Low Sodium Diet and Behavioral Intervention for Reversing Arterial Stiffening in Overweight Individuals

Obese individuals are at risk for developing cardiovascular disease (CVD). Increasing physical activity, losing weight, and reducing sodium intake may reverse arterial stiffness and blood vessel damage that is linked to obesity. This study will evaluate the effectiveness of a low sodium diet and a behavioral weight loss intervention in reducing arterial stiffness in overweight young adults.

CVD includes diseases that affect the heart and blood vessels. Arterial stiffness, in which arteries harden and become less flexible, increases the risk of developing CVD. Arterial stiffness increases both with age and in certain disease states, including high blood pressure, diabetes, and obesity. Young adults who are obese prematurely place themselves at risk for developing arterial stiffness and CVD. Physical activity and weight loss may reverse arterial stiffness in these individuals. Reducing sodium intake, which has been proven to decrease blood pressure, may also improve blood vessel function and arterial stiffness. The purpose of this study is to evaluate the effectiveness of a low sodium diet and a behavioral weight loss intervention in reducing arterial stiffness in young, moderately overweight individuals.

Participants will first attend a baseline study visit, at which time blood will be collected, and height, weight, waist circumference, and blood pressure will be measured. Questionnaires to assess medical history, physical activity levels, and dietary habits will be completed. An ultrasound will be used to evaluate blood vessel function and arterial stiffness. All participants will then take part in a 12-month behavioral and dietary intervention. The intervention will emphasize increasing physical activity and decreasing caloric intake by modifying lifestyle choices, physical and social environments, and attitudes toward food and exercise. Participants will be randomly assigned to follow either a low sodium diet or a normal sodium diet. During Months 1 through 4, participants will attend weekly study visits for group counseling sessions; during Months 4 through 8, study visits will occur once every two weeks; and during Months 8 through 12, they will occur once a month. At each study visit, weight, waist circumference, and blood pressure will also be measured. If necessary, individual counseling sessions will be scheduled. Participants will also document daily physical activity and caloric intake in a diary. Baseline evaluations will be repeated at Months 6, 12, and 24.

Eligibility Criteria:
Inclusion Criteria:

* Body mass index (BMI) between 25 and 35

Exclusion Criteria:

* High blood pressure currently being treated with medication
* Blood pressure greater than or equal to 140/90 mm Hg on two consecutive study visits
* Diabetes, defined as either a fasting glucose test result of .126 or current use of hypoglycemic medications
* Currently taking hyperlipidemia medication
* Currently taking vasoactive medications
* History of known atherosclerotic disease (e.g., angina, heart attack, lower extremity arterial disease)
* Underlying inflammatory condition (e.g., systemic lupus erythematosus, rheumatoid arthritis)
* Chronic infection
* Current participation in a formal exercise or weight loss program
* Pregnant or planning to become pregnant during the study