This proposed calibration study is designed to evaluate the correlation of urinary sodium excretion between NHANES timed urine and 24-hour urine collections.

The study will be conducted with 400 volunteer participants aged 18-39 years old. Participants will be asked to collect urine samples over a 24-hour period. One-third of the participants (n=133) will be asked to collect a second 24-hour urine 4-11 days later. A 24-hour dietary recall interview will be collected after the completion of each 24-hour urine collection. Results from this study will be used to assess how well the sodium excretion estimated from NHANES timed urine correlates with data from 24-hour urine collection. It will provide valuable information on the potential of NHANES timed urine collections to be used to characterize trends in U.S. population sodium intake.

Inclusion Criteria:

English speaking

• Aged 18-39 years old
• 50% Black; 50% all other
• 50% male; 50% female
• At least 50 (25 male; 25 female) of the 400 participants likely to have high sodium diet indicated by selected dietary behaviors
• At least 50 (25 male; 25 female) of the 400 participants likely to have low sodium diet indicated by selected dietary behaviors

Exclusion Criteria:

• Pregnant or trying to get pregnant.
• Taking loop diuretics
• Chronic kidney disease
• New hypertension treatment or change in hypertension treatment in the last 2 weeks

The study was conducted with 407 adult volunteer participants living in the Washington DC, Maryland areas who met the following criteria:

Data are available through the NCHS Research Data Center