Fasting, Shift Workers' Health, Time Restricted Eating
Conditions
Keywords
Firefighters, San Diego Fire and Rescue, Cardiometabolic Health, First Responder, Shift Workers, Time-Restricted Eating, Fasting
Brief summary
This is the first study of its kind to assess and test an intervention to improve biological rhythms and general health of shift workers, specifically first responders with San Diego Fire and Rescue. In a randomized control trial, investigators intend to measure the health impact of Time Restricted Eating in emergency responders who work a 24-hour shift schedule.
Detailed description
Participants will be randomly assigned to a control group of behavioral nutrition counseling (standard of care) or the intervention group of standard of care with the addition of adopting a 10 hour eating window for one year (TRE). For the first 3 months of intervention, participants will be monitored closely by the research team. For the following 9 months, participants will be in a self-monitored intervention period. Investigators will evaluate the impact of TRE on blood glucose levels, biomarkers, sleep/mood, and weight loss. These assessments will be made at baseline, at the end of the 12-week monitored intervention period, and every 3 months (months 6, 9, and 12) during the self-monitored intervention period for one year. Food/drink intake, activity, and sleep will be monitored with the smartphone myCircadianClock application (mCC app) throughout the study. A continuous glucose monitor, a wrist-worn actigraphy device, and questionnaires will also be used during the study.
Interventions
Participants in this arm will adhere to a daily, consistent 10-hr eating window for the course of the study as well as receive nutritional counseling from the study dietician.
BEHAVIORALStandard of Care
Participants in this arm will receive nutritional counseling from the study dietician, but will not be required to adopt a 10-hr eating window.
Sponsors
Salk Institute for Biological Studies
University of California, San Diego
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Investigator)
Eligibility
Sex/Gender
ALL
Age
21 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
As per recommendations from the fire department, fire department unions, and funding agencies, we did not require compromised health measures (e.g. hyperglycemia, hypertension, etc.) as inclusion criteria for they would be discriminatory against some firefighters. Inclusion Criteria: * Firefighter or work a 24-hr shift schedule with San Diego Fire and Rescue * Age: 21-65 years * Own a smartphone (Apple or Android Operating System) * If participants are on cardiovascular medications (HMG-CoA reductase inhibitors (statins), other lipid modifying drugs (including over the counter drugs such as red yeast rice and fish oil), anti-hypertensive, anti-diabetes drugs), no dose adjustments will be allowed during the study period
Exclusion criteria
* Insulin-dependent diabetes mellitus * Presence of acute chronic inflammatory or autoimmune disease (defined by acute symptoms or C-reactive protein \>10 mg/L), malabsorption syndromes, liver disease, or kidney disease (stage 3 or greater) * Uncontrolled thyroid disease * Intake of drugs likely to interfere with study endpoints, including corticosteroids, anabolic steroids, anti-psychotics, antiretroviral drugs, and immunosuppressive drugs (within 3 months of starting the study) * Presence or recent history of anemia (hematocrit \<33% within 3 months of starting the study) * History of bariatric surgery * Pregnant or breast-feeding women * Current or recent (within 12 months of starting the study) pregnancy or breastfeeding, or intention of becoming pregnant in the next 6 months * Any cancer other than non-melanoma skin cancer in the last 3 years * On a special or prescribed diet for other reasons (e.g. Celiac disease) * Depression determined by the Beck Depression Inventory (BDI) * Planned international travel during study period * Insufficient logging on the mCC app (does not log at least 2 entries a day for 10 of 14 days) during baseline will exclude from being randomized into the intervention period
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Evaluate the impact of TRE on glucose homeostasis at end of intervention compared to baseline | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured by an ambulatory continuous glucose monitoring device and blood work throughout the study. Note: Significant changes expected in participants who had elevated glucose homeostasis at baseline. No significant changes expected in those within normal ranges at baseline. Primary endpoint analysis will be done by comparing baseline and 12-week intervention. |
| Assess the feasibility and adherence of TRE | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured by percentage of days logged that participants ate within their 10-hour window and by end of study responses. Note: Significant changes expected in participants in the TRE arm of the study on and off shift. No significant changes expected in the standard of care arm of the study. Primary endpoint analysis will be done by comparing baseline and 12-week intervention. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Assess changes in metabolic biomarkers in response to TRE at end of intervention compared to baseline | Timeframe: primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured with blood biochemistry.Measured with blood biochemistry under TRE, including, but not limited to: fasting glucose, HbA1c, cholesterol, and triglycerides. Note: Significant changes expected in participants who had abnormal levels at baseline (e.g. elevated LDL cholesterol, low HDL cholesterol, elevated triglycerides). No significant changes expected in those were within normal ranges at baseline. |
| Systolic blood pressure (mmHg) in response to TRE at end of intervention compared to baseline | Timeframe: primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured at baseline and during TRE intervention. Note: Significant changes expected in participants who had elevated systolic blood pressure at baseline. No significant changes expected in those without elevated systolic blood pressure at baseline. |
| Diastolic blood pressure (mmHg) in response to TRE at end of intervention compared to baseline | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured at baseline and during TRE intervention. Note: Significant changes expected in participants who had elevated diastolic blood pressure at baseline. No significant changes expected in those without elevated diastolic blood pressure at baseline. |
| Body weight (kg) | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured on a digital scale. Note: Significant changes expected in participants who had elevated weight at baseline. No significant changes expected in those who were not overweight at baseline. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Waist and hip circumference (cm) | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured with standardized body tape measure. Note: Significant changes expected in participants who had increased waist and hip circumference at baseline. No significant changes expected in those without increased waist and hip circumference at baseline. |
| Hip (cm)/waist (cm) ratio | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured using tape measure. Note: Significant changes expected in participants who had an increased hip/waist ratio at baseline. No significant changes expected in those without increases at baseline |
| Body composition including but not limited to fat percentage (%), fat mass (kg), and lean mass (kg) | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured by Tanita Digital Scale. Note: Significant changes expected in participants who had elevations levels at baseline. No significant changes expected in those without elevations at baseline. |
| Questionnaires (quality of life, sleep, and health) | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Measured by SF-36, PSQI, and ESS. Note: Significant changes expected in participants who had decreased self-reporting of the above-mentioned questionnaires at baseline. No significant changes expected in those without decreases at baseline. |
| Body mass index (kg/m^2) | primary endpoint=12-week intervention (compared to 2-week baseline); follow-up will be at 1-year | Calculated from body weight (kg) and height (m). Note: Significant changes expected in participants who had elevated BMI at baseline. No significant changes expected in those whose BMI was not elevated at baseline. |
Countries
United States
Outcome results
None listed