Sodium hydroxide

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

other: review of articles

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original references are not available

Data source

Reference

Reference Type:

review article or handbook

Title:

Recommendations on dietary salt

Author:

Fodor, J.G.

Year:

1999

Bibliographic source:

CMAJ, May 4, 1999; 160 (9 Suppl), page S29-S34

Materials and methods

Objective of study:

other: evidence-based recommendations concerning effects of dietary salt intake on prevention and control of hypertension in adults (except pregnant women)

Principles of method if other than guideline:

A MEDLINE search was conducted for the period 1966-1996 using the terms hypertension, blood pressure, vascular resistance, sodium chloride, sodium, diet, sodium or sodium chloride dietary, sodium restricted/reducing diet, clinical trials, controlled clinical trial, randomized controlled trial and random allocation. Both trials and review articles were obtained, and other revelant evidence was obtained from the reference lists of the articles identified, from the personal files of the autors and through contacts with experts. The articles were reviewed, classified according to study design and graded according to level of evidence. In addition, a systematic review of all published randomized controlled trials relating to dietary salt intake and hypertension was conducted

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium

EC Number:

231-132-9

EC Name:

Sodium

Cas Number:

7440-23-5

IUPAC Name:

sodium

Details on test material:

- Name of test material (as cited in study report): sodium

Radiolabelling:

no

Test animals

Species:

human

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

STUDY SUBJECTS:
- Age at study initiation (in articles reviewed): subjects in the studies of normotensive people were generally younger (mean age 26 years) than those in the studies of hypertensive people (mean age 47 years)
- Diet: dietary salt intake was studied in the articles reviewed

Administration / exposure

Route of administration:

oral: feed

Vehicle:

not specified

Duration and frequency of treatment / exposure:

Studies of normotensive subjects tended to be short-term studies with less than 1 month of intervention. Only 3 long-term studies of normotensive subjects (lasting more than 1 year) were identified. Trials with hypertensive subjects had longer intervention periods, and 5 long-term studies were identified.

No. of animals per sex per dose / concentration:

number of subjects not specified.

Control animals:

other: normotensive population

Statistics:

A statistical analysis was performed to determine the effect of dietary interventions by correlating changes in urinary excretion of sodium with changes in blood pressure.

Results and discussion

Any other information on results incl. tables

Twenty-nine studies of normotensive subjects and 30 studies of hypertensive subjects were identified and reviewed. Studies of normotensive subjects tended to be shortterm studies with less than 1 month of intervention. Only 3 long-term studies of normotensive subjects (lasting more than 1 year) were identified. The subjects in the studies of normotensive people were generally younger (mean age 26 years) than those in the studies of hypertensive people (mean age 47 years). Trials with hypertensive subjects had longer intervention periods, and 5 long-term studies were identified. Apart from the meta-analysis, 19 additional studies were evaluated.

-Restriction of salt intake for normotensive people is not recommended at present because of insufficient evidence of hypertension (grade B recommendation)

-To avoid excessive intake of salt people should be counselled to choose foods low in salt (e.g., pre-prepared foods), to refrain from adding salt at the table and minimize the amount of salt used in cooking, and to increase their awareness of the salt content of food choices in restaurants (grade D recommendations)

-It is recommended that the salt consumption of hypertensive patients be determined by interview (grade D recommendation)