Cardiovascular Responses to Cold in Hypertension (ColdHTN)

This study has been completed.
Sponsor:
Collaborators:
National Institute for Health and Welfare, Finland
Finnish Institute of Occupational Health
Verve
Information provided by (Responsible Party):
Tiina Ikäheimo, University of Oulu
ClinicalTrials.gov Identifier:
NCT02007031
First received: December 5, 2013
Last updated: December 10, 2013
Last verified: December 2013
  Purpose

Wintertime is associated with increased morbidity and mortality and a majority is related to cardiovascular causes, such as myocardial infarctions, heart failures, and strokes. It is also known, that both acute and long-term cold exposure increase blood pressure and cardiac workload, and this may contribute to the observed excess morbidity and mortality during the cold season.

Although the effects of cold on blood pressure are known among healthy people, these responses among risk groups, such as hypertensive people, are not established. In addition, changes in cardiac electrical activity or autonomic regulation are largely unknown. The cardiovascular responses in the cold could be different among hypertensive people because of disturbances in the circulatory regulation or function, such as aortic stiffening and increased vasomotor tone of peripheral arteries due to endothelial dysfunction associated with the disease. To assess this, a controlled experiment employing a cold exposure similar to everyday winter circumstances in a subarctic climate was performed.


Condition
Hypertension

Study Type: Observational
Study Design: Time Perspective: Cross-Sectional
Official Title: Cardiovascular Responses to Cold Exposure in Hypertension

Resource links provided by NLM:


Further study details as provided by University of Oulu:

Primary Outcome Measures:
  • Blood pressure response of hypertensive and normotensive subjects to cold exposure [ Time Frame: 2 hours (measured within the controlled experiment) ] [ Designated as safety issue: No ]
    The study assesses the blood pressure response of hypertensive and normotensive subjects to facial cooling. Blood pressure is measured before (warm, +18°C), during (cold, 15°C) and after (warm, +18°C) the employed cold exposure. The duration of each of these exposures are 30, 15 and 30 min.


Secondary Outcome Measures:
  • Cardiac autonomic regulation [ Time Frame: 2 hours (measured within each controlled experiment), ECG recorded continuously ] [ Designated as safety issue: No ]
    ECG is recorded continuously during the controlled experiment (15 min warm 18 C, 15 min cold exposure -15 C and 20 min 18 C) from where cardiac electrical function, as well as autonomic nervous system regulation is assessed.


Enrollment: 91
Study Start Date: January 2010
Study Completion Date: November 2011
Primary Completion Date: November 2011 (Final data collection date for primary outcome measure)
Groups/Cohorts
Hypertensive subjects
Hypertensive subjects are exposed to brief cold exposure (-15 C for 15 min) mainly subjected to their facial region during which their cardiovascular responses are registered.
Normotensive subjects
Normotensive subjects are exposed to brief cold exposure (-15 C for 15 min) mainly subjected to their facial region during which their cardiovascular responses are registered.

  Show Detailed Description

  Eligibility

Ages Eligible for Study:   55 Years to 65 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

The study participants were included according to a population based recruitment where a random sample of 1000 men (55-65 years old) living in Oulu, Finland was drawn from the Finnish Population Register. They were screened by telephone interviews for eligibility for the study. Eligible attendees measured their blood pressure home for a week according to the recommendations of the European Society of Hypertension and were classified either to hypertensive (systolic blood pressure ≥135 and/or diastolic blood pressure ≥85 mmHg) or normotensive (blood pressure <135/85mmHg). For the study we aimed at a 2:1 ratio of hypertensive and normotensive. The final study group consisted of 56 hypertensive and 35 normotensive middle-aged men.

Criteria

Inclusion Criteria:

  • Measured BP (home measurements of one week) above 135/85 mmHg were selected to the group of hypertensive subjects.
  • Those with BP below 135/85 mmHg were selected as controls.

Exclusion Criteria:

  • Presence of coronary heart disease, respiratory diseases, and the use of antihypertensive drug treatment.
  • an average home BP ≥175/105 mmHg, initiating antihypertensive drug treatment, failed home BP measurements, and having a respiratory infection within a week prior to the controlled measurements
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT02007031

Locations
Finland
University of Oulu
Oulu, Finland, FI90014
Finnish Institute of Occupational Health
Oulu, Finland, FI90220
Sponsors and Collaborators
University of Oulu
National Institute for Health and Welfare, Finland
Finnish Institute of Occupational Health
Verve
Investigators
Principal Investigator: Tiina M Ikäheimo, Ph.D. University of Oulu
Principal Investigator: Jouni JK Jaakkola, MD, Ph.D. University of Oulu
  More Information

Additional Information:
Publications:

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Tiina Ikäheimo, Postdoctoral researcher, University of Oulu
ClinicalTrials.gov Identifier: NCT02007031     History of Changes
Other Study ID Numbers: 24300771KYTEM
Study First Received: December 5, 2013
Last Updated: December 10, 2013
Health Authority: Finland: Ethics Committee

Keywords provided by University of Oulu:
Hypertension
Cold temperature
Blood pressure
Electrocardiography

Additional relevant MeSH terms:
Hypertension
Vascular Diseases
Cardiovascular Diseases

ClinicalTrials.gov processed this record on October 19, 2014