Zwei Kinder sitzen auf einem kleinen Floß im Wasser. Beide lachen. Eines schaut durch ein Fernrohr.

Information
in English

Program

Inactivity and an unhealthy diet contribute to overweight and obesity among young children. Since these health behaviors develop during early childhood, it’s crucial that health promotion starts at a young age. 
The multi-component school- based health promotion program Join the Healthy Boat was developed for children aged 0-10 years and aims at promoting

  • daily physical activity
  • active, screen-free leisure time
  • higher consumption of fruits and vegetables and decreased consumption of sugar-sweetened beverages
  • relaxation and mindfulness

Through this program, children learn how to establish behaviors which contribute positively to their overall health and development. The program consists of training sessions and practice proven materials for educational professionals and families, which can be integrated into kindergarten and school curriculum. Join the Healthy Boat has been implemented in schools and kindergartens throughout Baden-Württemberg since 2009 and 2014, respectively. 

Development

At the heart of the program is an evidence-based and theory-driven intervention development. It consists of hands-on materials (in German) which were developed by an interdisciplinary team of researchers at the University Hospital of Ulm and an educational advisory board.
Join the Healthy Boat was developed by means of Bartholomew’s Intervention Mapping Approach (Bartholomew et al., 2006). Additionally, the social-cognitive theory by Bandura (Bandura, 2001) and Bronfenbrenner’s ecological framework for human development (Bronfenbrenner, 1979) were applied. 

Intervention strategy

Join the Healthy Boat applies a teacher-delivery model, whereby caregivers and educators are trained to implement the program directly in their own day care centers and classrooms. These training sessions take place in the form of workshops, which are offered free of charge to all interested teachers and educators living in Baden-Wurttemberg, Germany. Theoretical background knowledge as well as the handling of the materials is taught in the training sessions. The associated support materials are also provided to educators and teachers free of charge. 
This program aims at primary prevention and integrates children’s peer group and parents in order to involve their entire environment, thus promoting self-motivation. Using two pirate children, Finn and Fine, as identification figures, the content is conveyed in an engaging, child-friendly way.

Evaluation

Join the Healthy Boat is one of the few successful health promotion programs in Germany that can demonstrate significant intervention effects on different target parameters. The Program was evaluated as part of the “Health Survey” (kindergarten) and “Baden-Württemberg Study” (primary school). 
 

Baden-Württemberg study

The Baden-Württemberg Study assessed the efficacy of the Join the Healthy Boat Program among primary school children in Baden-Württemberg, Germany. For this study, a prospective, stratified, cluster randomized, longitudinal study design was chosen. Participating primary schools were recruited on a voluntary basis. As part of this study, 91 schools were randomized to receive the Join the Health Boat Program for one year or to the control group (45 in the intervention group, 46 in the control group).

Efficacy of the intervention was assessed by changes in the following primary outcomes: waist circumference, skinfold thickness, and 6-minute run. The following conditional skills were also measured, as secondary outcomes: standing long jump, sit-ups, push-ups, lateral jumps, and one-legged stand. Flexibility was measured with sit and reach tests. Additional behavioral and environmental changes, which were assessed through parental report, include the following parameters: physical, mental, and emotional health; health-related quality of life (HRQL); behavior-related cognition; physical activity behavior; screen media use, nutritional behaviors, self-efficacy, socio-demographic parameter; familial and social history; education; school environment; and health-economic aspects. Further secondary aspects, such as physical activity, inhibition and cognition were assessed objectively.

Parental questionnaires were issued at baseline, and one year later at follow-up, and returned within a six-week time period. Objective measurements took place during a school visit and included thorough assessments of children’s motor skills and body composition (Dreyhaupt et al., 2012).   

In total, 1,943 primary school children (7.1 ± 0.6 years) in 157 classes were assessed at baseline. Around 89% of them (1,736 primary school children) were also assessed at follow-up. Parental questionnaires were completed and returned from 1,583 parents (Dreyhaupt et al., 2012).

