Dietary Phosphate and Serum Phosphorus

Completed

• Conditions: Phosphorus Metabolism Disorders

• Registration Number: NCT02435017
• Lead Sponsor: Linda W. Moore

Brief Summary

Overall study design is to review National Health and Nutrition Examination Survey (NHANES) data 1999-2008 for nutrition risk according to kidney function. Substudies will be performed to review the association of nutrients and overall dietary intake compared to biomarkers available in NHANES during this period.

Detailed Description

Data from NHANES 2003-2006 were used to evaluate the relationship between estimated dietary phosphorus intake and the measured serum phosphorus. The following variables were used:

1. Demographics: Age, sex, race/ethnicity

2. Dietary variables: Foods, food groups (as reported by the United States Department of Agriculture (USDA) method, further standardized to the Academy of Nutrition and Dietetics method for portion size and then divided into groups having inorganic phosphate additives or no inorganic phosphate additives), food weight (g), phosphorus (mg), dietary supplements

3. Socioeconomic variables: education, family income

4. Laboratory variables: serum creatinine, phosphorus; urine albumin, creatinine

5. Clinical assessments: hypertension (proportion having blood pressure ≥140 millimeters of mercury (mmHg) diastolic or ≥90 mmHg systolic or taking antihypertensive medications); hyperglycemia (proportion having serum glucose \>126 mg/dL or taking medications for diabetes); kidney function based on Chronic Kidney Disease Epidemiology Collaboration (2009) equation, evaluated in 15 milliliters/min/1.73m2 increments from \<15 to \>105; anthropometrics (BMI, kg/m2; obesity class I, II, III)

Study Timeline

• Study Start: 2003-01
• Primary Completion: 2006-12
• Study Completion: 2009-07
• Study First Submitted: 2015-04-22
• Study First Submitted QC: 2015-04-30
• Study First Posted: 2015-05-06
• Status Verified: 2018-09
• Last Update Submitted: 2018-09-13
• Last Update Posted: 2018-09-17

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 7895

Inclusion Criteria

• Serum creatinine

Exclusion Criteria

• Pregnancy
• No dietary intake interview
• Dietary intake interview not valid
• Answered the question "Have you had dialysis in the past year?" as "Yes"

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Serum phosphorus concentration	approximately 24 hours	Serum phosphorus concentration on the day that 24-hour dietary recall was obtained (reflecting dietary intake the day prior to blood draw); measured in mg/dL

Secondary Outcome Measures

Name	Time	Method
Kidney function level	Baseline	Kidney function estimated from Chronic Kidney Disease Epidemiology Collaboration (2009) equation, mL/min/1.73m2, and separated into 15mL/min increments