The longitudinal relationship between dietary intake, physical activity and muscle strength among adolescents.

The longitudinal relationship between muscle strength, dietary intake and physical activity among adolescents is not well understood. We investigated the trend and longitudinal effects of dietary intakes and physical activity scores on muscle strength in adolescents. This prospective cohort study consisted of 436 adolescents (134 males; 302 females) aged 13 years at baseline (2012) who were followed up at the ages of 15 (2014) and 17 (2016) years, respectively. We measured muscle strength using a calibrated hand dynamometer, estimated dietary intake with a 7-d dietary history and physical activity scores with a validated physical activity questionnaire for older children. A generalised estimating equation was used to examine the effect of dietary intakes and physical activity on muscle strength changes. The analysis was performed separately by sex. The muscle strength for males and females had increased within the 5-year period. The dietary intakes (energy and macronutrients) also increased initially but plateaued after the age of 15 years for both sexes. Females recorded a significant declining trend in physical activity scores compared with males as they grew older. A significant positive longitudinal relationship was found between protein (ß = 0·035; P = 0·016), carbohydrate intake (ß = 0·002; P = 0·013) and muscle strength among males. However, no longitudinal relationship was found between dietary intake, physical activity and muscle strength among females. Higher protein and carbohydrate intake among males was associated with higher muscle strength but was not observed in females. Nutrition and physical activity focusing on strength building are required in early adolescence and need to be tailored to males and females accordingly.

Dietary inflammatory index® and cortical bone outcomes in healthy adolescent children.

Diet is thought to modulate inflammation. This study shows no relationships between the dietary inflammatory index (DII) and biomarkers of inflammation or bone after adjusting for covariates. Monocyte chemoattractant protein-1 was inversely associated with peripheral tibia cortical thickness and prospective childhood studies should be conducted to better understand this relationship and to determine if there are long-term consequences in adulthood. INTRODUCTION: Examine the relationships between the DII-scores and bone and biomarkers of inflammation in 290 adolescents, ages 9-13 years. METHODS: DII-scores were calculated from 3-day diet records and categorized into tertiles, low (< - 1.34), medium (- 1.34 to 1.41), and high (> 1.41) inflammation. Radius and tibia bone were assessed via peripheral quantitative computed tomography (Stratec XCT 2000) at the 66% site relative to the distal growth plate. Fasting serum was measured for tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1). The relationships between DII-scores and bone and biomarkers of inflammation were assessed using bivariate and partial correlations adjusting for sexual maturation, sex, race, muscle cross-sectional area, and height. ANOVA/ANCOVA models were used to compare DII-tertiles with dependent variables. RESULTS: DII-scores were negatively associated with tibia trabecular area (TtAr; r = - .141, P = .019), periosteal perimeter (PsPM; r = - .145, P = .016), endosteal perimeter (r = - .145, P = .016), strength strain index (SSI; r = - .129, P = .032), and radius TtAr (r = - .140, P = .020), PsPM (r = -.138, P = .027) and SSI (r = -.131, P = .036) but nullified when adjusting for covariates. Tibia PsPM was higher in the low DII group compared to the medium (P = .050) and high (P = .046) groups but nullified after controlling for covariates. DII-scores were not associated with TNF-α, VEGF, or IL-6, but were associated with MCP-1 only in the unadjusted model (r = .125, P = .042). In the adjusted model, MCP-1 was inversely associated with tibia cortical thickness (r = -.150 P = .030). CONCLUSION: The DII-scores were not related to biomarkers of inflammation or bone; however, the biomarker of inflammation, MCP-1 was negatively associated with tibia CtTh. Future prospective pediatric studies should be conducted to better understand this relationship and determine if there are long-term implications in adulthood.

