Background
Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopment disorder that typically manifests in early childhood and persists through adulthood. A diagnosis of ADHD is characterized by inattention, hyperactivity, and impulsivity. ADHD is generally diagnosed following concern by a parent, teacher or school official. The exact etiology of ADHD is unknown, but the following factors can contribute to the likelihood of a diagnosis: genetic factors, male gender, environmental factors such as preterm birth and maternal smoking. In addition, biopsychosocial risks such as low income, family dysfunction, and urban residence have also been suggested.
Objective
A pilot study to determine if there is non-random geographic distribution of ADHD in Milwaukee County, Wisconsin.
Design
- Cross section study
- Children ages 5-17
- Continuity care at three academic family medicine clinics in Milwaukee County
- Presenting 8/16/04 - 8/15/06
- With ADHD (N = 80)
- Without ADHD (N = 1,144)
Analysis
- Street addresses and demographic data geocoded with Map Marker Plus
- Mapped using ARC-GIS
- CrimeStat III used for spatial modeling, including mapping of ratio of case/control densities
- Univariate analysis: chi-square or Mann-Whitney U test
- Multivariate: binary logistic regression
Results
- All non-white ethnicities less frequently diagnosed with ADHD (p values < 0.02)
- 75% ADHD cases were male
- No apparent relationship to parks, freeway, toxic waste sites, and waterways
- Multivariate Analysis
- Zip code of residence and gender were significant risk factors (p values = 0.000)
- Race/ethnicity no longer significant
Observation
- ADHD cases overrepresented in south and western suburban school districts, compared to city of Milwaukee
- Cases were 7-fold above expected in zip code adjacent to major airport
Synthesis
- ADHD cases are non-randomly distributed in this Milwaukee County sample
- Certain suburban school districts may be more aggressive/efficient in referring children for ADHD diagnosis
- Could environmental features such as airport noise corridors play a role?
Limitations
- Sample size
- Single geographic location
- Interviews not conducted
Conclusion
Further studies are needed to confirm these very preliminary findings.
Project Investigators
- Jonathan Weimer, UWM Pre-Med Student
- Dennis Baumgardner, M.D.
- Andrea Schreiber, M.A.
