Prevalence, trends and risk factors of thinness among Greek children and adolescents.

INTRODUCTION: Thinness affects more children and adolescents than obesity. Thus, the aim of the study is to examine the recent estimates of thinness and associated risk factors, and to identify trends in thinness, among Greek schoolchildren. METHODS: Epidemiological study. Population data from the recent estimates are derived from a school-based health survey polled in 2015 on 336,014 participants aged 4- to 17-years-old. To assess trends of thinness (1996-2015) we included a total of 300,104 children aged 8- to 9-years-old. Physical activity, dietary habits and sedentary activities were assessed through self-completed questionnaires. The gender and age-specific body mass index cut-off points proposed by International Obesity Task Force were used in order to define weight groups. RESULTS: Percent 8.4% of girls and 6.5% of boys were thin (all grades included). The prevalence of thinness decreased with age more in boys (from 13.8% at 4-years-old to 5.1% at 17-years-old, p < 0.001), than in girls (from 10.9% at 4-years-old to 8.7% at 17-years-old, p < 0.001). Sufficient dietary habits (OR: 0.87, 95% CI: 0.77-0.97) and adequate physical activity levels (OR: 0.92, 95% CI: 0.85-0.99) were associated with decreased risk of thinness. Thin schoolchildren performed better in aerobic fitness test than normalweight ones. Between 1996 and 2015, thinness rates decreased from 8.0% to 6.5% in boys (p = 0.046) and from 10.6% to 8.4% in girls (p = 0.036). CONCLUSIONS: Our results suggest that thinness is a significant overlooked phenomenon. Although the prevalence of thinness has decreased the last two decades among Greek schoolchildren, actions need to be taken from public policy makers in order to establish and maintain a healthy body weight.

Current data in Greek children indicate decreasing trends of obesity in the transition from childhood to adolescence; results from the National Action for Children's Health (EYZHN) program.

INTRODUCTION: The aim of the study is to present the most recent estimates of obesity (total and central) prevalence in Greek children and associated risk factors. METHODS: Population data are derived from a yearly, school-based health survey polled in 2015 on 336,014 (51% boys) children aged 4 to 17 years old from almost 40% of all schools of primary and secondary education in Greece. Anthropometric and physical fitness measurements were obtained by trained investigators. Dietary habits, physical activity status, sedentary activities and sleeping hours were assessed through self-completed questionnaires. The gender and age-specific Body Mass Index (BMI) cut-off points were used in order to define BMI groups. RESULTS: The prevalence of overweight and obesity in the whole population was 22.2% and 9.0% in boys and 21.6% and 7.5% in girls, respectively. Obesity presented decreasing trends in the transition from childhood to adolescence. Central obesity was diagnosed in 95.3% and 93.5% of the simple obese boys and girls, respectively, in almost two to three of overweight children (68.6% of boys and 64.3% of girls), and in 12% of normal weight children. Age, physical fitness, low adherence to Mediterranean diet, insufficient sleeping hours, inadequate physical activity levels and increased screen time were all associated with higher odds of total and central obesity. CONCLUSIONS: Serious and urgent actions need to be taken from public health policy makers in order not only to prevent a further increase in obesity rates but, more important, to treat obesity and/or the obesity associated co-morbidities.

Adipose tissue uncoupling protein 1 levels and function are increased in a mouse model of developmental obesity induced by maternal exposure to high-fat diet.

