S.P.J. Kremers

Environmental correlates of physical activity in youth – a review and update

Obesogenic environments are thought to underlie the increased obesity prevalence observed in youth during the past decades. Understanding the environmental factors that are associated with physical activity (PA) in youth is needed to better inform the development of effective intervention strategies attempting to halt the obesity epidemic. We conducted a systematic semi‐quantitative review of 150 studies on environmental correlates of youth PA published in the past 25 years. The ANalysis Grid for Environments Linked to Obesity (ANGELO) framework was used to classify the environmental correlates studied. Most studies retrieved used cross‐sectional designs and subjective measures of environmental factors and PA. Variables of the home and school environments were especially associated with children’s PA. Most consistent positive correlates of PA were father’s PA, time spent outdoors and school PA‐related policies (in children), and support from significant others, mother’s education level, family income, and non‐vocational school attendance (in adolescents). Low crime incidence (in adolescents) was characteristic of the neighbourhood environment associated with higher PA. Convincing evidence of an important role for many other environmental factors was, however, not found. Further research should aim at longitudinal and intervention studies, and use more objective measures of PA and its potential (environmental) determinants.

Parenting style and adolescent fruit consumption

The importance of the social environment for dietary behaviour has been highlighted in the past decade. A type of environmental influence that has received increasing research attention in recent years is the influence that parents can have on their childrens dietary behaviour through food-related parenting practices. Much of the work done so far, however, has reported inconsistent findings and poorly understood mechanisms of influence. The present study aimed to explore the possible environmental influence of general parenting style on adolescent food choice patterns. Data were collected at schools (N=643; mean age 16.5 years), using self-administered questionnaires on parenting style, fruit intake behaviour and fruit-specific cognitions. Consistent and theoretically predictable differences were found between adolescents who described their parents as authoritative, authoritarian, indulgent or neglectful. Fruit consumption and fruit-specific cognitions were most favourable among adolescents who were being raised with an authoritative parenting style. Children of parents with indulgent parenting styles consumed more fruit than adolescents from authoritarian or neglectful homes. Consequences of these results for the interpretation of earlier studies on the influence of parenting practices are discussed, and a research model is proposed for future studies of parental influences on adolescent dietary behaviours.

General parenting, childhood overweight and obesity‐inducing behaviors: A review

Despite emerging efforts to investigate the influence parents have on their childrens weight status and related dietary and activity behaviors, reviews regarding the role of general parenting are lacking. We performed a systematic review regarding the relationship between general parenting and these weight-related outcomes to guide observational research. In total, 36 studies were included. Discrepancies across studies were found, which may be explained by differences in conceptualization of parenting constructs. Overall, however, results suggest that children raised in authoritative homes ate more healthy, were more physically active and had lower BMI levels, compared to children who were raised with other styles (authoritarian, permissive/indulgent, uninvolved/neglectful). Findings of some moderation studies indicate that general parenting has a differential impact on childrens weight-related outcomes, depending on child and parental characteristics. These findings underline the importance of acknowledging interactions between general parenting and both child and parent characteristics, as well as behavior-specific parenting practices.

Interrupting long periods of sitting: good STUFF

There is increasing evidence that sedentary behaviour is in itself a health risk, regardless of the daily amount of moderate to vigorous physical activity. Therefore, sedentary behaviour should be targeted as important health behaviour.It is known that even relatively small changes of health behaviour often require serious efforts from an individual and from people in their environment to become part of their lifestyle. Therefore, interventions to promote healthy behaviours should ideally be simple, easy to perform and easily available. Since sitting is likely to be highly habitual, confrontation with an intervention should almost automatically elicit a reaction of getting up, and thus break up and reduce sitting time. One important prerequisite for successful dissemination of such an intervention could be the use of a recognisable term relating to sedentary behaviour, which should have the characteristics of an effective brand name. To become wide spread, this term may need to meet three criteria: the “Law of the few”, the “Stickiness factor”, and the “Power of context”. For that purpose we introduce STUFF: Stand Up For Fitness. STUFF can be defined as “interrupting long sitting periods by short breaks”, for instance, interrupting sitting every 30 min by standing for at least five minutes.Even though we still need evidence to test the health-enhancing effects of interrupted sitting, we hope that the introduction of STUFF will facilitate the testing of the social, psychological and health effects of interventions to reduce sitting time.

