Associations between food portion sizes, insulin resistance, VO2 max and metabolic syndrome in European adolescents: The HELENA study

BACKGROUND AND AIMS

This study aims to examine the associations of food portion size (PS) with markers of insulin resistance (IR) and clustered of metabolic risk score in European adolescents.

METHODS

A total of 495 adolescents (53.5% females) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study were included. The association between PS from food groups and homeostasis model assessment of insulin resistance (HOMA-IR) index, VO2 max, and metabolic risk score was assessed by multilinear regression analysis adjusting for several confounders. Analysis of covariance (ANCOVA) was used to determine the mean differences of food PS from food groups by HOMA-IR cutoff categories by using maternal education as a covariable.

RESULTS

Larger PS from vegetables in both gender and milk, yoghurt, and milk beverages in males were associated with higher VO2 max, while larger PS from margarines and vegetable oils were associated with lower VO2 max (p < 0.05). Males who consumed larger PS from fish and fish products; meat substitutes, nuts, and pulses; cakes, pies, and biscuits; and sugar, honey, jams, and chocolate have a higher metabolic risk score (p < 0.05). Males with lower HOMA-IR cutoff values consumed larger PS from vegetables, milk, yoghurt, and milk beverages (p < 0.05). Females with lower HOMA-IR cutoff values consumed larger PS from breakfast cereals, while those with higher HOMA-IR cutoff values consumed larger PS from butter and animal fats (p = 0.018).

CONCLUSION

The results show that larger PS from dairy products, cereals, and high energy dense foods are a significant determinant of IR and VO2 max, and larger PS from food with higher content of sugar were associated with higher metabolic risk score.

Lifestyle patterns and endocrine, metabolic, and immunological biomarkers in European adolescents: The HELENA study

OBJECTIVE

To evaluate the association of lifestyle patterns related to physical activity (PA), sedentariness, and sleep with endocrine, metabolic, and immunological health biomarkers in European adolescents.

METHODS

The present cross-sectional study comprised 3528 adolescents (1845 girls) (12.5-17.5 years) enrolled in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study. Cluster analysis was performed by including body composition, PA by accelerometry, self-reported sedentary behaviors, and sleep duration. We also measured endocrine, metabolic, and immunological biomarkers.

RESULTS

Three-cluster solutions were identified: (a) light-PA time, moderate-vigorous-PA time and sedentary time, (b) light-PA time, moderate-vigorous-PA time, sedentary time and sleep time, (c) light-PA time, moderate-vigorous-PA time, sedentary time and body composition. In addition, each cluster solution was defined as: "healthy," "medium healthy," and "unhealthy" according to the presented rating. Analysis of variance showed that overall the healthiest groups from the three clusters analyzed presented a better metabolic profile. A decision tree analysis showed that leptin had a strong association with cluster 3 in both boys and girls, high-density lipoprotein cholesterol had the strongest association with clusters 1 and 3 in boys. Cortisol had the strongest association with cluster 1. HOMA index (homeostatic model assessment) and C3 showed a strong association with cluster 3 in girls.

CONCLUSIONS

Our results support the existence of different interactions between metabolic health and lifestyle patterns related to PA, sedentariness, and sleep, with some gender-specific findings. These results highlight the importance to consider multiple lifestyle-related health factors in the assessment of adolescents' health to plan favorable strategies.

Mediterranean diet, diet quality, and bone mineral content in adolescents: the HELENA study

Dietary scores, rather than individual nutrients, allow exploring associations between overall diet and bone health. The aim of the present study was to assess the associations between the Mediterranean Diet Score for Adolescents (MDS-A) and the Diet Quality Index for Adolescents (DQI-A) and bone mineral content (BMC) among Spanish adolescents. Our results do not support an association between dietary scores or indices and BMC in adolescents.

INTRODUCTION

To assess the associations between the MDS-A and a DQI-A with the BMC measured with dual-energy X-ray absorptiometry.

METHODS

The MDS-A and the DQI-A were calculated in 179 Spanish adolescents, based on two 24-h dietary recalls from the HELENA cross-sectional study. The associations between the diet scores and the BMC outcomes [total body less head (TBLH), femoral neck (FN), lumbar spine (LS), and hip] were analyzed using logistic regression models adjusting for several confounders.

RESULTS

Four hundred ninety-two models were included and only fruits and nuts and cereal and roots were found to provide significant ORs with regard to BMC. The risk of having low BMC reduced by 32% (OR 0.684; CI 0.473-0.988) for FN when following the ideal MDS-A, but this association lost significance when adjusting for lean mass and physical activity. For every 1-point increase in the cereal and root and the fruit and nut components, the risk of having low FN diminished by 56% (OR 0.442; CI 0.216-0.901) and by 67% (OR 0.332; CI 0.146-0.755), respectively.

CONCLUSION

An overall dietary score or index is not associated with BMC in our adolescent Spanish sample.

Dietary sources of sugars in adolescents' diet: the HELENA study

OBJECTIVE

To report dietary sugars consumption and their different types and food sources, in European adolescents.

METHODS

Food consumption data of selected groups were obtained from 1630 adolescents (45.6% males, 12.5-17.5 years) from the HELENA study using two nonconsecutive 24-h recalls. Energy intake, total sugars and free sugars were assessed using the HELENA-DIAT software. Multiple regression analyses were performed adjusting for relevant confounders.

RESULTS

Total sugars intake (137.5 g/day) represented 23.6% and free sugars (110.1 g/day), 19% of energy intake. Girls had significantly lower intakes of energy, carbohydrates, total sugars and free sugars. 94% of adolescents had a consumption of free sugars above 10% of total energy intake. The main food contributor to free sugars was 'carbonated, soft and isotonic drinks,' followed by 'non-chocolate confectionary' and 'sugar, honey, jam and syrup.' Older boys and girls had significantly higher intakes of free sugars from 'cakes, pies and biscuits.' Free sugars intake was negatively associated with low socioeconomic status for 'non-chocolate confectionary' and 'sugar, honey and jam' groups; with low maternal educational level for carbonated and 'soft drinks,' 'sugar, honey and jam,' 'cakes and pies' and 'breakfast cereals' groups; and with high paternal educational level for 'carbonated and soft drinks' and 'chocolates' group.

