Role of dietary intake and physical activity in reducing weight social inequalities among adolescents: an application of G-formula to PRALIMAP-INÈS trial

Interventions aiming to reduce social inequalities of weight status in adolescents usually focus on lifestyle behaviours, but their effectiveness is limited. This study analysed the effect of achieving levels of dietary intake (DI) and/or physical activity (PA) guidelines on reducing social inequalities in weight status among adolescents. We included adolescents from the PRomotion de l'ALIMentation et de l'Activité Physique - INÉgalité de Santé (PRALIMAP-INÈS) trial with weight status data available at baseline and 1-year follow-up (n=1130). PA and DI were measured using the International Physical Activity Questionnaire and a validated food frequency questionnaire, respectively. We estimated the likelihood of a 1-year reduction in body mass index z-score (BMIz) and population risk difference (PRD) under hypothetical DI and PA levels and socioeconomic status using the parametric G-formula. When advantaged and less advantaged adolescents maintained their baseline DI and PA, we found social inequalities in weight status, with a PRD of a 1-year reduction in BMIz of -1.6% (-3.0%; -0.5%). These inequalities were not observed when less advantaged adolescents increased their proportion of achieving DI guidelines by 30% (PRD=2.2% [-0.5%; 5.0%]) unlike the same increase in PA (PRD= -3.9% [-6.8%; -1.3%]). Finally, social inequalities of weight status were not observed when levels of achievement of both PA and DI guidelines increased by 30% (PRD= 2.2% [-0.5%; 4.0%]). Enhancing DI rather than PA could be effective in reducing social inequalities in weight status among adolescents. Future interventions aiming to reduce these inequalities should mostly target DI to be effective.

Proportionate universalism intervention is effective for tackling nutritional social gradient in adolescents: the PRALIMAP-INÈS mixed randomised trial

OBJECTIVE

This study aimed to investigate the effectiveness of proportionate universalism intervention to reduce the slope of the nutritional social gradient in adolescents.

STUDY DESIGN

A mixed (experimental and quasi-experimental) multicentre trial.

METHODS

Data from 985 adolescents of the PRALIMAP-INÈS trial (North-eastern France, 2012-2015) were analysed. For this, adolescents were split into five social classes according to the Family Affluence Scale: Highly Less Advantaged (H.L.Ad; n = 33), Less Advantaged (L.Ad; n = 155), Intermediate (Int; n = 404), Advantaged (Ad; n = 324) and Highly Advantaged (H.Ad; n = 69). The overweight care management was a standard care for all and a strengthened one adapted to the social class of adolescents. The main outcome was the 1-year change of the body mass index z-score (BMIz) slope. Other nutritional outcomes were BMI, ΔBMI_p95 (BMI minus 95th percentile of the WHO reference), %BMI_p95 (percent of 95th percentile of the WHO reference), leisure-time sport, consumption of fruits and vegetables and consumption of sugary foods and drinks.

RESULTS

The inclusion data confirmed a weight social gradient expressed by a significant BMIz linear regression coefficient (β = -0.09 [-0.14 to -0.04], P < 0.0001). The higher the social class, the lower the BMIz. The 1-year BMIz linear regression coefficient was -0.07 [-0.12 to -0.02], corresponding to a significant weight social gradient reduction of 23.3% (β = 0.021 [0.001 to 0.041]; P = 0.04). Consistent results were found for other nutritional outcomes.

CONCLUSIONS

PRALIMAP-INÈS shows that proportionate universalism intervention is effective to reduce the adolescents' nutritional social gradient and suggests that equitable health programmes and policies are a realistic goal.

Economic evaluation of a school-based strategy to prevent overweight and obesity in French adolescents: insights from the PRALIMAP randomised trial

OBJECTIVES

This study aimed to provide cost-effectiveness and budget impact analyses of a school-based overweight/obesity screening and care prevention strategy among adolescents.

STUDY DESIGN

Cost-effectiveness and budget impact analyses.

METHODS

Data from 3538 adolescents who participated in a school-based randomised controlled trial in the Northeast of France were used. Costs (from a public payer's perspective) included screening for overweight and obesity and subsequent care. Effectiveness was measured as the change in body mass index (kilogram per square metre), prevalence of overweight/obesity, moderate physical activity energy expenditure, duration and frequency and total sitting time. The incremental cost-effectiveness ratio was calculated, and a budget impact analysis was conducted.