The Effectiveness of Tailored Feedback and Action Plans in an Intervention Addressing Multiple Health Behaviors

Purpose. Examine the effects of three iterative tailored feedback letters addressing smoking; physical activity; and fruit, vegetable, and fat intake, and test the additional effects of providing feedback on action plans. Design. A tailored, print-based intervention was developed and tested in a randomized control trial with a posttest after 9 months. Setting. A total of 2827 respondents agreed to participate. They were recruited from a random sample of 35,000 addresses obtained through the Dutch national telephone company. Subjects. The mean age was 49 years, and 55% were female. Intervention. The experimental group received three printed tailored letters, and the control group received three printed generic letters. Respondents from the experimental group randomly received either a third letter with tailored information or tailored information and action-planning feedback. Measures. The questionnaire assessed physical activity; smoking; consumption of fruit, vegetables and fat; motivational determinants; action plans; and demographics. Results. Tailored information resulted in more improvement over time than generic information for the intake of fruit, vegetables, and fat and for physical activity. No differences between the conditions were found for smoking because of high cessation rates in all conditions. Action-planning feedback did not increase the effects. Conclusions. Tailored lifestyle information can be effective for adults in changing nutrition behavior and physical activity.

Does habit strength moderate the intention-behaviour relationship in the Theory of Planned Behaviour? The case of fruit consumption

The present study examined if habit strength moderated the influence of intention on fruit consumption in a Dutch adult sample (N = 521, 46.3% males, mean age = 34.50, SD = 10.87), using the theoretical relations of the Theory of Planned Behaviour (TPB). TPB variables and habit strength were assessed at baseline. Fruit consumption was assessed with a validated questionnaire five weeks later. Three groups were created: low habit strength (n = 180), medium habit strength (n = 185) and high habit strength (n = 156). Confirmatory factor analyses and multi-group path analyses were performed using AMOS 4.0. A good fit was obtained for the overall measurement model and the structural models. Multi-group path analyses showed that intention was a significant predictor of fruit consumption in the low habit (β = 0.36, p < 0.001) and medium habit group (β = 0.30, p < 0.001), but a non-significant predictor in the high habit group (β = 0.05, p = 0.596). Implications for information-based and motivation-based interventions are discussed.

Associations between physical activity, fitness, and academic achievement

OBJECTIVES To explore the associations between objectively assessed intensity levels of physical activity and academic achievement and test whether cardiovascular fitness mediates the association between physical activity and academic achievement. STUDY DESIGN Cross-sectional data were gathered in Swedish 9th-grade students (n = 232; mean age = 16 years; 52% girls). School grades, pubertal phase, skinfold thickness, cardiovascular fitness, and physical activity were measured objectively. Mothers education, family structure, and parental monitoring were self-reported. Data were analyzed with linear regression analyses. RESULTS After controlling for confounding factors, academic achievement was associated with vigorous physical activity in girls (beta = .30, P < .01; explained variance of the model 26%), which remained after inclusion of fitness (beta = .23, P < .05; explained variance 29%). The association was not mediated by fitness. In boys, academic achievement was associated with pubertal phase (beta = .25, P < .05). After inclusion of fitness, it was only associated with fitness (beta = .25, P < .05; explained variance of the model 30%). CONCLUSION In girls, academic achievement was associated with vigorous physical activity and not mediated by fitness, whereas in boys only fitness was associated with academic achievement. Further studies are necessary to investigate the potential longitudinal effect of vigorous physical activity on academic achievement, the role of fitness herein and the implications of these findings for schools.