CONCLUSIONS

The majority (94%) of studied adolescents consumed free sugars above 10% of daily energy intake. Our data indicate a broad variety in foods providing free sugars. Continued efforts are required at different levels to reduce the intake of free sugars, especially in families with a low educational level.

Inflammation in metabolically healthy and metabolically abnormal adolescents: The HELENA study

BACKGROUND AND AIMS

Inflammation may influence the cardio-metabolic profile which relates with the risk of chronic diseases. This study aimed to assess the inflammatory status by metabolic health (MH)/body mass index (BMI) category and to assess how inflammatory markers can predict the cardio-metabolic profile in European adolescents, considering BMI.

METHODS AND RESULTS

A total of 659 adolescents (295 boys) from a cross-sectional European study were included. Adolescents were classified by metabolic health based on age- and sex-specific cut-off points for glucose, blood pressure, triglycerides, high density cholesterol and BMI. C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin (IL-6), complement factors (C3, C4) and cell adhesion molecules were assessed.

RESULTS

Metabolically abnormal (MA) adolescents had higher values of C3 (p < 0.001) and C4 (p = 0.032) compared to those metabolically healthy (MHy). C3 concentrations significantly increased with the deterioration of the metabolic health and BMI (p < 0.001). Adolescents with higher values of CRP had higher probability of being in the overweight/obese-MH group than those allocated in other categories. Finally, high C3 and C4 concentrations increased the probability of having an unfavorable metabolic/BMI status.

CONCLUSIONS

Metabolic/BMI status and inflammatory biomarkers are associated, being the CRP, C3 and C4 the most related inflammatory markers with this condition. C3 and C4 were associated with the cardio-metabolic health consistently.

Ideal cardiovascular health and inflammation in European adolescents: The HELENA study

BACKGROUND AND AIMS

Inflammation plays a key role in atherosclerosis and this process seems to appear in childhood. The ideal cardiovascular health index (ICHI) has been inversely related to atherosclerotic plaque in adults. However, evidence regarding inflammation and ICHI in adolescents is scarce. The aim is to assess the association between ICHI and inflammation in European adolescents.

METHODS AND RESULTS

As many as 543 adolescents (251 boys and 292 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, a cross-sectional multi-center study including 9 European countries, were measured. C-reactive protein (CRP), complement factors C3 and C4, leptin and white blood cell counts were used to compute an inflammatory score. Multilevel linear models and multilevel logistic regression were used to assess the association between ICHI and inflammation controlling by covariates. Higher ICHI was associated with a lower inflammatory score, as well as with several individual components, both in boys and girls (p < 0.01). In addition, adolescents with at least 4 ideal components of the ICHI had significantly lower inflammatory score and lower levels of the study biomarkers, except CRP. Finally, the multilevel logistic regression showed that for every unit increase in the ICHI, the probability of having an inflammatory profile decreased by 28.1% in girls.

CONCLUSION

Results from this study suggest that a better ICHI is associated with a lower inflammatory profile already in adolescence. Improving these health behaviors, and health factors included in the ICHI, could play an important role in CVD prevention.

Fruit and vegetables consumption is associated with higher vitamin intake and blood vitamin status among European adolescents

BACKGROUND/OBJECTIVES

Current research in adults indicates that fruit and vegetable (FAV) consumption increases serum levels of vitamins C, E and folate of β-carotene and reduces homocysteine concentrations. The aim of the present study was to examine the association of FAV consumption on vitamin intakes and their impact on blood vitamin concentrations in European adolescents.

SUBJECT/METHODS

This multi-center cross-sectional study included 702 (53.7% females) adolescents, aged 12.50-17.49 years, from 10 European cities. Two independent self-administered 24 h dietary recalls were used to estimate the adolescent's diet. The total energy, vitamins and FAV consumption were calculated. Adolescents were categorized into three groups: (i) very low FAV intake (<200 g/day); (ii) low FAV consumption (200-399 g/day) and (iii) adequate FAV consumption (⩾400 g/day). Adolescent's fasted blood samples were taken for their analysis on vitamin concentrations.

RESULTS

The main results showed that those adolescents meeting the FAV recommendation, classified as FAV adequate consumers, presented higher intake of energy and some vitamins as B6, total folic acid, C, E and β-carotene compared with FAV very low consumers (P<0.05). Regarding their blood status, male adolescents who had a very low FAV consumption presented lower plasma folate, RBC folate blood concentrations compared with adequate FAV consumers (P<0.05). Female adequate FAV consumers had higher concentrations of pyridoxal phosphate (PLP), plasma folate, RBC folate, vitamin C, β-carotene and α-tocopherol compared with very low and low consumers (P<0.05).

CONCLUSIONS

Having a FAV dairy intake above 400 g/day is associated with higher vitamin intake and blood vitamin concentrations, especially for antioxidant and B-vitamins concentrations.

Abdominal obesity and its association with socioeconomic factors among adolescents from different living environments

BACKGROUND

Socioeconomic status has been associated with obesity in children and adolescents. This association may be dependent according with where adolescents lives.

OBJECTIVE

The aim of this study was to evaluate the association between different socioeconomic indicators such as parental education and occupation and socioeconomic status with abdominal obesity in adolescents from two observational studies: the Healthy Lifestyle in Europe by Nutrition in Adolescence cross-sectional study (HELENA-CSS) and the Brazilian Cardiovascular Adolescent Health (BRACAH) study.

