Search PubMed⌕ Search

Biomedical subjects

P van Assema

Publications and source records attributed to P van Assema.

At least 19 recordsLinked to original sources
PubMed2005

Why do adolescents eat what they eat? Personal and social environmental predictors of fruit, snack and breakfast consumption among 12-14-year-old Dutch students.

OBJECTIVE: The aim of the study was to investigate the relative importance of personal and social environmental predictors of the consumption of fruit, high-fat snacks and breakfast. DESIGN: A school-based cross-sectional survey. Data were collected through written questionnaires. SETTING: Students from eight schools in the southern part of The Netherlands. SUBJECTS: Six hundred and one students from preparatory secondary vocational education schools. RESULTS: About a quarter of the variation in actual behaviours and intentions to change the behaviours could be explained. Stepwise multiple regression analysis revealed that, for all three behaviours, higher intention to change was especially associated with a more positive attitude and subjective norm, and higher intentions to increase fruit intake with more positive self-efficacy expectations. With regard to actual consumption, a more positive attitude towards eating fruit was the only significant correlate of a higher consumption of fruit. A more positive attitude towards eating high-fat snacks, perceived lower intake of the mother, and higher food availability and accessibility were associated with consumption of high-fat snacks, and a more positive attitude to breakfast more frequently was associated with more frequent breakfast consumption. CONCLUSION: The results indicate that adolescents' attitudes are the most important determinants of different health-related eating behaviours and intentions to change. Interventions promoting a healthy diet for adolescents should include creative strategies to achieve positive associations with healthy dietary changes.

Adolescent↗
PubMed2005

The impact of a nutrition education intervention on main meal quality and fruit intake in people with financial problems.

BACKGROUND: As part of a course teaching household budgeting, a nutrition education intervention was provided to people with financial problems. The present study aimed at assess the effects of this intervention on the nutritional quality of their main meal and fruit intake, and to collect process information on intervention participation, reactions and opinions. METHODS: For the effect study, a quasi-experimental multiple pre and post-test control group design was used. Telephone dietary recalls were conducted with 35 people in the intervention group and 39 people in the control group. Observations, personal interviews and written questionnaires were used to collect the process data. RESULTS: A significant reduction in saturated fat intake during the mail meal was found. Also, an intervention effect was found for fruit juice consumption, but not for daily fruit intake or vegetable intake during main meal occasions. CONCLUSIONS: The process data revealed some improvements that should be made to the intervention, such as providing more individualized information and tailored recipes.

Adult↗
PubMed2004

Explaining fruit and vegetable consumption: the theory of planned behaviour and misconception of personal intake levels.

The influence of individuals' misconceptions in assessing fruit and vegetable consumption on the ability of the theory of planned behaviour to explain variance in the consumption of these foods was studied. Dutch women (mean age 41, n=159) completed a questionnaire assessing the theory's constructs with regard to the daily consumption of at least two pieces of fruit and 200 gram of vegetables. Consumption was assessed using a self-rated measure and more objectively with a food-frequency questionnaire. Both measures were combined to classify participants according to the accuracy of their self-assessed intake levels ('realists' vs. 'overestimators'). The model explained variation in objective fruit and vegetable intake much better among realists (R2 = 45% for fruits and 39% for vegetables) than among overestimators (R2 = 18% and 5%, respectively). Perceived behavioural control was the strongest predictor of intentions and behaviour. When plasma vitamin C and carotenoid concentrations were used as objective indicators for fruit and vegetable intake, the explanatory value of the model was lower, but again more variance was explained among realists than among overestimators. We conclude that awareness of personal behaviour should be taken into account when applying the theory of planned behaviour to explain dietary behaviours as well as to design health education interventions.

Adult↗
PubMed2004

Process evaluation of two environmental nutrition programmes and an educational nutrition programme conducted at supermarkets and worksite cafeterias in the Netherlands.