In conjunction with age and sex, corresponding weight statuses were determined based on German reference data (Kromeyer-Hauschild et al., 2001). Overall, 91% of the children were of normal weight, 9% were either overweight or obese, and 4% were obese at baseline (Kobel et al., 2014) . Significant changes in weight status were not seen during the intervention.

The number of children who were classified as abdominally obese increased from baseline to follow-up (7.8% to 9.2%, respectively). The odds of developing abdominal obesity in the intervention group were less than half as great as in the control group (Kobel et al., 2019a).

Children in the intervention group saw greater improvements in their endurance capability (measured with a 6-minutes-run) from baseline to follow-up, as children in the control group (70.51 ± 128.62 m; p = 0.046) (Kobel et al., 2019a).

Primary children in the intervention group showed also significant improvements in their conditional skills (described in METHODS) (F (1,1571) = 5.20, p ≤ 0.02), and less decline in their flexibility than those in the control group (F (1,1715) = 6.68, p ≤ 0.01) (Lämmle et al., 2017).

Assessed subjectively, at baseline, children engaged in 60 minutes of moderate-to-vigorous physical activity (MVPA) on 2.74 (± 1.66) days per week. 31.9% and 22.2% of boys and girls, respectively, spent at least four days per week being moderately to vigorously physically active for at least 60 minutes. At follow-up, boys spent marginally more time in MVPA and there was a tendency towards more physical activity in the intervention group and a slight, although not statistically significant, reduction of physical activity in the control group (Kobel et al., 2014).

Physical activity was also assessed objectively. At follow-up, significant effects were found for MVPA and gender as well as MVPA and weight status, with boys being more active than girls and overweight/obese children being more active than normal weight children (T -5.646 p < 0.01; T -3.998 p < 0.01, respectively)͘. Further, more children in the intervention group reached the recommended activity guidelines of 60 minutes daily in MVPA; yet no significant significance was reached (Kobel et al., 2017b).

Fruit and vegetable intake increased significantly for first graders (p = 0.050), children from families with high parental education levels (p = 0.023), and children with overweight fathers (p = 0.034). Significant group differences were found in the fruit and vegetable intake of children with migration backgrounds (p = 0.01) and those with parents who have a high school degree (p = 0.019) (Kobel et al., 2022a).  When controlling for migration background, the proportion of children in the intervention group who never or rarely ate fruit and vegetables decreased significantly from baseline to follow-up (p = 0.010) (Kobel et al., 2017c).

At baseline, 24.6% of boys and 22.6% of girls drank sugar-sweetened beverages at least once per week. A significant reduction of soft drink consumption was seen in both the intervention and control group, with trends in a greater reduction among the intervention group (Kobel et al., 2014).

Among children with migration backgrounds, there was a significant decrease in their parental reported regular pure juice consumption from baseline to follow-up (29% to 20.2%; p = 0.004.) Children from households with low incomes also saw a reduction of pure juice consumption (32.9% at baseline – 22.4% at follow-up; p = 0.012) (Kobel et al., 2022a).

At baseline, 12.9% of children reported that they rarely eat breakfast before leaving for school. At follow-up, a tendency could be observed of children in the control group skipping breakfast more often, whereas the number of children who skipped breakfast in the intervention group remained the same. Considering children in grade one and grade two separately, this trend becomes significant among second graders: the second graders in the control group skipped breakfast significantly more often than those in the intervention group (OR = 0.52, p = 0.024, 95% CI [0.30;0.92]) (Kobel et al., 2014).

Baseline results of screen media use show that 15.4% and 11.2% of boys and girls, respectively, spent a minimum of one hour per day using screen media. At follow-up, there was a tendency towards less screen media use in the intervention group, whereas the opposite trend could be observed in the control group. Considering girls and boys separately, there is a significant difference between control and intervention groups with only girls in the intervention group using significantly less screen media per day than their counterparts in the control group (OR = 0.58, p = 0.04, 95% CI [0.35;0.96]).

