Autonomic Nervous System and Exercise In Gestational Diabetes
Condition: Gestational Diabetes; Cardiovascular Risk Factors
MeSH terms: Diabetes, Gestational; Diabetes Mellitus
Study type: Interventional

Summary: 
      The focus of this study is on individualized exercise prescription on primary prevention of
      cardiovascular diseases (CVD). Special attention is set on autonomic nervous system function
      and inflammation.

      This study will seek novel, cost-effective models of exercise prescription that will
      emphasize individuals own response on her health and which would be easily implemented to
      primary health care as primary prevention for CVD. According to power calculation,sixty women
      planning pregnancy with BMI equal or over 30 and/or history of GDM will be recruited and
      randomized to an individual exercise arm (n=20), a general exercise arm (n=20) and a control
      arm (n=20). General intervention group will receive general exercise and dietary counselling
      whereas a personal exercise and dietary programs will be planned for individualized exercise
      group. Those randomized to the control arm will receive no dietary and exercise information.

      Clinical exercise tests and autonomic nervous system tests will be performed in the beginning
      of the study and after 3 months intervention. Blood samples for markers of inflammation,
      glucose homeostasis and lipid status will be collected from prepregnancy period until 1 years
      after delivery.
    

Detailed description: 
      Gestational diabetes (GDM) is one of the earliest signs for increased risk of developing CVD.
      In addition to this independent association, GDM increases CVD risk through type 2 diabetes.
      The physiological basis for his disease progression is not yet fully understood. Increasing
      evidence exists on interplay of insulin resistance and subclinical inflammation, and more
      recently on unbalance of the autonomic nervous system.

      There is unequivocal evidence that increased physical activity and regular exercise can
      prevent risk factors that give rise to cardiovascular complications. According to a recent
      meta-analysis, exercise started before and continued throughout pregnancy may lead to marked
      GDM risk reduction. Unfortunately, exercise in most lifestyle studies is usually unstructured
      or unsupervised or does not meet current guidelines. There is also a significant gap in our
      understanding of how to target, deliver and prescribe the beneficial type of exercise to
      patients at risk in the community.

      Sixty women planning pregnancy with BMI equal or over 30 and/or history of GDM will be
      recruited and randomized to an individual exercise arm (n=20), a general exercise arm (n=20)
      and a control arm (n=20). General intervention group will receive general exercise and
      dietary counselling whereas a personal exercise and dietary programs will be planned for
      individualized exercise group. Those randomized to the control arm will receive no dietary
      and exercise information. All subjects will be followed by diabetes nurses every 3 months as
      follows: at the time of recruitment, after 3 months intervention period, int the 1st, 2nd and
      3rd trimester of pregnancy and 6 weeks, 6 months and 1 year postpartum. The following
      measurements will be performed at every visit:blood pressure, weight, waist-to-hip ratio,
      glucose homeostasis (2-h OGTT, Pf- insulin, Pf- glucose, insulin resistance (Homa-IR),
      GHbA1c, lipids (total cholesterol, LDL, HDL, triglycerides), inflammatory markers
      (sCRP,S-amyloid A, IL-1 and 6, alpha 1-glycoprotein, SHBG), adipokines (endothelin,
      adrenomedullin, adiponectin),dipeptidyl peptidase-4 (DPP-4), atrial natriuretic peptides
      (ANP, proBNP).For all study participants, 15 D and EDPS questionnaires are used for
      assessment of quality of life and mental health. Registered costs of the intervention will be
      calculated for cost-effectiveness analysis.

      Both endurance and strength training will be included in the exercise program of the
      individual exercise study group. Heart rate will be monitored with heart rate belt and
      registered in internet-based exercise diary which can be instantly followed by the exercise
      professionals. This information will be used for fine-tuning of their exercise prescription
      during the intervention period. Diet and weight target will be planned individually by a
      dietician. Actualized diet will be registered in an internet-based diary instantly followed
      by the study dietician who will guide the subjects personally by e-mail and suggest further
      dietary changes if needed.

      All subjects will perform an exercise test in the beginning of the study and after 3 months
      intervention with a step incremental protocol on a cycle ergometer until volitional fatigue.
      Extensive and advanced technologies will be used to monitor exercise responses, including
      breath-by-breath ventilation and alveolar gas exchange; exercise ECG; impedance cardiography;
      automatic arterial blood pressure; analysis system for heart rate variability and blood
      pressure variability, baroreflex sensitivity, muscle electrical activity, arterial O2
      saturation and local cerebral and muscle tissue oxygenation with near-infrared spectroscopy.
      The autonomic nervous system measurements, including 24 hour ECG monitoring, heart rate
      variability assessment with controlled breathing rate, the orthostatic test and a 5 min
      handgrip test, will be performed during another visit to the laboratory. Total haemoglobin
      mass and blood volume will be determined by carbonmonoxy rebreathing method.
    

Intervention name(s): individual exercise; general exercise
Intervention type(s): Other; Other
Intervention description(s): individual exercise and dietary prescription; general exercise counselling
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: gestational diabetes; inflammation; autonomic nervous system