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Biomarkers from urine and saliva are provided, assessing energy expenditure and dietary intake.

DLW Energy Expenditure

Doubly Labeled Water (DLW) provides an assessment of a participant’s total energy expenditure (TEE) over an approximately-2-week period.

TEE is assessed by lab analysis of urine collected at several time points, looking for rates of elimination of two heavy atoms, deuterium and oxygen-18. After a loading dose of doubly labeled water (a mixture of deuterium and oxygen-18), deuterium is eliminated from the body as water and oxygen-18 as both water and carbon dioxide. The difference between the elimination rates provides a measure of carbon dioxide production. Carbon dioxide is the end product of energy metabolism and so provides a measure of energy expenditure.

The DLW measurement protocol involves the administration of the labeled water and collection of urine specimens on two days separated by two weeks. Participants consume dosing water at a clinic visit and provide 1 pre- and 3 post-dose urine samples. They are provided with materials to collect 2 additional urine samples at home on the day two weeks after the clinic visit.

The DLW protocol was initiated in the Study Center (at Clinic Visit 1 for Groups 1 and 3, and at Clinic Visit 2 for Groups 2 and 4). For a subsample of participants, the protocol was repeated at the Study Center approximately 6 months after the initial clinic visit (i.e., at Clinic Visit 2 for subsample participants in Groups 1 and 3 and at Clinic Visit 3 for subsample participants in Groups 2 and 4).

You may view data dictionaries and formats for the DLW Energy Expenditure files. Datasets can be obtained by submitting a request.

Summary Available Data
  • A set of urine samples, with a small subsample providing a second set 6 months later
  • 750 participants have DLW results (38 have two)
  • DLW summary results: TEE, dosing dates and other information from the lab

Urine Collections

Two 24-hour urine samples were collected at home by participants. Participants were asked to provide sets of urine samples twice, six months apart. The 24-hour period started after the first void of the morning and included the first void from the following day. Couriers picked up the samples and delivered them to the clinic. The 24-hour urine samples were then analyzed for total nitrogen, sodium, and potassium.

You may view data dictionaries and formats for the Urine Result files. Datasets can be obtained by submitting a request.

Summary Available Data
  • Two urine samples taken 6 months apart
  • 930 participants have results
    • 831 completed both administrations
    • 69 completed only the 1st
    • 30 completed the 2nd
  • Date and Time
  • Mean levels within the sample and derived estimates of daily dietary intake of Potassium, Sodium, and Nitrogen.

Saliva

The Saliva Collection Form collects data about the timing and medication being taken during the saliva sample collection. Participants were asked to provide saliva samples twice during the study with six months between administrations.

Saliva collection form data is provided in one format: 1 record per person containing both collection forms.

Click here for data dictionaries and formats for the Saliva Collection Form files. Datasets can be obtained by submitting a request.

Summary Available Data
  • Saliva Collection Form Data
  • Collected twice
    • Groups 1&3 in Month 0 and Month 6
    • Groups 2&4 in Month 5 and Month 11
  • 912 Participants
    • 764 completed both administrations
    • 64 completed only the 1st
    • 84 completed only the 2nd

SALIVA COLLECTION FORM DATA

  • Date
  • Time
  • Completion Status
  • Medication being taken
  • Sample ID