INTRODUCTION: This article describes the process evaluation of two environmental programmes and an educational nutrition programme, implemented at supermarkets and worksite cafeterias. Studies conducted earlier, indicated that the programmes had no effect on consumers' eating behaviour. Consequently, the more specific purpose of the present study was to identify explanations for the ineffectiveness of the programmes and to formulate recommendations for future programmes. MATERIALS AND METHODS: The environmental programmes included labelling of healthy products and increasing the range of healthy foods on offer. The education programme consisted of several elements, such as brochures and a self-help guide. Semi-structured interviews were conducted with 21 managers of supermarkets and worksite cafeterias where the programmes were implemented. RESULTS: Although materials were not always entirely compatible with the different supermarkets and worksite cafeterias, the degree of implementation was satisfactory. According to the managers, the programmes were not striking enough, the labelling would have been more effective if it had discriminated between different brands of a product, and the number of new products was too small compared with the total range of foods on offer. CONCLUSIONS: The findings suggest that programmes should be promoted intensively. Furthermore, the relevant manufacturers and wholesalers supplying worksite cafeterias should be encouraged to increase their range of suitable low-fat products. Finally, the feasibility and possible effects of brand-specific labelling should be investigated further.

Feeding Behavior↗
PubMed2001

The relative validity of a short Dutch questionnaire as a means to categorize adults and adolescents to total and saturated fat intake.

BACKGROUND: To assess the relative validity of a short food frequency questionnaire, the Fat list, to be used in (the evaluation of) nutrition education programmes. METHODS: Forty-five adults and 50 adolescents (12-18 years old) completed the Fat list at home, and subsequently kept diet records for seven subsequent days. RESULTS: Pearson correlations of about 0.7 for adults and 0.6 for adolescents were observed between fat scores derived from the Fat list and total and saturated fat intake in grams estimated by the 7-day diet records. Correlations varied among subpopulations based on sex, age, education, household size and responsibility for cooking and shopping. Lower correlations were especially found for female adolescents and older adolescents (16-18 years old). Pearson correlations between the Fat list and percentages energy from fat were low for both adults and adolescents. Gross misclassification, defined as disagreement between the two fat consumption assessments beyond an adjacent tertile, was less than 6% for all but the female adolescents. CONCLUSIONS: The Fat list can be used in adult and male adolescent populations to classify subjects in broad categories of total and saturated fat intake in grams and to assess differences in absolute and saturated fat intake between groups as a result of nutrition education programmes.

Adolescent↗
PubMed2001

Framing of nutrition education messages in persuading consumers of the advantages of a healthy diet.

BACKGROUND: Educational dietary messages can stress either the positive consequences of performing a recommended dietary behaviour (positive frame) or the negative consequences of not performing a recommended dietary behaviour (negative frame). From studies on other health behaviours, there is evidence that positive frames have a stronger impact in encouraging preventive behaviours than negative frames. The main hypothesis of the present study was therefore that positively framed messages on eating a low-fat diet and eating enough fruit and vegetables (F & V) are more persuasive than negatively framed messages. METHODS: In a 2 (Frame: positive vs. negative) x 2 (Dietary behaviour: fat vs. F & V) design, 152 adult respondents randomly received one of four messages. Subsequently, they completed a questionnaire measuring cognitive attitude, affective attitude and intention to change the dietary behaviours. RESULTS: No significant differences in attitudes and intentions were found between the positive frame conditions and the negative frame conditions. CONCLUSIONS: Based on the current study no advice can be given yet to dietitians and other nutrition educators about whether they should emphasize the positive consequences of a dietary change or the negative consequences of not making the dietary change.

Adult↗
PubMed2000

Differences in use and impact of computer-tailored dietary fat-feedback according to stage of change and education.

