Obesogenic diet and physical activity: independent or associated behaviours in adolescents?

An mHealth Intervention Promoting Physical Activity and Healthy Eating in a Family Setting (SMARTFAMILY): Randomized Controlled Trial

BACKGROUND

Numerous smartphone apps are targeting physical activity (PA) and healthy eating (HE), but empirical evidence on their effectiveness for the initialization and maintenance of behavior change, especially in children and adolescents, is still limited. Social settings influence individual behavior; therefore, core settings such as the family need to be considered when designing mobile health (mHealth) apps.

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of a theory- and evidence-based mHealth intervention (called SMARTFAMILY [SF]) targeting PA and HE in a collective family-based setting.

METHODS

A smartphone app based on behavior change theories and techniques was developed, implemented, and evaluated with a cluster randomized controlled trial in a collective family setting. Baseline (t0) and postintervention (t1) measurements included PA (self-reported and accelerometry) and HE measurements (self-reported fruit and vegetable intake) as primary outcomes. Secondary outcomes (self-reported) were intrinsic motivation, behavior-specific self-efficacy, and the family health climate. Between t0 and t1, families of the intervention group (IG) used the SF app individually and collaboratively for 3 consecutive weeks, whereas families in the control group (CG) received no treatment. Four weeks following t1, a follow-up assessment (t2) was completed by participants, consisting of all questionnaire items to assess the stability of the intervention effects. Multilevel analyses were implemented in R (R Foundation for Statistical Computing) to acknowledge the hierarchical structure of persons (level 1) clustered in families (level 2).

RESULTS

Overall, 48 families (CG: n=22, 46%, with 68 participants and IG: n=26, 54%, with 88 participants) were recruited for the study. Two families (CG: n=1, 2%, with 4 participants and IG: n=1, 2%, with 4 participants) chose to drop out of the study owing to personal reasons before t0. Overall, no evidence for meaningful and statistically significant increases in PA and HE levels of the intervention were observed in our physically active study participants (all P>.30).

CONCLUSIONS

Despite incorporating behavior change techniques rooted in family life and psychological theories, the SF intervention did not yield significant increases in PA and HE levels among the participants. The results of the study were mainly limited by the physically active participants and the large age range of children and adolescents. Enhancing intervention effectiveness may involve incorporating health literacy, just-in-time adaptive interventions, and more advanced features in future app development. Further research is needed to better understand intervention engagement and tailor mHealth interventions to individuals for enhanced effectiveness in primary prevention efforts.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00010415; https://drks.de/search/en/trial/DRKS00010415.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/20534.

Adherence to Southern European Atlantic Diet and physical fitness on the atherogenic index of plasma in adolescents

We sought (i) to evaluate the associations of cardiorespiratory fitness (CRF), muscular fitness (MF) and Southern European Atlantic Diet (SEADiet) with atherogenic index of plasma (AIP) and (ii) to investigate de combined association of MF, CRF and SEADiet on AIP in adolescents. A cross-sectional school-based study was conducted on 493 adolescents (285 girls and 208 boys) aged 15-18 years, from the Portuguese Azorean Archipelago. CRF was measured by shuttle run test and MF by curl up and push up tests. Adherence to SEADiet was assessed with a semi-quantitative food frequency questionnaire (FFQ). The AIP was estimated as log (TG/HDL-C). Measures of pubertal stage and socioeconomic status were assessed. Linear regression showed a significant inverse association between MF (standardized β = -0.165; p < 0.001), CRF (standardized β = -0.081; p < 0.030) and SEADiet (standardized β = -0.081; p < 0.045) with AIP, after adjustments for age, sex, pubertal stage and parental education. Furthermore, participants classified with an optimal as well as those with low adherence to a SEADiet but with LowMF/LowCRF had on average the highest AIP (F(7.482) = 3.270; p = 0.002). Moreover, optimal SEADiet with HighMF/HighCRF group showed the lowest AIP when compared with those with low adherence to a SEADiet with HighMF/HighCRF group (p = 0.03). AIP is inversely associated with MF, CRF and SEADiet. The low MF combined with a low CRF levels seems to overcome the potential healthy effect of having an optimal adherence to the SEADiet on AIP. However, an optimal adherence to SEADiet seems to improve the AIP in those adolescents with high fitness levels.

