Health Interventions for Firefighter Cardiovascular Risk Reduction

(FCRP Trial)

Recruiting at 6 trial locations

Overseen By Robert Corbell

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Arizona

Must not be taking: Antidiabetics, others

Disqualifiers: Smoking, Pregnancy, Diabetes, Cancer, others

Compensation: Varies

Number of Visits: Unknown

1500 Participants Needed

Trial Summary

What is the purpose of this trial?

The goal of this research is to test interventions to reduce firefighter cardiovascular, cognitive, and overall disease risks, including but not limited to risks associated with Per- and Polyfluorinated Substances (PFAS) exposure. Approximately 1,500 - 2,000 firefighters will be enrolled in the Fire Fighter Cancer Cohort Study (FFCCS). Among these individuals, those that express interest will then be screened for eligibility for the Firefighter Collaborative Research Project (FCRP) using information they provided for the Fire Fighter Cancer Cohort Study. Firefighters enrolled in the study will provide an initial blood sample and urine sample. The blood sample will be analyzed to determine the participant's PFAS levels. Based upon serum PFAS levels and responses from the screening survey, eligible participants will be randomly assigned into one of the following interventions: 1. Blood Donation, or Plasma Donation or Blood/Plasma Control Group; 2. Zone 2 Training or Zone 2 Control; 3. Intermittent Fasting or Intermittent Fasting Control. Individuals participating in the blood donation, plasma donation or blood/plasma control group would donate blood every 12 weeks, plasma every 6 weeks, or not donate blood or plasma. Participants in this intervention arm would continue this for a 12-month period. Individuals in the zone 2 training, zone 2 training control, intermittent fasting or intermittent fasting control group would participate in their intervention or control for a 4-month period. After 4 to 12 months participating in an intervention or control group, participants will be asked to provide a final urine sample and blood draw to determine if and to what degree their PFAS levels or other cardiovascular disease and other health risks have changed.

Will I have to stop taking my current medications?

The trial protocol does not specify if you need to stop taking your current medications. However, if you are using antidiabetic medications like Semaglutide or Tirzepatide, you may be excluded from the intermittent fasting group.

What data supports the effectiveness of the treatment for reducing cardiovascular risk in firefighters?

Research shows that time-restricted feeding can reduce inflammation and stress responses in firefighters, which may help lower their risk of heart disease. Additionally, alternate-day fasting combined with exercise has been found to improve body weight and blood fat levels, which are important for heart health. ^{1 2 3 4 5}

Is alternate-day fasting safe for humans?

Research shows that alternate-day fasting is generally safe for weight loss and improving health markers in both obese and normal-weight individuals, with no significant adverse events reported. ^{6 7 8 9 10}

How does the treatment for reducing cardiovascular risk in firefighters differ from other treatments?

This treatment is unique because it focuses on dietary interventions, such as time-restricted feeding and the Mediterranean diet, to reduce cardiovascular risk in firefighters. These approaches aim to improve health by changing eating patterns and food choices, rather than relying on medication. ^{1 5 11 12 13}

Eligibility Criteria

This trial is for active Arizona firefighters over 18, who plan to stay in service for the next 2 years and are part of the Fire Fighter Cancer Cohort Study. They must speak English fluently, have a BMI over 17.5 kg/m2, weigh more than 115 pounds, and be able to donate blood if needed. Smokers or those with significant health issues can't participate.

Inclusion Criteria

My BMI is over 17.5 and I weigh more than 115 pounds.

I am eligible to donate blood and blood products.

Complete a signed and dated informed consent document that indicates the participant has been informed of all aspects of the study prior to enrollment

Exclusion Criteria

Those who are pregnant, breastfeeding, or have given birth within the past year

I am under 18 years old.

Not able to fluently speak or write in English

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Initial Assessment

Participants provide an initial blood sample and urine sample to determine PFAS levels

1 week

Intervention

Participants are randomly assigned to interventions: Blood/Plasma Donation, Zone 2 Training, or Intermittent Fasting, or their respective control groups

4-12 months

Final Assessment

Participants provide a final urine sample and blood draw to assess changes in PFAS levels and other health risks

1 week

Follow-up

Participants are monitored for safety and effectiveness after the intervention

4 weeks

Treatment Details

Interventions

• Blood Donation
• Intermittent Fasting
• Plasma Donation
• Zone 2 Training

Trial Overview The study tests whether blood donation, plasma donation, Zone 2 Training (a type of exercise), or intermittent fasting can reduce cardiovascular disease risks and PFAS levels in firefighters. Participants will follow their assigned intervention for either four months or one year before retesting.

