Several scientific papers with results from one of Europe's largest health surveys of young children with focus on overweight and obesity, the IDEFICS study, have been published the last years. Research at the Nordic School of Public Health NHV reveals that some types of families seem to be underrepresented in the health survey. This knowledge can prove to be valuable when the data is interpreted and can contribute to efficient actions for improved child health.
During 2007-2008 16,000 2-9-year-old children from eight European countries participated in a health survey in the IDEFICS study (Identification of life-style induced health effects in children and infants). The purpose of the survey was to characterize the children's lifestyle, with a particular focus on factors associated with the development of overweight and obesity. A second aim of the IDEFICS study was to develop, implement and evaluate a community-wide health-promoting program. To interpret findings from the study it is important to assess to what extent study participants represent the target population. Since high-quality population registers are available in Sweden, a special study was set up here to assess selection bias. A research group led by Susann Regber from the Nordic School of Public Health NHV has used this opportunity and compared socioeconomic characteristics of the study participants with register-data from the general population.
"The IDEFICS study is one of the largest of its kind and if correctly interpreted, the research findings will be able to play a significant role for the health of the children of Europe. Our analysis shows that families with foreign background, with low level of education or low income or single-parents are underrepresented in the survey. This fact must be taken into consideration, in future surveys and in the design of health-promoting measures," Susann Regber explains.
Susann Regber and her colleagues have used data from Statistics Sweden (Statistiska Centralbyrån) to compare more than 1,800 participants from the Swedish part of the survey with a group of individuals matched for age, sex and place of residence. In contrast to the selection by socioeconomic factors, no difference according to the children's BMI (Body Mass Index) was demonstrated.
"Recommended in future surveys, is to target and include families that were underrepresented in the IDEFICS study. Of equal importance is the fact that health-promoting activities really reach the families where the problems may be the largest, for example that information is adapted and translated to residents with foreign background and short education; use more flexible time-schedules in time and setting; and to get support by using culture bearers and focus groups with local officials" says Susann Regber.
Susann, R. et al. Assessment of selection bias in a health survey of children and families—the IDEFICS Sweden-study, BMC Public Health, 2013, 13:418. www.biomedcentral.com/1471-2458/13/418