Optimal Adherence to a Mediterranean Diet May Not Overcome the Deleterious Effects of Low Physical Fitness on Cardiovascular Disease Risk in Adolescents: A Cross-Sectional Pooled Analysis

To examine the combined association of cardiorespiratory fitness (CRF), muscular fitness (MF), and adherence to a Mediterranean diet (MeDiet) on cardiovascular risk in adolescents, a pooled study, including cross-sectional data from two projects [2477 adolescents (1320 girls) aged 12–18 years], was completed. A shuttle run test was used to assess CRF. MF was assessed by the standing-long jump and handgrip tests. Adherence to a MeDiet was assessed by the Kidmed questionnaire. A cardiovascular risk score was computed from the following components: Age and sex, waist circumference, triglycerides, systolic blood pressure, high-density lipoprotein cholesterol (HDL), and glucose. Analysis of covariance showed that participants classified as having optimal (High) adherence to a MeDiet/HighMF/HighCRF, as well those classified as low adherence to a MeDiet/HighMF/HighCRF, had, on average, the lowest cardiovascular risk score (F = 15.6; p < 0.001). In addition, the high adherence to a MeDiet/LowMF/LowCRF group had the highest odds of having a high cardiovascular risk (OR = 7.1; 95% CI: 3.4–15.1; p < 0.001), followed by the low adherence to a MeDiet/LowMF/LowCRF group (OR = 3.7; 95% CI: 2.2–6.3; p < 0.001), high adherence to a MeDiet/HighMF/LowCRF group (OR = 3.1; 95% CI: 1.4–7.0; p = 0.006), and low adherence to a MeDiet/LowMF/HighCRF group (OR = 2.5; 95% CI: 1.5–4.4; p = 0.002) when compared to those with high adherence to a MeDiet/HighMF/HighCRF, after adjustments for potential confounders. In conclusion, our findings showed that, regardless of the MeDiet status, adolescents with low MF and low CRF cumulatively, presented the highest cardiovascular disease risk. Therefore, these findings suggest that the combination of these two fitness components may be beneficial to adolescents’ cardiometabolic profile, independent of MeDiet behaviour.

Accelerometer-determined peak cadence and weight status in children from São Caetano do Sul, Brazil

The purpose of this study was to determine the relationship between peak cadence indicators and body mass index (BMI) and body fat percentage (BF%)-defined weight status in children. The sample comprised 485 Brazilian children. Minute-by-minute step data from accelerometry were rank ordered for each day to identify the peak 1-minute, 30-minute and 60-minute cadence values. Data were described by BMI-defined and bioelectrical impedance-determined BF% weight status. BMI-defined normal weight children had higher peak 1-minute (115.5 versus 110.6 and 106.6 steps/min), 30-minute (81.0 versus 77.5 and 74.0 steps/min) and 60-minute cadence (67.1 versus 63.4 and 60.7 steps/min) than overweight and obese children (p<.0001), respectively. Defined using %BF, normal weight children had higher peak 1-minute (114.5 versus 106.1 steps/min), 30-minute (80.4 versus 73.1 steps/min) and 60-minute cadence (66.5 versus 59.9 steps/min) than obese children (p<.0001). Similar relationships were observed in boys; however, only peak 1- minute cadence differed significantly across BMI and %BF-defined weight status categories in girls. Peak cadence indicators were negatively associated with BMI and BF% in these schoolchildren and significantly higher among normal weight compared to overweight or obese children.

Correlates of compliance with recommended levels of physical activity in children

The purpose of this study was to describe children’s daily compliance with moderate-to-vigorous physical activity (MVPA) recommendations across a week in different parts of the world, and to identify individual- and school-level correlates that may explain differences in daily MVPA compliance. The sample included 6553 children aged 9–11 years from 12 countries, and multilevel statistical analyses were used, including both child- and school-level variables. Most children did not comply with the MVPA guidelines on a daily basis: Chinese children complied the least, whereas Finnish, Australian, Colombian, UK, and Kenyan children complied the most. Boys (rate ratio [RR] = 1.47) and children with higher unhealthy diet scores (RR = 1.08) complied more, but overweight/obese children (RR = 0.81), earlier maturing children (RR = 0.93), and those who spent more time in screen activities (RR = 0.98) and sleeping (RR = 0.96) had the lowest compliance. At the school level, children with access to playground or sport equipment (RR = 0.88, for both) tended to comply less, whereas those with access to a gymnasium outside the school hours complied more with the MVPA guidelines (RR = 1.14). Significant between-country differences in children’s daily MVPA compliance were observed, reflecting not only site characteristics, but also the importance of individual traits and local school contexts.

