Type 2 diabetes (T2D) is a serious chronic disease that causes multiple complications. It is estimated that it is the third leading cause of death worldwide1 and its prevalence continues to increase, having reached epidemic proportions.2,3

Type 2 diabetes has gone from being primarily a disease of adulthood to having onset at younger ages, mainly in relation to the increase in the prevalence of obesity and sedentary lifestyles.4 There has been an increase in the prevalence of T2D in young adults and adolescents, with an incidence that varies between geographical areas5,6 that continues to increase in individuals aged less than 30years.7–9 The data for the population of Spain are scarce, with a lower incidence compared to neighbouring countries.10–12 Until 2002, T2D was not considered a paediatric disease. It was that year that the World Health Organization (WHO) started to issue recommendations for its early detection.13 Furthermore, the progression from glucose intolerance to T2D is accelerated in the young adult and paediatric populations.14 Due to all the above, early intervention in this subpopulation is considered of great importance.3,15,16

Evidence from observational studies shows that 80%–90% of cases of T2D result from unhealthy lifestyle habits.17,18 Randomised controlled trials focused on T2D performed in different countries and populations19,20 have evinced that interventions based on lifestyle changes can reduce the risk of progression from glucose intolerance to T2D.21 There is also evidence that for interventions to be effective they need to be multidisciplinary, intensive and led by professionals specifically trained for the purpose.22–25

Several systematic reviews26–30 and clinical practice guidelines16,31 highlight the most efficacious aspects of strategies for the management of obesity in youth: a combination of sedentary lifestyle, dietary and behavioural changes, involvement of parents and legal guardians and improving the knowledge and motivation of children in addition to assessing their mood.

The above aspects, combined with the lessons learned in implemented strategies for the prevention of diabetes and associated risk factors in other countries and the need to improve the evidence currently available,25,32,33 motivated the development of the PRE-STARt tool and implementation of the PRE-STARt study at the European level,34 a multidisciplinary intervention seeking to promote healthy lifestyles in adolescents at risk of T2D. The aim of this study is to assess the efficacy of the intervention at 24 months of follow-up in the PRE-STARt study in Euskadi (Basque Country) based on the prevention of increases in body mass index (BMI) in adolescents aged 12–14 years and changes in lifestyle habits (diet and physical activity). The global outcomes of the European study are currently being reviewed.

We included a total of 92 participants in the study, 47 in the IG and 45 in the CG. During the 2-year follow-up, the attrition rate was 21% in the IG and 51% in the CG, a difference that was statistically significant (P=0.006). Fig. 2 presents a flow chart of participation throughout the follow-up.

Figure 2.

Flow chart of the study sample.

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Table 1 summarises the baseline characteristics of the participants. We did not find differences between the IG and the CG. The mean age of participants was 13 years (SD, 0.7), and the sex distribution was similar in both groups, with a predominance of female participants (56%). Eighty percent of participants were white. The mean BMI at baseline was 26.5 (SD, 3.3), without differences between the groups. We also found no differences between groups in the prevalence of risk factors for T2D.36

We found significant differences in the temporal trends of the BMI and BMI z-score (Table 2). At 12 months, they both decreased in the IG and increased in the CG. And at 2 years, we found an increase in both groups, but smaller in the IG (Fig. 3). The waist circumference increased significantly in the CG but was maintained in the IG. We did not find significant differences in the neck and arm circumference trends. We also found no differences in the blood pressure z-score trends.

Figure 3.

Changes in body mass index (BMI) during the follow-up. Data expressed as mean (standard deviation).

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The temporal trends in physical activity showed that the mean number of days a week that participants engaged in at least 1h of physical activity increased significantly in the IG compared to the CG (linear model, P=0.002) (Fig. 4), a difference that was more marked at the midpoint of the follow-up compared to the end (quadratic fit, P=0.003) (Table 3). The estimated values at 12 months showed a difference of nearly 1.5 days a week with performance of physical activity in the IG compared to the CG.

Figure 4.

Changes in the level of physical activity during follow-up. Data expressed as mean (standard deviation).

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We also found differences in diet-related variables (Table 3), although in this case the difference was linear, without the quadratic effect, which suggests that the changes are maintained over time. The consumption of fruits and vegetables increased significantly in the IG both in terms of the servings per day and the number of days a week these foods were consumed. The estimated values at 2 years of follow-up suggested that participants in the IG consumed fruits and vegetables up to 1 more day a week compared to participants in the CG, in addition to one more serving of fruit and one half more serving of vegetables a day. When it came to foods the consumption of which was discouraged, we found a decrease in both the weekly and daily consumption of unhealthy snacks and sugary drinks, with an estimated difference between the IG and CG of more than half a serving a day at the 2-year timepoint. Fig. 5 shows the percentage of participants that adhered to dietary recommendations. We also analysed the overall effect on BMI trends of the changes in diet and physical activity, and found that changes in all variables were associated with a reduction of the BMI with similar coefficients, with the exception of the consumption of vegetables (P=0.485) and fruit (P=0.905).