METHODS

European (n = 3192, aged 12.5-17.5 years, with 53.1% girls from HELENA-CSS) and Brazilian (n = 991, aged 14-18 years, with 54.5% girls from BRACAH study) adolescents from two cross-sectional studies were included in this analysis. Complete data on waist circumference (WC), height, socioeconomic status indicators and several confounders were collected. Socioeconomic indicators were measured using a self-reported questionnaire in order to assess the family social status of the adolescents. Multilevel linear regression models were used to examine associations, and results were adjusted for potential confounders.

RESULTS

Adjusted results showed inverse associations between mother's and father's education levels (p < 0.001) and father's occupation level (p < 0.001) with waist-to-height ratio (WHtR) and WC in HELENA-CSS girls. Similarly in European girls, socioeconomic indicators by socioeconomic status and maternal occupation level were associated with WHtR. In HELENA-CSS boys, the same significant association was found between WHtR and WC with maternal occupation level. Moreover, in European boys WHtR was also associated with parental education. In Brazilian adolescents, both indicators of abdominal obesity did not remain associated with the independents variables, after adjustment for potential confounders.

CONCLUSIONS

Abdominal obesity was associated with socioeconomic indicators in higher-income countries, but this association was not observed in a lower-middle-income country.

Folate and vitamin B12 concentrations are associated with plasma DHA and EPA fatty acids in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

This study aimed to examine the association between vitamin B6, folate and vitamin B12 biomarkers and plasma fatty acids in European adolescents. A subsample from the Healthy Lifestyle in Europe by Nutrition in Adolescence study with valid data on B-vitamins and fatty acid blood parameters, and all the other covariates used in the analyses such as BMI, Diet Quality Index, education of the mother and physical activity assessed by a questionnaire, was selected resulting in 674 cases (43 % males). B-vitamin biomarkers were measured by chromatography and immunoassay and fatty acids by enzymatic analyses. Linear mixed models elucidated the association between B-vitamins and fatty acid blood parameters (changes in fatty acid profiles according to change in 10 units of vitamin B biomarkers). DHA, EPA) and n-3 fatty acids showed positive associations with B-vitamin biomarkers, mainly with those corresponding to folate and vitamin B12. Contrarily, negative associations were found with n-6:n-3 ratio, trans-fatty acids and oleic:stearic ratio. With total homocysteine (tHcy), all the associations found with these parameters were opposite (for instance, an increase of 10 nmol/l in red blood cell folate or holotranscobalamin in females produces an increase of 15·85 µmol/l of EPA (P value <0·01), whereas an increase of 10 nmol/l of tHcy in males produces a decrease of 2·06 µmol/l of DHA (P value <0·05). Positive associations between B-vitamins and specific fatty acids might suggest underlying mechanisms between B-vitamins and CVD and it is worth the attention of public health policies.

Liver enzymes and clustering cardiometabolic risk factors in European adolescents: the HELENA study

OBJECTIVES

This study aimed to explore the associations of liver biomarkers with cardiometabolic risk factors and their clustering, and to provide reference values (percentiles) and cut-off points for liver biomarkers associated with high cardiometabolic risk in European adolescents.

METHODS

Alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), aspartate aminotransferase to ALT ratio (AST/ALT), waist circumference, blood pressure, triglycerides, high-density lipoprotein cholesterol and insulin were measured in 1084 adolescents. We computed a continuous cardiometabolic risk score and defined the high cardiometabolic risk.

RESULTS

Higher ALT and GGT and lower AST/ALT were associated with adiposity and with the number of adverse cardiometabolic risk factors (Ps < 0.05). Higher GGT and lower AST/ALT were associated with higher cardiometabolic risk score (Ps < 0.001) in males and females, and ALT only in males (Ps < 0.001). Gender- and age-specific percentiles for liver biomarkers were provided. Receiver operating characteristic analyses showed a significant discriminatory accuracy of AST/ALT in identifying the low/high cardiometabolic risk (Ps < 0.01) and thresholds were provided.

CONCLUSIONS

Higher GGT and lower AST/ALT are associated with higher cardiometabolic risk factors and their clustering in male and female European adolescents, whereas the associations of ALT were gender dependent. Our results suggest the usefulness of AST/ALT as a screening test in the assessment of adolescents with high cardiometabolic risk and provide gender- and age-specific thresholds that might be of clinical interest.

Inflammation profile in overweight/obese adolescents in Europe: an analysis in relation to iron status

BACKGROUND/OBJECTIVES

The objectives of this study were to investigate the relationship between inflammatory parameters (CRP, c-reactive protein; AGP, α1-acid glycoprotein), iron status indicators (SF, serum ferritin; sTfR, soluble transferrin receptor) and body mass index (BMI) z-score, fat-free mass (FFM) and fat mass (FM) in European adolescents. Differences in intake for some nutrients (total iron, haem and non-haem iron, vitamin C, calcium, proteins) were assessed according to BMI categories, and the association of nutrient intakes with BMI z-score, FM and FFM was evaluated.

METHODS

A total of 876 adolescents participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence-Cross Sectional Study were included in the study sample.

RESULTS

Mean CRP values (standard error; s.e.) were significantly higher in overweight/obese adolescents (1.7±0.3 and 1.4±0.3 mg/l in boys and girls, respectively) than in thin/normal-weight adolescents (1.1±0.2 and 1.0±0.1 mg/l in boys and girls, respectively) (P<0.05). For boys, mean SF values (s.e.) were significantly higher in overweight/obese adolescents (46.9±2.7 μg/l) than in thin/normal-weight adolescents (35.7±1.7 μg/l) (P<0.001), whereas median sTfR values did not differ among BMI categories for both boys and girls. Multilevel regression analyses showed that BMI z-score and FM were significantly related to CRP and AGP (P<0.05). Dietary variables did not differ significantly among BMI categories, except for the intake of vegetable proteins, which, for boys, was higher in thin/normal-weight adolescents than in overweight/obese adolescents (P<0.05).

