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.
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