National nutrition survey menuCH

The first Swiss National Nutritional Survey, menuCH, was conducted from January 2014 to February 2015 in ten study centres that cover the three main language regions, that is, German, French and Italian. Ethical approval for the survey was obtained from the main ethics committee in Lausanne (Protocol 26/13, 12 February 2013) and by the corresponding regional ethics committees. Guidelines of the Declaration of Helsinki were respected, including written informed consent from the study participants. ISRCTN registration number is 16778734 (https://doi.org/10·1186/ISRCTN16778734). A representative sample was drawn by the Federal Statistical Office⁽¹¹⁾, and 13 606 individuals aged between 18 and 75 years were invited to participate in the survey. This sample targeted 4 627 878 women and men living in the twelve major cantons. Eventually, 2086 people responded, 2081 answered the questionnaire and 2057 completed the two 24-h dietary recalls (24-HDR)⁽¹²⁾. The design of two non-consecutive interviews was chosen to minimise inter- and intra-individual variation in dietary intake and to increase accuracy, as the survey was conducted during all seasons and included both weekdays and weekends. The first 24-HDR was assessed at the study centre, the second one by telephone 2–6 weeks later, both conducted by a trained dietitian and using the standardised software GloboDiet®⁽¹²⁾. Food consumption data from the 24-HDR were linked with the Swiss Food Composition Database⁽¹³⁾ to compute intake of energy, proteins, carbohydrates and fats.

To assess the overall diet quality of menuCH participants, a modified version of the Alternate Health Eating Index was computed⁽¹⁴⁾. The original score, aiming to assess the adherence to the Dietary Guidelines for Americans, includes the following eleven components: vegetables, fruits, whole grains, sugar-sweetened beverages, nuts and legumes, red and processed meat, trans fat, fish, PUFA, Na and alcohol⁽¹⁴⁾. However, since meat is the outcome variable in the present analyses, the Alternate Health Eating Index was modified to exclude the component meat. The modified total score can range from 0 to 100 points, indicating minimal adherence to maximal adherence to the Dietary Guidelines for Americans. A more detailed description about the original calculation of the score was previously published⁽¹⁵⁾.

In addition to diet, using a self-administered questionnaire, the study assessed sociodemographic information of the study participants, including age, sex, education, marital status, nationality and household income; lifestyle characteristics such as smoking habits, physical activity and use of dietary supplements; information about the participants’ self-reported health and avoidance of certain foods including meat. The food avoidance question generated data about avoidance of meat, fish and seafood, as well as other food groups, however without specifying a time frame.

Body weight and height were measured at the study centres following a standardised protocol and used to calculate the BMI. In case measurements of weight and height were impossible (n 7), self-reported measures were used. In additions, for pregnant and lactating women (n 27), BMI was calculated using self-reported weight before pregnancy and measured height⁽¹²⁾.