Computer-tailored written nutrition education has been found to be more effective in motivating people to reduce their consumption of fat than traditional written information. The present study aimed to test whether this innovative nutrition education intervention is also suitable for people with low motivation to change and low education among a self-selected sample of 699 adults. Computer-tailored feedback proved to be more effective in motivating precontemplators to proceed towards fat reduction than general information. Higher appreciation and use of the computer-tailored fat-feedback was found among respondents in contemplation than in other stages. No difference in impact of computer-tailored fat-feedback on fat intake was found between educational groups. Respondents with low education were more positive about how interesting and how personally relevant the tailored letters were. It was concluded that printed computer-tailored fat-feedback can be applied successfully to motivate precontemplators and people with low education to (consider to) reduce their fat intake.

Adult↗
PubMed1999

The application and impact of computer-generated personalized nutrition education: a review of the literature.

Computer-tailored nutrition education may be more effective than general nutrition education because messages are tailored to individual behavior, needs and beliefs of subjects. Therefore, the messages are likely to be of more personal relevance and may have stronger motivational effects. Computer-generated nutrition education has been studied for different dietary behaviors, in different target populations, and in different settings. In recent years, eight studies have been published that assessed the impact of comprehensive computer-generated nutrition interventions that were based on behavior change theory. In this article, the process of providing people with computer-tailored nutrition education is described and the studies on the impact of computer-tailored nutrition education are reviewed. The results point to the conclusion that computer-tailored nutrition education is more likely to be read, remembered, and experienced as personally relevant compared to standard materials. Furthermore, computer-tailored nutrition education also appears to have a greater impact in motivating people to change their diet, their fat intake in particular, although at present no definite conclusions can be drawn.

Attitude to Health↗
PubMed1999

Computer-tailored nutrition education: differences between two interventions.

The impact of two computer-tailored nutrition education interventions was assessed and compared in a randomized trial among 315 subjects with a pre-test-post-test comparison group design. Respondents in both the experimental and the comparison group received feedback tailored to their consumption of fat, fruit and vegetables. Respondents in the experimental group received additional psychosocial feedback tailored to their attitudes, perceived social support and self-efficacy expectations towards reducing their fat consumption and increasing their consumption of fruit and vegetables. A significant reduction in fat consumption and increase in the consumption of fruit and vegetables were found in both the experimental and the comparison group between pre-test and post-test. Respondents in the experimental group more often indicated that the feedback they received was interesting and easy to understand. Respondents in the comparison group more often reported having reduced their fat consumption because of the feedback they received. No significant differences in consumption of fat, fruit and vegetables were found at post-test between the experimental group and the comparison group. These results do not support the hypothesis that additional psychosocial information is an essential component of effective tailored feedback. The results indicate that tailored feedback might be effective in inducing dietary changes.

Adult↗
PubMed1998

Nationwide implementation of guided supermarket tours in The Netherlands: a dissemination study.

The purpose of this study was to assess adoption, implementation and maintenance of a guided supermarket tour program of nutrition education by Dutch Public Health Services (PHSs), and the factors associated with program dissemination. A first questionnaire was sent to all 60 PHSs, and measured program adoption, perceived program attributes, and characteristics of the adopting organization and person. A second questionnaire was only sent to adopting PHSs, and measured extent and success of implementation, intentions to continue the program, and characteristics of the main implementing person. Of the 59 PHSs who responded, 30 adopted the program and 17 implemented it sufficiently. Perceived program complexity, social influence within the PHS toward program participation and existence of a separate health education department were predictors of adoption. Perceived program complexity was also a predictor of extent of implementation. The number of health educators within each PHS was a predictor of sufficient implementation. It was concluded that adoption and implementation of the program was reasonable, considering the limited dissemination strategy. Dissemination might have been more successful if the program had been less complex and required less effort, if positive social influence had been generated, and if specific attention had been given to PHSs without a separate health education department.

Attitude of Health Personnel↗
PubMed1998

Fat Watch: a nationwide campaign in The Netherlands to reduce fat intake--effect evaluation.