Significant positive intervention effects on screen media use have been found in children (boys and girls) without a migration background as well as in children whose parents have a low education level (OR = 0.61, p = 0.043, 95% CI [0.38; 0.98] and OR = 0.64, p = 0.032, 95% CI [0.43; 0.96], resp.) (Kobel et al., 2014).

Objectively assessed, at baseline, children spent 211 (± 89) minutes daily being sedentary, at follow-up 259 (± 109) min/day with no significant difference between the intervention and control group. Sedentary behavior was higher during weekends (p < 0.01, for control and intervention group). At follow-up, daily screen time decreased in IG (screen time of >1 h/day: baseline: 33.3% vs. 27.4%; follow-up: 41.2% vs. 27.5%, for CG and IG, respectively) but not sedentary time (Kobel et al., 2020a).

Significant differences occurred in the number of days children missed at school because of sickness and in the number of maternal days off work in favor of the intervention group. Children in the intervention group had a significantly higher reduction in sick days. This effect remains stable for children in grade 1 after adjustment for gender, migration and baseline values for sick days. First grade children in the intervention and control group had a change of −5.15 vs. -3.64, respectively, in the numbers of sick days between baseline and follow up, indicating a group difference of 1.51 days (p = 0.02). ICC for the differences in sick days was 0.045 (95% CI [0.012;0.078]) (Kesztyüs et al., 2016)

Children who adhered to physical activity guidelines had significantly less days of absence due to illness than children who did not meet physical activity guidelines (p < 0.001) (Kobel et al., 2022b).

The costs for two seminars for the consulting teachers added up to €2164.48, with the highest amount of money spent on the teachers´ accommodation, travel and catering. The three vocational training sessions added up to €5872.00, the distributed folders for all teachers, advertising materials and the catering were the most expensive positions. The personnel costs contained costs for consulting teachers and the staff of the university and were, in total, the highest position at €28469.93. The total amount of the intervention for one year was €36506.41, which resulted in an intervention cost of €25.04 per pupil (Kesztyüs et al., 2017).

The incremental cost-effectiveness ratios, in this scenario the costs per case of incidental abdominal obesity averted, varied between €1515 and €1993, depending on the size of the observed target group. Hypothetical changes in the effect of the intervention on the incidence rate of ± 10% and ± 20% respectively, resulted in a minimum of costs per case averted of €1789.53 and a maximum of €1963.92 (Kesztyüs et al., 2017).

Health survey

The health study assessed the effectiveness of the Join the Healthy Boat Program among Kindergarten children in Baden-Württemberg, Germany. For this study, a prospective, stratified, cluster randomized, longitudinal study design was chosen. The study focused on changes in the behavior of the children, parents, and educators. Kindergartens were recruited on a voluntary basis. As part of this study, 57 kindergartens were randomized to receive the Join the Health Boat Program for one year or to the control group (30 in the intervention group, 27 in the control group).

Efficacy of the intervention was assessed by changes in the following primary outcomes: nutrition (consumption of sugar-sweetened beverages, fruit & vegetables, and high-calorie foods); screen media consumption; physical activity; and health knowledge and attitudes of parents and kindergarten teachers.

Changes in the following variables were assessed as secondary outcomes: anthropometric parameters (waist circumference, waist-to-height ration, BMI, and subcutaneous fat); children’s quality of life; sickness related absenteeism and medical appointments; motor skills (measured with standing long jumps, one-legged stands, sit and reach tests, and 3-minute runs); and kindergarten environments.

Additional behavioral and environmental changes, which were measured assessed through parental report, include the following parameters: physical, mental, and emotional health; physical activity perception and behavior; screen media use, nutritional behaviors, self-efficacy, body perception, socio-demographic parameter; familial and social history; education; school environment; and health-economic aspects. 

Parental questionnaires were issued at baseline and one year later at follow-up. Objective measurements were carried out by a team from the Ulm University Hospital, at the day care center (Kobel et al., 2017a).  

