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Biomedical subjects

H De Vries

Publications and source records attributed to H De Vries.

At least 19 recordsLinked to original sources
PubMed2000

Subtypes of precontemplating smokers defined by different long-term plans to change their smoking behavior.

Many smokers are not motivated to quit smoking. In the Stages of Change model these smokers are called precontemplators. When developing interventions designed to motivate these smokers to quit, it is of importance to know whether this group is homogeneous or not. In the present study, different groups of precontemplators were distinguished according to their long-term quitting smoking plan: 861 precontemplators were asked to indicate the one plan that best fitted their own plans with regard to their smoking behavior: (1) planning to never quit and not planning to cut down (n = 194), (2) planning to never quit but planning to cut down (n = 186), (3) planning to quit somewhere in the future but not within the next 5 years (n = 290), (4) planning to quit within the next 5 years (n = 136) and (5) planning to quit within the next year but not within the next 6 months (n = 54). These groups of smokers were compared on several variables cross-sectionally and longitudinally. The results indicate that the psychological factors that will have to be targeted in smoking cessation interventions in efforts to motivate smokers to quit could be assessed reliably in precontemplators. Furthermore, precontemplators with different quitting plans differed on several cognitive variables and the quitting plans at pre-test were predictive of quitting activity after 7 months. Precontemplators who received self-help smoking cessation materials made forward changes in quitting plans and these changes seemed to follow a certain order. Forward changes in plans were differentially related to positive outcome expectations, to self-efficacy expectations depending on the quitting plan and not to changes in negative outcomes. The present study is one step in mapping the psychology of low motivation to change behavior.

Adolescent↗
PubMed1999

Targeting smokers with low readiness to change with tailored and nontailored self-help materials.

BACKGROUND: Few smoking cessation self-help materials are available for smokers who are not planning to quit. However, computer-tailored interventions can be designed specifically for these smokers. METHODS: In a large randomized field trial (N = 843), two different tailored smoking cessation self-help interventions (multiple tailoring and single tailoring) and one standardized smoking cessation self-help guide were compared with a no-information control group and with each other. The contents of the tailored interventions were adapted to individuals' self-reported stage of change, outcome expectations, self-efficacy levels, and smoking behavior. RESULTS: The primary outcome measure was forward stage transition. The standardized self-help guide had no effect. Among smokers who were not planning to quit within the next 5 years the multiple-tailored intervention was more effective than the single-tailored intervention. This pattern was supported by the cognitive changes caused by the interventions. Among smokers who were planning to quit within the next 5 years but not within the next 6 months, none of the self-help materials had any effect. CONCLUSION: The present results show that the self-help material currently available in the Netherlands, the standardized self-help guide, was not effective among smokers with low readiness to change. However, computer-generated tailored interventions seem a promising means of communicating information on smoking and smoking cessation to these smokers.

Adult↗
PubMed1999

The development of computer-generated tailored interventions.

Tailoring information to individual characteristics of a person is a promising line of development of self-help interventions. This article presents a three-phase methodology for developing computer-generated tailored interventions. The first phase of the development concerns the formulation of intervention objectives on the basis of analyses of the cognitive determinants of behavior. The second phase concerns the core of the development of a tailored intervention. For each objective, a so-called tailoring matrix is developed which specifies the individual characteristics to which the message will be adapted to. The tailoring matrices are the basis of the tailored messages and the tailoring questionnaire which will assess the individual characteristics. In the third phase, all the separately written messages must be integrated to one coherent intervention text and the lay-out is designed. This methodology may result in largely different tailored interventions depending on the theoretical framework used, the adaptation of the messages and the inclusion of feedback.

Cognition↗
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↗
PubMed1999

Effectiveness of a social influence approach and boosters to smoking prevention.