In the Netherlands, the nationwide Fat Watch campaign aiming at a reduction in fat consumption was organized from 1991 onwards. This study describes the effects of the first three consecutive campaign years on attention to fat, diet and health, attitudes, self-efficacy expectations and intentions related to dietary fat reduction, and self-rated fat intake. Data were collected each year according to the Solomon design, by telephone interviews among about 1200 consumers responsible for household purchases. Campaign awareness was high in each campaign year, but a decrease in campaign awareness was found after the first campaign in 1991. The 1991 campaign was primarily aimed at getting the attention of the Dutch public for the fat-reduction message and indeed resulted in increased attention. The second campaign year resulted in small but statistically significant positive changes in attitudes, which was the specific target of the 1992 campaign. Intention to buy low-fat food products was also significantly increased. The 1993 campaign failed to realize the targeted increases in self-efficacy among the study population, but a significant campaign effect on intentions was found. The evaluation of all three campaigns indicated that the Dutch underestimate their personal fat intake and this has been identified as an important barrier to a further reduction in fat consumption. Making subjects aware of their personal fat consumption will be given priority in future campaigns.

Bias↗
PubMed1997

Are awareness of dietary fat intake and actual fat consumption associated?--a Dutch-American comparison.

OBJECTIVES: To compare dietary fat intake, the accuracy of individuals' awareness about their fat intake, and sociodemographic and psychosocial correlates of awareness, in Dutch and American samples of employed adults. A discrepancy between objective dietary intake data and subjective self-evaluation of dietary fat consumption has been recognized in the past and might undermine healthy diet promotion interventions, and this is important because people who believe that their diets are healthful are less likely to be interested in making changes. Further, international comparisons have not been examined to date. DESIGN: Data collected for the baseline surveys of the 'Healthy Bergeijk' study in the Netherlands and the 'Working Well Trial' in the United States were compared. SUBJECTS: Working adults from a Dutch community health intervention study (n = 768) and an American worksite health promotion trial (n = 15,440). MAIN OUTCOME MEASURES: Objectively assessed dietary fat intake, measured by food frequency questionnaires, and subjective ratings of fat intake (self-rated fat intake). RESULTS: Findings show that the Dutch respondents had higher objectively assessed fat intake and lower subjective ratings of fat intake (P < 0.001). American respondents perceived their diets as higher in fat, more often stated their intentions to reduce fat intake, and were slightly more likely to make realistic estimates of their dietary fat. Dutch subjects were significantly more likely to underestimate their fat intakes. In both samples, women were most likely to underestimate their fat consumption and the most educated persons were most likely to be realistic. CONCLUSIONS: A substantial proportion of adults, both in the United States and the Netherlands, lack accurate awareness about how much fat they consume, though errors tend to be in opposite directions in the two countries. This study is an important first step toward broadening our international understanding of human dietary behavior for disease prevention.

Adult↗
PubMed1997

Nutrition education interventions in a community setting: 2 Dutch examples.

This article presents the results of two studies among participants of two Dutch nutrition education interventions, i.e. a self-help program and a living room group session. Both interventions aim to reduce fat intake in the general population and were developed as part of the Dutch community health project 'Healthy Bergeyk'. The objectives of the studies were to assess number of participants, participant characteristics, use of the self-help program, participant satisfaction and self-reported effects. Telephone interviews and written questionnaires were completed by inhabitants after participating in the interventions. The results are encouraging and the interventions seem to be useful as part of community projects.

Adult↗
PubMed1996

The validation of a test to measure knowledge about the fat content of food products.

