Elling Bere

Determinants of fruit and vegetable consumption among children and adolescents: a review of the literature. Part I: quantitative studies

BackgroundIn order to more effectively promote fruit and vegetable intake among children and adolescents, insight into determinants of intake is necessary. We conducted a review of the literature for potential determinants of fruit and vegetable intake in children and adolescents.MethodsPapers were identified from Medline and PsycINFO by using all combinations of the search terms: fruit(s) or vegetable(s) and children or adolescents. Quantitative research examining determinants of fruit and/or vegetable intake among children and adolescents aged 6–18 years were included. The selection and review process was conducted according to a four-step protocol resulting in information on country, population, design, methodology, theoretical basis, instrument used for measuring intake, statistical analysis, included independent variables, and effect sizes.ResultsNinety-eight papers were included. A large number of potential determinants have been studied among children and adolescents. However, for many presumed determinants convincing evidence is lacking, mostly because of paucity of studies. The determinants best supported by evidence are: age, gender, socio-economic position, preferences, parental intake, and home availability/accessibility. Girls and younger children tend to have a higher or more frequent intake than boys and older children. Socio-economic position, preferences, parental intake, and home availability/accessibility are all consistently positively associated with intake.ConclusionThe determinants most consistently supported by evidence are gender, age, socio-economic position, preferences, parental intake and home availability/accessibility. There is a need for internationally comparative, longitudinal, theory-based and multi-level studies taking both personal and environmental factors into account.This paper is published as part of the special Pro Children series in the International Journal of Behavioral Nutrition and Physical Activity. Please see [http://www.ijbnp.org/content/3/1/26] for the relevant editorial.

Correlates of fruit and vegetable intake among Norwegian schoolchildren: parental and self-reports

OBJECTIVESnTo identify correlates of 6th and 7th graders (age 10-12 years) fruit and vegetable intake, to investigate parent-child correlations of fruit and vegetable intake, and to compare parents and childrens reports of childrens accessibility, skills and preferences with respect to fruit and vegetables.nnnDESIGNnThe results presented are based on the baseline survey of the Fruits and Vegetables Make the Marks Project, where 38 schools participated.nnnSETTINGnFruit and vegetable intake was measured by food frequency questions. Theoretical factors, based on Social Cognitive Theory, potentially correlated to intake were measured, including behavioural skills, accessibility, modelling, intention, preferences, self-efficacy and awareness of 5-a-day recommendations.nnnSUBJECTSnIn total, 1950 (participation rate 85%) 6th and 7th graders and 1647 of their parents participated.nnnRESULTSnOverall, 34% of the variance in the pupils reported fruit and vegetable intake was explained by the measured factors. The strongest correlates to fruit and vegetable intake were preferences and accessibility. The correlation between the childrens and their parents fruit and vegetable intake was 0.23. The parents perceived their childrens accessibility to be better than what was reported by the children (P<0.01), while the children reported their skills to be better than what was perceived by their parents (P<0.01).nnnCONCLUSIONnThe results from this study clearly point to a need for nutrition interventions aimed at parents. An important next step will be to investigate whether the identified correlates predict future fruit and vegetable intake, and whether they mediate any changes in intake in an intervention study.

Changes in accessibility and preferences predict children's future fruit and vegetable intake

BackgroundMost children eat fewer fruits and vegetables than recommended. To be able to design effective interventions, understanding the aetiology of the behaviour is important. Accessibility and preferences have shown to be strong correlates of fruit and vegetable intake in several cross-sectional studies. The aim of this study was to identify predictors of future fruit and vegetable intake and to explore longitudinal patterns of interactions between accessibility and preferences.MethodsData presented are based on baseline (September 2001) and follow-up (May/June 2002) surveys of 20 control schools in the Norwegian intervention study Fruits and Vegetables Make the Marks. A total of 816 pupils (77%) completed both baseline and follow-up questionnaires. The average age of the sample at baseline was 11.8 years. The research instrument assessing potential predictor variables was guided by Social Cognitive Theory, and included Accessibility at home, Accessibility at school, Modelling, Intention, Preferences, Self-Efficacy and Awareness of the 5-a-day recommendations. Multiple regression analyses were performed.ResultsAll independent variables (measured at baseline) were significantly correlated to future fruit and vegetable intake (measured at follow-up). When reported fruit and vegetable intake at baseline (past intake) was included in this model, the effect of the other independent variables diminished. Together with past intake, the observed change in the independent variables from baseline to follow-up explained 43% of the variance in the reported intake at follow-up. Past intake remained the strongest predictor, but changes in accessibility at home and at school, as well as changes in preferences for fruits and vegetables, also explained significant amounts of the variance in fruit and vegetable intake at follow-up. In addition, baseline accessibility was found to moderate the relationship between change in preferences and change in intake.ConclusionChange in accessibility and preferences appear to be important predictors of future fruit and vegetable intake among school children. Interventions should focus on strategies to modify these factors.

Free School Fruit--sustained effect three years later.

