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

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified September 2005 by Bayside Health.
Recruitment status was:  Recruiting
Information provided by:
Bayside Health Identifier:
First received: September 12, 2005
Last updated: July 31, 2007
Last verified: September 2005

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 Intervention
Metabolic Syndrome X Behavioral: Dietary weight loss +/- aerobic exercise

Study Type: Interventional
Study Design: 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

Resource links provided by NLM:

Further study details as provided by Bayside Health:

Primary Outcome Measures:
  • Whole-body sympathetic activity
  • Muscle sympathetic activity

Secondary Outcome Measures:
  • Insulin sensitivity
  • Lipid profile
  • Adipocytokines
  • Blood pressure
  • Baroreflex function
  • Forearm and calf blood flow

Estimated Enrollment: 66
Study Start Date: April 2005
Estimated Study Completion Date: December 2007
  Show Detailed Description


Ages Eligible for Study:   45 Years to 65 Years   (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
  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 identifier: 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
  More Information

Publications automatically indexed to this study by Identifier (NCT Number): Identifier: NCT00163943     History of Changes
Other Study ID Numbers: 7/05
Study First Received: September 12, 2005
Last Updated: July 31, 2007

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 processed this record on August 18, 2017