The objective of the study was to develop and validate a 21-item nutrition knowledge test to measure people's knowledge of the fat content of food-products. After pretesting and provisional development, the test was administered twice to study test-retest reliability. Furthermore, various sub-populations with expected differences in nutrition knowledge completed the test in order to study the construct validity of the questionnaire. The subpopulations consisted of lay-people (N = 81), students of human nutrition and dietetics (N = 108), and professional experts (N = 79) on human nutrition. The internal consistency and uni-dimensionality of the test were determined by calculating the KR-20 statistic and the log-likelihood ratio statistic for the Rasch model. Pearson's correlation and gross misclassification between T1 and T2 were calculated to assess the test-retest reliability. Analysis of variance was used to test for differences in mean knowledge scores between subpopulations. Test-retest reliability was found to be sufficient (R = .85). The internal consistency was moderate (KR20 = .68). According to the Rasch model, two items had to be removed from the test before the log-likelihood ratio statistic of the Rasch model indicated that knowledge about the fat content of food products as assessed by the questionnaire is a uni-dimensional construct. The differences in mean knowledge scores between the subpopulations were significant (p < .01) and in the expected direction (experts > students > lay people). It can be concluded that the test is a reliable and valid instrument to measure knowledge about total fat content in food products and that the Rasch model is a comprehensive method to indicate the reliability of nutritional knowledge tests.

Analysis of Variance↗
PubMed1994

Results of the Dutch community project "Healthy Bergeyk".

BACKGROUND: This article reports on the results of a community health project that was implemented in the Dutch municipality of Bergeyk. The major goal was to reduce four cancer-related risk behaviors: smoking, high fat consumption, excessive alcohol use, and exposure to artificial sunlight. A control community received no new intervention. Intervention methods included mass media messages, self-help materials, small group activities, lectures, and structural activities. Community organization principles such as a social network approach, community participation, and intersectoral cooperation were applied in the project. METHODS: Data were collected from both communities among cohort research samples on three occasions using telephone interviews. RESULTS: The results indicate a significant reduction in fat intake in the experimental community. No other significant behavioral effects were found. Further analysis among respondents in the experimental condition showed that those personally exposed to the project as indicated by familiarity with and discussion about the project, had a greater decrease in fat consumption between baseline survey and second post-test than those who were not. Also, the percentage of smokers who quit between baseline survey and second post-test was greater among those who knew about the project than among those who did not. Finally, discriminant analysis was used to further examine the determinants of project exposure. Community involvement, marital status, education, and sex were related to project exposure. CONCLUSIONS: It is concluded that with the time limitations of the project in mind, the findings are encouraging.

Adult↗
PubMed1993

The determinants of four cancer-related risk behaviours.

This paper reports research into the determinants of four cancer-related risk behaviours: smoking, excessive alcohol consumption, high fat consumption and exposure to artificial sunlight. The results indicate that the four types of risk behaviour are determined by several factors: the perceived behaviour of the social environment, individual's attitudes towards the risk behaviour and self-efficacy perceptions on changing the risk behaviour. High fat consumption differs from the other risk behaviours in that people tend not to be aware of their high fat consumption. No significant relationships were found among the risk behaviours apart from small correlations between smoking and heavy alcohol consumption, and between high fat consumption and heavy alcohol consumption. The implications of these results for the development of behaviour change programs are discussed.

Adult↗
PubMed1992

The reliability and validity of a Dutch questionnaire on fat consumption as a means to rank subjects according to individual fat intake.

In this paper a short, 25-item, telephone-administered questionnaire, designed to rank individuals according to their dietary intake of fat, is presented. Based on two studies of 52 and 639 men and women, respectively, its relative validity regarding a 7-day diet record and its reproducibility are discussed. A Pearson correlation of 0.59 was observed between fat intake estimated by 7-day diet records and fat score derived from the short questionnaire. Gross misclassification, defined as disagreement between the two fat consumption assessments beyond an adjacent tertile, was 15.4%. A Pearson correlation of 0.71 was calculated by a test-retest procedure. It is concluded that the Dutch short questionnaire on fat consumption is a rapid, simple and inexpensive method that can very well be used in nutrition education research to rank individuals according to their dietary fat intake.

Adolescent↗