Clinical trial NCT03808090: Obesity and Endogenous Oxalate Synthesis
Official title: Obesity and Endogenous Oxalate Synthesis
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Obesity
Keywords: oxalate
obesity
kidney stones
Lead sponsor: University of Alabama at Birmingham
Sponsor class: OTHER
Collaborators: name: National Institutes of Health (NIH)
name: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
First posted: 2019-01-17
Enrollment: 58
Sex: ALL
Minimum age (years): 19
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: The goal of this study is to determine if obesity is associated with increased endogenous oxalate synthesis as assessed by urinary oxalate excretion, which is a known risk factor for calcium oxalate kidney stones.

The study will recruit adult participants without history of kidney stones. Participants will

* Ingest fixed diets containing low amounts of oxalate for 4 days
* Collect 24-hr urine samples during the fixed diet

Detailed description: In this study the investigators propose to measure the excretion of urinary oxalate on a fixed diet with controlled amounts of oxalate, in individuals of varying body sizes without history of kidney stones. The 24-hr urinary oxalate excretion on such a low-oxalate normal calcium fixed diet is determined to be an appropriate surrogate for endogenous oxalate synthesis.

Screening phase. The study will enroll 60 individuals without history of kidney stones (30 males/30 females) at the University of Alabama at Birmingham (UAB).

Screening will include blood complete metabolic profile, 24-hr urine specimens collected at home on self-selected diets and anthropometric measurements.

Dietary phase Participants will ingest a low-oxalate (\<60 mg/day), normal calcium (1000 mg/day) fixed diet for 4 consecutive days, collect three 24-hr urines after 1 day of dietary equilibration and have a fasted blood draw on day 5.

Eligibility criteria: Inclusion Criteria

Age 19-70 yrs Body Mass Index \> 18.5 kg/m2 Normal fasting serum electrolytes on comprehensive metabolic profile Willing to ingest fixed diets

Exclusion Criteria

Chronic Kidney Disease, estimated glomerular filtration rate \< 60 ml/mn/1.73m2 Primary hyperoxaluria Liver, endocrine or renal diseases or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results, including: Cystic fibrosis, Cystinuria, Uric acid stone former, Nephrotic syndrome, Sarcoidosis, Renal tubular acidosis, Primary hyperparathyroidism, Neurogenic bladder, Urinary diversion Pregnancy or breast-feeding Incompatible dietary requirements with the study, food allergies or intolerance to any of the foods in study menus Active malignancy or treatment for malignancy within 12 months prior to screening Utilization of immunosuppressive medication Uncontrolled Hypertension or diabetes

Primary outcomes:
measure: Urinary Oxalate Excretion
timeFrame: 3 days on the fixed diet
Secondary outcomes:
measure: Urinary Glycolate Excretion
timeFrame: 3 days on fixed diet
measure: Urinary Creatinine Excretion
timeFrame: 3 days on the fixed diet
Other outcomes:
Locations:
city: Birmingham
country: United States
facility: University of Alabama at Birmingham
state: Alabama
Study officials:
affiliation: University of Alabama at Birmingham
name: Kyle D Wood, MD
role: PRINCIPAL_INVESTIGATOR
References: