Design, Methods, and Participation in Riksmaten Young Children—A Swedish National Dietary Survey

BackgroundNational dietary surveys provide essential data for risk benefit assessments of foods and nutrients, for management and policy development. Physical activity measurement and biomonitoring can provide important complementary data, but are less commonly included.ObjectiveTo describe the study design and methods of the cross-sectional Swedish national dietary survey Riksmaten Young Children (Riksmaten småbarn), of children aged 9 months, 18 months and 4 years. Participation/drop-out rates for the two older age groups are also presented. The impact of different recruitment strategies is discussed.MethodsChildren (N=16,655) were randomly selected from the population register, invitations to guardians were sent by post and where possible, followed up by phone. Food intake was assessed by a two-day food diary and/or questionnaire. Height and weight were reported after measurement. Physical activity (accelerometery, 7 days), stool, blood and urine were assessed in subgroups.ResultsFood consumption data were collected in 1828 children (11% of the invited; 18 months: N=1078, and 4 years: N=750). Of participants also in subgroups, 71% provided physical activity data (N=1307), 60% stool samples (N=630) and 51% blood and/or urine samples (N=593). The study population represented all geographical regions and types of municipalities in Sweden, but participating households had both higher education level and higher income than the target population. Only minor differences were seen in participation rates between recruitment via post and phone compared to post only (12 versus 10%). Repeated contact attempts were needed for the majority of participants (65%). Despite the low participation rate, 99% of the participants completed the study once started.ConclusionAlthough it was a challenge to recruit participants, Riksmaten Young Children provides a substantial amount of information at national level, representative in terms of sex, geography and family structure. The underrepresentation of households with lower socioeconomic position must be considered when generalising results.