Effects of activated carbon N-acetylcysteine sustained-release microcapsule on dipeptidyl peptidase IV expression in young rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) in children has become the most common liver disease influencing adolescent health and one of the most influencing chronic liver diseases among children in Chinese wealthy families, particularly in coastal regions. However, the medicine available for the treatment of NAFLD is deficient. In order to solve this problem, our team studied the activated carbon N-acetylcysteine (NAC) sustained-release microcapsule, which improves the oxidation resistance, bioavailability and drug stability of acetylcysteine and reduces toxic and side effects. In addition, it accords with the characteristics of medication in infants and children. The present study mainly discusses whether the activated carbon NAC sustained-release microcapsule has effects on dipeptidyl peptidase IV (DPPIV) activity and protein in young rats with NAFLD, and whether it has the effect of an DPPIV inhibitor, hoping to provide new thoughts and methods with respect of basic studies on young rats with NAFLD/non-alcoholic steatohepatitis.

Associations between physical activity patterns and dietary patterns in a representative sample of Polish girls aged 13-21 years: a cross-sectional study (GEBaHealth Project)

BACKGROUND

Similar to other countries, trends of decreasing levels of physical activity (PA) and an increasing prevalence of unhealthy dietary patterns are observed among girls in Poland. Better understanding of potentially inter-related behaviours within this population can help to design tailored interventions. The purpose of this study was to determine associations between PA patterns and dietary patterns in a representative sample of Polish girls.

METHODS

Girls aged 13-21 years (n = 1107) were randomly selected for the study. PA was assessed using International Physical Activity Questionnaire - Long (IPAQ-L). Dietary data were collected with food frequency questionnaires. PA patterns and dietary patterns were drawn separately by Principal Component Analysis (PCA). Logistic regression was used to find the associations between PA patterns and dietary patterns.

RESULTS

Four major PA patterns ('School/work activity', 'Active recreation', 'Yard activity' and 'Walking and domestic activity') and four dietary patterns ('Traditional Polish', 'Fruit & vegetables', 'Fast food & sweets' and 'Dairy & fats') were identified. Level of PA was the highest in the upper tertile of 'School/work activity' pattern (mean 1372.2 MET-minutes/week, 95 % Confidence Intervals [CI]: 1285.9-1458.5). Girls in upper tertiles of 'Yard activity', 'Active recreation' and 'School/work activity' patterns had significantly higher chances of being in the upper tertile of the 'Fruit and vegetables' dietary pattern (odds ratio [OR] 2.17, 95 % CI: 1.50-3.14, p < 0.0001; OR 2.02, 95 % CI: 1.41-2.91; p < 0.001 and OR 1.76, 95 % CI: 1.24-2.51, p < 0.01 respectively; all adjusted for confounders) in comparison to bottom tertiles. Weak, but significant inverse associations were found between upper tertiles of 'Active recreation' and 'Yard activity' patterns and unhealthy dietary patterns.

CONCLUSIONS

We found associations between PA patterns and dietary patterns in the population of Polish girls. Girls with the highest adherence to the 'School/work activity' pattern had the highest levels of PA and presented pro-healthy dietary behaviours. School should be recognised as potentially efficient and important setting to maximise girls' PA potential. The after-school time is the area that should also be targeted to increase daily PA or to at least sustain the level of PA after completing education.

Association between accelerometer-determined physical activity and flavonoid-rich fruit and vegetable consumption among a national sample of U.S. adults

Few population studies have examined the association between accelerometer-assessed physical activity and dietary behavior. Further, no studies have systematically examined the association between accelerometer-assessed physical activity and flavonoid rich fruits and vegetables in a national sample. As a result, the purpose of this study was to examine the association between objectively measured physical activity and consumption of flavonoid rich fruits and vegetables among a national sample of U.S. adults. Data from the 2003–2006 National Health and Nutrition Examination Survey (NHANES) were used (N = 2949). Physical activity was measured via accelerometry and fruit and vegetable consumption was measured from the NHANES Food Frequency Questionnaire. After adjustments, moderate-to-vigorous physical activity was positively associated (p < 0.05) with apples (β = 0.30), grapes (β = 0.27), strawberries (β = 0.32), oranges (β = 0.35), raw greens (β = 0.19), carrots (β = 0.23), peppers (β = 0.29) and an overall flavonoid index variable (β = 2.34). Future studies employing a longitudinal design are needed to better understand the direction of the observed associations. If future studies do indeed support the possibility that physical activity may help to foster changes in dietary behavior, then this will have strong implications for health behavior interventions, particularly among individuals finding it difficult to change multiple health behaviors concurrently.