In total, 973 kindergarten children (4.1 ± 0.75 years) in 57 kindergartens were assessed at baseline. 57% of them (567 kindergarten children) were assessed at follow-up. Parental questionnaires were completed by 784 parents.

In conjunction with age and sex, corresponding weight statuses were determined based on German reference data (Kromeyer-Hauschild et al., 2001). Overall, 82.7% of the children were of normal weight, 7.7% were underweight, and 9.6% were overweight or obese. The number of children who were classified as overweight increased from baseline to follow-up (5.8% to 6.5%). Children in the intervention group saw a decrease in body mass index percentile values from baseline to follow-up (51.9 ± 25.9 to 48.7 ± 26.3), whereas body mass index percentile values increased among the control group (47.9 ± 25.9 to 48.4 ± 26.2) (Kobel et al., 2019d). 

Children in the intervention group saw greater improvements in their endurance performance (measured with a 3-minutes-run) from baseline to follow-up, as children in the control group (305.8 ± 46.2 m and 286.9 ± 43.2 m, respectively; p ≤ 0.001) (Kobel et al., 2019d).  Significant intervention effects on endurance performance were not seen for children with low baseline values, or those with low socio-economic status. No intervention effects were found for the remaining three motor skills, which were assessed (flexibility, balance, and speed strength) (Kobel et al., 2020b).

Assessed subjectively, at baseline, children engaged in 60 minutes of moderate-to-vigorous physical activity (MVPA) on 2.77 (± 2.0) days per week. There was a significant gender difference in days being sufficiently physically active (p ≤ 0.001) with boys spending on average 2.9 (± 2.1) days/week with at least 60 minutes of MVPA, whereas girls spent on 2.3 (± 1.8) days/week 1h in that intensity.

One year later, at follow-up, children engaged in 60 minutes of MVPA on 2.8 (± 2.0) days/week and reached that hour of MVPA on 7days/ week significantly more often than the year before (p ≤ 0.001). Furthermore, children in the intervention group engaged in 60 minutes of moderate to vigorous physical activity (MVPA) on more days of the week than children in the control group at follow-up (p ≤ 0.005). This result remained significant when controlling for age, gender, weight status, and migration status. In addition, nearly twice as many children in the intervention group reported daily physical activity as in the control group at follow-up (p ≤ 0.03) (Kobel et al., 2019d).

At baseline, children ate 2.27 (± 1.73) portions of fruit and vegetables daily with 16.7% of children eating no fruit or vegetables and 9.9% of children eating five or more portions per day. At follow-up, children ate 2.39 (± 1.81) portions of fruit and vegetables per day with 17.9% of children eating no fruit or vegetables and 10.9% of children eating five or more portions daily. There was no significant difference between control and intervention group at baseline or follow-up (Kobel et al., 2019d).

At baseline, 24.6% of children never drank sugar-sweetened beverages, 9.5% drank those drinks at least once per day. At follow-up, 21.2% of children never consumed and sugar-sweetened beverages, 6.2% of children drank those beverages at least once daily with no significant difference between control and intervention group. However, the percentage of children who consumed sugar-sweetened beverages daily reduced by nearly half in the intervention group whereas the percentage of children in the control group whose parents reported to consume sugar-sweetened beverages at least daily remained the same (Kobel et al., 2019d).

At baseline, 49.5% of children reportedly used screen media (television, game console, computer, tablet, smartphone) for 1 h or more per day. This increased to 54.2% at follow-up, with no significant difference between control and intervention group (Kobel et al., 2019d).

Additional study results from both studies

The data from 1942 primary children (Baden Württemberg Study) was analyzed using binary-logistic regression analyses. A positive correlation was found between adherence to physical activity and screen media guidelines and less absenteeism from school. Children who were active on at least four days per week for 60 minutes were significantly less likely to have had more than five sickness-related absent days from school (p < 0.001). Children who had more than an hour of daily screen media usage missed significantly more days of school due to sickness than those who adhered to screen media guidelines (8.39 ± 9.13 days vs. 6.96 ± 6.58 days; p = 0.007). Physical activity promotion measures may also be effective in reducing the economic burden of sick days and should therefore be implemented early. (Kobel et al., 2022b).

