Investigating the association between early life exposure to PM<sub>2.5</sub> and ADHD prescribing in childhood: a longitudinal seven-year follow-up study — The Association Specialists
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  3. Investigating the association between early life exposure to PM2.5 and ADHD prescribing in childhood: a longitudinal seven-year follow-up study

Investigating the association between early life exposure to PM2.5 and ADHD prescribing in childhood: a longitudinal seven-year follow-up study (23518)

Richard J Martino 1 , Myriam Ziou 1 2 3 , Caroline X Gao 2 3 4 , Nicolas Borchers-Arriagada 1 5 , Marita Dalton 1 , Fay H Johnston 1 5 , Lieke EJM Scheepers 1
  1. Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
  2. Centre for Youth Mental Health, The University of Melbourne, Parkville, Victoria, Australia
  3. Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia
  4. School of Public Health and Preventative Medicine, Monash University, Melbourne, Victoria, Australia
  5. Centre for Safe Air, NHMRC Centre for Research Excellence, Hobart, Tasmania, Australia

Background

Epidemiological studies in countries with relatively high concentrations of air pollution have evaluated the association of particulate matter and Attention Deficit Hyperactivity Disorder (ADHD) with mixed results. Here, we examine the association between fine particulate matter (PM2.5) exposure for the first three years after birth and ADHD medication prescribing later in childhood in a low air pollution setting.

Methods

Perinatal data of 260,408 children born in Victoria, Australia between March 2012 and December 2015 were linked to the Australian Pharmaceutical Benefits Scheme dispensing records from 2012 to 2022 to identify dispensed ADHD medication and adjust for key confounding factors. Annual PM2.5 exposure was estimated using satellite-based land use regression and random forest models. We conducted mixed effects logistic regression models with a random intercept for the region of residence.

Results

A total of 9,121 (3.5%) children were prescribed ADHD medication by the age of seven.  Associations between PM2.5 exposure and ADHD dispensation differed by regional and urban areas. In regional areas, we found a positive association between PM2.5 exposure and ADHD prescriptions during childhood (aOR = 1.12 per 1 µg/m3 increase, 95% CI 1.06-1.19), while no association was found in urban areas (aOR = 0.98 per 1 µg/m3 increase, 95% CI 0.93-1.03).

Conclusion

Our findings suggest that the association between early life PM2.5 exposure and ADHD may differ between regional and urban environments even in low air pollution settings. This highlights the complexity of air pollution effects on neurodevelopment and suggests that exposure context may be important. These results support continued efforts to reduce PM2.5, even in low concentration settings, and strengthen public health messaging for parents and healthcare providers. Further research is warranted to better understand why associations may vary across geographic settings.