RESULTS

The screening and care strategy resulted in an incremental cost-effectiveness ratio of €1634.48 per averted case of overweight/obesity and €255.43 per body mass index unit decrease. The costs for increasing moderate physical activity by 1000 metabolic equivalent of task-min/week, duration by 60 min/week and frequency 1 day/week were €165.28, €39.21 and €93.66 per adolescent, respectively. Decreasing total sitting time by 60 min/week had a cost of €8.49 per adolescent. The cost of implementing the strategy nationally was estimated to be €50.1 million with a payback period from 3.6 to 7.3 years.

CONCLUSIONS

The screening and care strategy could be an efficient way to prevent overweight and obesity among adolescents. Future studies should investigate how the current results could be achieved in schools with different settings and thus justify its relevance for overweight and obesity prevention to policy-makers.

Behavioural risk patterns in adolescents with excess weight participating in the PRALIMAP-INÈS trial

OBJECTIVE

To investigate clustering of risk behaviours in adolescents with excess weight.

DESIGN

Cross-sectional analysis of baseline data from the PRALIMAP-INÈS trial. Information on food frequency consumption (fruit, vegetables, sugary products and beverages), physical activity, sedentary behaviour (week and weekend days), smoking and alcohol consumption (current frequency and intoxication episodes) and socio-demographic data was collected using self-reported questionnaires. Behavioural risk factors were entered as categorical variables in a two-step clustering procedure: multiple correspondence analysis followed by hierarchical clustering. Associations between cluster membership and socio-demographic variables were investigated using multivariable multinomial logistic regression.

SETTING

French PRALIMAP-INÈS trial.

PARTICIPANTS

Adolescents with excess weight.

RESULTS

A total of 1391 participants (13-18 years old, 58·2 % female) were included in the analysis, which resulted in the identification of four groups of participants, including, respectively, 543 (39·0 %), 373 (26·8 %), 246 (17·7 %) and 229 (16·5 %) participants. Clusters 1 and 4 showed associations of rather healthy behaviours (high physical activity and low consumption of sugary products; high consumption of fruit and vegetables, respectively), while clusters 2 and 3 showed associations of rather unhealthy behaviours (high sedentary behaviour and low consumption of fruit and vegetables; smoking and alcohol consumption, respectively). Both social status and family structure were associated with cluster membership.

CONCLUSIONS

Risk behaviour patterns in adolescents with excess weight were clustered in both healthier and less healthy ways, with a complex interplay with socio-demographic factors.

O7-8 Mediation effect of physical activity and sedentary behavior on the association of gender with quality of life in adolescents

Background

If boys and girls are known to have different levels of quality of life (HRQoL), less is known about behavioural factors such as physical activity (PA), sedentary behaviour (SB) that can explain it. We aimed to analyse the mediation effect of PA and SB on the association of sex and HRQoL among adolescents.

Methods

2448 adolescents (1378, 56.3% of Girls) from the PRALIMAP trial with 2-year follow-up were included. HRQoL (physical, mental, social and general dimension scores; range 0-100), PA (walking, moderate vigorous and total) and SB (sitting time) were assessed using the Duke Health profile and the IPAQ questionnaires, respectively. The 2-year mean PA and SB were calculated and categorized into high or low PA (? 1hour/day) or SB (2 hours/day out of school). We conducted a mediation analysis to investigate the causal mechanism of gender (reference=Girls) on HRQoL through PA and SB by estimating total effect (TE), natural direct effect (NDE), natural indirect effects (NIE) as well as proportion mediated (PM: proportion of sex-HRQoL relationship mediated by PA or SB).

Results

The direct relationship of gender and HRQoL (NDE) was significant whatever the HRQoL dimension. When using vigorous PA as mediator, PM was estimated at 13.7% (TE:11.0 [9.5 to 12.5]; NIE:1.5[0.9 to 2.1]), 19.4% (TE: 12.3 [10.6 to 14.1]; NIE: 2.4 [1.6 to 3.1]), 70.0% (TE:4.6 [3.1 to 6.2] ; NIE: 3.3 [2.5 to 4.0]) and 25.6% (TE: 9.3 [8.1 to 10.5]; NIE:2.4 [1.8 to 2.9]) for physical, mental, social and general HRQoL, respectively. Similar but less important mediation effect was observed for moderate and walking PA. For Total PA, PM was estimated 7.0%, 8.7%, 47.4% and 14.7% for physical, mental, social and general HRQoL while for SB, the mediation was inverse and less important (PM: -1.5%, -1.4%, -2.0% and -1.5% for physical, mental, social and general HRQoL respectively).

Conclusion

HRQoL is significantly higher in boys compared to girls among adolescents and this difference is shown to be partially mediated by differences in PA practice, especially vigorous PA. Additionally to the impact of adolescent PA in preventing non-communicable diseases in adulthood, it can also enhance their well-being.