Relative validation of the adapted Mediterranean Diet Score for Adolescents by comparison with nutritional biomarkers and nutrient and food intakes: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

OBJECTIVE: To investigate whether adherence to the adapted Mediterranean Diet Score for Adolescents (MDS_A) and the adapted Mediterranean Diet Quality Index for Adolescents (KIDMED_A) is associated with better food/nutrient intakes and nutritional biomarkers. DESIGN: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study is a cross-sectional study aiming to obtain comparable data on a variety of nutritional and health-related parameters in European adolescents aged 12·5-17·5 years. SETTING: Nine European countries. PARTICIPANTS: European adolescents (n 2330) recruited to the HELENA study. Dietary intake was obtained with 24 h dietary recalls, an FFQ and a Food Choices and Preferences questionnaire. MDS_A was calculated as a categorical variable using cut-offs (MDS_A), as a continuous variable (zMDS_A) and with energy adjustments (zEnMDS_A). The KIDMED_A score was also calculated. RESULTS: Multilevel linear regression analysis showed positive associations for zMDS_A and KIDMED_A with serum levels of vitamin D, vitamin C, plasma folate, holo-transcobalamin, ß-carotene and n-3 fatty acids, while negative associations were observed with trans-fatty acid serum levels. For categorical indices, blood biomarkers showed few significant results. zMDS_A and KIDMED_A showed positive associations with vegetables and fruits intake, and negative associations with energy-dense and low-nutritious foods. zMDS_A and KIDMED_A were positively associated with all macronutrients, vitamins and minerals (all P < 0·0001), except with monosaccharides and PUFA for KIDMED_A and cholesterol for both indices (P < 0·05). CONCLUSIONS: zMDS_A and KIDMED_A have shown the strongest associations with the dietary indicators and biomarkers that have been associated with the Mediterranean diet before, and are therefore considered the most appropriate and valid Mediterranean diet scores for European adolescents.

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.

Are milk and alternatives and fruit and vegetable intakes during adolescence associated with cortical and trabecular bone structure, density, and strength in adulthood?

We investigated the impact of food group intake during adolescence on bone structure and strength during adulthood. In females, we found a beneficial effect of adolescent milk and alternatives and fruit and vegetable intake on adult radius shaft and distal tibia bone structure, respectively. No association was observed in males. INTRODUCTION: The purpose of this study was to investigate whether adolescents with high intake of milk and alternatives (M&A) or fruit and vegetables (F&V) had better adult bone structure and strength compared to those with low intake levels. METHODS: We analyzed data from 47 males and 69 females enrolled in the Pediatric Bone Mineral Accrual Study (PBMAS 1991-2011), who had one peripheral quantitative computed tomography scan at age 29 ± 2 years. We measured radius and tibia shaft total area (ToA), cortical area (CoA), cortical content (CoC), cortical density, bone strength (SSIp), and muscle area, as well as distal radius and tibia ToA, total density, trabecular area, trabecular content, trabecular density, and bone strength (BSIc). Sequential 24-h recalls were used to assess M&A and F&V intake; participants were grouped for their mean intake during adolescence (low = bottom quartile, moderate = middle quartiles, high = top quartile) and were compared using multivariate analysis of covariance while adjusting for adult height, muscle area, physical activity, energy and calcium intake and adolescent energy intake, and physical activity. RESULTS: Females with high M&A intake compared to low M&A intake group (mean 3.8 vs. 1.3 servings/day, respectively) had greater adult ToA (14 %, p < 0.05), CoA (15 %, p < 0.01), and CoC (16 %, p < 0.01) at radius shaft. Females with moderate F&V intake compared to low F&V intake group (mean 3.7 vs. 2.1 servings/day, respectively) had greater adult ToA (8.5 %, p < 0.05) at distal tibia. CONCLUSION: Higher intake of M&A or F&V during adolescence had a long-term beneficial effect on bone structure in females, an association not observed in males.

Self-Efficacy and Self-Reported Dietary Behaviors in Adolescents at an Urban School With No Competitive Foods.

Over one third of U.S. adolescents are overweight. A descriptive, cross-sectional study examined the relationship between student dietary self-efficacy (SE), sugar-sweetened beverages, and low-nutrient energy-dense food consumption, and exposure to a healthy school food environment without competitive foods. The sample consisted of 292 urban, primarily African American students aged 11 to 16 years. Mantel-Haenszel χ(2) analyses revealed a significant but weak linear trend for girls between number of school meals and SE to drink less soda, χ(2)(1) = 6.882, p = .008, and between semesters attended with SE to eat more fruits and vegetables, χ(2)(1) = 5.908, p = .015. Obese students had significantly higher scores for two SE items than nonobese students, that is, plan better nutrition, χ(2)(1) = 3.998, p = .045, and eat healthy at a fast-food restaurant, χ(2)(1) = 4.078, p = .043. Further study of adolescent SE for healthy eating and school-based, food-focused obesity prevention interventions is needed.