This paper presents the short-term and long-term results of a randomized smoking prevention trial. The purpose was to evaluate two smoking prevention programs, a social influence (SI) program and a SI program with an additional decision-making component (SI(DM)). Moreover, the contribution of boosters was assessed as well. Fifty-two schools were randomly assigned to the SI program, the SI(DM) program or a control group. Half of the treatment schools were randomly assigned to the booster condition; the other half did not receive boosters. Both programs consisted of five lessons, each lasting 45 min, and were given in weekly sessions in grades 8 and 9 of high schools in the Netherlands. The most successful program was the SI program with boosters which resulted in a significantly lower increase in smoking rates (5.6 and 9.7%, respectively) compared to the control group (12.6 and 14.9%, respectively) at both 12 and 18 months follow-up. The results suggest that boosters can be an effective tool for maintaining or increasing the effectiveness of smoking prevention programs. It is recommended that the SI program with the booster be implemented at the national level, since this intervention showed the greatest behavioral effects.

Adolescent↗
PubMed1999

The reach and effectiveness of a national mass media-led smoking cessation campaign in The Netherlands.

OBJECTIVES: This study examined the reach, effectiveness, and cost-effectiveness of a mass media-led smoking cessation campaign including television shows, a television clinic, a quit line, local group programs, and a comprehensive publicity campaign. METHODS: A random sample of baseline smokers (n = 1338) was interviewed before and after the campaign and at a 10-month follow-up. A nonpretested control group (n = 508) of baseline smokers was incorporated to control for test effects. RESULTS: Most smokers were aware of the campaign, although active participation rates were low. Dose-response relations between exposure and quitting were found. The follow-up point prevalence abstinence rate attributable to the campaign was estimated to be 4.5% after control for test effects and secular trends. The cost per long-term quitter was about $12. CONCLUSIONS: In spite of a massive rise in tobacco promotion expenditures prior to the campaign and the absence of governmental control over the media, the campaign under study may have increased normal cessation rates substantially.

Community-Institutional Relations↗
PubMed1998

Tailored interventions to communicate stage-matched information to smokers in different motivational stages.

Smokers in stages of low readiness to quit (immotives and precontemplators) and smokers in stages of high readiness to quit (contemplators and preparers) were randomly allocated to 1 of 4 tailored intervention conditions offering outcome information, self-efficacy-enhancing information, both sorts of information, or no information. Data on 1,540 smokers, stratified by stage, were analyzed. The primary outcome measure was stage transition. The hypotheses with regard to stage-matched information for immotives and precontemplators were not verified. With regard to contemplators and preparers, the following was found: Compared with the control group, contemplators benefited the most from both sorts of information, whereas preparers benefited the most from self-efficacy-enhancing information only. Comparisons between contemplators and preparers who were assigned to the matched treatment and contemplators and preparers who were assigned to the mismatched treatment supported these findings.

Adult↗
PubMed1998

Tailoring information to enhance quitting in smokers with low motivation to quit: three basic efficacy questions.

Tailoring information to a target individual's features is a promising line of development in self-help interventions. In this article, 752 smokers with explicit low intention to quit were randomly assigned to 1 of 5 conditions: (a) multiple tailored letters with self-help guide, (b) multiple tailored letters only, (c) a single tailored letter with a self-help guide, (d) a single tailored letter only, or (e) a nontailored intervention. Follow-up assessment took place 4 months after the intervention. Results indicated that the single tailored intervention only had no surplus value compared with a nontailored look-alike intervention. The addition of a self-help guide to a tailored intervention was only useful in highly dependent smokers, and multiple tailoring was more effective than single tailoring. It remains important to elucidate why and for whom certain tailored interventions are more effective.

Adult↗
PubMed1998

Computerized tailored feedback to change cognitive determinants of smoking: a Dutch field experiment.

In the last decade, attempts have been made to improve the efficacy of minimal interventions by tailoring them to individual features. In the development of these tailored interventions, it is important to know which information in interventions is essential. Most smoking cessation interventions contain information on the outcomes of quitting and skills to be used in a quit attempt. The present study was designed to assess the cognitive changes caused by both sorts of information. Therefore, 246 smokers who were planning to quit within 6 months were randomly assigned to three different conditions. In the first condition, the respondents received a computer-generated tailored letter on the outcomes of smoking cessation. In the second condition, the respondents received a computer-generated tailored letter containing self-efficacy enhancing information, mainly on skills. In both conditions, the contents of the letters were based on the pre-test scores of the participants. Participants in the control condition did not receive any cessation information. The results show that information on the outcomes of quitting changed expected outcomes while information on coping skills changed self-efficacy expectations, in comparison with the control condition. Comparing both experimental conditions, information on the outcomes led to changes in expected outcomes, whereas information on coping skills did not lead to higher self-efficacy expectations than information on the outcomes of quitting. It is concluded that the hypothesized effects were partly verified.

