Ignite Creation Date:
2024-05-05 @ 11:53 AM
Last Modification Date:
2024-10-26 @ 9:15 AM
Study NCT ID:
NCT00163943
Status:
UNKNOWN
Last Update Posted:
2007-08-01
First Post:
2005-09-12
Brief Title:
Sympathetic Activity in Individuals With the Metabolic Syndrome Benefits of Lifestyle Interventions
Sponsor:
Bayside Health
Organization:
Bayside Health
Study Overview
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
Status:
UNKNOWN
Status Verified Date:
2005-09
Last Known Status:
RECRUITING
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
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
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
Detailed Description:
Background
Autonomic dysfunction namely increased sympathetic drive and reduced vagal tone may participate in the pathogenesis and complications of the MetS Weight loss and aerobic exercise are first-line therapeutic strategies that are known to be beneficial in lowering blood pressure enhancing insulin action and preventing the development of type 2 diabetes However there is a paucity of data regarding their effects on sympathetic nervous system SNS activity In a recently completed Pilot study in 22 MS subjects we demonstrated that moderate dietary weight loss 7 of initial body weight is associated with marked reductions in whole-body norepinephrine spillover rate by 43 P 0005 and muscle sympathetic nervous activity MSNA by 15 P001 In the proposed project we wish to extend these observations by evaluating the clinical benefits of aerobic exercise and weight loss maintenance
Aims
1 To determine whether dietary weight loss in combination with aerobic exercise WL EX is more beneficial than dietary weight loss alone WL in reducing SNS activity and improving cardiovascular and metabolic parameters in middle aged men and women with abdominal obesity and a diagnosis of the MetS
2 To investigate the determinants of achieved weight loss with a focus on the roles of SNS activity b2-adrenoceptor polymorphisms resting metabolic rate plasma and interstitial adipocytokines
3 To determine whether clinical benefits during active weight loss negative energy balance are sustained after a 4-month weight loss maintenance program and to investigate the determinants of successful weight loss maintenance as above
4 To examine the inter-relationships between SNS activity insulin sensitivity metabolic anthropometric and haemodynamic parameters
Subjects
Sedentary men and women n 66 aged 45 to 65 years with a body mass index of 26 to 39 kgm2 who fulfil Adult Treatment Panel III criteria for the MetS
Study design
Randomized controlled parallel design comparison of
1 WL
2 WL EX or
3 Control no treatment
Investigations will be performed at baseline and at the end of 3-month lifestyle intervention and a 4-month weight-maintenance program WL and WL EX groups
Diets
A modified version of the DASH diet will be used at different caloric levels
Exercise
Bicycle riding performed for 40 minutes on alternate days at a moderate intensity of 65 of maximum heart rate Compliance will be assessed by VO2 max measurements
Investigations
SNS activity measurements multiunit and single-unit microneurographic recordings of MSNA whole-body norepinephrine spillover and abdominal adipose tissue and skeletal muscle interstitial noradrenaline concentration determined by microdialysis will be made before and during an oral glucose tolerance test together with haemodynamic calf blood flow measured by venous occlusion plethysmography measurements Changes in fat mass will be quantitated by DEXA scan Metabolic measurements will include resting metabolic rate insulin sensitivity lipid profile non-esterified fatty acids plasma and interstitial adipokinescytokines
Clinical significance
The proposed project will provide novel information about whole-body and regional sympathetic activity the determinants of sympathetic activity and the relative clinical benefits of active weight loss weight loss maintenance and aerobic exercise in middle-aged MetS subjects
Autonomic dysfunction namely increased sympathetic drive and reduced vagal tone may participate in the pathogenesis and complications of the MetS Weight loss and aerobic exercise are first-line therapeutic strategies that are known to be beneficial in lowering blood pressure enhancing insulin action and preventing the development of type 2 diabetes However there is a paucity of data regarding their effects on sympathetic nervous system SNS activity In a recently completed Pilot study in 22 MS subjects we demonstrated that moderate dietary weight loss 7 of initial body weight is associated with marked reductions in whole-body norepinephrine spillover rate by 43 P 0005 and muscle sympathetic nervous activity MSNA by 15 P001 In the proposed project we wish to extend these observations by evaluating the clinical benefits of aerobic exercise and weight loss maintenance
Aims
1 To determine whether dietary weight loss in combination with aerobic exercise WL EX is more beneficial than dietary weight loss alone WL in reducing SNS activity and improving cardiovascular and metabolic parameters in middle aged men and women with abdominal obesity and a diagnosis of the MetS
2 To investigate the determinants of achieved weight loss with a focus on the roles of SNS activity b2-adrenoceptor polymorphisms resting metabolic rate plasma and interstitial adipocytokines
3 To determine whether clinical benefits during active weight loss negative energy balance are sustained after a 4-month weight loss maintenance program and to investigate the determinants of successful weight loss maintenance as above
4 To examine the inter-relationships between SNS activity insulin sensitivity metabolic anthropometric and haemodynamic parameters
Subjects
Sedentary men and women n 66 aged 45 to 65 years with a body mass index of 26 to 39 kgm2 who fulfil Adult Treatment Panel III criteria for the MetS
Study design
Randomized controlled parallel design comparison of
1 WL
2 WL EX or
3 Control no treatment
Investigations will be performed at baseline and at the end of 3-month lifestyle intervention and a 4-month weight-maintenance program WL and WL EX groups
Diets
A modified version of the DASH diet will be used at different caloric levels
Exercise
Bicycle riding performed for 40 minutes on alternate days at a moderate intensity of 65 of maximum heart rate Compliance will be assessed by VO2 max measurements
Investigations
SNS activity measurements multiunit and single-unit microneurographic recordings of MSNA whole-body norepinephrine spillover and abdominal adipose tissue and skeletal muscle interstitial noradrenaline concentration determined by microdialysis will be made before and during an oral glucose tolerance test together with haemodynamic calf blood flow measured by venous occlusion plethysmography measurements Changes in fat mass will be quantitated by DEXA scan Metabolic measurements will include resting metabolic rate insulin sensitivity lipid profile non-esterified fatty acids plasma and interstitial adipokinescytokines
Clinical significance
The proposed project will provide novel information about whole-body and regional sympathetic activity the determinants of sympathetic activity and the relative clinical benefits of active weight loss weight loss maintenance and aerobic exercise in middle-aged MetS subjects
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None