Weight and height were measured in 1646 primary school children and were used to determine their BMI and weight status. Socio economic status and migration status were obtained through parental questionnaires. Compared to children from families with higher income, children from families with a net income < 1750 € were 96.2% more likely to be overweight (CI 1.316-2.924, p = 0.001). A significant correlation was also found between migration status and childhood weight; children with a migration background were 81.9% more likely to be overweight (CI 1.323-2.502, p < 0.001). Future public health policies should consider socio economic status and migration status to effectively combat further health inequalities (Hermeling et al., 2022).

Data from 558 kindergarten children, collected by parental report, was analyzed using a prospective randomized controlled trail, to investigate the influence of parental self-efficacy on children’s physical activity and screen media use. Baseline measures for parental-self efficacy significantly predicted children’s physical activity measures at follow-up. In addition, a significant positive correlation was found between parental-self efficacy and both children’s physical activity (B = 0.33, p = 0.025) and screen media usage (B = 0.42, p = 0.006). Parental self-efficacy influences both physical activity and screen media use of children and should be considered in future health promotion interventions (Kieslinger et al., 2021).  The data detailed above was also analyzed in a further study, to evaluate the influence of parental self-efficacy on children’s nutrition behavior. Parental self-efficacy was positively associated with fruit and vegetable intake (B = 0.237; p < 0.001) and showed a protective effect on soft drink consumption (OR 0.728; p = 0.002). Parental nutrition was shown to be a stronger predictor of children’s fruit and vegetable consumption (B = 0.451; p < 0.001), and soft drink intake (OR 7.188; p < 0.001). Interventions should therefore seek to promote self-efficacy and healthy nutrition for both children and parents to promote positive nutrition behaviors among children (Möhler et al., 2020).  

Parental reports provided data on lifestyle characteristics, socio-economic variables, and parents’ willingness to pay for childhood obesity preventative measures; 1,593 reports were completed at post measurement (T2), and 906 reports at follow-up (T3). The general willingness of parents to pay for childhood obesity preventive measures decreased overtime (48.9% at T2 and 35.8% at T3; p < 0.001, n = 760). Families with overweight or obese children, and those with higher socioeconomic status, were more likely willing to pay for obesity prevention. At follow-up, nearly all parents (97.8%) indicated that overweight and obesity are serious public health problems. This reflects a general public awareness that should be considered and translated into public preventive strategies (Lauer et al., 2020).

Parental reports provided data on trait-based emotional intelligence and body image dissatisfaction among 991 primary school children. 42% of girls and 34% of boys indicated that they wish to have a thinner body; girls had significantly higher body image dissatisfaction as boys (p < 0.01). Higher trait-based emotional intelligence was associated with lower body image dissatisfaction among girls and boys. Lower health-related quality of life was associated with lower trait-based emotional intelligence. Prevention programs should seek early on to improve aspects of emotional intelligence in order to prevent lifestyle habits, which later lead to disordered eating behaviors (Pollatos et al., 2020).

The sedentary behavior of 231 primary children was measured using a multi-sensor device, worn for 10 hrs a day for at least three days. Screen time was measured by parental reports. The time that children spent being sedentary increased from baseline to follow-up (211 ± 89; 259 ± 109, respectively). Children had significantly more sedentary time during the weekends than on weekdays (p < 0.01) (Kobel et al., 2020a).

Screen time did not differ significantly among primary children with high sedentary time (83.8 ± 55.0 min; 27.4% of sedentary time) and those with low sedentary time (77.2 ± 59.4 min; 71.3% of sedentary time). Screen time and sedentary time were shown to be largely independent of each other. Screen time should, therefore, not be considered the key to predicting or changing the sedentary behavior of children (Hoffman et al., 2019).