Analysis of Variance↗
PubMed1998

Long-term effectiveness of computer-generated tailored feedback in smoking cessation.

Although tailored interventions consisting of only a few pages of information lead to more quitting than no intervention in the short term, the long-term efficacy of a single tailored intervention still has to be proven. In the present study smokers were reactively recruited and randomly allocated to one of four intervention conditions: (1) outcome information, (2) self-efficacy enhancing information, (3) both sorts of information or (4) no information. Smokers in the three experimental groups received computer-generated tailored feedback containing the condition-specific information, by mail. The results from the 14 months follow-up can be summarized as follows. Compared to the no information condition, all three experimental conditions led to significantly more smokers who had engaged in 24-h quit attempts. However, no experimental condition led to more 7-day quitting than the no information condition. With regard to continuous abstinence, the experimental condition offering a combination of outcome information and self-efficacy enhancing information had a significant effect, compared to the no information condition. It is concluded that a minimal six-page tailored intervention can be beneficial in supporting smokers to quit smoking, even after 14 months.

Adult↗
PubMed1998

Measuring support for tobacco control policy in selected areas of six countries.

OBJECTIVE: To explore the validity, reliability, and applicability of using a short, psychometrically sound survey instrument to measure population attitudes toward tobacco control policies. DESIGN: Surveys. SUBJECTS AND SETTING: Student respondents attending university in Australia (n = 403), Hong Kong (n = 336), the Netherlands (n = 351), South Africa (n = 291), the United Kingdom (n = 164) and the United States (n = 241); total n = 1786. MAIN OUTCOME MEASURE: The Smoking Policy Inventory (SPI), a 35-item scale. SPI scores were adjusted for age, income, gender, and smoking status. Estimates of internal consistency and tests of factorial invariance were conducted in each sample. RESULTS: Across all six countries, the SPI was found to be highly reliable and to have a consistent factor structure, indicating that the SPI scale represents a higher order construct that assesses general attitudes about tobacco control policy with five dimensions. In general, the degree of endorsement of anti-tobacco policies as measured by the SPI reflected the extent and strength of tobacco control legislation in those countries. Dutch students were the least likely, and Australian and Hong Kong students the most likely, to support tobacco control policies. CONCLUSIONS: It is possible to develop appropriate and meaningful measurement tools for assessing support of tobacco control policies. Strong evidence was found for internal reliability and structural invariance of the SPI. The SPI may be a useful mechanism for monitoring ongoing policy initiatives, making cross-cultural comparisons, and evaluating population receptiveness to proposed policy approaches.

Adolescent↗
PubMed1996

The Dutch cancer information helpline: experience and impact.

A study was performed to evaluate the experience and impact of the Dutch national cancer information helpline. During a period of 4 weeks all callers from the target groups general public, cancer patients and friends/relatives of patients were asked to fill in a structured postal questionnaire (response 73%; N = 532). Different characteristics of the helpline were evaluated: the overall quality of the information given, the communication skills of the educators and the telephone as a channel for getting information concerning cancer. Also, several outcomes were measured: the overall satisfaction with the helpline, the impact on anxiety and the impact on meeting expectations. Most of the callers evaluated the different characteristics of the helpline very positively. Most callers were positive concerning the outcomes of the helpline. However, different target groups showed different predictors of these outcomes. The general public were mostly interested in general information, while relatives/friends and patients also seemed much in need of communicational feedback and reassurance. To maintain the high quality of the helpline it is of great importance to keep the line's expertise at a constant high level. This can be realized by training educators to attune more to the specific needs and questions of the different target groups and to try to get the 'real' questions to the surface.

