Am. J. Respir. Crit. Care Med., Vol 154, No. 4, 10 1996, 974-980.
A regression approach to the analysis of serial peak flow among fuel oil ash exposed workers
R Hauser, C Daskalakis and DC Christiani
Department of Environmental Health (Occupational Health Program), Harvard School of Public Health, Boston, Massachusetts, USA.
We investigated the association between exposure to fuel oil ash and acute
airway obstruction in 31 boilermakers and 31 utility workers during the
overhaul of a large oil-fired boiler. Air flow was assessed with
self-recorded serial peak expiratory flow rate measurements (PEFR) using a
mini-Wright meter. Exposure to thoracic particulates with an aerodynamic
diameter of 10 gm or smaller (PM10) was assessed using personal sampling
devices and detailed work diaries. All subjects were male, with an average
age of 43 yr, and an average of 18 yr at their current trade. Average PM10
exposure on work days was 2.75 mg/m3 for boilermakers and 0.57 mg/m3 for
utility workers. Three daily PEFR measurements (start-of-shift,
end-of-shift, and bed-time) were analyzed simultaneously, using Huber
linear regression. After adjustment for job title, welder status, age,
height, smoking, and weld-years, for each mg/m3 increase in PM10, the
estimated decline in PEFR was 13.2 L/min (p = 0.008) for end-of-shift, 9.9
L/min (p = 0.045) for bed-time, and 6.6 L/min (p = 0.26) for start-of-shift
of the following day. This decline of the exposure effect over the 24-h
period that follows was statistically significant (p = 0.004). No other
factors were found to significantly modify the effect of exposure. Our
results suggest that occupational exposure to fuel oil ash is associated
with significant acute decrements in peak flow.