Nutrient intake of European adolescents: results of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study.

OBJECTIVE: An adequate nutritional intake in childhood and adolescence is crucial for growth and the prevention of youth and adult obesity and nutrition-related morbidities. Improving nutrient intake in children and adolescents is of public health importance. The purpose of the present study was to describe and evaluate the nutrient intake in a European sample using the D-A-CH nutrient intake recommendations and the Nutritional Quality Index (NQI). DESIGN: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, the main objective of which is to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12·5-17·5 years. SETTING: Eight cities in Europe. SUBJECTS: The initial sample consisted of 3528 European adolescents. Among these, 1590 adolescents (54% female) had sufficient and plausible dietary data on energy and nutrient intakes from two 24 h recalls using the HELENA-DIAT software. RESULTS: The intakes of most macronutrients, vitamins and minerals were in line with the D-A-CH recommendations. While the intakes of SFA and salt were too high, the intake of PUFA was too low. Furthermore, the intakes of vitamin D, folate, iodine and F were less than about 55% of the recommendations. The median NQI was about 71 (of a maximum of 100). CONCLUSIONS: The intakes of most nutrients were adequate. However, further studies using suitable criteria to assess nutrient status are needed. Public health initiatives should educate children and adolescents regarding balanced food choices.

Dietary pattern of schoolgoing adolescents in urban Baroda, India.

Diet plays a very important role in growth and development of adolescents, during which the development of healthy eating habits is of supreme importance. There is a dual burden of undernutrition and overnutrition in this age-group. The study assessed the food habits, food preferences, and dietary pattern of schoolgoing urban adolescents in Baroda, India. Both quantitative and qualitative methods were used in this study. A quantitative survey was carried out using a pre-tested self-administered structured questionnaire among 1,440 students from class 6 to 12 in 7 English medium and 23 Gujarati medium schools. Focus group discussions, 5 each with adolescent boys and girls, were held, along with 5 focus group discussions with teachers of Gujarati and English medium schools. Nearly 80% of adolescents had consumed regular food, like dal, rice, chapati, and vegetables, including green leafy vegetables. Nearly 50% of them had consumed chocolates, and about one-third consumed fast foods. Nearly 60% of adolescents had their breakfast daily while the remaining missed taking breakfast daily. Nearly one-third of adolescents were missing a meal once or twice a week. A large majority had consumed regular foods. However, more than half of them had consumed chocolates, soft drinks, and over one-third had taken fast foods.

Efficacy of the I Can Control Asthma and Nutrition Now (ICAN) pilot program on health outcomes in high school students with asthma.

Asthma is the most prevalent chronic illness in childhood affecting 7 million youth. Many youth with asthma face another risk factor in obesity. Obesity, in turn, increases disorders such as asthma. Studies have recommended that asthma programs also address weight management in youth. Taking this into consideration, the I Can Control Asthma and Nutrition Now (ICAN) program is an innovative school-based program composed of (1) nutrition and weight management education, (2) asthma education, and (3) monthly reenforcement visits. This pilot study tested the initial effectiveness of the ICAN pilot program on a variety of asthma and nutrition outcomes in 25 urban minority students with asthma. Over the course of the pilot program, significant increases in asthma knowledge, asthma self-efficacy, asthma quality of life, asthma self-care, nutrition knowledge, nutrition self-efficacy, and asthma control were observed. The ICAN program has demonstrated promising preliminary results in improving nutrition and asthma health outcomes with urban minority high school students.

Food intake in Slovenian adolescents and adherence to the Optimized Mixed Diet: a nationally representative study.