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A national sample was employed.

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An objective measure of physical activity was used.

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More active adults consumed more flavonoid-rich fruits/vegetables.

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Mechanistic work on this topic is needed.

Diet, growth, and obesity development throughout childhood in the Avon Longitudinal Study of Parents and Children

Publications from the Avon Longitudinal Study of Parents and Children covering diet, growth, and obesity development during childhood are reviewed. Diet was assessed by food frequency questionnaires and food records. Growth data were collected by routine measurements, and in standardized clinics, body fatness was assessed by bioelectrical impedance and DXA (dual-energy X-ray absorptiometry) scans. Diets changed dramatically during the preschool period with an increase in the intake of free (added) sugars (12.3% rising to 16.4% of energy) that remained similar until adolescence. This was due to increased intake of energy-dense, nutrient-poor foods. Two periods of rapid growth were identified; infancy and mid-childhood (ages 7-11 y) and both were associated with obesity development. Diets with high energy density were associated with increasing fat mass from mid-childhood until adolescence. Genetic and dietary factors showed independent associations with increasing adiposity. At all ages studied, there were dietary inequalities related to maternal educational attainment that may influence inequalities found in obesity development. The Avon Longitudinal Study of Parents and Children has provided valuable insights into how disparities in diet and growth may affect the development of ill health in adulthood.

Challenges in finding and measuring behavioural determinants of childhood obesity in Europe

Aim

Childhood obesity is an important concern for child health. However, despite widespread concern about the increase in childhood obesity, its causes are not monitored systematically in Europe. In 2007, the Scientific Platform Project on Lifestyle Determinants of Obesity identified routine data sources nationally available in European countries to measure childhood obesity. This work was revisited in 2014 to monitor any progress made.

Subject and methods

In 2007, a literature review and project discussion resulted in a list of desirable indicators that could be collected in Europe to describe child populations at risk of overweight and obesity. Participants from EU member states, the EEA, Croatia, Macedonia and Turkey set out to discover which countries collected these indicators. Eight years later, a literature search sought to establish if the surveillance of children’s nutrition and physical activity behaviour had changed.

Results

In 2007, no countries collected all variables for all ages, leading to major gaps in knowledge. A literature search carried out in 2014 suggests that this is unchanged. There remains inconsistency of data surveillance in Europe, and disagreement on which age groups to collect data from or how to define obesity and overweight.

Conclusion

There is a lack of consistent data collection on upstream influences on obesity. The true causes of the childhood obesity epidemic remain undiscovered, and the ability of research to identify effective prevention and treatment methods is compromised.

Physical activity, diet and BMI in children aged 6-8 years: a cross-sectional analysis

OBJECTIVE

To assess relationships between current physical activity (PA), dietary intake and body mass index (BMI) in English children.

DESIGN AND SETTING

Longitudinal birth cohort study in northeast England, cross-sectional analysis.

PARTICIPANTS

425 children (41% of the original cohort) aged 6-8 years (49% boys).

MAIN OUTCOME MEASURES

PA over 7 days was measured objectively by an accelerometer; three categories of PA were created: 'active' ≥60 min/day moderate-to-vigorous-intensity PA (MVPA); 'moderately active' 30-59 min/day MVPA; 'inactive' <30 min/day MVPA. Dietary intake over 4 days was measured using a prospective dietary assessment tool which incorporated elements of the food diary and food frequency methods. Three diet categories were created: 'healthy', 'unhealthy' and 'mixed', according to the number of portions of different foods consumed. Adherence to the '5-a-day' recommendations for portions of fruit and vegetables was also assessed. Children were classified as 'healthy weight' or 'overweight or obese' (OW/OB) according to International Obesity Taskforce cutpoints for BMI. Associations between weight status and PA/diet categories were analysed using logistic regression.

RESULTS

Few children met the UK-recommended guidelines for either MVPA or fruit and vegetable intake, with just 7% meeting the recommended amount of MVPA of 60 min/day, and 3% meeting the 5-a-day fruit and vegetable recommendation. Higher PA was associated with a lower OR for OW/OB in boys only (0.20, 95% CI 0.04 to 0.88). There was no association detected between dietary intake and OW/OB in either sex.

CONCLUSIONS

Increasing MVPA may help to reduce OW/OB in boys; however, more research is required to examine this relationship in girls. Children are not meeting the UK guidelines for diet and PA, and more needs to be done to improve this situation.

