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

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.

Study Overview

• Status: Completed
• Conditions: Inflammatory Response; Symptoms and Signs
• Intervention / Treatment: Other: Candle 1; Other: Candle C

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 17
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Central Region Denmark
    • Aarhus, Central Region Denmark, Denmark, 8000
      • Climate Chambers, Dept. Public Health, Aarhus University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 25 years (ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: QUADRUPLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: Standard Stearin Candle; 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; Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.
EXPERIMENTAL: Modified low emission candle; 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; Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.
NO_INTERVENTION: Clean Air; No candles in the chamber.

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University of Aarhus
• Collaborators: Lund University; University of Copenhagen; Danish Technological Institute; ASP-HOLMBLAD A/S; COOP Denmark; Danwax; Liljeholmens Stearinfabrik; Promol; European Candle Association
• Investigators: Principal Investigator: Torben Sigsgaard, Prof., University of Aarhus

Study record dates

Study Major Dates

• Study Start (ACTUAL): September 1, 2020
• Primary Completion (ACTUAL): December 31, 2020
• Study Completion (ACTUAL): December 31, 2020

Study Registration Dates

• First Submitted: November 4, 2020
• First Submitted That Met QC Criteria: April 28, 2021
• First Posted (ACTUAL): April 29, 2021

Study Record Updates

• Last Update Posted (ACTUAL): April 29, 2021
• Last Update Submitted That Met QC Criteria: April 28, 2021
• Last Verified: April 1, 2021

More Information

Terms related to this study

• Keywords: Inflammation; Indoor air; Asthmatics; Health effects; Particle contamination; Stearin candle; Pollutant
• Other Study ID Numbers: 201100

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No