Figure 5.

Adherence to dietary recommendations. Percentage of participants that adhered to dietary recommendations at different timepoints in the intervention and control groups.

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The European PRE-STARt study aims to address excess weight as the main risk factor for the development of T2D.

The conventional approach to the management of excess weight, which in our region is carried out by a single health care professional, a paediatrician or nurse, is based on the recommendation of diet changes and the promotion of physical activity, allocates little time to intervention, fails early and does not achieve favourable outcomes.23,28

To date, the strategies that have proven most effective in the management of excess weight are multidisciplinary and intensive interventions22,23,28 delivered by professionals with specific training and experience in the delivery of these programmes, which seek to achieve behavioural changes at the individual and family levels to improve physical and mental health. The intervention performed in this study adhered to current evidence-based recommendations regarding intervention at the family level.24

The data at the 2-year timepoint evince significant changes in the IG in BMI and BMI z-score compared to the CG. The intervention succeeding in halting the increase in BMI, given that there is a physiological increase in BMI in the age range of the participants.

Another important outcome concerns dietary patterns. In the IG, the consumption of fruits and vegetables increased and the consumption of sugary drinks and unhealthy snacks decreased compared to the CG. Some studies have found changes in BMI associated with partial diet modification,25 such as a decrease in BMI associated with a decreased consumption of sugary drinks.37 In our study, decreases in the consumption of snacks and of sugary drinks achieved significant and similar reductions in BMI, while the consumption of fruits and vegetables did not have the same impact, although they still offer well-known health benefits.38

Combined interventions that include dietary and physical activity measures achieve better outcomes compared to isolated interventions.25 When it comes to physical activity, the heterogeneity of the interventions and the methods used for assessment poses barriers to comparative analyses aiming to identify the most effective approach.39 In agreement with previous evidence, our study found significant changes in the IG compared to the CG in the number of days per week that participants engaged in at least 1h of vigorous physical activity.

A large proportion of studies on the subject highlight the poor adherence to treatment plans, and therefore the importance of specific and accredited training for the health care professionals that deliver these interventions.25 In our study, we found a low attrition rate in the IG compared to the CG during the 2-year follow-up, which is relevant considering that membership in the IG imposed greater demands and required considerable involvement of the family. We also found significant differences in BMI, diet and physical activity in Phase 1, and, more importantly, that these differences remained at the 2-year follow-up. This suggests that the achieved behavioural changes could be sustained in the future, which would be beneficial by reducing the impact of modifiable risk factors for T2D, especially in children that have non-modifiable risk factors from birth.

Another strength is that the recruitment of participants, the delivery of intervention and the assessments were performed in the primary care setting, unlike previous studies that involved community- and school-based interventions.25,33 This was possible due to the universal and free coverage offered by our regional public health system, which provides access to paediatric care to the entire population.

The main limitation of our study was the method used to recruit participants. Although participants were randomly allocated to groups, the choice to participate, especially given the intensive nature of the intervention, may have been a source of bias with overrepresentation of individuals motivated to change. However, the comparable characteristics of the intervention and control groups at baseline indicates a lack of selection bias. The losses to follow-up in the control group constituted another limitation, although in this case it is possible that the individuals that dropped out of the study were the ones that had the least favourable health outcomes. Also, since the sample was greater than the minimum size calculated for the study, a 50% attrition rate would correspond to a statistical power of 80%. Yet another limitation is that all participants in both the IG and CG were past the onset of puberty (Tanner stages 2–5), so our study cannot contribute any information regarding potential differences in the response to the intervention in prepubertal children. It would be interesting to analyse differences in outcomes in 2 groups (prepubertal and pubertal) on account of the potential impact of, on one hand, the younger age of the former and, on the other, the physical and psychological changes associated with puberty, when it comes to implementing an intensive multidisciplinary intervention.

We did not observe any adverse effects in the intervention group in terms of eating, mood or anxiety disorders.

The findings of the study confirm the effectiveness at 2 years of follow-up of a multidisciplinary programme, adapted to the sociocultural characteristics of our region, in the adolescents included in the intervention group, slowing the increase in BMI and improving dietary and physical activity habits, factors associated with the risk of developing metabolic diseases in the future, including T2D.

A programme of these characteristics is one of several possible strategies to fight obesity and sedentary lifestyles in the paediatric and young adult population and for prevention of metabolic diseases. Child obesity is currently one of the most serious global public health problems and it needs to be addressed through the development of preventive strategies and the identification of risk factors from birth, areas in which primary care paediatric teams play a crucial role.

Study funded by the European Commission through the Call for tender system (file no. SANCO/2013/C1/004).

The authors have no conflicts of interest to declare.