OBJECTIVES: To investigate the food intake of Slovenian adolescents and to compare it with food-based dietary guidelines developed for children and adolescents, named the Optimized Mixed Diet (OMD). The OMD is a useful tool for the evaluation of food intake of adolescents. DESIGN: All adolescents completed an FFQ at a regional health centre; a subgroup also completed a 3 d weighed dietary protocol at home. SETTING: This study is a part of the first national representative study on the dietary habits of Slovenian adolescents. SUBJECTS: This cross-sectional study included a representative sample of 2813 Slovenian adolescents entering high school, aged 14-17 years, from all ten geographical regions of Slovenia. RESULTS: The greatest deviations from the recommended intakes of the main food groups in the OMD were significantly lower intakes of (P < 0·001, mean): vegetables (179 and 163 g/d in boys and girls, respectively), bread/cereals (271 and 226 g/d), potatoes/rice/pasta (212 and 163 g/d); in boys also a significantly lower intake of fruits (mean: 321 g/d, P < 0·001) and a significantly higher intake of meat/meat products (mean: 126 g/d, P < 0·001). Additionally, the results show too high intake of sugar-sweetened beverages and too low intakes of fish and plant oils in both genders. CONCLUSIONS: The food intake pattern of Slovenian adolescents deviates markedly from a healthy eating pattern. Nutrition education and interventions are needed for Slovenian adolescents.

Maternal work hours in early to middle childhood link to later adolescent diet quality.

OBJECTIVE: Previous studies on maternal work hours and child diet quality have reported conflicting findings possibly due to differences in study design, lack of a comprehensive measure of diet quality and differing ages of the children under investigation. The present study aimed to prospectively examine the impact of parental work hours from age 1 year to age 14 years on adolescent diet quality. DESIGN: Multivariate linear regression models were used to examine independent associations between parents' work hours at each follow-up and across 14 years and adolescent diet quality at age 14 years. A diet quality index was based on the international literature and Australian recommendations, consisting of six food groups and nine nutrients. SETTING: Perth, Western Australia. SUBJECTS: Children (n 1629) participating in the Western Australian Pregnancy Cohort (Raine) Study. RESULTS: Compared with children of mothers in full-time employment, children of mothers who were not employed in early childhood up to age 5 years had a higher average diet quality score at age 14 years, independent of maternal and family socio-economic status. Across 14 years the number of years the mother worked full time and increasing average weekly hours were associated with lower diet quality. Father's work hours had little association with adolescent diet quality. CONCLUSIONS: Having a mother stay at home in early to middle childhood is associated with better diet quality in adolescence. Support may be beneficial for families where the mother returns to full-time employment before the child reaches 8 years of age.

Nutritional supplement use among Slovenian adolescents.

OBJECTIVE: Little is known about the prevalence of nutritional supplement use in European adolescents. We conducted the present study to analyse the prevalence of nutritional supplement use and factors associated with this use among Slovenian adolescents. DESIGN: The nutritional supplementation practices of 818 adolescents were studied using an anonymous questionnaire. Information was sought on the type of supplements used, frequency of use and sources of information. SETTING: The region of north-west Slovenia. SUBJECTS: Schoolchildren from twenty primary schools and twelve secondary schools. RESULTS: Some 19·3% of all adolescents reported using at least one nutritional supplement and the prevalence of use was significantly higher in adolescents who were members of sports clubs. Multivitamins were the most common nutritional supplement. Older adolescents were significantly more likely to be supplementing with iron, protein and minerals. Less than 16% of supplement users in our study sought information from health-care professionals. Nearly 62% obtained information from parents and coaches, and many adolescents appear to decide on nutritional supplementation themselves, without advice. Older adolescents were significantly more likely to combine supplements than younger adolescents. CONCLUSIONS: One-fifth of Slovenian adolescents use nutritional supplements. There are clear differences in supplement use between younger (age 12 years) and older (age 17 years) adolescents. Multiple use of supplements, coupled with self-managed supplementation in older adolescents, is concerning. Hence, there is an urgent need to provide accurate information regarding nutritional supplements, which will help adolescents, their parents and coaches to make informed choices about their use.

Parent calcium-rich-food practices/perceptions are associated with calcium intake among parents and their early adolescent children.