CONCLUSIONS

The adiposity of the European adolescents was sufficient to cause chronic inflammation but not sufficient to impair iron status and cause iron deficiency.

Muscular fitness, fatness and inflammatory biomarkers in adolescents

BACKGROUND

Muscular fitness, cardiorespiratory fitness (CRF) and fatness are mutually related with chronic inflammation.

PURPOSE

To examine the independent association of muscular fitness with inflammatory biomarkers in adolescents from nine European countries.

METHODS

A total of 639 adolescents (296 boys) aged from 12.5 to 17.5 year were included in this report. Data collection took place in 2006-2007 and analyses in 2012. A muscular fitness score was computed from handgrip strength and standing long jump. CRF was measured using the 20 m shuttle run test. Z-scores of C-reactive protein, complement factors C3 and C4, leptin and white blood cell counts were summed to create a cluster of inflammatory biomarkers. Sex, age, pubertal stage and centre were used as main confounders. Additional models were further adjusted for insulin resistance (HOMA-IR) and sum of four skinfolds.

RESULTS

Muscular fitness was negatively associated with single and clustered inflammatory biomarkers (standardized β from -0.399 to -0.100, all P-values < 0.05). Additional adjustments for CRF and HOMA-IR weakened the associations, but they still remained significant. The association was no longer significant when adjusting for skinfolds. Decreasing values of inflammatory score were observed across incremental levels of muscular fitness in both non-overweight and overweight adolescents (P ≤ 0.05).

CONCLUSIONS

Adolescents with higher levels of muscular fitness present a lower chronic inflammation, and this seems to be explained by lower levels of fatness. Yet, overweight and obese adolescents may exhibit a less adverse profile if they maintain appropriate levels of muscular fitness.

Mechanisms of stress, energy homeostasis and insulin resistance in European adolescents--the HELENA study

BACKGROUND AND AIMS

Stress is hypothesized to facilitate the development of obesity, whose the foundations are already set during childhood and adolescence. We investigated the relationship between the stress-system, selected mechanisms of energy homeostasis and insulin resistance (IR) in a sample of European adolescents.

METHODS AND RESULTS

Within HELENA-CSS, 723 adolescents (12.5-17.5 years) from 10 European cities provided all the necessary data for this study. Fasting blood samples were collected for cortisol, leptin, insulin and glucose analysis. HOMA-IR was calculated from insulin and glucose concentrations. Adolescents' body fat (BF) %, age and duration of exclusive breastfeeding were assessed. For boys and girls separately, the relationship of cortisol with leptin, insulin, glucose and HOMA-IR was examined by computing Pearson correlation coefficients and Hierarchical Linear Models (HLMs), with 'city' as cluster unit, adjusting for age, BF% and duration of exclusive breastfeeding. In boys, Pearson correlation coefficients illustrated positive correlations of cortisol with insulin (r = 0.144; p = 0.013), glucose (r = 0.315; p < 0.001) and HOMA-IR (r = 0.180; p = 0.002), whilst in girls, this positive relationship was observed for leptin (r = 0.147; p = 0.002), insulin (r = 0.095; p = 0.050) and HOMA-IR (r = 0.099; p = 0.041), but not for glucose (r = 0.054; p = 0.265). Observed associations were independent of adolescents' age, BF% and duration of exclusive breastfeeding after computing HLMs.

CONCLUSION

This study suggests that the stress-system is positively related to mechanisms of energy homeostasis and IR in European adolescents, and reveals a potential small gender difference in this relationship. The hypothesis that stress might facilitate the development of obesity during adolescence is supported.

Is dairy consumption associated with low cardiovascular disease risk in European adolescents? Results from the HELENA Study

OBJECTIVE

To identify those food groups best discriminating individuals at high/low cardiovascular disease (CVD) risk and to investigate the relationship between dairy consumption and CVD risk factors (individual and scores) in adolescents (12.5-17.5 years) from eight European cities participating in the cross-sectional (2006-2007) HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) project.

METHODS

Diet, waist circumference, skin-folds thickness, systolic blood pressure, insulin resistance, triglycerides, total cholesterol/high-density lipoprotein ratio and cardiorespiratory fitness (CRF) were assessed in 511 (49.9% boys) adolescents. Individual z-scores of CVD risk factors were summed to compute sex-specific clustered CVD risk scores.

RESULTS

Dairy emerged as the food group best discriminating adolescents at low/high CVD risk. In both genders, waist circumference and sum of skin-folds were inversely associated with consumption of milk and yogurt, and milk- and yogurt-based beverages, whereas a positive association was observed with CRF. Moreover, CVD risk score (β = -0.230, P = 0.001) was also inversely associated with overall dairy consumption only in girls.

DISCUSSION

Dairy consumption is associated with lower adiposity and higher CRF in these adolescents. An inverse association between CVD risk score and dairy consumption is also depicted in girls. The study adds further evidence to the scarce literature on the influence of milk and dairy products on adolescents' cardiovascular health.

The role of dietary fat on the association between dietary amino acids and serum lipid profile in European adolescents participating in the HELENA Study

BACKGROUND/OBJECTIVES

The objective of this study was to examine the relationship between amino acid (AA) intake and serum lipid profile in European adolescents from eight European cities participating in the cross-sectional (2006-2007) HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study, and to assess whether this association was independent of total fat intake.

SUBJECTS/METHODS

Diet, skinfold thickness, triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), TC/HDL-c ratio, low-density lipoprotein cholesterol (LDL-c), apolipoprotein B (Apo B), apolipoprotein A1 (Apo A1) and Apo B/Apo A1 ratio were measured in 454 12.5- to 17.5-year-old adolescents (44% boys). Intake was assessed via two non-consecutive 24-h dietary recalls. Data on maternal education and sedentary behaviors were obtained via questionnaires. Physical activity was objectively measured by accelerometry.