Adult↗
PubMed1995

Psychosocial determinants of fruit and vegetable consumption.

Psychosocial correlates of fruit and vegetable consumption were studied in an adult Dutch population (n = 367) based on the ASE model of attitudes, social influence and self-efficacy. Attitudes were a summation of beliefs about taste, different health consequences, and costs in time and money. Social influences were measured through the social stimulation respondents expected to get from important others to consume adequate amounts of fruit and vegetables and by asking the subjects about the behaviour of important others. Self-efficacy reflected the respondents' ability to consume adequate amounts of fruit and vegetables in various situations. Self-efficacy and attitudes were consistently and significantly associated with consumption of boiled or otherwise heated vegetables, of salads, and of fruit. Furthermore, respondents reporting low consumption of these food groups had lower self-efficacy expectations and less positive attitudes than subjects with relatively high consumption of fruit and vegetables. It is concluded that nutrition education aimed at stimulating fruit and vegetable consumption should focus especially on changing attitudes and self efficacy expectations.

Adult↗
PubMed1995

Starting participation in an employee fitness program: attitudes, social influence, and self-efficacy.

BACKGROUND: This article presents a study of the determinants of starting participation in an employee fitness program. Information from 488 employees, recruited from two worksites, was obtained. From these employees the determinants of participation were studied. METHODS: A questionnaire based on two theoretical models was used. The Stages of Change model was used to measure the health behavior, consisting of precontemplation (no intention to participate), contemplation (considering participation), preparation (intending to participate within a short period), and action (participating in fitness). The possible determinants were measured according to the ASE model, including the attitude toward an employee fitness program, social influence, and self-efficacy expectations. RESULTS: Subjects in action stage were most convinced of the benefits of participation in the employee fitness program and of their own skills to participate in a fitness program. Subjects in precontemplation stage were least convinced of the advantages of participation and had the lowest self-efficacy scores. Subjects in action stage experienced the most social support to participate in the employee fitness program. CONCLUSIONS: Health education for employees within industrial fitness programs can be tailored toward their motivational stage. Promotional activities for industrial fitness programs should concentrate on persons in the precontemplation and contemplation stages, since people in these stages are insufficiently convinced of the advantages of a fitness program and expect many problems with regard to their ability to participate in the program.

Adult↗
PubMed1995

Behavior of conduct disordered children in interaction with each other and with normal peers.

This study investigated the behavior of children with conduct disorder or oppositional defiant disorder (CD/ODD) in interaction with each other and with normal control (NC) children in a semi-standardized setting over a period of 25 minutes. This short time turned out to be sufficient to demonstrate the behavioral manifestations of CD/ODD in children's interactions with peers. In addition, the role of the interactional partner on antisocial behaviour of CD/ODD children became apparent.

Aggression↗
PubMed1995

Differences between conduct disordered and normal control children in their tendencies to escalate or neutralize conflicts when interacting with normal peers.

The behavior of conduct disordered (CD) children was compared with normal control (NC) children in interaction with normal peers. Dyads consisting of a) a CD child and a normal peer and b) an NC child and the same normal peer as in a) were observed. CD boys were less able than NC boys to neutralize incipient conflicts. Hitherto most behavioral studies of CD boys have concentrated on their tendency to escalate conflicts but have paid very little attention to their difficulty in neutralizing conflicts.

Aggression↗
PubMed1995

Participation in an employee fitness program: determinants of high adherence, low adherence, and dropout.

This article presents the results of a study of the determinants of adherence level in an employee fitness program. Of all 236 employees who started participating in the program the determinants of level of participation (high adherence, low adherence, and dropouts) during the program were studied by means of a pretest and posttest design. The questionnaire was based on different theoretical concepts. The determinants measured included the attitude toward an employee fitness program, self-efficacy expectation, and social support. The results show that there were no differences in determinants between the groups at the start of the program. During the second measurement the high- and low-adherence groups were most convinced of the benefits of participation in the program. The low-adherence group and the dropouts were least convinced of their ability to participate in a fitness program. Theoretical and practical implications are discussed.

Analysis of Variance↗