Assessing salt consumption in Switzerland

Increased salt consumption may have adverse effects on health. Consequently, the FSVO has commissioned a new study to survey current data on salt consumption. These data enable a better understanding of the health of the adult population in Switzerland. The valuable collaboration of the participants in the study is extremely important to accomplish the study.

Background

“All things are poison; there is nothing without poison; only the dose makes a thing non-poisonous.” (Paracelsus)

Whether something is poisonous, depends on the ingested amount – this also applies to salt. Although indispensable to life, a high intake of salt on a regular basis is associated with health problems, such as high blood pressure or cardiovascular illnesses.
According to the report in 2005 of the Federal Commission for Nutrition (FCN), older people, as well as overweight people, are prone to high blood pressure or diabetes, and ranked as a population group at risk. It is difficult to determine an individual’s salt sensitivity in respect to blood pressure. It is therefore recommended to seek to reduce the salt intake by the whole population, especially as this is not detrimental to any population group.

In comparison to the daily salt consumption recommended by the WHO, previous studies indicated that the salt consumption in Switzerland was too high. Consequently, the Salt Strategy 2008 – 2016 formulated for the first time the aim of reducing the daily consumption of salt by the Swiss population. These efforts were continued in the newly launched Swiss Nutrition Policy 2017 – 2024.

What is the aim of the study?

The aim of the study is to determine the daily salt consumption of the adult population in Switzerland. The measurement is performed on 24-hour urine.
The last salt study was carried out between 2010 and 2011. A periodic monitoring is important to understand how the salt consumption has developed.

Who may take part in the study?

A sub-group (random sample) of the population will be invited to take part in the study. The study participants will be selected at random by the Federal Statistics Office (FSO) on the basis of the register of residents.
Participation is voluntary for all persons, notwithstanding an invitation.

What will be done? - Course of the study

The study will be carried out countrywide by taking into consideration the three largest language regions. A total of four study centres will be created for this purpose in Lausanne, Bern, Zurich and Bellinzona.

The participants in the study visit their designated study centre twice. In their first visit their blood pressure, weight, height and waist circumference will be measured.
In addition, the participants receive the material and exact instructions for the 24-hour urine collection.
In the second visit the participants return their filled urine bottles to the study centre. Their blood pressure will be measured again. Furthermore, the participants will be asked to fill out a web-based questionnaire on their lifestyle, dietary habits and physical activity.

Sodium, potassium, chloride, creatinine and iodine will be measured in the urine samples.
A small quantity of the anonymised urine sample will also be frozen and serves as a sample material for further analyses.
Both this study and also all further studies, which use the collected urine as a sample material, require authorisation from the National Ethics Commission.

What happens to the data?

All personal data will be anonymised. The analyses are made for whole groups at the population level (e.g. according to gender or age group). Thus, any inference to the individual person is not possible.

When will the study be carried out?

Insofar as the corona situation allows, the recruitment of participants will begin in October 2021. The study runs up to the end of 2022.

Who will carry out the study?

The contracting authority of the study is the FSVO. The Centre universitaire de médecine générale et santé publique (Unisanté) and the Centre hospitalier universitaire vaudois (CHUV) in Lausanne are carrying out the study in collaboration with the Inselspital Bern, the Universitätsspital Zürich and the Ospedale Regionale di Bellinzona.