With brown adipose tissue (BAT) becoming a possible therapeutic target to counteract obesity, the prenatal environment could represent a critical window to modify BAT function and browning of white AT. We investigated if levels of uncoupling protein 1 (UCP1) and UCP1-mediated thermogenesis are altered in offspring exposed to prenatal obesity. Female CD-1 mice were fed a high-fat (HF) or standard-fat (SF) diet for 3 months before breeding. After weaning, all pups were placed on SF. UCP1 mRNA and protein levels were quantified using quantitative real-time PCR and Western blot analysis, respectively, in brown (BAT), subcutaneous (SAT) and visceral (VAT) adipose tissues at 6 months of age. Total and UCP1-dependent mitochondrial respiration were determined by high-resolution respirometry. A Student's t-test and Mann-Whitney test were used (significance: P<0.05). UCP1 mRNA levels were not different between the HF and SF offspring. UCP1 protein levels, total mitochondrial respiration and UCP1-dependent respiration were significantly higher in BAT from HF males (P=0.02, P=0.04, P=0.005, respectively) and females (P=0.01, P=0.04, P=0.02, respectively). In SAT, the UCP1 protein was significantly lower in HF females (P=0.03), and the UCP1-dependent thermogenesis was significantly lower from HF males (P=0.04). In VAT, UCP1 protein levels and UCP1-dependent respiration were significantly lower only in HF females (P=0.03, P=0.04, respectively). There were no differences in total respiration in SAT and VAT. Prenatal exposure to maternal obesity leads to significant increases in UCP1 levels and function in BAT in offspring with little impact on UCP1 levels and function in SAT and VAT.

Association between Siesta (Daytime Sleep), Dietary Patterns and the Presence of Metabolic Syndrome in Elderly Living in Mediterranean Area (Medis Study): The Moderating Effect of Gender.

OBJECTIVES: Several lifestyle parameters including diet, physical activity and sleep were associated in isolation with the presence of Metabolic Syndrome (MetS) in adults, to date there is a paucity of studies which evaluated their combined role aging populations and especially with respect to gender. Therefore, the aim of the present study was to provide a global consideration of the lifestyle factors associated with MetS among elderly individuals. DESIGN: Cross-sectional observational study. SETTING: 21 Mediterranean islands and the rural Mani region (Peloponnesus) of Greece. PARTICIPANTS: during 2005-2015, 2749 older (aged 65-100 years) from were voluntarily enrolled in the study. MEASUREMENTS: Dietary habits, energy intake, physical activity status, socio-demographic characteristics, lifestyle parameters (sleeping and smoking habits) and clinical profile aspects were derived through standard procedures. The presence of MetS was defined using the definition provided by NCEP ATP III (revised) and cluster analysis was used to identify overall dietary habit patterns. RESULTS: The overall prevalence of MetS in the study sample was 36.2%, but occurred more frequently in females (40.0% vs. 31.8%, respectively, p=0.03). Individuals with MetS were more likely to sleep during the day (89.4% vs. 76.8% respectively, p=0.039) and frequent 'siesta' was positively linked to the odds of MetS presence in females (Odds Ratio (OR) =3.43, 95% Confidence Intervals (CI): 1.08-10.9), but not for men (p=0.999). The lower carbohydrate (i.e., 45.2% of total daily energy, 120±16gr/day) dietary cluster was inversely associated with the odds for MetS presence, but only for men (OR=0.094, 95%CI: 0.010-0.883). CONCLUSIONS: Lifestyle parameters including sleep and diet quality are strongly associated with the presence of MetS in elderly cohort, but different their level of influence appears to be different, depending on gender. Further research is needed to better consider the role of lifestyle characteristics in the management of MetS in clinical practice.

Association between gestational weight gain and risk of obesity in preadolescence: a longitudinal study (1997-2007) of 5125 children in Greece.

BACKGROUND: The present study aimed to investigate the association between gestational weight gain (GWG) and birth weight, as well as the body mass index (BMI) status, of children at the ages of 2 and 8 years. METHODS: Population-based data were obtained from a database of all 7-9-year-old Greek children who attended primary school during 1997-2007. The study sample consisted of 5125 children matched with their mothers, randomly selected according to region and place of residence, and equally distributed (approximately 500 per year) throughout the study period (1997-2007). A standardised questionnaire was applied; telephone interviews were carried out to collect maternal age, BMI status at the beginning and the end of pregnancy and GWG, birth weight of offspring and BMI status at the ages of 2 and 8 years, as well as several other pregnancy characteristics (e.g. pregnancy duration, gestational medical problems, maternal smoking and alcohol consumption habits, and lactation of offspring after pregnancy). RESULTS: Gestational weight gain was positively associated with the weight status of offspring at all three life stages studied: newborn (birth weight), infant (BMI) and child (BMI) [b = 0.008 (0.001), b = 0.053 (0.009) and b = 0.034 (0.007), respectively, all P < 0.001], after adjusting for maternal age at pregnancy (significant inverse predictor only at age 2 years). The same applied to excessive GWG, as defined by the Institute of Medicine guidelines. CONCLUSIONS: Excessive GWG was associated with a higher risk of greater infant size at birth and a higher BMI status at the ages of 2 and 8 years. Healthcare providers should encourage women to limit their GWG to the range indicated by the current guidelines.

