Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
| NCT number |
NCT05256966 |
| Other study ID # |
A19-131 |
| Secondary ID |
|
| Status |
Enrolling by invitation |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
November 1, 2021 |
| Est. completion date |
July 30, 2024 |
Study information
| Verified date |
April 2024 |
| Source |
HealthPartners Institute |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The purpose of the study is to evaluate whether sauna use after active-duty firefighting is
effective in reducing exposure to certain harmful chemicals called polycyclic aromatic
hydrocarbons (PAHs). PAHs are found in soot and several types are known to be carcinogens.
This study is a cross-sectional pilot study that will be performed in active-duty
firefighters. The firefighters will be subdivided into those who will use a sauna immediately
after fighting a fire versus those who will not, the latter of which will serve as a
metabolism control group. There will thus be two comparison groups within the study: 1)
active-duty firefighters using a sauna after fire suppression (sauna group); 2) active-duty
firefighters not using a sauna after fire suppression (metabolism control).
Description:
Study Rationale
Firefighters are exposed to toxic materials during fire suppression activities and have a
higher rate of cancer than the general population, despite a high level of physical fitness.
Some studies suggest the use of sauna (infrared or traditional) may increase excretion of
harmful and toxic chemicals. Biomonitoring is the measure of chemicals or metabolites present
in the human body and is used to evaluate exposure. This proposed study is a biomonitoring
pilot study to evaluate the effectiveness of use of a sauna at modulating excretion of select
classes of chemicals from firefighters.
One of the most well-established occupational hazards to firefighters is soot, the black
particulate matter generated during combustion of organic materials. The chemical composition
of soot varies based on the original material undergoing combustion, but the primary organic
components of soot comprises a class of compounds known as polycyclic aromatic hydrocarbons
(PAHs), which includes many carcinogens.3 PAH exposure can be measured through the analysis
of hydroxy metabolites (OH-PAHs) in urine, the methods of which are well-established and have
been conducted in the general population and in firefighters in several studies.4-6 The
existing literature evaluating excretion of compounds via sweat is suggestive that some
compounds may be more quickly eliminated by inducing sweating, such as via use of the sauna.
There is a lack of standardization in sweat biomonitoring and further development of these
methods is still needed.15 This proposed pilot study will contribute to the biomonitoring
literature particularly in the firefighting population by addressing the gaps in knowledge of
whether PAHs are excreted in sweat, and whether use of a sauna can affect rates of PAH
excretion in firefighters.
Study Objective(s)
Aim 1. This study aims to demonstrate that sauna use immediately after active-duty
firefighting will result in measurable (above the level of detection) PAH biomarkers in
sweat.
Aim 2. This study secondarily aims to demonstrate that sauna use immediately after
active-duty firefighting will result in significantly different mean levels of PAH biomarkers
in urine as compared to no use of a sauna.
Study Design
This study is a cross-sectional pilot study that will be performed in active-duty
firefighters. The firefighters will be subdivided into those who will use a sauna immediately
after fighting a fire versus those who will not, the latter of which will serve as a
metabolism control group. There will thus be two comparison groups within the study: 1)
active-duty firefighters using a sauna after fire suppression (sauna group); 2) active-duty
firefighters not using a sauna after fire suppression (metabolism control).
Subject Population
This study's population is established based on convenience, as the St. Paul Fire Department
already has a single station where a sauna has been installed for several decades. The study
intervention population will include St. Paul Firefighters working within Station 4, the only
station at present where a sauna is installed. The metabolism control group will include St.
Paul Firefighters working in stations 7 and 17, who may be called to actively perform at the
same fires as the firefighters at Station 4.
St. Paul Firefighters work full-time, on 24-hour shifts, with three different shifts
delineated. Station 4 comprises 9 firefighters across 3 shifts, totaling 27 firefighters. The
study will be opened to all firefighters in the St. Paul Fire Department, and the Department
Chief and department staff will work to schedule individuals enrolled into the study to work
at Station 4, 7, or 17.
Inclusion criteria:
1. Willingness to collect urine samples before, during, and/or after work shift
2. Willingness to refrain from eating barbecued or smoked foods during the duration of the
study
3. Willingness to use a sauna after active fire suppression and to collect sweat samples at
that time
Exclusion criteria:
1. Declined participation in the study
2. Unwilling or do not agree to complete all data collection components of the study
3. Limited from active-duty firefighting (regardless of reason)
4. Medical conditions precluding the use of a sauna
5. Pregnancy (as sauna use is contraindicated in pregnancy)
Number Of Subjects
A minimum of 20 people (10 per group) and a maximum of 60 people (30 per group) will be
recruited. As this is a convenience sample, and as not all possible individuals within each
sample subpopulation may opt to participate in this study, these samples may be drawn from
the same individuals after different active fire runs. Each participant may be asked to
provide biosamples up to four times.
The sauna group will comprise 30 urine and 30 sweat samples, whereas the metabolism control
group will comprise 30 urine samples, totaling 90 study samples for analysis. The study
sample size is limited on resources available for conducting this study and processing
samples, and is not intended to meet statistical significance as much as demonstrate
differential exposures to PAHs and metabolism of PAHs in the context of this pilot study.
Study Duration
Each subject will be asked to contribute biosamples up to four times. The biosample
collection phase is expected to last approximately three months.
The entire study is expected to last 12 months. Study Phases
1. Screening: screening for eligibility and obtaining consent
2. Enrollment: Collection of demographic info and instruction on sample collection
3. Data Collection: Participants collect bio-samples
4. Analysis: MDH analyses of lab samples; statistical analysis to determine study outcomes
5. Results: results provided to participants and analyzed to determine study results
6. Publication: writing and publication of manuscript Statistical And Analytic Plan
Statistical testing will comprise a two-tailed t-test (or non-parametric equivalent test
if conditions of normality are not met), where statistical significance will be
considered at a p-value of <= 0.05.
Aim 1. Detection of PAH parent compounds and metabolites in sweat. Number of detections will
be descriptively reported in addition to means and standard deviations of those samples above
the report levels.
Aim 2. Comparison of urine PAH biomarkers in sauna group versus metabolism control group. A
statistical test of means will be performed on the mean levels of urine PAH biomarkers in the
sauna group and the metabolism control group.
The Investigators will use a chi-square test to compare the baseline characteristics of the
two groups. If the investigators find a significant difference, the investigators will plan
on adjusting for the role of the participant in analysis. Similarly, if the investigators
find other baseline characteristic(s) to significantly differ between groups, the
investigators will adjust for those variables using multivariate regression that includes
treatment group as a variable (Sauna, Metabolism) along with the variables that are
unbalanced between the groups.
Statistical analysis will be conducted by the principal investigator (Dr. Zeke McKinney) with
the assistance of the Research Methodology Group at the HealthPartners Institute.