Participant Groups

Group I: Plasma Donation Active Control 2 Interventions

Group II: Zone 2 Training Active Control 2 Interventions

Group III: Intermittent Fasting Active Control 2 Interventions

Group IV: Blood Donation Active Control 2 Interventions

Group V: Zone 2 Control Placebo Group 1 Intervention

Group VI: Intermittent Fasting Control Placebo Group 1 Intervention

Group VII: Blood/Plasma Control Placebo Group 1 Intervention

Who Is Running the Clinical Trial?

University of Arizona

Lead Sponsor

Trials

545

Recruited

161,000+

Arizona State University

Collaborator

Trials

311

Recruited

109,000+

Findings from Research

A 28-day carbohydrate-restricted diet (CRD) significantly reduced body fat and blood pressure in professional firefighters, indicating improvements in cardiometabolic health.

The CRD also enhanced physical performance, as evidenced by improved run times and pull-up repetitions, without negatively affecting high-intensity exercise capabilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A 28-Day Carbohydrate-Restricted Diet Improves Markers of Cardiometabolic Health and Performance in Professional Firefighters. Waldman, HS., Smith, JW., Lamberth, J., et al.[2020]

In a study of 64 obese subjects over 12 weeks, the combination of alternate day fasting (ADF) and exercise led to a significant weight loss of 6 kg and improved body composition, including reduced fat mass and waist circumference, while retaining lean mass.

The combination group also showed significant improvements in lipid profiles, with a decrease in LDL cholesterol and an increase in HDL cholesterol, indicating a lower risk of heart disease compared to ADF or exercise alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Alternate day fasting and endurance exercise combine to reduce body weight and favorably alter plasma lipids in obese humans. Bhutani, S., Klempel, MC., Kroeger, CM., et al.[2013]

In a 12-month study involving 34 obese participants, those who lost 5% or more of their body weight on alternate-day fasting (ADF) reported feeling fuller and less hungry, indicating improved satiety.

Successful weight losers on ADF also increased their dietary protein intake from 15% to 20% of their total calories and showed better adherence to calorie goals on fasting days, suggesting effective behavioral changes associated with this diet.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Eating behavior traits of successful weight losers during 12 months of alternate-day fasting: An exploratory analysis of a randomized controlled trial. Kroeger, CM., Trepanowski, JF., Klempel, MC., et al.[2020]

Modified alternate-day fasting (ADF) led to significant weight loss (5.6 kg) and reduced body fat percentage in 16 obese adults over 8 weeks, demonstrating its efficacy as a weight management strategy.

ADF also improved cardiovascular health indicators, with notable reductions in total cholesterol, LDL cholesterol, and triglycerides, suggesting it may lower the risk of coronary artery disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. Varady, KA., Bhutani, S., Church, EC., et al.[2023]

In a study involving 13 firefighters over an 8-week period, time-restricted feeding (TRF) significantly reduced the stress response, as indicated by lower salivary cortisol levels after a simulated firegrounds test.

TRF also led to decreased levels of inflammatory markers IL-6 and IL-1β, suggesting potential cardiometabolic benefits for firefighters who are at higher risk for cardiovascular disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Time Restricted Feeding Reduces Inflammation and Cortisol Response to a Firegrounds Test in Professional Firefighters. McAllister, MJ., Gonzalez, AE., Waldman, HS.[2021]

In an 8-week study with 59 obese participants, alternate day fasting (ADF) led to a significant weight loss of 4.2%, while only a small percentage reported mild adverse effects like constipation and dizziness.

ADF was associated with improvements in eating disorder symptoms, including a decrease in depression and binge eating, suggesting that it may have beneficial effects on body image and eating behaviors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of alternate day fasting and effect on disordered eating behaviors. Hoddy, KK., Kroeger, CM., Trepanowski, JF., et al.[2018]

In a study of 32 non-obese individuals over 12 weeks, alternate day fasting (ADF) led to a significant weight loss of 5.2 kg (6.5%) and a reduction in fat mass without affecting fat-free mass, indicating its efficacy for weight management.

ADF also improved cardiovascular risk factors, as evidenced by decreased triacylglycerol levels, increased LDL particle size, and changes in adipokine levels, suggesting potential cardio-protective benefits in normal weight and overweight adults.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Varady, KA., Bhutani, S., Klempel, MC., et al.[2021]

Alternate-day fasting (ADF) is a safe and well-tolerated weight loss method, with 93% of participants completing the 8-week study without adverse effects.

While ADF and a standard caloric restriction diet produced similar weight loss results after 8 weeks, ADF showed more favorable changes in body composition, particularly in fat and lean mass, during the follow-up period.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A randomized pilot study comparing zero-calorie alternate-day fasting to daily caloric restriction in adults with obesity. Catenacci, VA., Pan, Z., Ostendorf, D., et al.[2019]

A meta-analysis of seven randomized controlled trials with 269 participants found that alternate-day fasting (ADF) significantly reduced weight and body mass index compared to control groups, indicating its effectiveness for weight loss.