RESULTS

Alanine, arginine, asparaginic acid, glycine, histidine, lysine and serine intakes were inversely associated with serum TG concentrations in both boys and girls. Intake of other AA like alanine and/or arginine was also inversely associated with serum TC, LDL-c and Apo B/Apo A1 ratio only in girls. An inverse association was observed between intakes of alanine, isoleucine, leucine, methionine, serine, tryptophan, tyrosine and valine and TC/HDL-c ratio among female adolescents. Similar results were found in males for serine and tryptophan intakes. It is noteworthy, however, that associations were no longer significant in both genders when total fat intake was considered as a confounding factor.

CONCLUSIONS

In this sample of adolescents, the association between AA intakes and serum lipid profile did not persist when dietary fat was considered. Therefore, dietary interventions and health promotion activities should focus on fat intake to improve lipid profile and potentially prevent cardiovascular disease.

Weight loss maintenance in overweight subjects on ad libitum diets with high or low protein content and glycemic index: the DIOGENES trial 12-month results

BACKGROUND

A high dietary protein (P) content and low glycemic index (LGI) have been suggested to be beneficial for weight management, but long-term studies are scarce.

OBJECTIVE

The DIOGENES randomized clinical trial investigated the effect of P and GI on weight loss maintenance in overweight or obese adults in eight centers across Europe. This study reports the 1-year results in two of the centers that extended the intervention to 1 year.

METHOD

After an 8-week low-calorie diet (LCD), 256 adults (body mass index >27 kg m(-)(2)) were randomized to five ad libitum diets for 12 months: high P/LGI (HP/LGI), HP/high GI (HP/HGI), low P/LGI (LP/LGI), LP/HGI and a control diet. During the first 6 months, foods were provided for free through a shop system and during the whole 12-month period, subjects received guidance by a dietician. Primary outcome variable was the change in body weight over the 12-month intervention period.

RESULTS

During the LCD period, subjects lost 11.2 (10.8, 12.0) kg (mean (95% confidence interval (CI))). Average weight regain over the 12-month intervention period was 3.9 (95% CI 3.0-4.8) kg. Subjects on the HP diets regained less weight than subjects on the LP diets. The difference in weight regain after 1 year was 2.0 (0.4, 3.6) kg (P=0.017) (completers analysis, N=139) or 2.8 (1.4, 4.1) kg (P<0.001) (intention-to-treat analysis, N=256). No consistent effect of GI on weight regain was found. There were no clinically relevant differences in changes in cardiometabolic risk factors among diet groups.

CONCLUSION

A higher protein content of an ad libitum diet improves weight loss maintenance in overweight and obese adults over 12 months.

Cardiorespiratory fitness in males, and upper limbs muscular strength in females, are positively related with 25-hydroxyvitamin D plasma concentrations in European adolescents: the HELENA study

BACKGROUND

High prevalence of vitamin D insufficiency (<75 nmol/l) has been previously reported in European adolescents. Vitamin D deficiency has been related to physical fitness and adiposity but it is not clearly known whether this relationship applies to growing children and adolescents.

AIM

To determine how body composition and physical fitness are related to 25-hydroxyvitamin D [25(OH)D] concentrations in European adolescents.

DESIGN

The HEalthy Lifestyle in Europe by Nutrition in Adolescence-CSS study was a multi-centre cross-sectional study.

METHODS

Plasma 25(OH)D, body composition and physical fitness measures were obtained in 1006 European adolescents (470 males) aged 12.5-17.5 years. Stepwise regression and ANCOVA were performed by gender using 25(OH)D as dependent variable, with body composition, physical fitness as independent variables controlling for age, seasonality and latitude.

RESULTS

For males, maximum oxygen consumption (VO2max) (B = 0.189) and body mass index (BMI) (B = -0.124) were independently associated with 25(OH)D concentrations (both P < 0.05). For females, handgrip strength (B = 0.168; P < 0.01) was independently associated with 25(OH)D concentrations. Those adolescents at lower BMI and high fitness score presented significant higher 25(OH)D concentrations than those at lower fitness score in the other BMI groups (P < 0.05).

CONCLUSION

Cardiorespiratory fitness and upper limbs muscular strength are positively associated with 25(OH)D concentrations in male and female adolescents, respectively. Adiposity in males and low fat free mass in females are related to hypovitaminosis D. The interaction between fitness and BMI has a positive effect on 25(OH)D concentrations. Therapeutic interventions to correct the high rates of vitamin D deficiency in adolescents should consider physical fitness.

Physical activity attenuates the negative effect of low birth weight on leptin levels in European adolescents; the HELENA study

We examined whether physical activity (PA) influences the association between birth weight and serum leptin in adolescents. The study comprised a total of 538 adolescents (315 girls), aged 12.5-17.49 years, born at term (≥ 37 weeks of gestation). We measured serum leptin levels and time engaged in moderate-vigorous PA (MVPA) by accelerometry. There was an interaction effect between birth weight and meeting the PA recommendations (60 min/day MVPA) on leptin levels in girls (P = 0.023) but not in boys (P = 0.809). Birth weight was negatively associated with leptin levels in girls not meeting the PA recommendations (i.e. more than 60 min/day of MVPA) (β = -0.096, P = 0.009), whereas no significant association was observed in those meeting the PA recommendations (β = -0.061, P = 0.433). In conclusion, meeting the PA recommendations may attenuate the negative effect of low birth weight on serum leptin levels in European female adolescents.

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.

Differences in food consumption according to weight status and physical activity levels among Greek children between 1992/93 and 2006/07

BACKGROUND

There is a lack of data in Greece on trends in food intake according to weight status and physical activity (PA), despite the high prevalence of obesity. The present study aimed to examine differences in these parameters among first-grade children from Crete, Greece, over a 15-year period.

