Increased Impulsivity in Urban-Dwelling Teens: Role of Ambient Air Temperature and Lack of Neighborhood Greenspace

Abstract

Ambient temperature and lack of residential greenspace have been associated with increased externalizing behavior, but the neuropsychological processes are unclear. We conducted a longitudinal analysis to examine the association between temperature, greenspace, and impulsivity in urban-dwelling adolescents. Participants (N=982) of the Risk Factors for Antisocial Behavior Study, a multi-ethnic cohort of Southern California twins/triplets examined in 2000-2014 (aged 9-21 years), each with repeat measures of impulsivity assessed by the Go/No Go test. Ambient temperature near the residence (6.8±3.0 km) were obtained from local Meteorological Information System and Normalized Difference Vegetation Index was used as a proxy for neighborhood greenspace (in 1000-m buffer). A monthly exposure time-series was created and aggregated in short-term (1-, 3-, and 6-month) and long-term (1-, 2-, and 3-year) averages prior to each behavioral assessment. Generalized Poisson mixed models were used to estimate the exposure effects on number of false alarms, adjusting for within-family/-individual correlations and confounders. In separate adjusted analyses, we found average temperature from 1-month to 2-years significantly (all p<0.05) increased impulsivity, while long-term greenspace decreased impulsivity. In models mutually adjusting for temperature and greenspace, the neurotrophic benefits of greenspace disappeared, while the adverse effects of 1- and 3-month temperature remained. These associations could not be explained by sociodemographics, neighborhood quality and socioeconomic characteristics, or season. This is the first epidemiologic evidence supporting the adverse temperature effects on impulsivity, which may contribute to the behavioral effect of diminished greenspace. Future studies need to examine whether increased impulsivity mediates the adverse behavioral effect and how neural networks underlying such neuropsychological processes are perturbed by ambient temperature.