Relationship between raised BMI and sugar sweetened beverage and high fat food consumption among children

OBJECTIVE

Longitudinal evidence of relationships between unhealthy diets and BMI in children is crucial for appropriately targeting obesity prevention activities. The objective was to determine the relationship between frequency of consumption of sugar sweetened beverages (SSBs) and high fat foods (HFFs) and body weight in Australian children aged from 4 to 10 years.

METHODS

Data from 4,164 children participating in four waves (wave 1, 2004; wave 2, 2006; wave 3, 2008; and wave 4, 2010) of the Longitudinal Study of Australian Children were analyzed. A multi-level growth model tested relationships between consumption of SSB and HFF and BMI z-scores.

RESULTS

BMI z-scores were associated with daily consumption of HFF, SSB and maternal BMI independent of BMI z-scores at wave 1 (baseline); with each additional occurrence of SSB and HFF consumption intake per day, BMI z-score increased by 0.015 U (P < 0.01) and 0.014 U (P < 0.001), respectively. With each additional maternal BMI unit, BMI z-score increased by 0.032 (P < 0.001).

CONCLUSIONS

Higher BMI z-scores were strongly associated with the consumption of SSBs and HFFs. Future efforts to prevent obesity should consider urgent action to address the impact of the consumption of SSBs and HFFs in childhood.

Association between diet and physical activity and sedentary behaviours in 9-10-year-old British White children

OBJECTIVES

To examine the association between diet and physical activity and sedentary behaviours in 9-10-year-old children.

STUDY DESIGN

A cross-sectional study using data from the SPEEDY (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young People) study undertaken in Norfolk, UK.

METHODS

Data from 4-day food diaries and 7 days of accelerometery were matched on concurrent days. Time spent in moderate-to-vigorous physical activity (MVPA), time spent in sedentary behaviour and various measures of dietary intake were collected. Covariates included age, sex, weight status, family socio-economic status, and energy intake reporting quality. Multivariable regression models, adjusted for clustering of children by school and stratified by sex, were fitted to examine the associations between dietary measures and physical activity and sedentary outcomes.

RESULTS

In total, 1317 children (584 boys and 733 girls) provided concurrent data. Boys in the highest quartile of energy percentage from protein spent approximately 6 min [95% confidence interval (CI) 0-12] less in MVPA compared with boys in the lowest quartile. Those in the highest quartiles of fruit and vegetable intake and fruit juice intake had respective average activity counts per minute that were 56 above (95% CI 8-105) and 48 below (95% CI 2-95) those in the lowest quartiles, whilst those in the highest quartile of fizzy drink consumption spent approximately 7 min (95% CI 2-13) more in MVPA and approximately 14 min (95% CI 5-24 min) less in sedentary behaviour. Boys in the highest quartile of savoury snack consumption spent approximately 8 min (95% CI 2-13 min) more in MVPA per day, and approximately 12 min (95% CI 2-23) less in sedentary behaviour. No significant associations were apparent among girls.

CONCLUSIONS

Few associations were detected, and the directions of those that were apparent were mainly counterintuitive. The extent to which this reflects a true lack of association or is associated with the measurement methods used for diet and physical activity needs further investigation.

Combined influence of healthy diet and active lifestyle on cardiovascular disease risk factors in adolescents

To investigate the combined influence of diet quality and physical activity on cardiovascular disease (CVD) risk factors in adolescents, adolescents (n = 1513; 12.5-17.5 years) participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence study were studied. Dietary intake was registered using a 24-h recall and a diet quality index was calculated. Physical activity was assessed by accelerometry. Lifestyle groups were computed as: healthy diet and active, unhealthy diet but active, healthy diet but inactive, and unhealthy diet and inactive. CVD risk factor measurements included cardiorespiratory fitness, adiposity indicators, blood lipid profile, blood pressure, and insulin resistance. A CVD risk score was computed. The healthy diet and active group had a healthier cardiorespiratory profile, fat mass index (FMI), triglycerides, and high-density lipoprotein cholesterol (HDL-C) levels and total cholesterol (TC)/HDL-C ratio (all P ≤ 0.05). Overall, active adolescents showed higher cardiorespiratory fitness, lower FMI, TC/HDL-C ratio, and homeostasis model assessment index and healthier blood pressure than their inactive peers with either healthy or unhealthy diet (all P ≤ 0.05). Healthy diet and active group had healthier CVD risk score compared with the inactive groups (all P ≤ 0.02). Thus, a combination of healthy diet and active lifestyle is associated with decreased CVD risk in adolescents. Moreover, an active lifestyle may reduce the adverse consequences of an unhealthy diet.

