despite higher ∑₅BDE exposure among females (Male GM=35.30 ng/g lipid, GSE=1.09; Female GM=40.15 ng/g lipid, GSE=1.10). In sex-stratified models, log₁₀ transformed data revealed increased maternal ∑₅BDE concentration among males was associated with decreased caregiver-reported Social Skills composite score (β=−10.2, 95% CI: −19.5, −1.0), increased adolescent-reported Problem Behaviors composite score (β=12.1, 95% CI: 5.4, 18.8), and increased caregiver-reported Problem Behaviors composite score (β=6.2, 95% CI: 0.7, 11.7). Further analysis on SSiS subscales revealed similar patterns in significant associations among males. There were no statistically significant associations in stratified models among females. We found gestational PBDE exposure in males was associated with poorer behavioral outcomes, extending previous findings among this cohort into early adolescence.

While the literature supports positive associations between nature and adolescent mental health, mechanisms are not well understood, and assessment of nature varies widely among existing studies. To partner with the most insightful informants, we enrolled eight adolescent participants from a conservation-informed summer volunteer program, applying qualitative photovoice methodology to understand their use of nature to relieve stress. Across five group sessions, participants identified four themes: (1) Nature shows us different aspects of beauty; (2) nature helps us relieve stressful experiences by balancing our senses; (3) nature gives us space to find solutions; and (4) we want to find time to enjoy nature. At the conclusion of the project, youth participants reported that the research experience was overwhelmingly positive, enlightening, and inspired appreciation of nature. We found that, while our participants unanimously reported that nature relieved their stress, prior to this project, they were not always intentional in seeking time in nature for this purpose. Through the photovoice process, these participants noted the usefulness of nature for stress relief. We conclude with recommendations for leveraging nature to decrease adolescent stress. Our findings are relevant for families, educators, students, healthcare professionals, and anyone who works with or cares for adolescents.