OBJECTIVE: The study aimed to (i) segment parents of early adolescents into subgroups according to their Ca-rich-food (CRF) practices and perceptions regarding early adolescent CRF intake and (ii) determine whether Ca intake of parents and early adolescents differed by subgroup. DESIGN: A cross-sectional convenience sample of 509 parents and their early adolescent children completed a questionnaire in 2006-2007 to assess parent CRF practices and perceptions and to estimate parent and child Ca intakes. SETTING: Self-administered questionnaires were completed in community settings or homes across nine US states. SUBJECTS: Parents self-reporting as Asian, Hispanic or non-Hispanic White with a child aged 10-13 years were recruited through youth or parent events. RESULTS: Three parent CRF practice/perception segments were identified, including 'Dedicated-Milk Providers/Drinkers' (49 %), 'Water Regulars' (30 %) and 'Sweet-Drink-Permissive Parents' (23 %). Dedicated-Milk Providers/Drinkers were somewhat older and more likely to be non-Hispanic White than other groups. Ca intakes from all food sources, milk/dairy foods and milk only, and milk intakes, were higher among early adolescent children of Dedicated-Milk Providers/Drinkers compared with early adolescents of parents in other segments. Soda pop intakes were highest for early adolescents with parents in the Water Regulars group than other groups. Dedicated-Milk Providers/Drinkers scored higher on culture/tradition, health benefits and ease of use/convenience subscales and lower on a dairy/milk intolerance subscale and were more likely to report eating family dinners daily than parents in the other groups. CONCLUSIONS: Parent education programmes should address CRF practices/perceptions tailored to parent group to improve Ca intake of early adolescent children.

[Hygienic substantiation of rational nutrition for grammar schoolchildren].

The article presents the results of a study of factual nutrition and nutritional status of schoolchildren and grammar schoolchildren. The data obtained indicate that the nutrition of pupils is irrational and inadequate and does not satisfy the needs of the body of the grammar-schoolchildren in nutrients, which leads to a decrease in the level of efficiency, adaptive reserve capacity of the body and the low supply of vitamin B2, A, E, compared with schoolchildren.

Calcium nutrition in adolescence.

Adolescence is an important period of nutritional vulnerability due to increased dietary requirements for growth and development and special dietary habits. Calcium needs are elevated as a result of the intensive bone and muscular development and thus adequate calcium intake during growth is extremely important to reach the optimum peak bone mass and to protect against osteoporosis in the adult age, a major public health threat whose incidence is increasing in Western countries. However, most children and adolescents worldwide fail to achieve the recommended calcium intake. The hormonal changes associated with the pubertal period promote greater mineral utilization, which needs to be satisfied with suitable calcium consumption. Diet, therefore, must contribute nutrients in sufficient quality and quantity to allow maximum bone mass development. Consequently, adolescents should be educated and encouraged to consume adjusted and balanced diets that, together with healthy lifestyles, enable optimal calcium utilization.

Validity and reproducibility of the FFQ (FFQW82) for dietary assessment in female adolescents.

OBJECTIVE: To assess the validity and reproducibility of a self-administered FFQ with eighty-two food items (FFQW82) for assessing the habitual diet in female adolescents. DESIGN: The validity of the FFQW82 for assessment of nutrient intake was evaluated by comparison with a 7 d weighed food record (7d-FRRI) reported as 'gold standard'. Reproducibility of the FFQW82 was assessed at an interval of 1 month (test-retest method). The first survey (FFQW82 and 7d-FRRI) was conducted in April 2007 and the second FFQW82 survey was conducted in May 2007. Daily consumption of energy from eleven food groups and nine nutrients were calculated from both instruments for breakfast, lunch, dinner and the whole day. Crude and energy-adjusted Pearson correlation coefficients were calculated using log-transformed data. SETTING: Middle school, Tokyo, Japan. SUBJECTS: Female adolescents aged 12-13 years. RESULTS: Sixty-three female adolescents completed both surveys. The relative difference between the energy intake calculated by the FFQW82 and the 7d-FRRI for the whole day, breakfast, lunch and dinner was 8 %, 10 %, 15 % and 10 %, respectively. As for validity, the correlation coefficient of total energy intake for the whole day was 0·31. The result for breakfast was relatively higher (0·59) compared with that for lunch (0·40) and dinner (0·32). For macronutrients, the energy-adjusted correlation coefficient ranged from 0·28 (carbohydrates) to 0·53 (protein). Reproducibility of total energy intake was 0·62 and ranged from 0·46 (fat) to 0·69 (carbohydrate) for macronutrients. CONCLUSIONS: These results suggest that the FFQW82 has proved to have some potential with regard to reproducibility among our study population.

Energy and nutrient intakes in relation to sex and socio-economic status among school adolescents in urban Cameroon, Africa.

