Salt intake is the name of an additional assessment which includes additional urine analyses and an additional questionnaire. This additional assessment was implemented in Lifelines at the initiative of the National Institute for Public Health and the Environment (RIVM) . The aim of this project was to determine whether the average intake of sodium, potassium, and chloride of Lifelines participants in 2020 has changed compared to 2006-2007 as the result of initiatives and policy changes.
Note that the additional urine analyses are linked to the 24-h urine samples collected during the third assessment.

During the first invitation period (October-December 2020), all adult participants who made a third assessment visit 2 appointment in November or December 2020 were invited to participate in the salt intake additional assessment. The goal was to include participants from all age groups (18-30, 31-50, and 50+) and both genders. The first invitation period resulted in ~2,900 participants with additional urine analyses. After this first period, the additional assessment came to a stop due to COVID-19. During the second invitation period (third assessment visit 2 appointment in April-May 2021) ~4,000 additional participants were included (total ~6,900).

All adult participants meeting the inclusion criteria above, were also invited to participate in an additional questionnaire. Resulting in ~8,300 invites with a response of ~4,500 completed questionnaires (54%).

• Dinnissen and Hendriksen (2022). Zout- en kaliuminname in 2020/2021 en trend in inname voor volwassenen in Noord Nederland (Report RIVM).

The additional urine analyses can be found in the subsection Biospecimen: Urine (3 items), while the questionnaire variables can be found in the subsection Salt intake (55 items).