Physical activity rather than sedentary behaviour is socially determined in French adolescents with overweight and obesity

Social differences in prevalence of overweight and obesity among adolescents, known as the weight social gradient, could be explained by differences in behaviours between social classes. This study examined the respective association of physical activity (PA), sedentary behaviour (SB) and weight status with adolescents' socioeconomic status. We used cross-sectional data for 1935 adolescents (13-18 years old) with overweight or obesity who participated in the PRALIMAP-INÉS (PRomotion de l'ALImentation et de l'Activité Physique - INÉgalités de Santé) trial conducted in northeastern France between 2012 and 2015. Adolescents completed the International Physical Activity Questionnaire for PA and SB and the Family Affluence Scale for socioeconomic status. Weight status was assessed by the body mass index (BMI) and BMI z-score. Social gradient of weight status, PA and SB were described according to the Family Affluence Scale (slopes) and evidenced by the linear trend test (p). Adolescents' socioeconomic status was positively associated with PA practice (frequency, vigorous PA and leisure-time PA), but there was no association with their SB. The results confirmed a significant weight social gradient: BMI (β = 0.37, p < .0001) and BMI z-score (β = 0.07, p = .0001). The weight social gradient in adolescents was mostly associated with PA (5.7% to 8.1%) rather than SB (2.7% to 5.7%). Nearly 14% of BMI z-scores could be related to a combined PA and SB effect. PA was found an important factor of weight social gradient in adolescence. Actions aimed at preventing weight social inequalities among adolescents could include PA promotion as lever. CLINICAL TRIALS REGISTRY AND NUMBER: ClinicalTrials.gov (NCT01688453).

Effectiveness of a socially adapted intervention in reducing social inequalities in adolescence weight. The PRALIMAP-INÈS school-based mixed trial

BACKGROUND

A high prevalence of overweight/obesity among low socioeconomic status adolescents contributes to health inequalities. However, evidence-based interventions for reducing social inequalities in adolescent weight are lacking. We aimed to investigate whether strengthened care management for adolescents with low socioeconomic status has an equivalent effect in reducing overweight as standard care management in adolescents with high status.

METHODS

PRALIMAP-INÈS was a multicentre trial including 35 state-run high and middle schools in the north-eastern France. A population-based sample of 1639 adolescents aged 13-18 years with screened and clinically confirmed overweight/obesity were proposed for inclusion and divided into two groups by the Family Affluence Scale score: advantaged (score > 5), receiving standard care management (A.S) and less-advantaged randomly assigned to two groups (1:2 ratio): standard care management (LA.S) and standard and strengthened care management (LA.S.S). Interventions were based on the proportionate universalism principle: universal standard care for all groups and proportionate care for the LA.S.S group. Main outcome was body mass index z-score (BMIz) assessed before and 1 year after inclusion.

RESULTS

A total of 1419 adolescents were included and 1143 followed up at 1 year: 649 in A.S, 158 in LA.S and 336 in LA.S.S groups. BMIz decreased significantly for boys (-0.11 [95% CI, -0.13 to -0.08]; p < 0.0001) and girls (-0.05 [-0.08 to -0.03]; p < 0.0001). No equivalence between LA.S.S and A.S groups was evidenced. For girls, the trend to superiority for LA.S.S was confirmed by the more favourable change (-0.06 [-0.11 to -0.01]; p = 0.01) observed on superiority analysis, with no differential change for boys (0.02 [-0.03 to 0.08]; p = 0.41).

CONCLUSIONS

A public health school-based intervention using the proportionate universalism principle may be effective in not worsening or even reducing overweight social inequalities in adolescents, especially for girls. Overcoming social barriers may help health professionals dealing with the burden and inequalities of overweight in adolescents.

Universal School-Based Intervention Does Not Reduce Socioeconomic Inequalities in Weight Status among Adolescents

