The Links Between Water and Salt Intake, Body Weight, Hypertension and Kidney Stones: a Difficult Puzzle

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01100580
Recruitment Status : Unknown
Verified April 2010 by University of Parma.
Recruitment status was:  Not yet recruiting
First Posted : April 9, 2010
Last Update Posted : April 9, 2010
Information provided by:
University of Parma

Brief Summary:

Nephrolithiasis is a disease that strikes roughly 10% of the Italian population and its incidence in industrialized countries is on the increase. The most common form of the disease (80%) is Idiopathic Calcium Nephrolithiasis (ICN) with calcium-oxalate (CaOx) and/or calcium-phosphate (CaP) stones. The etiopathogenesis involves both genetic and acquired factors, the interplay of which leads to urinary biochemical anomalies at the root of stone formation. The elements and urinary compounds involved are known as "urinary stone risk factors". The risk factors for CaOx stones consist of low urine volume, hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia and hypomagnesuria. In the case of CaP stones, the hyperphosphaturia and pH parameters are of particular importance; a pH>7 promotes the formation of stones prevalently composed of phosphates, while a pH of between 6 and 7, associated with a volume <1l/day, can raise CaP supersaturation to a dangerously high level and lead to the formation of mixed CaOx and CaP stones. For uric acid stones, the elements involved are hyperuricosuria and pH<5.5. In general, the most prevalent alteration in ICN is hypercalciuria (50%). Hypertension and obesity are also social diseases with important epidemiological similarities to nephrolithiasis. These affinities have led to the search for a common pathogenic moment. As far as hypertension is concerned, various studies have demonstrated high calciuria in hypertensives with a linear relationship between 24-h calciuria and arterial blood pressure. The incidence of stone disease is greater in hypertensives than in normotensives and, by the same token, the incidence of hypertension is greater in stone formers than in non stone formers, but it is not clear whether nephrolithiasis is a risk factor for hypertension or vice versa. Moreover, a linear relationship exists between calciuria and natriuria, where the calcium is the dependent variable, with a much steeper slope of the straight line in stone formers and hypertensives compared to controls. It has, in fact, been demonstrated that to reduce calcium, it is more efficacious to reduce sodium intake as opposed to calcium intake. Finally, BMI and body weight are independently associated with an increase in stone risk even though, due to a number of bias (limited weight categories, low number of obese persons in the study populations, no control group, no recording of food intake) the studies published failed to be conclusive. In the final analysis, stone disease, arterial hypertension and excess weight/obesity prove to be closely interconnected and it is possible to intervene with targeted diets aimed at reducing the risk of illness and death from these diseases. Among such dietary approaches, the reduction of sodium chloride in food, increased hydration and an increased intake of foods with an alkaline potential seem to play an important role.

For many years now, the investigators research unit has been involved in projects, partially financed by the Italian Ministry of University and Research (MIUR), geared towards studying the effects induced by dietary changes in patients with calcium stone disease. The aim of the present project is to analyse in depth the relationship between stone disease, hypertension, body weight and water and salt intake both in the general population of the area of Parma (where historically and by gastronomic tradition, the usual diet tends to have a high salt content) and in a selected population of stone formers and hypertensives not under treatment. A representative sample of the population of the area of Parma will be studied, divided on the basis of weight category, in order to assess water and salt intake and relationships with the presence of hypertension, and a sample of normal and hypertensive stone formers randomized to receive for one year either water therapy+low salt diet or water therapy alone.

Condition or disease Intervention/treatment Phase
Urinary Stones Hypertension Overweight Obesity Dietary Supplement: low salt diet Dietary Supplement: water therapy Not Applicable

  Show Detailed Description

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 350 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: The Links Between Water and Salt Intake, Body Weight, Hypertension and Kidney Stones: a Difficult Puzzle
Study Start Date : May 2010
Estimated Primary Completion Date : May 2011
Estimated Study Completion Date : May 2012

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: water therapy
The term "water therapy" refers to an abundant intake of water with a low mineral and low sodium content (at least 2 litres in winter and 3 in summer).
Dietary Supplement: water therapy
abundant intake of water with a low mineral and low sodium content (at least 2 litres in winter and 3 in summer).

Experimental: low salt diet + water therapy
low salt diet refers to a salt intake of 4 g/day
Dietary Supplement: low salt diet
Daily salt intake less than 4 g/day

Primary Outcome Measures :
  1. normalization of urinary stone risk factors [ Time Frame: one year ]

Secondary Outcome Measures :
  1. urinary sodium/calcium relationship [ Time Frame: one yaer ]
  2. blood pressure reduction [ Time Frame: one year ]
  3. relationship between 24h-calciuria and blood pressure [ Time Frame: one year ]
  4. stone rate reduction [ Time Frame: one year ]
  5. correlation BMI-urinary stone risk factors [ Time Frame: one year ]
  6. compliance [ Time Frame: one year ]

Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

For the stone formers main inclusion criteria

  • age between 20 and 70 years
  • caucasian race
  • idiopathic calcium stone disease
  • normal renal function (creatininemia <1.2 mg/dl)

Main exclusion criteria

  • other major diseases
  • diseases affecting the mineral and electrolyte metabolism (diabetes, endocrine diseases, inflammatory diseases etc.)
  • treatments affecting the mineral and electrolytic metabolism (vitamin D, acetazolamide, anti-epilectic drugs, steroids etc).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01100580

Contact: Loris Borghi, Prof +390521703375

University of Parma Not yet recruiting
Parma, Italy, 43100
Contact: Loris Borghi, Prof    +390521703375   
Principal Investigator: Loris Borghi, Prof         
Sponsors and Collaborators
University of Parma
Principal Investigator: Loris Borghi, Prof University of Parma

Responsible Party: Prof. Loris Borghi, University of Parma Identifier: NCT01100580     History of Changes
Other Study ID Numbers: FORST-1028
First Posted: April 9, 2010    Key Record Dates
Last Update Posted: April 9, 2010
Last Verified: April 2010

Keywords provided by University of Parma:
Low-salt diet
blood pressure
urinary stone risk factors

Additional relevant MeSH terms:
Kidney Calculi
Body Weight
Urinary Calculi
Vascular Diseases
Cardiovascular Diseases
Signs and Symptoms
Pathological Conditions, Anatomical
Kidney Diseases
Urologic Diseases