Participants following ADF also showed improvements in several health markers, including lower total cholesterol, triglycerides, and blood pressure, suggesting that ADF may enhance overall health and reduce disease risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis. Cui, Y., Cai, T., Zhou, Z., et al.[2020]

In a 10-week study involving 16 obese adults, alternate-day fasting (ADF) led to significant reductions in body weight (5.7 kg) and waist circumference (4.0 cm), along with a decrease in fat mass (5.4 kg), indicating its efficacy in improving body composition.

ADF also improved cardiovascular risk factors by increasing beneficial adiponectin levels by 30% and reducing harmful LDL cholesterol and triglycerides by 25% and 32%, respectively, suggesting a protective effect against coronary heart disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Improvements in coronary heart disease risk indicators by alternate-day fasting involve adipose tissue modulations. Bhutani, S., Klempel, MC., Berger, RA., et al.[2015]

A 7-week time-restricted feeding (TRF) intervention improved ventilatory threshold in professional firefighters, suggesting potential benefits for endurance performance.

While TRF did not negatively impact muscular strength, endurance, or power, it did lead to a decrease in body fat, indicating a positive effect on overall fitness without compromising performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of Time Restricted Feeding on Fitness Variables in Professional Resistance Trained Firefighters. Gonzalez, AE., Waldman, HS., Abel, MG., et al.[2021]

The 'Feeding America's Bravest' trial is a 12-month study involving about 1000 firefighters from the Indianapolis Fire Department, aiming to improve their diet by implementing Mediterranean diet principles to reduce cardiovascular disease risk.

The trial compares a Mediterranean Diet Nutritional Intervention (MDNI) with usual care, assessing changes in diet quality, body weight, and cardiometabolic risk markers, which could lead to effective strategies for promoting healthier eating in the fire service.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Rationale and design of feeding America's bravest: Mediterranean diet-based intervention to change firefighters' eating habits and improve cardiovascular risk profiles. Sotos-Prieto, M., Cash, SB., Christophi, CA., et al.[2018]

A 12-month study involving 485 US firefighters showed that those who participated in a Mediterranean diet intervention significantly improved their dietary habits, with an increase in their modified Mediterranean diet score by 2.67 points at 12 months compared to the control group.

Despite the positive changes in diet, the intervention did not lead to statistically significant improvements in cardiometabolic risk factors after one year, indicating that while dietary adherence improved, it may not have immediately impacted health outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of a Nutrition Intervention on Mediterranean Diet Adherence Among Firefighters: A Cluster Randomized Clinical Trial. Hershey, MS., Chang, CR., Sotos-Prieto, M., et al.[2023]

References

1. United States pubmed.ncbi.nlm.nih.gov

A 28-Day Carbohydrate-Restricted Diet Improves Markers of Cardiometabolic Health and Performance in Professional Firefighters. [2020]

2. United States pubmed.ncbi.nlm.nih.gov

Alternate day fasting and endurance exercise combine to reduce body weight and favorably alter plasma lipids in obese humans. [2013]

3. England pubmed.ncbi.nlm.nih.gov

Eating behavior traits of successful weight losers during 12 months of alternate-day fasting: An exploratory analysis of a randomized controlled trial. [2020]

4. United States pubmed.ncbi.nlm.nih.gov

Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. [2023]

5. United States pubmed.ncbi.nlm.nih.gov

Time Restricted Feeding Reduces Inflammation and Cortisol Response to a Firegrounds Test in Professional Firefighters. [2021]

6. England pubmed.ncbi.nlm.nih.gov

Safety of alternate day fasting and effect on disordered eating behaviors. [2018]

7. England pubmed.ncbi.nlm.nih.gov

Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. [2021]

8. United States pubmed.ncbi.nlm.nih.gov

A randomized pilot study comparing zero-calorie alternate-day fasting to daily caloric restriction in adults with obesity. [2019]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis. [2020]

10. United States pubmed.ncbi.nlm.nih.gov

Improvements in coronary heart disease risk indicators by alternate-day fasting involve adipose tissue modulations. [2015]

11. United States pubmed.ncbi.nlm.nih.gov

Impact of Time Restricted Feeding on Fitness Variables in Professional Resistance Trained Firefighters. [2021]

12. United States pubmed.ncbi.nlm.nih.gov

Rationale and design of feeding America's bravest: Mediterranean diet-based intervention to change firefighters' eating habits and improve cardiovascular risk profiles. [2018]

13. United States pubmed.ncbi.nlm.nih.gov

Effect of a Nutrition Intervention on Mediterranean Diet Adherence Among Firefighters: A Cluster Randomized Clinical Trial. [2023]