Dietary patterns and mortality in Switzerland

ISRCTN	ISRCTN10294463
DOI	https://doi.org/10.1186/ISRCTN10294463
Secondary identifying numbers	DP2017JPK

Submission date: 21/09/2017
Registration date: 04/10/2017
Last edited: 03/10/2017

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Other

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
Dietary patterns and quality can be assessed based on a posteriori approach which is based on a study population. The association of a posteriori dietary patterns with mortality allows researchers to assess the influence of dietary choices on the development of disease. In Switzerland, several population-based surveys included comparable nutrition-related information that can be linked to mortality data. The MONICA participants to fill out questionnaires about their dietary patterns and provide body measurements. The NFP1A study was a study that invited participants to complete a questionnaire about nutrition, physical activity, demographic and socioeconomic information. Then participants are provided in a programme to lower risk factors for heart diseases. Another study linked these studies to the Swiss census data to see if the participants are still alive. The aims of this study is to study a posteriori dietary patterns in Switzerland, to characterize groups of individuals sharing similar dietary patterns and to examine whether certain dietary patterns are associated with changes in all-cause, cancer or cardiovascular mortality.

Who can participate?
Participants from the MONICA or NRP1A studies with successful linkages to the Swiss National Cohort.

What does the study involve?
This is a secondary analysis of the MONICA and the NFPA1A studies, as well as the linkage study between those two studies to the census data of Switzerland to determine whether they are dead or alive. The data is analysed to examine posteriori dietary patterns, the association between dietary patterns and demographics and the mortality ratio for different dietary patterns.

What are the possible benefits and risks of participating?
There are no benefits or risks with participation.

Where is the study run from?
University of Zurich (Switzerland)

When is the study starting and how long is it expected to run for?
February 2017 to September 2018

Who is funding the study?
Swiss National Science Foundation (Switzerland)

Who is the main contact?
Dr Jean-Philippe Krieger

Contact information

Dr Jean-Philippe Krieger
Scientific

University of Zurich
Hirschengraben 82
Zurich
8001
Switzerland

ORCID ID	0000-0003-1913-4466

Study information

Study design	Observational cohort study
Primary study design	Observational
Secondary study design	Cohort study
Study setting(s)	Other
Study type	Prevention
Participant information sheet	No participation information sheet available
Scientific title	A posteriori dietary patterns and mortality in a general population sample of Switzerland
Study objectives	A posteriori dietary patterns are associated with changes in all-cause or disease-specific mortality in the general population.
Ethics approval(s)	Ethics Committee of the Canton of Zurich, 12/06/2008, ref: KEK-StV no. 13/06
Health condition(s) or problem(s) studied	Mortality (all-cause; cancer; cardiovascular; others)
Intervention	This study is an analysis of already available and published data. It is based upon two original studies: MONICA from the WHO and NFPA1A from the Swiss National Science Foundation and the linkage of these studies with census data to create a cohort. There are no interventions for participants in this study. This study includes a secondary analysis of the original studies and the linkage study. This study included 15,936 participants from 2 population-based studies (NFP1A, MONICA1-3 - 1977 to 1993) who fully answered a simplified 24-hour recall. Mortality data was available through anonymous record linkage with the Swiss National Cohort. Multiple correspondence analysis (MCA) and hierarchical clustering on principal components (HCPC) are used to identify dietary patterns and cluster individuals with similar patterns. The association between dietary patterns and demographics or behavioral data will be further examined. Mortality hazard ratios (HR) are calulated for all-cause, cancer and cardiovascular mortality using Cox regression. For the linkage study the data is matched between the MONICA or NFP1A study and the census data of Switzerland to determine whether they are dead or alive. The two original studies include: MONICA: The selected persons were invited to attend a health examination in their community of residence and to complete a self-administered questionnaire. Weight and height were measured, blood pressure, blood lipids and other biological parameters were obtained following standardized procedures methods of the MONICA Project. NFP: NFP was a community-based intervention led in four cities of Switzerland. In a first phase (1977-1978) participants were submitted to health examination and had to complete a self-administered questionnaire (that includes nutrition, physical activity, demographic and socioeconomic information). In a second phase, participants of two of the four cities were encouraged to enrol in a broad program of actions aimed at reducing the exposure to cardiovascular risk factors, while the two other cities were used as controls. A final evaluation was done in 1980. For our analysis, we only used the original evaluation of the participants (1977-1978).
Intervention type	Other
Primary outcome measure	A posteriori dietary patterns are not directly measured, but are calculated based on the questionnaires that participants to the MONICA and NFP1A studies had to fill out, which included a simplified 24-hour recall checklist (from this information, we use the diets of the overall population to cluster diets into coherent patterns, the so-called dietary patterns). The questionnaires are answered at study entry (which spans from 1977 to 1992, depending on whether we talk about NFP1A or MONICA).
Secondary outcome measures	1. Association between dietary patterns and demographic (age, sex, language region of residence, nationality), socioeconomic (education), morphologic (BMI) and behavioural (smoking, physical activity) factors are measured using testing whether the distribution (for continuous variables) or the proportion of categories (for qualitative variables) differ from those obtained from the rest of the population, using v-test as previously described at study entry 2. Mortality hazard ratio for groups of individuals following different dietary patterns is measured using Cox proportional hazards regression models at the most recent update of the Swiss National Cohort (30.06.2016)
Overall study start date	20/02/2017
Completion date	30/09/2018

Eligibility

Participant type(s)	All
Age group	Adult
Sex	Both
Target number of participants	15,000
Key inclusion criteria	1. All participants from MONICA or NRP1A study with successful Swiss National Cohort Linkage 2. Aged 16 to 74 years old
Key exclusion criteria	Participants who do not fully answered the 24 hour recall checklist.
Date of first enrolment	05/06/2017
Date of final enrolment	06/06/2017

Locations

Countries of recruitment

Switzerland

Study participating centre

University of Zurich

Epidemiology, Biostatistics and Prevention Institute
Hirschengraben 82
Zurich
8001
Switzerland

Sponsor information

Swiss National Science Foundation
Research council

Wildhainweg 3
Bern
3001
Switzerland

Phone	+41 31 308 22 22
Email	com@snf.ch
Website	http://www.snf.ch/en/Pages/default.aspx
"ROR"	https://ror.org/00yjd3n13

Funders

Funder type

Charity

Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Private sector organisation / Trusts, charities, foundations (both public and private)

Alternative name(s): Schweizerischer Nationalfonds, Swiss National Science Foundation, Fonds National Suisse de la Recherche Scientifique, Fondo Nazionale Svizzero per la Ricerca Scientifica, Fonds National Suisse, Fondo Nazionale Svizzero, Schweizerische Nationalfonds, SNF, SNSF, FNS
Location: Switzerland

Results and Publications

Intention to publish date	01/01/2018
Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not expected to be made available
Publication and dissemination plan	We expect one publication structured by the study questions.
IPD sharing plan	Individual data from different data sets were used for the construction of the Swiss National cohort (SNC). All these data are the property of the Swiss Federal Statistical Office (SFSO) and can only be made available by legal agreements with the SFSO. This also applies to derivatives such as the analysis files used for this study. However, after approval of the SNC Scientific Board, a specific SNC module contract with the SFSO would allow researchers to receive analysis files for replication of the analysis. Data requests should be sent to Prof. Milo Puhan (chairman of the SNC Scientific Board, miloalan.puhan@uzh.ch).