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

NCT01100580 | Unknown DMC

• 1 other identifier: FORST-1028
• Study Type: interventional
• Target: 350
• Locations: 1 country
• Sites: 1

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.

Conditions

Urinary Stones; Hypertension; Overweight; Obesity

Keywords

Low-salt diet; calciuria; blood pressure; nephrolithiasis; hypertension; BMI; urinary stone risk factors

Outcome Measures

Primary Outcomes (1)

• normalization of urinary stone risk factors

  one year

Secondary Outcomes (6)

• urinary sodium/calcium relationship

  one yaer

• blood pressure reduction

  one year

• relationship between 24h-calciuria and blood pressure

  one year

• stone rate reduction

  one year

• correlation BMI-urinary stone risk factors

  one year

Study Arms (2)

water therapy

ACTIVE COMPARATOR

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

low salt diet + water therapy

EXPERIMENTAL

low salt diet refers to a salt intake of 4 g/day

Dietary Supplement: low salt diet

Interventions

low salt diet DIETARY_SUPPLEMENT

Daily salt intake less than 4 g/day

low salt diet + water therapy

water therapy DIETARY_SUPPLEMENT

abundant intake of water with a low mineral and low sodium content (at least 2 litres in winter and 3 in summer).

water therapy

Eligibility Criteria

• Age: 20 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• 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).

Sponsors & Collaborators

• University of Parma: lead

Study Sites (1)

University of Parma

Parma, 43100, Italy

Location

Related Publications (5)

• Goldfarb DS. Increasing prevalence of kidney stones in the United States. Kidney Int. 2003 May;63(5):1951-2. doi: 10.1046/j.1523-1755.2003.00942.x. No abstract available.

  PMID: 12675877 BACKGROUND

• Elliott P, Stamler J, Nichols R, Dyer AR, Stamler R, Kesteloot H, Marmot M. Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. Intersalt Cooperative Research Group. BMJ. 1996 May 18;312(7041):1249-53. doi: 10.1136/bmj.312.7041.1249.

  PMID: 8634612 BACKGROUND

• Goulding A, McParland BE. Fasting and 24-h urinary sodium/creatinine values in young and elderly women on low-salt and salt-supplemented regimens. J Cardiovasc Pharmacol. 1990;16 Suppl 7:S47-9.

  PMID: 1708023 BACKGROUND

• Borghi L, Schianchi T, Meschi T, Guerra A, Allegri F, Maggiore U, Novarini A. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med. 2002 Jan 10;346(2):77-84. doi: 10.1056/NEJMoa010369.

  PMID: 11784873 BACKGROUND

• Taylor EN, Stampfer MJ, Curhan GC. Obesity, weight gain, and the risk of kidney stones. JAMA. 2005 Jan 26;293(4):455-62. doi: 10.1001/jama.293.4.455.

  PMID: 15671430 BACKGROUND

MeSH Terms

Conditions

Urinary Calculi; Hypertension; Overweight; Obesity; Nephrolithiasis

Interventions

Diet, Sodium-Restricted; Water

Condition Hierarchy (Ancestors)

Urolithiasis; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms; Vascular Diseases; Cardiovascular Diseases; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Kidney Diseases

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena; Hydroxides; Alkalies; Inorganic Chemicals; Anions; Ions; Electrolytes; Oxides; Oxygen Compounds

Study Officials

• Loris Borghi, Prof

  University of Parma

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Loris Borghi, Prof

CONTACT

+390521703375; loris.borghi@unipr.it

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: March 29, 2010
• First Posted: April 9, 2010
• Study Start: May 1, 2010
• Primary Completion: May 1, 2011
• Study Completion: May 1, 2012
• Last Updated: April 9, 2010

Record last verified: 2010-04

Locations

IT (1)