Associations between road traffic noise exposure at home and school and ADHD in school-aged children: the TRAILS study

Environmental noise may play a role in the manifestation and severity of attention deficit/hyperactivity disorder (ADHD) symptoms, but evidence is limited. We investigated the cross-sectional associations between residential and school road traffic noise exposure and ADHD symptoms and diagnosis. The sample included n = 1710, 10-12-year-old children from the TRAILS study in The Netherlands. ADHD symptoms were measured using a DSM-IV based subscale from the Child Behavior Checklist. Children with diagnosed ADHD originated from the clinic-referred cohort. Road traffic noise (L_den) was estimated at the residence and school level, by model calculation. Risk ratios for ADHD symptoms and ADHD diagnoses, and regression coefficients for symptom severity were estimated separately and simultaneously for residential and school road traffic noise. Adjusted multinomial models with residential road traffic noise showed that residential noise was not associated with ADHD symptoms, but was associated with lower risks for ADHD diagnosis (RR = 0.93; 95% CI 0.89, 0.97). Similar associations were observed for models including school road traffic noise and models including both exposures. No clear exposure response relationship was observed for associations between residential or school noise and ADHD symptom severity. We found no evidence for a harmful association between road traffic noise and ADHD. Associations between noise and lower risks for ADHD were observed only in referred cases with a confirmed ADHD diagnosis and may be due to residual confounding or selection bias. Future studies should focus on residential and school noise exposure, and study associations with ADHD symptoms and diagnosis over time.

The association between natural outdoor environments and common somatic symptoms

There is growing evidence that urban natural outdoor environments (NOE) may positively impact health by reducing stress and stress-related symptoms. However, there is limited research investigating this link across a range of NOE indicators. This cross-sectional study investigated the association between neighbourhood NOE (availability, use, and satisfaction with NOE) and common somatic symptoms and the role of potential mediators. Data were analysed from 3481 adults from Barcelona (Spain), Doetinchem (Netherlands), Kaunas (Lithuania) and Stoke-on-Trent (United Kingdom). NOE data were obtained through self-reported data and environmental measurements. Common somatic symptom data were self-reported. Mixed effects regression models were used for analysis, with models adjusted for potential sociodemographic confounders. Higher satisfaction with neighbourhood NOE was associated with lower prevalence of common somatic symptoms (exp(β) 0.97; 95% CI 0.96, 0.98); an association partially mediated by mental health, social cohesion and air quality concern. A longer time spent in NOE was associated with lower prevalence of common somatic symptoms in low socioeconomic status neighbourhoods (exp(β) 0.98; 95% CI 0.96, 1.00). A higher number of neighbourhood green spaces (300m buffer) was associated with higher prevalence of common somatic symptoms (exp(β) 1.03; 95% CI 1.00, 1.05). No statistically significant associations were found for other NOE indicators. Study findings suggest that higher satisfaction with NOE may be associated with lower prevalence of common somatic symptoms, with mental health, social cohesion and concern about air quality playing partial mediating roles. Little evidence was found of an association between objective NOE measurements and common somatic symptoms, underlining the importance of perceptions of NOE for conferring health benefits.

Noise and somatic symptoms: A role for personality traits?

OBJECTIVES

We investigated the role of a stress-sensitive personality on relations between noise, noise annoyance and somatic symptom reporting. First, we investigated the cross-sectional association of road traffic noise exposure and somatic symptoms, and its modification by hostility and vulnerability to stress. Second, we investigated the cross-sectional association of noise annoyance from eight sources (e.g. road traffic, aircraft, neighbours) and somatic symptoms, and it's confounding by hostility and vulnerability to stress.

METHODS

Data were obtained from LifeLines, a general population cohort from the Netherlands. Road traffic noise was estimated using the Common Noise Assessment Methods in Europe (CNOSSOS-EU) noise model. Noise annoyance, hostility, vulnerability to stress, and somatic symptoms were assessed with validated questionnaires.

RESULTS

Poisson regression models adjusted for demographic and socioeconomic variables indicated no association of noise exposure and somatic symptoms (incidence rate ratio (IRR) 1.001; 95% confidence interval (CI) 1.000-1.001; n=56,937). Interactions of noise exposure and hostility and vulnerability to stress were not statistically significant. Small positive associations were found for noise annoyance from each of the eight sources and somatic symptoms, when adjusted for demographic and socioeconomic variables (e.g. for road traffic noise annoyance IRR 1.014, 95% CI 1.011-1.018; n=6177). Additional adjustment for hostility and vulnerability to stress resulted in small decreases of the IRRs for noise annoyance from each of the eight sources, but the associations remained statistically significant.

CONCLUSIONS

Personality facets hostility and vulnerability to stress did not modify the relation between road traffic noise exposure and somatic symptom reporting, or confound relations between noise annoyance and symptoms.