Sympathetic Activity in Individuals With the Metabolic Syndrome: Benefits of Lifestyle Interventions

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00163943
Recruitment Status : Unknown
Verified September 2005 by Bayside Health.
Recruitment status was:  Recruiting
First Posted : September 14, 2005
Last Update Posted : August 1, 2007
Information provided by:
Bayside Health

Brief Summary:

An abdominal distribution of fat is associated with the greatest heart disease risk, because commonly, several risk factors of metabolic origin (high blood pressure, unfavourable cholesterol profile, elevated blood sugar, impaired insulin action) cluster in these individuals. When this occurs the condition is called the 'metabolic syndrome' (MetS). The cause of the MetS is yet to be fully elucidated. Increased activity of the nervous system resulting in enhanced release of the stress hormone 'norepinephrine', may be one mechanism by which adverse cardiovascular and metabolic sequelae of the MetS might be mediated. Dietary weight loss, and exercise are first-line treatments for the MetS and provide an opportunity to prevent or delay the development of type 2 diabetes and heart disease in this high risk group. However, there is a paucity of data regarding the effects of these lifestyle factors on the nervous system. Furthermore, it is also unknown whether active weight loss ('negative energy balance') or a stable lower weight (weight loss maintenance) is more important in modifying MetS components and nervous system activity. The aims of the proposed project are:

  1. To determine whether dietary weight loss in combination with aerobic exercise is more beneficial than dietary weight loss alone in reducing nervous system activity and improving metabolic and cardiovascular parameters in middle-aged men and women with abdominal obesity and the MetS.
  2. To determine whether weight loss maintenance four months after active weight loss is associated with a preservation of clinical benefits.
  3. To study biological determinants of successful weight loss and weight loss maintenance.

Condition or disease Intervention/treatment Phase
Metabolic Syndrome X Behavioral: Dietary weight loss +/- aerobic exercise Not Applicable

  Show Detailed Description

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 66 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Neural Mechanisms Predisposing to Cardiovascular Risk in Individuals With the Metabolic Syndrome: Benefits of Dietary Weight Loss, Weight Loss Maintenance and Aerobic Exercise
Study Start Date : April 2005
Estimated Study Completion Date : December 2007

Primary Outcome Measures :
  1. Whole-body sympathetic activity
  2. Muscle sympathetic activity

Secondary Outcome Measures :
  1. Insulin sensitivity
  2. Lipid profile
  3. Adipocytokines
  4. Blood pressure
  5. Baroreflex function
  6. Forearm and calf blood flow

Information from the National Library of Medicine

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Ages Eligible for Study:   45 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Sixty six (33 male and 33 postmenopausal female) weight-stable (body mass index 26 to 39 kg/m2), sedentary, non-smoking subjects, aged 45 to 65 years will be recruited on the basis of having > 3 indices of the MetS as defined by Adult Treatment Panel (ATP) III criteria:

    • waist circumference > 102 cm for men and > 88 cm for women;
    • fasting plasma glucose level > 6.1 mmol/L, but nondiabetic (< 7.1 mmol/L);
    • fasting plasma triglyceride level > 1.69 mmol/L;
    • plasma high-density lipoprotein (HDL) level < 1.04 mmol/L (males) and < 1.29 mmol/L (females);
    • supine resting blood pressure > 130/85 mmHg and < 165/105 mmHg, at least 4 weeks off blood pressure lowering medications.

Exclusion Criteria:

Exclusion criteria will comprise:

  • A history of diabetes, secondary hypertension, sleep apnoea, cardiovascular, cerebrovascular, renal, liver, or thyroid disease
  • Inability to cease medications which may affect measured parameters
  • Inability or contraindication to exercise

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00163943

Contact: Nora E Straznicky, BPharm, PhD, MPH 61 3 8532 1371
Contact: Elisabeth A Lambert, Bsc, MSc, PhD 61 8532 1345

Australia, Victoria
Baker Heart Research Institute Recruiting
Melbourne, Victoria, Australia, 8008
Contact: Nora E Straznicky, BPharm, PhD, MPH    61 3 8532 1371   
Principal Investigator: Nora E Straznicky, BPharm, PhD, MPH         
Sponsors and Collaborators
Bayside Health
Principal Investigator: Nora E Straznicky, BPharm, PhD, MPH Baker Heart Research Institute

Publications automatically indexed to this study by Identifier (NCT Number): Identifier: NCT00163943     History of Changes
Other Study ID Numbers: 7/05
First Posted: September 14, 2005    Key Record Dates
Last Update Posted: August 1, 2007
Last Verified: September 2005

Keywords provided by Bayside Health:
Metabolic syndrome
Sympathetic nervous system activity
Insulin sensitivity
weight loss
aerobic exercise

Additional relevant MeSH terms:
Metabolic Syndrome X
Pathologic Processes
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases