Clinical trial NCT06711614: FIRE-Diet: Food as an Intervention to Reduce the Effects of Woodsmoke Exposure on Respiratory Health
Official title: FIRE-Diet: Food as an Intervention to Reduce the Effects of Woodsmoke Exposure on Respiratory Health
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Healthy Individuals
Keywords: Diet Intervention
EPA
DHA
Omega-3 fatty acids
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2024-12-02
Enrollment: 48
Sex: ALL
Minimum age (years): 19
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Each participant will be randomized to begin the study with the control diet (their usual diet) or the intervention diet (aimed at increasing intake of fatty fish high in omega-3 fatty acids, fruits, and vegetables) x \~4 weeks. After a washout period of at least 4 weeks the participant will complete the alternate assignment. At the end of each assignment (control or intervention diet) the participant will undergo a controlled exposure to wood smoke x 2 hours, following which lung health outcomes will be assessed as described.
Primary purpose: OTHER

Brief summary: Research suggests that consuming more fatty fish, fruits, and vegetables could potentially shield the lungs from the negative impacts of air pollution. The research team will look at whether a dietary intervention aimed at increasing intake of these foods can protect the lungs from woodsmoke as the air pollutant and look into how this works.

Detailed description: This study aims to recruit 48 healthy adult volunteer participants (24 male and 24 female biologic sex assigned at birth) with no known respiratory diseases (as assessed by the study physician) who will breathe in woodsmoke while they are supported to eat a diet higher in fatty fish, fruits, and vegetables (the intervention diet), or not (the control diet).

All participants will undergo a screening visit to assess eligibility for the study. Once deemed eligible, they will experience three exposure visits: one fresh air (filtered air - FA) exposure and two woodsmoke (WS) exposures. The study will span a minimum duration of 15 weeks with 10 in-person visits to the site at Vancouver General Hospital, totaling approximately 34.5 hours. During these visits, participants will complete a series of questionnaires, sample collections (blood, urine, sputum (clumps of mucus that are coughed up from the lungs)), and lung function tests, in addition to the exposures mentioned above.

Off-site commitments will require participants to follow the recommended diet assigned at the time, complete some electronic questionnaires and breathing tests at home after exposures, and complete telephone calls with the study dietician (approximately 30-minute calls, weekly).

Participants will be provided with meal and grocery deliveries to meet intake goals specified by the study or a subsidized amount of groceries per week depending on the diet intervention assigned at that time.

Eligibility criteria: Inclusion Criteria:

* Healthy, and specifically with no respiratory disease
* Not taking any supplements, or willing to abstain from supplement use for 4-weeks prior to study start and the whole duration of the study,
* Must currently consume, on average, less than 2 servings of fish per week and fewer than 5 servings of fruits and vegetables per day based on screening questionnaires.
* Must have a null GSTM1 genotype determined at screening.
* Must be able to provide a sufficient sputum sample during the screening visit.

Exclusion Criteria:

* Pregnant or planning to become pregnant during the study period.
* Health conditions that would pose an unacceptable risk of dietary change, or conditions that are uncontrolled based on principal investigator's judgement.
* Actively attempting to lose weight.
* Frequent wood smoke exposure (e.g. at home or employment).
* Unable to store provided meals and food safely.
* Food allergies/intolerance or food aversion preventing adherence to the intervention diet, or unwillingness/medically unable to adjust diet in line with the intervention.
* Relocation during the study period to an area which will prevent food delivery.
* History of smoking tobacco, marijuana, or and other substance or vaping within the past 6 months, or having smoked the equivalent of 0.5 pack-years ever.
* Body mass index (BMI) \<18.5, as determined during the in-person screening visit.

Primary outcomes:
measure: Within-individual change in sputum neutrophil %
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in sputum neutrophil activation and function
timeFrame: Across study duration, anticipated ~15 weeks
measure: Within-individual change in airway resistance
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in sputum biomarkers of inflammation
timeFrame: Across study duration, anticipated ~15 weeks.
Secondary outcomes:
measure: Within-individual change in sputum biomarkers/arbiters of inflammation
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in upper airway (nasal) markers of neutrophil activation and function
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in upper airway (nasal) biomarkers/arbiters of inflammation
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in blood neutrophil %
timeFrame: Across study duration, anticipated ~15 weeks.
measure: Within-individual change in blood neutrophil activation and function
timeFrame: Across study duration, anticipated ~15 weeks
measure: Within-individual change in spirometry
timeFrame: Across study duration, anticipated ~15 weeks.
Other outcomes:
measure: Within-individual change in systemic biomarkers/arbiters of inflammation and oxidative stress
timeFrame: Across study duration, anticipated ~15 weeks.
Locations:
city: Vancouver
country: Canada
facility: University of British Columbia
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Emily Brigham, MD
role: PRINCIPAL_INVESTIGATOR
References: