Assessing How the Body Responds to Increased Phosphate Intake, and How This Response Depends on Age and Sex.

NCT ID: NCT07149337

Last Updated: 2025-09-02

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 40 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-09-30
• Study Completion Date: 2027-09-30

Brief Summary

Kidney function declines with age and this could affect phosphate balance after an acute phosphate load (increased phosphate intake). In daily life, we regularly experience acute phosphate loads through our diet.

The aim of this clinical study is to determine whether the body's response to increased phosphate intake changes with age and whether there are sex differences in this response.

Detailed Description

Forty subjects (males and females aged 18-25 or 63-70) will ingest an oral phosphate load, after which their body's response will be assessed by collecting blood and urine samples over a period of ten hours.

Conditions

Aging; Kidney Disease; Mineral Metabolism

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Oral phosphate load

Participants will eat a standard phosphate dinner. The next morning, after consuming a standard phosphate breakfast, they will ingest a phosphate load (558 mg phosphorus) and provide blood and urine samples for nine hours.

Group Type: EXPERIMENTAL

Oral phosphate load

Intervention Type: OTHER

Participants ingest an oral phosphate load containing 558 mg of phosphorus once.

Interventions

Oral phosphate load

Participants ingest an oral phosphate load containing 558 mg of phosphorus once.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Healthy volunteers 18-25 and 63-70 years old
• 18.5 ≥ BMI < 26 kg/m2
• 0.84 ≥ phosphate in plasma ≤ 1.45 mM
• 2.20 ≥ calcium in plasma ≤ 2.50 mM
• 15 ≥ PTH in plasma ≤ 65 pg/ml
• eGFR ≥ 60 ml/min/1-73 m2
• 90 ≥ Systolic blood pressure ≤ 140 mmHg
• 60 ≥ Diastolic blood pressure ≤ 85 mmHg
• No hematuria and no acute urinary tract infection
• Ability and willingness to participate in the study
• Voluntary signed inform consent

Exclusion Criteria

• Diabetes mellitus
• Pregnancy
• History of kidney stones
• History of parathyroidectomy
• History of anorexia nervosa
• History of bulimia
• History of solid organ transplantation.
• Nephrolithiasis
• Sarcoidosis
• Chronic pancreatitis
• Chronic diarrhea
• Chronic liver disease
• Complete distal renal acidosis (dRTA)
• Cystinuria
• Hypo- or hyperaldosteronism
• Hyper- or hypotension
• Hypernatremia
• Gastrointestinal disorders
• Known hypersensitivity reactions to azoic dyes, acetylsalicylic acid, as well as antirheumatic drugs and painkillers (prostaglandin synthesis inhibitors).

Intake of vitamin D and calcium supplements, phosphate, bisphosphonates, cinacalcet, denusomab, teriparatide, systemic glucocorticoids or mineralcorticoids, antiepileptics, carboanydrase inhibitors or diuretics

• Minimum Eligible Age: 25 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Zurich

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Central Contacts

Carsten A Wagner, Prof. MD

Role: CONTACT

carsten.wagner@physiol.uzh.ch

41 44 635 50 23

Other Identifiers

2024-02538

Identifier Type: -

Identifier Source: org_study_id