CANDLE - A Study of Acute Health Effects of Exposure to Particles Generated by Candles

Study Overview
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Brief Summary
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INTRODUCTION: Particle contamination is suggested to have substantial negative effects on health, with candles emitting huge amount of particles, thus being one of the largest contributors to indoor air pollution. Chronic low levels of exposure to indoor particles over time is an important risk factor for the health of the population as a whole and it becomes particularly important for vulnerable groups like people suffering from respiratory diseases such as asthma. AIM: In a randomized controlled cross-over trial the difference in health effects between two candles I) a standard candle and II) a low emission candle modified from the standard candle is studied.

Detailed Description
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INTRODUCTION; Particle contamination is suggested to have substantial negative effects on health, with candles emitting the huge amount of particles, thus being one of the largest contributors to indoor air pollution. Chronic low levels of exposure to indoor particles over time is an important risk factor for the health of the population as a whole and it becomes particularly important for vulnerable groups like children and the elderly or people already suffering from allergies and respiratory diseases such as asthma. AIM: To study the difference in health effects between two candles I) a standard candle and II) a low emission candle modified from the standard candle. The following hypothesis will be examined: Short-term exposure to particles generated by the standard candle is associated with more objectively measurable effects in metabolomics inflammation compared to exposure to modified low-emission candle particles. METHODS: Separated by two weeks 20 young asthmatics will be exposed in a randomized cross-over double-blind study under controlled conditions in a climate chamber to three different exposures; A) a standard (Scandinavian) stearin candle, B) a modified low emitting version of the same candle, and C) clean air from the adjacent chamber. The experiment will be carried out in groups of 3-6 participants. MEASUREMENTS: TSI P-TRAK Ultrafine Particle Counter and SMPS will be used for particle counts. Health effects, including spirometry and fraction of exhaled nitric oxide (FeNO) will be evaluated in relation to local and systemic effects prior to, right after and 24 h. after exposure. ANALYSIS: Mixed methods approach taking both time and exposure into account.

Official Title
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CANDLE - A Study of Acute Health Effects of Exposure to Particles Generated by Candles

Conditions
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Inflammatory Response, Symptoms and Signs

Intervention / Treatment
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* Other: Candle C
* Other: Candle 1


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-25 Medically treated / physician diagnosed mild seasonal asthma GINA guidelines step 1 or 2 (https://ginasthma.org/) Never smoker or ex-smoker ≥ 6 months Allergy > 1 common allergy Exclusion Criteria: Any other disease that could influence the study parameters Conditions that prevent safe access to the climate chambers (such as claustrophobia) Perennial asthma Need for continuous medical treatment for asthma Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: A randomized cross-over double-blind study under controlled conditions in a climate chamber having three different exposures; A) a standard (Scandinavian) stearin candle, B) a modified low emitting version of the same candle, and C) clean air
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Stearin Candle<br>Several candles will be lit. We will be using realistic burning cycles i.e. burning candles which extinguish and new ones being lit. | Other: Candle 1<br>* Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.<br>|
| Experimental: Modified low emission candle<br>Several candles will be lit. We will be using realistic burning cycles i.e. burning candles which extinguish and new ones being lit. | Other: Candle C<br>* Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.<br>|
| No Intervention: Clean Air<br>No candles in the chamber. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Particles in Exhaled Air (Surfactant Protein A & Albumin) | PExA: Subjects performed repeated breath maneuvers allowing for airway closure and re-opening, and exhaled particles were optically counted and collected on a membrane using the PExA® instrument set-up | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Lung Function (FEV1 & FVC) | Spirometry | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in Fractional exhaled nitric oxide (FENO) | NIOX VERO system; Aerocrine AB, Sweden | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in white blood cells in Blood | White blood cells | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in Endothelial Progenitor Cells (EPCs) in Blood | Endothelial progenitor cells (EPC) further divided into early and late EPCs | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in inflammatory markers in Blood | Interleukin 8, interleukin 1 | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in biomarkers in Blood | Metabolomics | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in nasal volume (using Acoustic rhinometry) | Acoustic rhinometry is used to assess the nasal cross sectional area and volume. The left and right nasal cavity were studied alternatively until three reproducible measurements were obtained. The minimum cross sectional cavity area is calculated from the means of the measurements. By integration of the area-distance curve, the sum of the volume 2 to 4 (vol2-4) from the nostril is determined on both sides. | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in biomarkers in Saliva Sample | An oral svap from Salivette was placed in the mouth of the participant to collect saliva by gently chewing the swab for one minute. Afterwards the saturated swab was removed to the suspended insert and closed firmly with a lid. Then the sample was transferred to a freezer and stored for -80 C until further analysis. The sample will be analyzed for biomarkers (amylase, cortisol, substance P, lysozyme and secretory IgA. (same unit measure)) | after exposure (5 hours), and the day after exposure (24 hours) | 
| ReCIVA | Sampling of VOCs and particles in exhaled air. Breathing through a mask for 10-15 minutes makes it possible to collect VOCs and particles into tenax air sampling tubes. | At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours) | 
| Change in Subjective Symptoms | n the exposure chamber participants are asked to fill out a symptom questionnaire every 30 minute regarding their well-being and experienced symptoms in eyes, nose and throat. The participants are asked to score their evaluation / rate the strength of symptoms on a Linear Numeric Scale from 0-10, with 10 being worst. Health effects are evaluated in relation to rated changes in symptoms | Every 30 minute during 5 hours of exposure | 
| Heart rate using a Fitbit | Using a Fitbit watch participants' heart rate is measured. | From exposure start until the morning after exposure (in total 24 hours) | 
| Sleep quality using a Fitbit | Using a Fitbit watch participants' sleep quality is measured. | during 48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Particle contamination, Asthmatics, Indoor air, Pollutant, Stearin candle, Health effects, Inflammation