BackgroundNorwegian children consume less fruit and vegetables (FV) than recommended. In order to increase the intake, a School Fruit subscription programme is now offered to all Norwegian elementary and junior high schools. This programme has limited effect due to low participation by schools and pupils. However, recent evaluations of the programme offered for free have reported good effects in increasing FV intake. The purpose of the present study is to evaluate the long term effects of the Norwegian School Fruit programme, provided at no-cost to the pupils, three years after it was provided for free.MethodsA total of 1950 (85%) 6th and 7th grade pupils from 38 Norwegian elementary schools participated in the project. Nine schools were selected as intervention schools and participated for free in the Norwegian School Fruit programme for a school year (October 2001 until June 2002). A baseline questionnaire survey was conducted in September 2001, and follow-up surveys were conducted in May 2002 and May 2005. FV intake was assessed by a written 24-h recall (reporting FV intake at school and FV intake all day), and by four food frequency questions (reporting usual FV intake). Data were analysed by a linear mixed model for repeated measures.ResultsThe pupils in the free fruit group increased their FV intake compared to pupils in the control group as a result of the intervention. Some of the effect was sustained three years later. The estimated long-term effects for FV all day were 0.38 and 0.44 portion/day for boys and girls, respectively.ConclusionThe results show long-term effects of a free school fruit programme.

Determinants of adolescents’ soft drink consumption

OBJECTIVEnTo identify determinants of adolescents consumption of carbonated soft drinks (regular and diet), both of total consumption and of consumption at school.nnnDESIGN/SETTING/SUBJECTSnRegular and diet soft drink consumption was measured by food frequency questions that were dichotomised. Several potential environmental and personal determinants of consumption were measured. A total of 2870 (participation rate: 85%) 9th and 10th graders, within 33 Norwegian schools, participated in the study. Multilevel logistic regression analyses were preformed for total soft drink consumption (twice a week or more vs. less) and for consumption at school (once a week or more vs. less).nnnRESULTSnA total of 63% and 27% of the participants reported to drink respectively regular and diet soft drinks twice a week or more, and 24% and 8%, respectively, reported to drink soft drinks once a week or more at school. Preferences, accessibility, modelling and attitudes were the strongest determinants of both regular and diet soft drink consumption. In addition, gender, educational plans and dieting were related to both total soft drink consumption and consumption at school. Pupils with longer distance from school to shop and those in schools with rules concerning soft drink consumption tended to have lower odds of drinking both regular and diet soft drinks at school.nnnCONCLUSIONnThis study shows that gender, educational plans, dieting, accessibility, modelling, attitudes and preferences all seem to be strong determinants of adolescents soft drink consumption. Parents and the home environment appear as great potential intervention targets.

Why do boys eat less fruit and vegetables than girls

OBJECTIVEnTo explore why boys eat less fruit and vegetables (F&V) than girls, using longitudinal data following pupils from the age of 12.5 to 15.5 years, including perceived accessibility, modelling, intention, preferences, self-efficacy and knowledge of recommendations as potential mediators.nnnDESIGN/SETTING/SUBJECTSnA longitudinal study, based on data collected among the control schools within the intervention project Fruits and Vegetables Make the Marks. This sample contains 896 6th and 7th graders from 20 randomly selected elementary schools within two Norwegian counties. Questionnaires were administered in May 2002 and May 2005 (when the participants were in 9th and 10th grade in 18 secondary elementary schools).nnnRESULTSnIn single mediation analyses all determinants mediated parts of the gender difference, but only preferences decreased the gender difference to a level below statistical significance. Preferences alone explained 81% of the gender difference. In the multiple mediation analyses, the six mediators together explained 91% of the gender difference, but only preferences and perceived accessibility contributed uniquely to the explanation, with 25% and 10% respectively.nnnCONCLUSIONSnPreference appears as the strongest mediator of the difference in F&V intakes between boys and girls. Further research should explore why girls like F&V more than boys.

Personal, social and environmental factors regarding fruit and vegetable intake among schoolchildren in nine European countries.

Background/Aims: Children in Europe are consuming less fruit and vegetables than recommended. Knowledge about the potential determinants of fruit and vegetable intake is vital to understand discrepancies in intake and to guide interventions. The aim of the present study was to assess personal, social and environmental factors regarding fruit and vegetable intake among 11- to 12-year-old children in Europe. Methods: A cross-sectional survey was undertaken, with nationally or regionally representative samples of in total 13,305 children (mean age 11.4 years) from nine European countries. Pupils in the classroom completed a self-administered questionnaire measuring fruit and vegetable intake and personal, social and environmental factors during one school lesson. Age-adjusted covariance analyses were carried out by gender, for the full sample and for each country separately. Proportions responding positively to the constructs are presented. Results: Overall, European children held a positive attitude towards fruit and vegetable intake. For some constructs, large between-country differences were found. Children had a more positive attitude towards fruit than towards vegetables, and girls were on average more positive than boys. The children perceived their social environment as supportive towards fruit and vegetable intake. They reported good to very good availability of fruit and vegetables at home. However, availability at school and during leisure time activities seemed to be low, both for fruit and for vegetables. Conclusion: A large majority of the children reported positively to the personal and social factors regarding fruit and vegetable intake. As regards availability of fruit and vegetables at school and leisure time, and accessibility of fruit and vegetables at home, there is room for improvement.

Reliability of parental and self-reported determinants of fruit and vegetable intake among 6th graders

OBJECTIVEnTo assess the reliability of newly developed questionnaires measuring theoretical constructs believed to predict fruit and vegetable consumption among 6th-grade pupils.nnnDESIGNnParticipating pupils and parents completed questionnaires twice, 14 days apart.nnnSETTINGnOne hundred and twenty-nine pupils from 6th-grade classes (average age: 11.9 years) at two schools in Norway and their parents were invited to participate.nnnRESULTSnThe test-retest reliability was found to be good or very good for scales reported both by the pupils and their parents. All scales showed acceptable to strong correlations between time 1 and time 2, and only one scale had significant different mean values at the two times. The internal consistency reliability of the scales was acceptable to good.nnnCONCLUSIONSnSixth graders and their parents are able to provide reliable reports on theoretical determinants of the pupils fruit and vegetable consumption.