METHODS

Children (aged 5.9-7.6 years) from two representative cross-sectional studies participated during 1992/93 (n = 245) and 2006/07 (n = 257). Estimated 3-day food records were used to assess food consumption and energy-density (ED) [kJ g(-1) (kcal g(-1) )]. Moderate-to-vigorous-PA (MVPA) and cardiorespiratory-fitness were assessed by questionnaires and the 20-m shuttle-run test (20mSRT), respectively.

RESULTS

In 2006/07, compared to 1992/93, both sexes had a significantly higher intake of dairy products and snacks (P < 0.001), a lower intake of cereals (P < 0.001) and higher cardiorespiratory fitness levels (P < 0.001). Among girls, fruit/vegetable consumption was higher (P < 0.05), although legume intake was lower (P < 0.005). Among overweight/obese (OW/OB) children, ED significantly decreased (P < 0.05) and the mean consumption of fruits/vegetables was higher (P < 0.001). The percentage of OW/OB boys was significantly higher (P < 0.001); however, MVPA was significant higher in this group compared to 1992/93 (P < 0.001). During the two time-periods, active children in 2006/07 appeared to have a lower ED than active ones in 1992/93 (P < 0.001).

CONCLUSIONS

Several differences in food intake were observed among first-grade children of Crete between 1992/93 and 2006/07, as characterised by significant increases in the consumption of dairy products and snacks and a decrease in the intake of cereals, among both sexes. Future school-based interventions in this population should emphasise the need to increase fruit/vegetable, unrefined cereal and legume consumption.

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

Impact of REV-ERB alpha gene polymorphisms on obesity phenotypes in adult and adolescent samples

BACKGROUND

REV-ERBα has been shown to regulate adipogenesis and lipid metabolism as well as to link the circadian timing system to whole body metabolic homeostasis. We thus tested whether polymorphisms in REV-ERBα could be associated with metabolic phenotypes in human population samples.

METHODS

We analyzed the associations between 5 REV-ERBα polymorphisms and anthropometric (body weight, body mass index (BMI), waist and hip circumferences), biochemical (plasma lipid, glucose and insulin levels) and clinical (systolic and diastolic blood pressure) variables in three population-based studies (MONICA Lille n=1155 adults, MONA LISA Lille n=1170 adults and HELENA n=1155 adolescents). We assessed in vitro, the potential influence of one REV-ERBα polymorphism in transient transfection assays using two different cell lines.

RESULTS

We observed significant and consistent associations between the T minor allele of the REV-ERBα rs2071427 polymorphism (located in intron 1) and higher BMI (mean allele effect=+0.33 kg m(-2)) in the MONICA Lille (P=0.02), MONA LISA (P=0.02) and HELENA (P=0.03) studies. The odds ratios for obesity associated with this allele were 1.67 (1.00-2.79) (P=0.05) in MONICA Lille, 1.29 (1.01-1.65) (P=0.04) in MONA LISA Lille and the odds ratio for overweight was 1.48 (1.08-2.03) (P=0.01) in HELENA. In transfection experiments in human hepatocyte-derived cell lines, the REV-ERBα intron 1 directed the transcription of a luciferase reporter gene independently of the rs2071427 polymorphism.

CONCLUSION

Our results suggest that the REV-ERBα rs2071427 polymorphism modulates body fat mass in both adult and young people.

Risk factors of obesity in a cohort of 1001 Cypriot adults: An epidemiological study

BACKGROUND AND AIMS

To measure the prevalence of overweight and obesity in adults in the Republic of Cyprus, and to evaluate and relate possible obesity risk factors of the adult Cypriot population.

METHODS

This is an epidemiological cross-sectional study on a stratified random sample of 1001 (48.5% males-51.5% females) subjects, aged 18-80 years old. Anthropometric, biochemical, and dietary/lifestyle characteristics included in the study.

RESULTS

The prevalence of overweight (Ow) and obesity (Ob) was 46.9% and 28.8% for males and 26% and 27% for females, respectively. Overweight and obese subjects were found to have statistically significant higher levels of Body Mass Index (p<0.001), Waist circumference (p<0.001), Total serum cholesterol (p<0.001), Low density lipoprotein (p<0.005), Glucose (p<0.007) and Triglycerides (p<0.001) compared to normal peers. In addition, Ow and Ob participants consumed significantly lower levels of fruits and vegetables (p<0.001), exercised less time/d (p<0.001) and smoke more cigarettes/d (p<0.001), compared to normal subjects, respectively. In multiple regression analysis of factors associated with overweight and obesity, Waist Circumference (beta: 1.132, p<0.001), Glucose (beta: 0.892, p<0.045), alcohol consumption (beta: 0.563, p<0.001), and exercise levels (beta: -0.444, p<0.001), were the most significant ones.

CONCLUSION

The prevalence of overweight and obesity is very high in Cypriot adults. The current study also revealed a significant positive relation of Ow and Ob with waist circumference, high blood glucose levels and increased consumption of alcohol and a negative one with decreased levels of exercise.

Short sleep duration is associated with increased obesity markers in European adolescents: effect of physical activity and dietary habits. The HELENA study

BACKGROUND

Adequate sleep is a critical factor for adolescent's health and health-related behaviors.

OBJECTIVE

(a) to describe sleep duration in European adolescents from nine countries, (b) to assess the association of short sleep duration with excess adiposity and (c) to elucidate if physical activity (PA), sedentary behaviors and/or inadequate food habits underlie this association.

DESIGN

A sample of 3311 adolescents (1748 girls) aged 12.5-17.49 years from 10 European cities in Austria, Belgium, France, Germany, Greece, Hungary, Italy, Spain and Sweden was assessed in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study between 2006 and 2008. We measured anthropometric data, sleep duration, PA (accelerometers and questionnaire), television watching and food habits (Food Frequency Questionnaire).

