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[ Recorded presentation ] Recorded presentation

Are peak expiratory flow rates of asthmatics impaired by levels of SO2 in the EPA 'safe' zone?

Stanley H. Weiss, MD, Epidemiology, UMDNJ - New Jersey Medical School & NJ School of Public Health, 30 Bergen St, Bldg 16, Suite ADMC 1614, Newark, NJ 07107-3000, Azadeh Tasslimi, BA, Dept. Preventive Medicine & Community Health / Epidemiology, UMDNJ - New Jersey Medical School, 30 Bergen St, Bldg 16, Suite ADMC 1614, Newark, NJ 07107-3000, 973 972-7721, tassliaz@UMDNJ.EDU, Amy L. Davidow, PhD, Department Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School, 185 South Orange Ave, Newark, NJ 07103-2714, and Clifford P. Weisel, PhD, Environmental and Occupational Health Sciences Institute, UMDNJ - EOHSI /Robert Wood Johnson Medical School & NJ School of Public Health, 170 Frelinghuysen Road, EOSHI 3-314, Piscataway, NJ 08855.

In spring 2003, a prospective study in northwestern NJ was conducted. Participants recorded daily symptoms, medication use, exposures and PEFR via Internet with ongoing monitoring. Average hourly air concentrations of SO2 were determined. 27 (59% female) students, ages 9-17 years (mean=12.9), participated; mean study participation 115 days. PEFR recorded 88% of participant-days (2205/3098). Mean PEFR 346LPM (range=200-710).

A linear mixed-effects model with longitudinal data and random intercept was used (SAS-ProcMIXED). The outcome measure was logarithm(ln) of PEFR. Model building included stepwise assessments of effects of peak (maximum hourly mean) and mean SO2 (linear, quadratic, cubic terms using orthogonal polynomials), peak and mean 1- and 2-day lagged SO2, mean daytime (7AM-6PM) temperature, age, gender, and same-day medication use.

Controlling for daytime temperature and same-day medication use, there is an inverse relationship between ln(PEFR) and peak same-day SO2 and mean prior-day SO2. The effect of prior-day mean SO2 is roughly 10-fold the effect of peak same-day SO2 value (coefficients -0.00112 vs. 0.00015), controlling for temperature and medication use. Increase of 10 parts per billion (ppb) in mean prior-day SO2 reduced PEFR 1.2%. 10ppb increase in peak same-day SO2 reduced PEFR 0.15%. Daily mean and peak SO2 ranged up to 21ppb and 131ppb, respectively. The model would predict 4% change in PEFR across entire population for this range. Prior-day mean SO2 values ranged up to 20.5ppb, just 15% of national mandated 24-hour toxicity standard (140ppb). Thus, the effect observed is far below current environmental standards. Further analyses including additional environmental measures are ongoing.

Learning Objectives:

Keywords: Asthma, Air Pollutants

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.

[ Recorded presentation ] Recorded presentation

Public Health in the Environment 1

The 132nd Annual Meeting (November 6-10, 2004) of APHA