Clinical trial NCT05753254: Effect on Markers of Cardiovascular, Reproductive and Cancer Risk From Firefighting Training
Official title: Effect on Markers of Cardiovascular, Reproductive and Cancer Risk From Firefighting Activities - a Study Under Different Training Methods
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Reactive Hyperemia
Micro RNA
Heart Rate Variability
DNA Strand Breaks
Oxidative Stress
Heat Stress
Keywords: Comet assay
8-oxodG
PAH CALUX
hydroxyl-PAHs and nitro-PAH metabolites
microRNA
AhR activation
scrotal temperature
core body temperature
urine
serum
blood
follicle-stimulating hormone
inhibin B
EndoPAT
Lead sponsor: National Research Centre for the Working Environment, Denmark
Sponsor class: OTHER_GOV
Collaborators: name: University of Copenhagen
name: University Hospital Bispebjerg and Frederiksberg
name: Rigshospitalet, Denmark
First posted: 2023-03-03
Enrollment: 35
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Participants will perform firefighting full day exercises under 3 different conditions (without fire, under wood fire and under gas fire), sessions which will occur with weeks in between, and biological markers will be assessed and compared in relation to a baseline session, where the participants are having theoretical classes.
Primary purpose: BASIC_SCIENCE

Brief summary: Epidemiological studies based on Danish registries have observed that Danish male firefighters have more cardiovascular disease, infertility diagnose and a trend to increased risk of cancer than other Danish employed males. Firefighting activities include a combination of stressors such as strenuous work under heat, smoke and soot known to be able to affect cardiovascular and reproductive health, with smoke and soot also being known to increase the risk of cancer.

The training facilities of real-fire extinguishing exercises in Denmark operate using wood or natural gas fire, which will have differential gradients of smoke, soot and possibly heat. The investigators will use different training conditions to create gradients of the different stressors and investigate health effects thereof. With this approach, the investigators expect to be able to evaluate the individual contribution of the different stressors in markers of cardiovascular, cancer and reproductive health risk. The project will include approx. 35 young conscript participants on a firefighting course, followed in four sessions, three firefighting training sessions under different fire conditions (no fire, wood fire and gas fire) and one control scenario.

Detailed description: The study methodology is based on a crossover design on firefighting training under different conditions, with characterization of exposure and assessment of cardiovascular, cancer and reproductive effect biomarkers. The study will be performed in cooperation with the Danish Emergency Management Agency.

The study will have one baseline session, while conscripts are in a classroom, and three sessions of firefighting-related exercises under different fire conditions, used currently in firefighting training programs in Denmark. The three firefighting training sessions will be controlled for equivalent work exercise using full protective gear and under different ambient conditions of firefighting training:

* Firefighting equivalent work (no fire), with exercises performed in a clean environment, without fire (no ambient temperature, soot or smoke). This type of exercise precedes or complements the training under real fire conditions.
* Firefighting under wood fire (wood fire), with exposure to ambient heat, smoke and soot. This is the most common training scenario used by Danish Emergency Management Agency training centres.
* Firefighting under gas fire (gas fire), with exposure to ambient heat, and expectably less smoke and soot than with wood fire. These conditions are used in some Danish training centres, with logistical advantages (ease of turning or putting out the fire and managing the fire fuel) and unknown effect relating to exposure prevention (smoke and soot).

The order of the firefighting sessions will be as randomized as possible, and according to a selection of three sequence order options (no-wood-gas; wood-gas-no and gas-wood-no). Each campaign (corresponding to each rescue course) would desirably have one of these session sequences. It is not possible to blind the participants to the different scenarios, neither the field staff, but all the samples will be blinded for the subsequent laboratory analysis. The training sessions will have 1-3 weeks in between (accordingly with programmatic educational course schemes).

Eligibility criteria: The participants will be volunteers (both males and females) recruited among conscripts in training in a desirable involved group up to 35 individuals.

Inclusion Criteria:

* legally competent,
* conscript subjects following a Rescue Specialist Educational course

Exclusion Criteria:

* current smoking status,
* pregnancy,
* on prescribed medication,
* body mass index (BMI) bellow 19 or over 30,
* alcohol or drug abuse.

