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Completed

NCT Number: NCT04864600

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.

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Key information

Conditions

Inflammatory Response Asthma Bronchial Diseases Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Inflammation Lung Diseases Lung Diseases, Obstructive Pathologic Processes Pathological Conditions, Signs and Symptoms Respiratory Hypersensitivity Respiratory Tract Diseases Signs and Symptoms Symptoms and Signs

Age range

18 year–25 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Climate Chambers, Dept. Public Health, Aarhus University

Aarhus, Central Region Denmark, 8000, Denmark

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Candle C

Other

Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.

Candle 1

Other

Burning candles will produce particulate air pollution being passed on an exposure chamber where the participants will be sitting for 5 hours.

Primary outcomes

  1. Change in Particles in Exhaled Air (Surfactant Protein A & Albumin)

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    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

Secondary outcomes

  1. Change in Lung Function (FEV1 & FVC)

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    Spirometry

  2. Change in Fractional exhaled nitric oxide (FENO)

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    NIOX VERO system; Aerocrine AB, Sweden

  3. Change in white blood cells in Blood

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    White blood cells

  4. Change in Endothelial Progenitor Cells (EPCs) in Blood

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    Endothelial progenitor cells (EPC) further divided into early and late EPCs

  5. Change in inflammatory markers in Blood

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    Interleukin 8, interleukin 1

  6. Change in biomarkers in Blood

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    Metabolomics

  7. Change in nasal volume (using Acoustic rhinometry)

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    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.

  8. Change in biomarkers in Saliva Sample

    Time frame: after exposure (5 hours), and the day after exposure (24 hours)

    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))

  9. ReCIVA

    Time frame: At baseline (0 hour), after exposure (5 hours), and the day after exposure (24 hours)

    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.

  10. Change in Subjective Symptoms

    Time frame: Every 30 minute during 5 hours of exposure

    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

  11. Heart rate using a Fitbit

    Time frame: From exposure start until the morning after exposure (in total 24 hours)

    Using a Fitbit watch participants' heart rate is measured.

  12. Sleep quality using a Fitbit

    Time frame: during 48 hours

    Using a Fitbit watch participants' sleep quality is measured.

Sponsors and collaborators

Lead sponsor

University of Aarhus

Other

Collaborators

  • ASP-HOLMBLAD A/S
  • COOP Denmark
  • Danish Technological Institute
  • Danwax
  • European Candle Association
  • Liljeholmens Stearinfabrik
  • Lund University
  • Promol
  • University of Copenhagen

Registry information

Important dates

Study start
2020
Primary completion
2020
Study completion
2020
First posted
Apr 29, 2021
Registry last updated
Apr 29, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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