Residential green space and mental health in a prospective cohort of tree pollen allergy patients

Abstract

GREEN, AIR, LMIC: PECHAKUCHA COMES TO ISEE! Johan Friso Foyer, Floor 1, August 27, 2019, 10:30 AM - 12:00 PM BACKGROUND: Green space may improve human health, for example by promoting physical activity and by reducing stress. Conversely, green space may exacerbate the burden of allergic disease by emitting aeroallergens. OBJECTIVES: We examined whether residential exposure to green space had impacts on mental health in adults sensitized to tree pollen allergens during two airborne tree pollen seasons (2017, 2018). METHODS: In this cross-sectional study, data from a prospective Belgian cohort of tree pollen allergy patients (N = 88) were analyzed using Poisson regression. The primary outcome was self-reported mental health, assessed with the standardized 12-item General Health Questionnaire (GHQ-12). Predictors of distress included perceived presence of allergenic trees near the residence (hazel, alder, birch) and cumulative green space area within 1 km distance. Results were compared to distress in a representative sample of the general population (N = 2,467). RESULTS: Short-term distress [mean GHQ-12 score 2.1 (95% confidence interval 1.5–2.7)] was higher in the study population than in the general population [1.5 (1.4–1.7)]. Distress increased with BMI {adjusted odds ratio [95% confidence interval] 1.06 (1.02–1.10)}, smoking [2.10 (1.02–4.38)] and perceived presence of allergenic trees [2.04 (1.36–3.07)]. Physical activity [>1×/week 20 minutes of activity vs. less: 0.59 (0.42–0.85)], age [0.97 (0.96–0.99)] and green space [≥ 3m tall, per combined surface area of 10 ha: 0.94 (0.90–0.99); < 3m tall, per 10 ha: 0.85 (0.78–0.93)] had protective effects against short-term distress. CONCLUSIONS: The perceived proximity to allergenic tree species modulates the protective effect of residential green space against short-term emotional distress during the airborne pollen season. Negative expectations of adults sensitized to tree pollen allergens regarding exposure to allergenic tree species may affect short-term mental health outcomes during the pollen season.