Primary outcomes:
measure: Change in reactive hyperemia index - afternoon
timeFrame: Baseline afternoon measurement, afternoon measurement immediately after firefighting without fire, afternoon measurement immediately after firefighting under wood fire and afternoon measurements immediately after firefighting under gas fire
measure: Change in reactive hyperemia index - morning
timeFrame: Baseline morning measurement, morning measurement in subsequent day after firefighting without fire, morning measurement in subsequent day after firefighting under wood fire and morning measurement in subsequent day after firefighting under gas fire
measure: Change in Heart Rate Variability pNN50 at rest - afternoon
timeFrame: Baseline afternoon measurement, afternoon measurement immediately after firefighting without fire, afternoon measurement immediately after firefighting under wood fire and afternoon measurements immediately after firefighting under gas fire
measure: Change in Heart Rate Variability pNN50 at rest - morning
timeFrame: Baseline morning measurement, morning measurement in subsequent day after firefighting without fire, morning measurement in subsequent day after firefighting under wood fire and morning measurement in subsequent day after firefighting under gas fire
measure: Change in Heart Rate Variability RMSSD at rest - afternoon
timeFrame: Baseline afternoon measurement, afternoon measurement immediately after firefighting without fire, afternoon measurement immediately after firefighting under wood fire and afternoon measurements immediately after firefighting under gas fire
measure: Change in Heart Rate Variability RMSSD at rest - morning
timeFrame: Baseline morning measurement, morning measurement in subsequent day after firefighting without fire, morning measurement in subsequent day after firefighting under wood fire and morning measurement in subsequent day after firefighting under gas fire
measure: Change in Heart Rate Variability ratio LF/HF at rest - afternoon
timeFrame: Baseline afternoon measurement, afternoon measurement immediately after firefighting without fire, afternoon measurement immediately after firefighting under wood fire and afternoon measurements immediately after firefighting under gas fire
measure: Change in Heart Rate Variability ratio LF/HF at rest - morning
timeFrame: Baseline morning measurement, morning measurement in subsequent day after firefighting without fire, morning measurement in subsequent day after firefighting under wood fire and morning measurement in subsequent day after firefighting under gas fire
measure: Changes in levels of 8-oxodG excretion in first morning urine
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in levels of DNA strand breaks in peripheral blood mononuclear cells
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in core temperature
timeFrame: Baseline day, during the day of firefighting without fire, during the day of firefighting under wood fire and during the day of firefighting under gas fire.
measure: Changes in scrotal temperature
timeFrame: Baseline day, during the day of firefighting without fire, during the day of firefighting under wood fire and during the day of firefighting under gas fire.
measure: Changes in scrotal thermoregulation
timeFrame: Baseline day, during the day of firefighting without fire, during the day of firefighting under wood fire and during the day of firefighting under gas fire.
measure: Changes in levels of circulating micro RNA
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in urinary potency of AhR activation
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in potency of AhR activation from skin deposits
timeFrame: Baseline, before firefighting without fire, immediately after firefighting without fire, before firefighting under wood fire, immediately after firefighting under wood fire, before firefighting under gas fire, immediately after firefighting under gas
Secondary outcomes:
measure: Changes in levels of follicle-stimulating hormone in serum
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in levels of serum inhibin B
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in urinary levels of PAH metabolites excretion
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in levels of PAHs in skin wipes from the neck
timeFrame: Baseline, before firefighting without fire, immediately after firefighting without fire, before firefighting under wood fire, immediately after firefighting under wood fire, before firefighting under gas fire, immediately after firefighting under gas
measure: Changes in FEV1 spirometric measurements
timeFrame: Baseline, immediately after firefighting without fire, immediately after firefighting under wood fire and immediately after firefighting under gas fire
measure: Changes in FVC spirometric measurements
timeFrame: Baseline, immediately after firefighting without fire, immediately after firefighting under wood fire and immediately after firefighting under gas fire
measure: Changes in PEF spirometric measurements
timeFrame: Baseline, immediately after firefighting without fire, immediately after firefighting under wood fire and immediately after firefighting under gas fire
measure: Changes in FEV1/FVC ratio from spirometric measurements
timeFrame: Baseline, immediately after firefighting without fire, immediately after firefighting under wood fire and immediately after firefighting under gas fire
measure: Changes in blood troponin levels
timeFrame: Baseline, before firefighting without fire, day after firefighting without fire, before firefighting under wood fire, day after firefighting under wood fire, before firefighting under gas fire, day after firefighting under gas fire
measure: Changes in work load measured by muscle activity
timeFrame: Baseline day, firefighting without fire day, firefighting under wood fire day and firefighting under gas fire day
Other outcomes:
Locations:
city: Copenhagen
country: Denmark
facility: The National Research Centre for the Working Environment
city: København Ø
country: Denmark
facility: Maria Helena Guerra Andersen
Study officials:
affiliation: The National Research Centre for the Working Environment (NRCWE)
name: Maria Helena G Andersen, PhD
role: PRINCIPAL_INVESTIGATOR
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