Adult active transportation: adding habit strength to the theory of planned behavior

BACKGROUND Many health behaviors have a history of repetition and, as a result, may become habitual. Because including a measure of habit strength may add depth to current theoretical models on health behavior, the present study explored the issue of habit strength within the context of the theory of planned behavior regarding adult bicycle use as a means of transportation. METHODS Cross-sectional data were gathered in a Dutch adult sample (n=317; mean age=42.09 years; 46.7% men) in 2006 using self-administered questionnaires. Variables for the theory of planned behavior were assessed regarding bicycle use as a means of transportation; habit strength regarding bicycle use as a means of transportation was assessed with the validated Self-Reported Habit Index. Hierarchical regression analyses and interaction analyses using simple slope analyses were conducted. RESULTS After controlling for variables for the theory of planned behavior, habit strength was the strongest predictor of bicycle use. In addition, simple slope analyses based on a significant interaction term, intention x habit, showed that intention was a significant predictor of bicycle use among those at low levels of habit strength for bicycle use (beta=0.67, p<0.001) but a weaker and nonsignificant predictor at high levels of habit strength (beta=0.10, p=0.136). CONCLUSIONS Habit strength is a moderator of the intention-behavior relationship regarding bicycle use, with intention becoming less relevant when bicycle use increases in habit strength. Future determinant and intervention studies on physical activity may benefit from including a measure of habit strength--for instance, by identifying the differential effects of informational and environmental interventions.

Correlates of motivation to prevent weight gain: a cross sectional survey

BackgroundThis study is an application of the theory of planned behaviour (TPB) with additional variables to predict the motivations to prevent weight gain. In addition, variations in measures across individuals classified into Precaution Adoption Process stages (PAPM-stages) of behaviour change were investigated.MethodsA cross-sectional survey among 979 non-obese Dutch adults aged 25–35 years was conducted. Multiple binary logistic regression analysis was conducted to assess the associations of Body Mass Index (BMI), demographic factors and psychosocial variables from the TPB with the intention to prevent weight gain. Differences in BMI, demographic and psychosocial factors between PAPM-stages were explored using one-way analysis of variance and chi-square tests.ResultsEighty-five percent of respondents intended to prevent weight gain. Age, attitudes and risk perceptions related to weight gain were the strongest correlates of intention (age: OR = 1.12, 95%CI: 1.04–1.20; attitude OR = 7.91, 95%CI: 5.33–11.74; risk perception OR = 1.24, 95%CI: 1.11–1.38). Significant differences were detected between the PAPM-stages in almost all variables. Notably, perceived behavioural control was lowest among people who had decided to prevent weight gain.ConclusionMessages to influence attitudes towards the prevention of weight gain and risk perception may affect people who are not yet motivated to prevent weight gain. Interventions increasing peoples perceived behavioural control in overcoming barriers to prevent weight gain may help people to act on their intentions.

A systematic review of associations between environmental factors, energy and fat intakes among adults: is there evidence for environments that encourage obesogenic dietary intakes?

OBJECTIVE To review the literature examining associations between environmental factors, energy and fat intakes among adults, and to identify issues for future research. METHODS Literature searches of studies published between 1980 and 2004 were conducted in major databases (i.e. PubMed, Human Nutrition, Web of Science, PsychInfo, Sociofile). Additional articles were located by citation tracking. RESULTS Twenty-one articles met the inclusion criteria. No study provided a clear conceptualisation of how environmental factors may influence these dietary intakes. Availability, social, cultural and material aspects of the environment were relatively understudied compared with other factors such as seasonal/day of the week variation and work-related factors. Few studies examined the specific environmental factors implicated in the obesity epidemic, and there was little study replication. All studies were observational and cross-sectional. CONCLUSIONS It is too premature to conclude whether or not environmental factors play a role in obesogenic and unhealthy dietary intakes. More studies need to examine associations with those environmental factors thought to contribute to obesogenic environments. There needs to be more development in theories that conceptualise the relationship between environmental factors and dietary intakes.