Changing Population Salt Consumption in Lithgow, Australia

A Before After Comparison of the Effectiveness of a Community-based Salt Reduction Program Done in Lithgow, Australia

The objective of this study is to determine whether a community-based salt reduction program can reduce average salt consumption levels. Baseline levels of salt consumption were measured in 2011, the salt reduction program was then implemented, and now in 2014 investigators are remeasuring salt consumption levels in the community. The hypothesis investigators are testing is that the salt reduction program will have led to a change in salt consumption levels between 2011 and 2014. The study is being done in Lithgow, a regional town in New South Wales , Australia.

Study Overview

• Status: Completed
• Conditions: Hypertension; Cardiovascular Disease; Blood Pressure
• Intervention / Treatment: Behavioral: Community-based salt reduction

Detailed Description

The primary objective of this project is to determine whether there have been changes in average salt consumption levels in the Lithgow population from 2011 to 2014. The primary null hypothesis to be tested is that there will be no difference between the mean 24-hour urinary sodium excretion levels between 2011 and 2014.

The sample of 419 individuals with 24-hour urine samples in the baseline survey and 600 individuals in the follow-up survey will provide 80% power to detect a difference of 0.7 g/day salt between the mean levels of excretion before and after the intervention. There will be more than 95% power to detect a difference of 1.0 g/day salt or greater.

• Study Type: Interventional
• Enrollment (Actual): 991
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Australia
  • New South Wales
    • Camperdown, New South Wales, Australia, 2050
      • The George Institute for Global Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• All adults over the age of 20 years residing in the Lithgow area are eligible
• No exclusion based on inter-current illness, use of medications or any other aspect of demography or personal history.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Salt reduction; Community-based salt reduction	Behavioral: Community-based salt reduction; Other Names: Education; Salt-substitute; Smartphone application - FoodSwitch/Saltswitch

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary sodium excretion (mmol/l)	A single 24-hour urine collection will be obtained with the first voided urine upon waking on the day of collection being discarded and participants then collecting all voided urine up to and including the first void the following morning. The times at the beginning and the end of urine collection are recorded.	up to 4 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sources of sodium	The multiple pass 24-hour dietary recall is used to determine all food and beverages consumed from midnight to midnight on the day before the interview, this method has been described in detail by prior reports. Food model booklets are used to assist with the reporting of quantity and prompts provided by interviewers are used to probe for complete food descriptions, variable recipe ingredients, and food preparation including salt added during cooking and at the table. Dietary data are entered into the nutrient analysis package FoodWorks Professional version 7. The food coding guidelines are used to code each food and beverage into major, sub-major and minor food categories.	up to 4 years
Knowledge, attitudes and behaviors towards salt intake	The measurement of knowledge attitude and behaviors towards salt is based upon a questionnaire adapted from the World Health Organization/Pan American Health Organization protocol for population level sodium determination. The questionnaire contains nine questions; four related to knowledge of personal consumption, recommended daily intake and possible harmful effects of salt and five assessing attitudes and behaviors to lowering salt intake.	up to 4 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary iodine excretion (ug/l)	UIE will be assessed in the spot urine samples of females aged 20-45 years old. The measurement will be completed by using ammonium persulfate digestion prior to Sandell-Koltoff reaction in a microtitre plate format.	up to 4 years

Collaborators and Investigators

• Sponsor: The George Institute
• Collaborators: National Health and Medical Research Council, Australia; New South Wales Health; New South Wales Food Authority; Australian Food and Grocery Council

Publications and helpful links

General Publications

• Land MA, Webster J, Christoforou A, Johnson C, Trevena H, Hodgins F, Chalmers J, Woodward M, Barzi F, Smith W, Flood V, Jeffery P, Nowson C, Neal B. The association of knowledge, attitudes and behaviours related to salt with 24-hour urinary sodium excretion. Int J Behav Nutr Phys Act. 2014 Apr 4;11(1):47. doi: 10.1186/1479-5868-11-47.
• Land MA, Webster J, Christoforou A, Praveen D, Jeffery P, Chalmers J, Smith W, Woodward M, Barzi F, Nowson C, Flood V, Neal B. Salt intake assessed by 24 h urinary sodium excretion in a random and opportunistic sample in Australia. BMJ Open. 2014 Jan 16;4(1):e003720. doi: 10.1136/bmjopen-2013-003720.
• Land MA, Jeffery P, Webster J, Crino M, Chalmers J, Woodward M, Nowson C, Smith W, Flood V, Neal B. Protocol for the implementation and evaluation of a community-based intervention seeking to reduce dietary salt intake in Lithgow, Australia. BMC Public Health. 2014 Apr 14;14:357. doi: 10.1186/1471-2458-14-357.
• Land MA, Wu JH, Selwyn A, Crino M, Woodward M, Chalmers J, Webster J, Nowson C, Jeffery P, Smith W, Flood V, Neal B. Effects of a community-based salt reduction program in a regional Australian population. BMC Public Health. 2016 May 11;16:388. doi: 10.1186/s12889-016-3064-3.

Study record dates

Study Major Dates

• Study Start: March 1, 2011
• Primary Completion (Actual): April 1, 2014
• Study Completion (Actual): April 1, 2014

Study Registration Dates

• First Submitted: March 30, 2014
• First Submitted That Met QC Criteria: April 2, 2014
• First Posted (Estimate): April 7, 2014

Study Record Updates

• Last Update Posted (Estimate): November 18, 2014
• Last Update Submitted That Met QC Criteria: November 17, 2014
• Last Verified: November 1, 2014

More Information

Terms related to this study

• Keywords: Dietary sodium; Urinary sodium excretion; Urinary iodine excretion
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: 2014079