RESULTS

Average duration of daily sleep was 8 h. Shorter sleepers showed higher values of BMI, body fat, waist and hip circumferences and fat mass index (P<0.05), particularly in females. Adolescents who slept <8 h per day were more sedentary, as assessed by accelerometry, and spent more time watching TV (P<0.05). The proportion of adolescents who eat adequate amounts of fruits, vegetables and fish was lower in shorter sleepers than in adolescents who slept ≥8 h per day, and so was the probability of having adequate food habits (P<0.05). Correlation analysis indicated that short sleep is associated with higher obesity parameters.

CONCLUSIONS

In European adolescents, short sleep duration is associated with higher adiposity markers, particularly in female adolescents. This association seems to be related to both sides of the energy balance equation due to a combination of increased food intake and more sedentary habits.

Dietary strategy to manipulate ad libitum macronutrient intake, and glycaemic index, across eight European countries in the Diogenes Study

The aim of this study was to describe the development and implementation of a multifaceted, low-fat, weight-loss strategy for a Pan-European randomized controlled dietary intervention study, Diogenes. There were 891 families with at least one overweight/obese parent who underwent screening. Eligible, overweight/obese adults followed an 8-week weight-loss phase with a fixed low-energy diet (800 kcal). On attaining weight loss of > or = 8%, families were randomized to a 6- or 12-month low-fat (25-30%E) diet either based on national dietary guidelines or one of four interventions: low protein (LP)/low glycaemic index (LGI), LP/high GI (HGI), high protein (HP)/LGI and HP/HGI. The impact of each diet in preventing weight (re)gain was tested. A points-based system was used to manipulate dietary protein and carbohydrate. Manipulating carbohydrate composition involved substituting foods with a relatively high or low GI. A questionnaire was designed and completed by study investigators, providing feedback on the dietary intervention methods used to inform future interventions. The points system allowed macronutrient manipulations without compromising dietary flexibility or enforcing energy restrictions. Reported centre/participant differences in the ease of implementing the intervention may reflect dietary diversity and personal preferences for specific weight-management strategies. The points system provides a useful starting point for designing improved experimental paradigms for the manipulation of dietary intake in future trials.

The Diet, Obesity and Genes (Diogenes) Dietary Study in eight European countries - a comprehensive design for long-term intervention

Diogenes is a Pan-European, randomized, controlled dietary intervention study investigating the effects of dietary protein and glycaemic index on weight (re)gain, metabolic and cardiovascular risk factors in obese and overweight families in eight European centres. The article is methodological in character, and the presentation of 'results' will be limited to baseline characteristics of the study populations included. A total of 891 families with at least one overweight/obese parent underwent screening. The parents started an initial 8-week low-calorie diet and families with minimum one parent attaining a weight loss of > or = 8%, were randomized to one of five energy ad libitum, low-fat (25-30 E%) diets for 6 or 12 months: low protein/low glycaemic index, low protein/high glycaemic index, high protein/low glycaemic index, high protein/high glycaemic index or control (national dietary guidelines). At two centres the families were provided dietary instruction plus free foods for 6 months followed by 6-month dietary instruction only. At the remaining six centres the families received dietary instruction only for 6 months. The median weight loss during the low-calorie diet was 10.3 kg (inter-quartile range: 8.7-12.8 kg, n = 775). A total of 773 adults and 784 children were randomized to the 6-month weight (re)gain prevention phase. Despite major cultural and dietary regional differences in Europe, interventions addressing effects of dietary factors are feasible with a reasonable attrition.

Adipose tissue fatty acids in breast cancer patients versus healthy control women from Crete

BACKGROUND

Few studies have implemented biomarkers of fatty acid intake in relation to breast cancer.

AIMS

To examine possible differences in adipose tissue fatty acid composition between breast cancer patients and healthy control women. The relationship between tumor promotion and adipose tissue fatty acid synthesis was also investigated.

METHODS

The study was conducted at the University of Crete. Subjects included 94 women with clinically diagnosed cancer of the breast and 131 healthy control women. Histological tumor grading and breast cancer staging were assessed. Fatty acids were determined by gas chromatography in gluteal adipose tissue.

RESULTS

Conditional logistic regression analysis controlling for potential confounders indicated that elevated adipose monounsaturated fatty acids and oleic acid are associated with reduced odds of breast cancer [OR (T2 vs. T1) 0.15; 95% CI 0.03-0.64, and OR (T2 vs. T1) 0.18; 95% CI 0.04-0.71, respectively]. Adipose myristic acid was associated with an increase in breast cancer risk [OR (T3 vs. T1) 5.66; 95% CI 1.3-23.9].

CONCLUSIONS

Adipose oleic acid is inversely related, whereas adipose myristic acid is positively related to breast cancer risk. These relations could be mediated by Her-2/neu and FAS oncogenes.

Environmental tobacco smoke exposure as a risk factor for infections in infancy

AIM

This prospective observational study investigated the effect of environmental tobacco smoke (ETS) on frequency and severity of common infantile infections.

METHODS

In a representative sample of 926 infants, parental smoking was recorded at months 1 and 9 postpartum, and all infantile infectious episodes were recorded at 1, 3, 6, 9 and 12 months postpartum.

RESULTS

Both parents were regular smokers all through the first year in 107 (11.6%), at least one smoked regularly or occasionally in 492 (53.1%), and parents did not smoke at all in 327 (35.3%) families. Among mothers, 168 (18.1%) smoked perinatally. Infantile ETS exposure was associated with increased frequency of total infectious episodes (p = 0.025) and hospitalizations for infection (p = 0.007). In ETS exposed infants, birth in autumn and presence of siblings contributed to increased frequency of most infections and of hospital admissions for infection. By contrast, exclusive breastfeeding protected against the effect of ETS on total infantile infections (OR 0.982, 95% CI 0.965-0.999; p = 0.036), hospital admissions for infection (OR 0.980, 95% CI 0.961-0.999; p = 0.036) and thrush (OR 0.973, 95% CI 0.951-0.996; p = 0.022).