Background: Differences in weight status by socioeconomic position occur during adolescence and is known as weight social gradient (WSG). The PRALIMAP (Promotion de l'ALIMentation et de l'Activité Physique) trial highlighted that a universal intervention was effective in reducing overweight and obesity prevalence among adolescents. However, its ability to reduce the WSG is unclear. This study aimed to evaluate the impact of the PRALIMAP intervention on the WSG among adolescents. Methods: Data were obtained from 3504 adolescents who participated in the school-based PRALIMAP trial between 2006 and 2009. The PRALIMAP study consisted of three interventional strategies: educational, environmental, screening and care. Weight status was assessed by body mass index (BMI) z-score and overweight and obesity prevalence. The "indice de position sociale des élèves" was used to measure adolescents' socioeconomic status. Linear regression and hierarchical models were used to assess the WSG and its evolution, respectively. Results: Among all adolescents (14-18 years old), significant WSG was identified at baseline: BMI z-score (β = -0.06; p < 0.0001), overweight and obesity prevalence (β = -2.86; p < 0.0001). Overall, the intervention conferred no significant reduction in the WSG: BMI z-score (β = -0.01 [-0.02 to 0.01], p = 0.48), overweight and obesity prevalence (β = -0.01 [-0.07 to 0.05], p = 0.73). Similar results were observed for adolescents whatever the interventional strategy they benefited from in the PRALIMAP trial. Conclusions: This study provided no evidence that the PRALIMAP universal intervention was effective in reducing the socioeconomic inequalities in weight status among adolescents. Different interventions that account for social differences should be considered to tackle these inequalities.

Using facilitator-receiver peer dyads matched according to socioeconomic status to promote behaviour change in overweight adolescents: a feasibility study

OBJECTIVE

To evaluate the feasibility of an innovative peer intervention promoting healthy eating and physical activity, which purposefully selected peer facilitators according to socioeconomic status to target less-advantaged overweight receivers.

SETTING

Nine high schools, two middle schools.

PARTICIPANTS

One hundred and fifty-six adolescents were approached to become facilitators, of whom 18 were trained. Thirty-two of 56 potential receivers agreed to participate.

INTERVENTION

The peer intervention was carried out in 2013-2014 and embedded in a larger trial: PRALIMAP-INÈS (Promotion de l'ALIMentation et l'Activité Physique-INEgalité de Santé). Facilitanoators were selected and trained to organise weight-control activities with specific peer receivers participating in the programme.

PRIMARY AND SECONDARY OUTCOME MEASURES

Different types of data were collected to assess demand, acceptability, implementation and practicality of the intervention. For the facilitators, this included 6 training sessions, 11 mid-programme interviews, 4 end-of-programme sessions, telephone notes and text message exchanges. All six potential receivers in one school were also interviewed. Sociodemographic and health characteristics were also analysed.

RESULTS

Agreeing to participate was more likely when asked by a peer compared with a professional (51.2% discordant pairs; p<0.02). Twelve activities, mostly based on physical activity and implemented during weekends or holidays, were carried out. The mean age of active receivers was 16 and their body mass index was higher than other participants. For both facilitators and active receivers, there were more participating girls. Qualitative analysis reveals key implementation challenges for facilitators. Interviews with the receivers highlight social difficulties, with most feeling bad about their appearance and wanting to lose weight. Those who participated in peer activities were very positive about the experience especially social support.

CONCLUSIONS

The present study suggests the peer intervention is feasible provided organisational difficulties are addressed. Good practice recommendations are formulated, including a longer training session, organising a joint meeting with the facilitators and receivers, matching dyads on place of residence and multiplying modes of contact.

TRIAL REGISTRATION NUMBER

NCT01688453.

Reach and Acceptability of a Mobile Reminder Strategy and Facebook Group Intervention for Weight Management in Less Advantaged Adolescents: Insights From the PRALIMAP-INÈS Trial

Background

Although information and communication technology interventions appear to be a promising means of reducing the health inequality gap in overweight and obesity prevention, research on information and communication technology interventions is lacking outside the Anglo-Saxon world.

Objective

The aim of this study was to assess the reach and acceptability of 2 information and communication technology interventions delivered as part of a French nutritional program: an SMS text messaging (short message service, SMS) attendance-reminder for collective sessions strategy and a Facebook challenge group.

Methods

This study sample comprised 262 socially less advantaged overweight adolescents aged between 13 and 18 years. The information and communication technology interventions were carried out during the 2013-2014 academic year in 33 French state-run schools. For the SMS attendance-reminder for collective sessions strategy, at the start of the academic year, adolescents were asked to give their mobile number. SMS attendance-reminders were sent shortly before each of the 5 collective sessions. For the Facebook challenge group, adolescents were invited to join a closed Facebook group in which challenges on physical activity and on diet were posted weekly. Process data and 2 sets of face-to-face interviews were also used to interpret participation rates and access to Facebook. Appreciation for both interventions was evaluated by a questionnaire at the end of the academic year.