Components of the diet associated with child adiposity: a cross-sectional study

OBJECTIVE

This study sought to determine which components of youths' diets were related to adiposity while controlling for potential often-neglected confounders such as moderate to vigorous physical activity (MVPA) and dietary reporting error. Secondary goals of this study were to determine the extent to which MVPA confounded the associations between diet and adiposity and whether associations between diet and adiposity would differ depending on reporting error.

METHODS

An ethnically diverse urban sample of 342 children aged 9-10 years and 323 adolescents aged 17-18 years were recruited for this cross-sectional study. Body mass index (BMI) and waist circumference (WC) were measured in the school; dietary assessment included three 24-hour recalls via telephone in the evenings, and MVPA assessment included 5 days of accelerometry. Over (n = 68), under (n = 250), or plausible (n = 347) dietary intake reporters were identified with the Huang calculation method. Linear regression assessed the relationship between adiposity indicators (BMI z-score and WC) and components of the diet (energy intake, food groups, macronutrients) after controlling for reporting error, demographic variables, and MVPA.

RESULTS

When dietary reporting error and potential confounders such as MVPA and demographic variables were controlled, energy intake (EI), vegetables, refined grains, total fat, total protein, and total carbohydrate were positively related to BMI z-score and WC and artificially sweetened beverages to WC. MVPA was a significant confounder. For BMI z-score, but not WC, relationships and strength of these relationships differed depending on dietary reporting error group (plausible, underreporter, overreporter).

CONCLUSIONS

Among plausible reporters, as expected, EI, refined grains, and all macronutrients were positively related to adiposity; however, artificially sweetened beverages and vegetables, which are low-energy-dense foods, were also positively related to adiposity. Reporting error interfered with associations between diet and BMI z-score but not WC, suggesting WC is a more robust measure of adiposity in relation to diet.

Combined influence of lifestyle risk factors on body fat in Spanish adolescents--the Avena study

OBJECTIVE

To examine the combined influence of four lifestyle risk factors related to physical activity, television viewing, sleep duration, and meal frequency on body fat (BF) in adolescents.

METHOD

This cross-sectional study comprised 1,310 Spanish adolescents (age 13-18.5 years). Lifestyle variables were self-reported and BF indicators (weight, height, six skinfold thicknesses, waist circumference) measured during the years 2000-2002. Lifestyle risk factors were: physically inactive, ≥ 3 h/day watching television, <8 h/day sleep duration, and <5 meals a day. The number of lifestyle risk factors was calculated for each participant, ranging from 0 to 4.

RESULTS

The number of lifestyle risk factors was positively associated with sum of six skinfolds, %BF, waist circumference, and waist-height ratio (all p < 0.001). The odds ratios (95% confidence interval) of overweight (including obesity) for groups with 1, 2, and 3-4 lifestyle risk factors compared with those with 0 were 2.86 (1.77-4.62), 3.61 (2.16-6.04), and 5.81 (3.07-10.99), respectively (p for trend <0.001). All the observations were independent of age, gender, race, socioeconomic status, and fat free mass.

CONCLUSION

The combined influence of four lifestyle risk factors is positively associated with BF and an approximately sixfold risk of overweight in adolescents.

Behavioural correlates of active commuting to school in Spanish adolescents: the AFINOS (Physical Activity as a Preventive Measure Against Overweight, Obesity, Infections, Allergies, and Cardiovascular Disease Risk Factors in Adolescents) study

OBJECTIVE

To examine the associations between lifestyle factors and active commuting to school in Spanish adolescents.

DESIGN

Cross-sectional study. Lifestyle factors (overall/extracurricular physical activity, television viewing, reading as a hobby, sleep duration, breakfast/fruit intake, smoking and alcohol intake) as well as mode and duration of commuting to school were self-reported. Active commuters were defined as those adolescents who walked or cycled to school.

SETTING

Secondary schools in Madrid, Spain.

SUBJECTS

Adolescents (n 2029) aged 13 to 17 years.

RESULTS

Similar percentages of adolescent boys (57·6 %) and girls (56·1 %) were classified as active commuters to school (P = 0·491). The analysis showed that only adequate sleep duration (OR = 1·35, 95 % CI 1·11, 1·66; P = 0·003) and breakfast consumption (OR = 0·66, 95 % CI 0·49, 0·87; P = 0·004) were independently associated with active commuting to school.

CONCLUSIONS

Only those behaviours that occur immediately before commuting to school (sleep and breakfast) are associated with active commuting in Spanish adolescents.