OBJECTIVE: To assess energy and nutrient intakes and physical activity of adolescents in urban Cameroon according to sex and socio-economic status (SES). DESIGN: Cross-sectional study with adolescents randomly selected from schools in low-, middle- and high-SES areas. Weight and height were measured and information about food intake and physical activity was obtained through repeated individual 24 h recalls. Under- and over-reporting of energy intake and inadequacy of nutrient intake were assessed. SETTING: Yaoundé, Cameroon. SUBJECTS: Boys and girls aged 12-16 years (n 227). RESULTS: Boys had a lower BMI and reported higher energy expenditures and physical activity levels (PAL) than girls. Under-reporting of energy intake was large among boys and girls regardless of PAL; boys under-reported more than girls. Among those with low PAL, over-reporting of energy intake was common. Over 50% of boys and girls had protein below the recommendations. The intake of fat varied; 26% of the adolescents were below and 25% were above the recommendations. Inadequate intakes of vitamin B1, vitamin B3 and Fe were more common among girls, while boys more often had inadequate intake of vitamin A. Adolescents with low SES were more likely to be below the recommendations for fat and vitamins B2, B3, B6 and B12 than those with high SES. CONCLUSIONS: A high proportion of boys and girls reported inadequate intakes. However under- and over-reporting were also very common. Boys under-reported energy intake more than girls and inadequate nutrient intake was more frequently reported by adolescents with low SES than by those with high SES.

Impact of group-based dietary education on the dietary habits of female adolescents: a cluster randomized trial.

OBJECTIVE: The number of extremely thin young women has increased and education at school on maintaining an optimal weight has become important. The aim of the present study was to assess the effectiveness of a group-based home-collaborative dietary education (HCDE) programme to maintain appropriate dietary intake compared to conventional school classroom education. DESIGN: Two-arm cluster randomized controlled trial. Twelve classes were randomly assigned as clusters to either the HCDE group or the control group. Each participant in the HCDE group received twelve sessions of group counselling aimed at increasing energy intake at breakfast by modifying dietary intake and adopting appropriate habits. The hypothesis underlying the study was that after 6 months of HCDE the total energy intake would be increased by 627 kJ from baseline (primary endpoint). Secondary outcomes were differences in intake of various nutrients from baseline. Outcome measures after log transformation were examined by t tests and linear mixed models (crude and baseline-adjusted). SETTING: Young women among Japanese female adolescents in Tokyo. SUBJECTS: Four hundred and seventy-four participants aged 13-15 years. RESULTS: Students in twelve classes were used for analysis (n 459). Energy intake was decreased in many of the classes during the 6-month period, especially for those in the control group. After adjustment for the baseline value, significant increases in energy intake and protein, calcium, magnesium and iron intakes at breakfast were observed (P<0.05) CONCLUSIONS: Although energy intake was increased in the HCDE group compared to the control group, further study of the HCDE is warranted.

Socio-economic differences in eating-related attitudes, behaviours and environments of adolescents.

OBJECTIVE: The aim of the present study was to investigate the relationship between area-level socio-economic status and healthy and less healthy eating behaviours among adolescents and to determine whether the relationship between area-level socio-economic status and dietary behaviours was related to the relevant attitudes and environments. DESIGN: Data were collected as part of Youth'07, a nationally representative survey of the health and well-being of New Zealand youth. SETTING: New Zealand secondary schools, 2007. SUBJECTS: A total of 9107 secondary-school students in New Zealand. RESULTS: Students from more deprived areas perceived more supportive school environments and cared as much about healthy eating as students in more affluent areas. However, these students were significantly more likely to report consuming fast food, soft drinks and chocolates. CONCLUSIONS: Addressing area-level socio-economic disparities in healthy eating requires addressing the availability, affordability and marketing of unhealthy snack foods, particularly in economically deprived areas.

[Perimenarchial growth spurt of the bone].

Peak bone mass negatively predicts the lifetime cumulative incidence of osteoporosis and fractures. Osteoporosis is a highly prevalent disease and fractures at an advanced age worsen life expectancy. It is therefore important to prevent progression of this disease. However, curbing the loss of already osteoporotic bone is not an easy task. Adolescence is a critical period for bone acquisition. Maximizing peak bone mass during puberty will ultimately guard against osteoporosis. In this review, we focus on the hormonal effects of puberty on bone growth and the importance of appropriate exercise and nutrition to optimize bone accrual.