Research Abstract
Effects of an Immunomodulating Supplement on Upper Respiratory Tract Infection
Symptoms in Wildland Firefighters
Stephanie G. Harger-Domitrovich, Joseph W. Domitrovich, Brent C. Ruby, FACSM
Montana Center for Work Physiology and Exercise Metabolism, University of Montana,
Missoula MT.
Previous research from our lab has demonstrated increased water turnover and energy
expenditure in the wildland firefighter (WLFF). PURPOSE: The purpose of this study
was to determine the effects of a yeast based (beta glucan) antioxidant supplement on
symptoms of upper respiratory tract infections (URTI) in WLFF. METHODS: Fifty-four
members from eight Type I and II hand crews were recruited from national regions I, III,
V and VI, and served as subjects for this study. In a single blind, random cross-over
design subjects consumed either the beta glucan supplement (βG) or the placebo (P) daily for 14 days, followed by a 3-day wash out period and another 14-day treatment period.
Two cross-sectional, non-incentive based health surveys were completed during and at
the end of each treatment period. Subjects were classified with a URTI if symptoms
occurred on two or more consecutive days. Twenty-four subjects wore accelerometers in
order to quantify activity counts between trials. A Wilcoxon’s signed ranks test was used
to examine differences in URTI symptoms between treatments. A dependent t-test was
used to examine differences in days of work missed during each trial, and a 2-way ANOVA with repeated measures was used to analyze activity counts. Statistics from the
surveys were also performed on the subset of subjects that used the accelerometers.
Significance was set the 0.05 level. RESULTS: There was a trend for the βG trial to demonstrate a lower incidence of URTI symptoms of URTI (p=0.06) compared to
placebo. Perceived overall health was significantly higher in the βG compared to the
placebo trial (p=0.006). No differences were found in days missed from work between
the two trials. In the subset of subjects that wore activity monitors, there were no
differences in the average daily activity over the 14-day work period (154.9+/-508.5 and
180.4+/-534.0 counts/min for the ßG and P trials, respectively). CONCLUSIONS: A
beta glucan antioxidant supplement may help to suppress symptoms of URTI and
increase perceptions of overall health in WLFF during 14 days of arduous wildfire
management.
Supported by Biothera, The Immune Health Company and Air Force Research
Laboratories, FA8650-06-1-679