Air Pollution and Public Health

• Limited time, we will discuss:

• Asthma

• Ischemic Stroke

• Otitis Media

• Myocardial Infarction

Co-Authors for many projects

• Leonard Bielory, MD

• Van Dunn, MD MPH

• Susan Meehan RPh

• William Gauff, EMT

• Yu-Feng Chan, MD

• Hosseinali Shahidi, MD MPH

• Ronald B. Low MD

Most Data from New York City

• Hospital data available to me now from NYC Health and Hospitals Corporation (HHC)

• Pollution data from EPA

• Weather data from NWS

• Pollen data from Dr. Bielory

• NJ, NYC Issues pretty much the same

• Inferred NJ calculations

Similar atmospheric Conditions: NJ & NYC

• Weather

• Pollution

• Pollens: Only measured in NJ

NOx: NY and NJ

• Not as close as temperature, but clearly related (p<.0001)

• The closer to NYC, the tighter the relationship

• Generally, NJ levels only slightly lower than NYC levels: both 0.01-0.20 ppm

Asthma

• One of the most studied diseases related to air pollution

• Our model is conservative, ascribing changes in asthma rates to:

• Time (seasons)

• Then weather and airborne allergens

• Last pollution effects

Basic Statistics

• NJ: 16,390 admissions in 2003

• HHC: 15,914 admission in 2003

• HHC: 59,865 ED Visits for asthma in 2003

Other effects

• Confounded with temperature, hard to show graphically in 3 or more dimensions

Model

• Time modeled first: Autoregressive effects of 1,2 and 7 days earlier; moving average effects of 6 and 365 days earlier

• 4 visits/day increase with weed pollen count increase of 1000

• 100 more URI visits1 more asthma

• 10μg/m3 particles<10μ, 2 more visits

Rough estimate of the effect small particles on NJ asthma

• Assuming causality

• Conservative Model

• 900 additional admissions in 2003

• 3000 additional ED Visits in 2003

Ischemic Stroke

• Not as seasonal/time dependent as asthma

• Weekly effect and holiday effects. Conservatively, we adjust for them before looking for a pollution effect.

Ischemic Stroke

• NJ 2003:– 21,899 Admissions for all ischemic events

• NYC study average 9.34 strokes/day*2556 days. In 2003:– 2615 Admissions for all ischemic events– 1338 Ischemic Strokes

• Entire 8 year NYC: 23,888 ischemic strokes

Weekend, Holiday Effects

• Holiday=New Years, Martin Luther King, President’s Day, Easter, Memorial Day, July 4, Labor Day, Thanksgiving, Christmas

• Average 0.9 fewer strokes (0.7-1.3) on weekends (p<0.0001)

• Average 1.1 fewer strokes (0.5-1.6) on holidays, p=.0002

White Stroke and Pollution

• Probably a real NOx effect, p=0.0455.

• Best modeled as a logarithmic effect (Normality)

• Average effect 0.47 strokes/day, 2118 strokes during study, adjusted for weekends, holidays and temperature

• Assuming causality, ESTIMATED 2003 NJ effect: 1,900 strokes; 95th % 112 strokes

Otitis Media

• Like asthma, seasonal and weekly effects

• We looked at clinic visits as well as ED visits

• Again, we model conservatively

Otitis visits: Basic Statistics

• HHC:– 809,252 visits during study– Average 181/day (lots of seasonal variability)– 2003: 55,533 visits

• NJ: We do not have outpatient data

Otitis Model

• Except for NOx, I will not discuss coefficients: Log transform makes interpretation difficult– Temperature: lower is worse, p=0.0144– Weekends better than weekdays, p<.0001– Holidays better than workdays, p<.0001– 365 day seasonal pattern, p<.0001– URIs make otitis worse, p<.0001

Effect of NOx on NJ Otitis

• The log*log effect means that high levels are more problematic than low levels

• Assuming Causality: Lowering NOx to low levels should reduce OMV visits by between 2% to 8%, depending on starting levels and other assumptions.

Model Works Prospectively

Myocardial Infarction

• NJ in 2003: 22,464

• HHC: – in 2003: 2,623– Entire study: 22,371 (very close to NJ 2003)

MI Model

• No significant seasonal effect• Worse on weekdays (p<.0001)• Worse as temperature drops, p<.0001• No significant snow effect• Curvilinear exacerbating effect of NOx,

worse at highest levels, p=0.0051. The effect is statistically small except until around the top 5th% (>.14ppm). Difficult to accurately estimate effect.

Reservations

• Observational Studies– Limited to temperature and pollutant ranges

we observed– Diagnostic accuracy dependent upon

clinicians and coders– Pollutants co-correlated with each other, with

weather, seasons, ?weekday traffic– These studies do not prove causality– Pollutant effects may be underestimated, they

were always added last to model

Overall Conclusions

• Air pollution, at current levels, has some measurable relationship to asthma, otitis media, ischemic strokes and MI.

• NOx and suspended particles have the most widespread associations.

• If you assume causality, the health effects are significant

Questions?