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Completed

NCT Number: NCT01475968

Physiological Changes in Adults With Metabolic Syndrome Exposed to Ultrafine Air Particles

The purpose of this study is to examine the acute health effects of concentrated ambient ultrafine (UF) particulate matter (PM) exposure in patients with metabolic syndrome. Without lifestyle changes or medical intervention these patients are at considerable risk for developing diabetes and cardiovascular disease. Subjects (25-70) were exposed to both UF PM and filtered air for 2hr (at least 2 week interval), physiologic endpoints were measure pre-, post-, and 20hr post-exposure. Our hypothesis is that PM exposure in this population will result in changes in vascular and endothelial response as assessed by flow-mediated dilatation of the brachial artery and various heart rate variability and blood endpoints. This study and similar studies of susceptible populations are needed to provide the EPA with information regarding the health risks associated with ambient levels of UF PM.

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Key information

Age range

25 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

EPA Human Studies Facility

Chapel Hill, North Carolina, 27599, United States

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age between 25-70 years old
  • Metabolic syndrome as defined by the participant having at least three of the following criteria:
  • Abdominal obesity: Men waist circumference >102 cm (>40 in) Women waist circumference >88 cm (>35 in)
  • Triglycerides: ≥150 mg/dL
  • HDL cholesterol: Men <40 mg/dL and Women <50 mg/dL
  • Blood pressure: ≥130/≥85 mmHg OR have a history of high blood pressure requiring medication
  • Fasting glucose: ≥100 mg/dL and ≤126 mg/dL
  • Normal resting electrocardiograph (ECG).

Exclusion criteria

  • Current smoker or smoking history within 3 months of study (defined as more than one pack of cigarettes in the past 3 months).
  • Oxygen saturation below 95% at the time of physical exam.
  • Blood pressure ≥160/≥100 mmHg
  • Fasting blood glucose >126 mg/dl
  • Hypersensitivity to nitroglycerin or other nitrates
  • Any chronic medical condition including active pulmonary disease, cardiovascular disease (coronary artery disease, heart failure, rhythm disturbances, etc.), neurological disease, liver disease, kidney disease, muscular disease, diabetes, other endocrine disease, hematologic/lymphatic disease, immune deficiency or autoimmune disease.
  • Medications specifically prohibited include nitrates or other vasodilators (exception here includes erectile dysfunction medications if the participant agrees to refrain for 96 hours prior to study), anti-arrhythmics, physician prescribed anti-inflammatory agents, physician prescribed antioxidants, insulin and other medications for the treatment of diabetes. Participants must refrain from all over-the-counter anti-inflammatory agents, including aspirin, ibuprofen, and naproxen, and anti-oxidants for a period of one week prior to exposure. Low dose aspirin and statin regimens are acceptable. Medications not specifically mentioned here may be reviewed by the investigators prior to a participant's inclusion in the study. Additionally, medication regimens must remain constant during the study.
  • Hepatitis B carriers
  • Skin diseases or sensitivity precluding the use of ECG electrodes
  • Active cancer, history of cancer within the last 5 years, untreated cancer. Potential participants may have a history of mild, treated skin cancer provided the condition does not interfere with ECG electrode placement.
  • No exposure will be conducted within 4 weeks of a respiratory tract infection.
  • History of serve migraines
  • Pregnant women or nursing mothers

Treatment and study plan

Ultrafine Air Pollution Particulate Matter

Other

Ultrafine (particle diameter less than 2.5 microns) Air Pollution Particulate Matter, concentrated from the ambient air outside of the Chapel Hill EPA Human Studies Facility

Other names: ultrafine particulate matter, concentrated ambient particulates (CAPS)

Filtered Air

Other

Filtered Air

Other names: clean air

Primary outcomes

  1. Changes in Vascular Function

    Time frame: change from baseline 0 hr after exposure, and change from baseline 20 hr after exposure. There will be at leat 2 weeks between the exposures

    • Measurement of dilatation of the brachial artery (flow mediated and nitroglycerin mediated)
    • Measurement of vasoconstrictor/vasodialtor, pro-coagulant, or pro-inflammatory mediators into systemic circulation (by ELISA of plasma)
    • Measurement of changes in plasma levels of circulating microparticles and endothelial progenitor cells (as indicators of vascular injury or remodeling)

Secondary outcomes

  1. Changes in heart rate variability

    Time frame: change from baseline 0 hr after exposure, and change from baseline 20 hr after exposure. There will be at leat 2 weeks between the exposures

    10 minute electrocardiogram recording (measure by Holter ECG) in which the subject has been resting for 20 minutes prior. Collected on a Mortara H12+ 12-Lead ECG Recorder (Mortara Instrument, Inc., Milwaukee, WI). The digitally recorded ECGs were sampled at 180 Hz and all data were stored on flash cards before processing.

Sponsors and collaborators

Lead sponsor

David Diaz-Sanchez

Fed

Collaborators

  • Environmental Protection Agency (EPA)

Registry information

Official study title

Physiological Changes in Adults With Metabolic Syndrome Exposed to Concentrated Ultrafine Chapel Hill Air Particles

Acronym: XCON

Important dates

Study start
2004
Primary completion
2011
Study completion
2013
First posted
Nov 22, 2011
Registry last updated
Nov 7, 2013

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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