Results

Of the recruited adolescents, 79.0% (207/262) gave their mobile number, reflecting high access to a mobile phone. Giving a number was significantly more likely for girls (odds ratio [OR] 2.1, 95% CI 1.1-3.9; P=.02) and adolescents in a vocational or general high school as opposed to middle school (OR 1.0, 95% CI 0.4-2.7; OR 0.2, 95% CI 0.1-0.5; P<.001). Indicating a mobile number at the start of the year was not significantly associated with participation in collective sessions. Of the adolescents seen at the start-of-year face-to-face interviews, 78.1% (153/196) declared an interest in the Facebook challenge group, which implies having a Facebook account or being able to have access to one. However, only 21 adolescents went through the process of joining the group. Although there was satisfaction with the Facebook group among the participants, the low participation rate in the Facebook group does not allow conclusions to be drawn with confidence.

Conclusions

The results are in line with the claim that using information and communication technologies in health programs is unlikely to widen health inequalities. However, in this population of French adolescents, mobile phone strategies seem more adapted to a high school context, and caution should be exercised with a younger audience. Although there is positive appreciation of the SMS attendance-reminders and a Facebook intervention is initially highly appealing to less advantaged adolescents, no evidence of impact could be demonstrated. These results highlight the difficulty in assessing the impact of specific interventions in complex health programs.

Trial Registration

Clinicaltrials.gov NCT01688453; https://clinicaltrials.gov/ct2/show/NCT01688453 (Archived by WebCite at http://www.webcitation.org/6yy6EQ0SM)

Reducing social inequalities in access to overweight and obesity care management for adolescents: The PRALIMAP-INÈS trial protocol and inclusion data analysis

Background

Despite social inequalities in overweight/obesity prevalence, evidence-based public health interventions to reduce them are scarce. The PRALIMAP-INÈS trial aimed to investigate whether a strengthened-care management for adolescents with low socioeconomic status has an equivalent effect in preventing and reducing overweight as a standard-care management for high socioeconomic status adolescents.

Methods

PRALIMAP-INÈS was a mixed, prospective and multicenter trial including 35 state-run schools. It admitted overweight or obese adolescents, age 13–18 years old, for 3 consecutive academic years. One-year interventions were implemented. Data were collected before (T0), after (T1) and post (T2) intervention. Among 2113 eligible adolescents who completed questionnaires, 1639 were proposed for inclusion and 1419 were included (220 parental refusals). Two groups were constituted according to the Family Affluence Scale (FAS) score: the less advantaged (FAS≤5) were randomly assigned to 2 groups in a 2/1 ratio. The 3 intervention groups were: advantaged with standard-care management (A.S, n = 808), less advantaged with standard-care management (LA.S, n = 196), and less advantaged with standard and strengthened-care management (LA.S.S, n = 415). The standard-care management was based on the patient education principle and consisted of 5 collective sessions. The strengthened-care management was based on the proportionate universalism principle and consisted of activities adapted to needs.

Inclusion results

The written parental refusal was less frequent among less advantaged and more overweight adolescents. A dramatic linear social gradient in overweight was evidenced.

Discussion

The PRALIMAP-INÈS outcomes should inform how effectively a socially adapted public health program can avoid worsening social inequalities in overweight adolescents attending school.

Trial registration

ClinicalTrials.gov (NCT01688453).

Association of socioeconomic, school-related and family factors and physical activity and sedentary behaviour among adolescents: multilevel analysis of the PRALIMAP trial inclusion data

BACKGROUND

Social differences among adolescents in physical activity and sedentary behaviour have been identified but are not well explained. The current study aimed to identify socioeconomic, family and school-related associated factors with physical activity and sedentary behaviour among high-school adolescents.

METHODS

This was a cross-sectional analysis of T0 physical activity and sedentary behaviour of 2523 students 14 - 18 years old recruited for the PRALIMAP trial from 24 French state-run high schools. Data were collected by self-administered questionnaire at the start of grade 10. Adolescents completed the International Physical Activity Questionnaire for physical activity and sedentary behaviour and an ad hoc questionnaire for active commuting and sport participation. Statistical analyses involved linear and logistic regressions.

RESULTS

Socioeconomic, family or school variables were associated with levels of physical activity and sedentary behaviour for both boys and girls, but no factor, except perceived parental physical activity level, was associated with total energy expenditure (total physical activity) for either gender. Adolescents with privileged and less privileged socioeconomic status reported the same total amount of energy expenditure.

CONCLUSIONS

Total physical activity score alone is not sufficient to assess the physical activity of adolescents. These findings may have implications for better understanding of social inequalities in this context and recommendations to prevent overweight.

TRIAL REGISTRATION

This trial is registered at ClinicalTrials.gov ( NCT00814554 ). The date of registration: 23 December 2008. Registration was not required at the time of the start of PRALIMAP for public health and prevention programmes and trials.