The aim of this study was to investigate the feasibility and efficacy of a high intake of milk and/or cheese products compared to phosphate tablets in patients with hypophosphatemic rickets when evaluating the S-phosphate levels as a main effect parameter. The study was designed as a randomized, multiple crossover study.

Objectives:

Standard treatment of hypophosphatemic rickets consists of oral phosphate tablets and vitamin D analogous. Due to their rapid absorption, serum-phosphate fluctuations can occur and secondary hyperparathyroidism may be a consequence. Our aim was to evaluate, if phosphate supplement administered as milk or cheese is superior or equal to phosphate tablets in patients with hypophosphatemic rickets

Study population:

Patients with genetic verified hypophosphatemic rickets were included in the period from August 2015 to June 2016. Patients were excluded from the study if they presented with tertiary hyperparathydoism, were treated with Cinacalcet or suffered from milk allergy.

Study design:

The study was designed as a randomized, multiple crossover study with three treatment periods consisting of the regular oral phosphate supplement, a high milk intake or a high cheese intake (randomization.com). Patients were instructed to discontinue their regular treatment, except for their usual doses of D vitamin analogs, three days prior to sample collection and instead engage in the study treatment. Furthermore, they should follow their normal eating habits while undergoing the study treatment, which was controlled by food and liquid registrations.

At the phosphate supplement session, the patients were treated with an 800 mg oral phosphor supplement distributed over five times a day independently of any prior treatment dose. At the cheese session, the patients were treated with an estimated phosphate content of 800 mg distributed over 5 meals. At the milk session, the patients were treated with 800 ml of milk daily corresponding to approximately 800 mg phosphor per day.

Sampling:

After three days of treatment, the patients visited our clinic for anaerobically handled blood samples, which were collected 5 times through out one day for calcium, phosphate, parathyroid hormone, fibroblast growth factor 23 and basic phosphatase. Urine samples for calcium and phosphate was collected in containers from 0800 to 1200 and from 1200 to 1600. A 24-hour urine samples was obtained from the day before the sampling from 0800 to 0800 hours the following morning.

Inclusion Criteria:

• Genetic verified hypophosphatemic rickets.
• In treated with oral phosphate tablets.

Exclusion Criteria:

• Tertiary hyperparathydoism.
• In treatment with Cinacalcet.
• Suffered from milk allergy.

Publication.