CONCLUSION

Our findings point to harmful effect of ETS on infantile health and further suggest that this effect may be enhanced or diminished by other factors. ETS should be regarded as a preventable risk factor for infections in infancy.

Design and implementation of the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study

OBJECTIVE

To provide an overview of the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) design, with particular attention to its quality control procedures. Other important methodological aspects are described in detail throughout this supplement.

DESIGN

Description of the HELENA-CSS sampling and recruitment approaches, standardization and harmonization processes, data collection and analysis strategies and quality control activities.

RESULTS

The HELENA-CSS is a multi-centre collaborative study conducted in European adolescents located in urban settings. The data management systems, quality assurance monitoring activities, standardized manuals of operating procedures and training and study management are addressed in this paper. Various quality controls to ensure collection of valid and reliable data will be discussed in this supplement, as well as quantitative estimates of measurement error.

CONCLUSION

The great advantage of the HELENA-CSS is the strict standardization of the fieldwork and the blood analyses, which precludes to a great extent the kind of immeasurable confounding bias that often interferes when comparing results from isolated studies.

Prevalence and independent predictors of insulin resistance in children from Crete, Greece: the Children Study

BACKGROUND

It has been proposed that insulin resistance (IR) is associated with the development of Type 2 diabetes mellitus and cardiovascular disease. The aim of this study is to determine the prevalence of IR in Greek schoolchildren and to investigate factors associated with IR.

METHODS

Between October 2005 and March 2006, 522 children were recruited from Crete. Physical activity and dietary habits, anthropometric and biochemical characteristics, as well as medical history of pupils' parents were recorded. IR was estimated using the homeostasis model assessment (HOMA-IR), fasting glucose-to-insulin ratio (FGIR) and quantitative insulin sensitivity check index (QUICKI). Multiple linear regression was used to determine independent predictors for IR.

RESULTS

Fasting insulin levels and HOMA-IR scores were higher in obese children and girls compared with their normal-weight peers (P < 0.001). Moreover, the former had lower values in FGIR and QUICKI indices compared with the latter, indicating that obese children and girls are more insulin resistant compared with their counterparts (P < 0.001). The prevalence of IR was 9.2% (2.9% in normal-weight, 10.5% in overweight and 31.0% in obese children), using as a threshold HOMA-IR > 2.10 97.5th percentile of normal-weight participants). Multiple linear regression revealed that central adiposity, female gender and intake of simple carbohydrates is associated positively with HOMA-IR values, even after controlling for many other factors.

CONCLUSION

These findings demonstrate that girls and obese children, particularly those with central adiposity, are at high risk of developing IR. Therefore, these groups should be targets of Type 2 diabetes mellitus and cardiovascular disease preventive interventions.

Stakeholder appraisal of policy options for tackling obesity in Greece

The study aimed to map stakeholders' evaluations of policy options to counter the rising prevalence of obesity in Greece, where the case for action on obesity is only now being made. The multi-criteria mapping method was used to capture and compare stakeholders' appraisals and to provide a policy analysis. Efficacy and practical feasibility were the issues most frequently used by stakeholders to evaluate options and were weighted more highly than cost criteria, which were often defined in terms of governmental costs. There was a broad favourable appraisal for downstream measures offering individuals the skills, information and opportunities to make healthier choices, rather than options to modify the obesogenic environment. Consistently, high rankings were given to educational options, for improving communal facilities and for some information-related options (food labelling, advertising), with particular support for policies targeting the young. There was also significant advocacy by a few for the creation of a new government body charged with intersectoral policy co-ordination. The Policy Options for Responding to the Growing Challenge of Obesity Research Project analyses thus point to support for a portfolio of measures to combat the problem of obesity in Greece as well as an appreciation that political will is an essential prerequisite.

Health and nutrition education program in primary schools of Crete: changes in blood pressure over 10 years

OBJECTIVE

To examine the long-term effects of the 'Cretan Health and Nutrition Education Program' on blood pressure.

SUBJECTS

A representative population of 176 pupils (85 from the intervention schools and 91 from the control schools).

DESIGN

Blood pressure, dietary, anthropometrical and physical activity data were obtained at baseline (academic year 1992-1993) and at follow-up examination (academic year 2001-2002).

RESULTS

The findings of the current study revealed that the increase over the 10-year period in systolic (SBP) and diastolic blood pressure (DBP) was higher in the control group (CG) than in the intervention group (IG) (P=0.003 and P<0.001 respectively). Regarding dietary indices, the IG were found to have a significantly higher intake of potassium (P=0.018) and magnesium (P=0.011) compared to the CG. Furthermore, the decrease in body mass index (BMI) z-score observed in the IG was found to differentiate significantly from the increase observed in the CG (P=0.042). On the contrary, the increase in leisure time, moderate to vigorous physical activities (MVPA) observed in the IG, was found to differentiate significantly from the decrease observed in the CG (P=0.032). Intervention's effect on SBP was mediated by changes in MVPA (beta=-0.20, P=0.030) and BMI (beta=0.19, P=0.048). Similarly, intervention's effect on DBP was mediated by changes in MVPA (beta=-0.18, P=0.048), BMI (beta=0.26, P=0.007) and magnesium intake (beta=-0.20, P=0.048).

CONCLUSION

The findings of the current study are encouraging, indicating favorable changes in blood pressure, micronutrients intake, BMI and physical activity over the 10 years of follow-up and 4 years after program's cessation, thus providing some support for the effectiveness of school-based health education programs in successfully tackling certain chronic disease risk factors early in life.