Αcute Exercise Alters the Levels of Human Saliva miRNAs Involved in Lipid Metabolism.

The response of micro-ribonucleic acid (miRNA) expression to exercise has not been studied in saliva, although saliva combines non-invasive collection with the largest number of miRNA species among biological fluids and tissues. Thus, the purpose of this study was to investigate the effect of acute exercise on the expression of 8 human saliva miRNAs involved in lipid metabolism. 19 healthy, physically active men (VO2max, 40.9±1.6 mL·kg(-1)·min(-1), mean±se) performed a 50-min interval exercise program on stationary bicycle (spinning). Saliva samples were collected before and after exercise for miRNA expression analysis by real-time polymerase chain reaction. Statistically significant (p<0.05) changes after exercise were found in 2 of the 8 miRNAs, namely, hsa-miR-33a (fold change, 7.66±2.94; p=0.012), which regulates cholesterol homeostasis and fatty acid metabolism in the liver, and hsa-miR-378a (fold change 0.79±0.11, p=0.048), which regulates energy homeostasis and affects lipogenesis and adipogenesis. These alterations may contribute to our understanding of physiological responses to exercise and the therapeutic potential of exercise against cardiovascular disease, obesity, and the metabolic syndrome. Moreover, our findings open the possibility of noninvasively studying miRNAs that regulate the function of specific organs.

Intracellular diglycerides in relation to glycaemic control in the myocardium: A pilot study in humans.

AIM: Intramyocellular diglycerides have been implicated in the development of insulin resistance in skeletal muscle. In the myocardium, excess lipid storage may also contribute to the appearance of diabetic cardiomyopathy, while diglycerides may have certain cardio-protective functions. However, little is known on intracellular diglyceride accumulation in the human heart. We aimed to determine diglyceride accumulation in the human myocardium in relation to diabetes status. METHODS: Six diabetic and six non-diabetic aged human subjects undergoing by-pass surgery participated in the study. Subjects were matched for age and body mass index. Intracellular diglyceride levels were measured in heart biopsy samples. Additional samples were taken from pectoralis major muscle that served as control. Whole body glycaemic control was assessed as the percent glycated haemoglobin. RESULTS: Intracellular diglycerides were significantly higher in the myocardium compared to pectoralis major (P<0.05). Although not statistically significant, diabetic subjects tended to accumulate smaller amounts of diglycerides compared to non-diabetic subjects in the myocardium. A linear negative correlation was observed between myocardial diglycerides and glycaemic control (r=0.632, P<0.05). CONCLUSIONS: Our data suggest that poor glycaemic control and diabetes may be associated with a defective accumulation of myocardial diglycerides, possibly blunting intracellular processes and contributing to the development of cardiomyopathy.

A percutaneous needle biopsy technique for sampling the supraclavicular brown adipose tissue depot of humans.

Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its related metabolic complications. Although the molecular and functional characteristics of BAT have been intensively studied in rodents, only a few studies have used human BAT specimens due to the difficulty of sampling human BAT deposits. We established a novel positron emission tomography and computed tomography-guided Bergström needle biopsy technique to acquire human BAT specimens from the supraclavicular area in human subjects. Forty-three biopsies were performed on 23 participants. The procedure was tolerated well by the majority of participants. No major complications were noted. Numbness (9.6%) and hematoma (2.3%) were the two minor complications noted, which fully resolved. Thus, the proposed biopsy technique can be considered safe with only minimal risk of adverse events. Adoption of the proposed method is expected to increase the sampling of the supraclavicular BAT depot for research purposes so as to augment the scientific knowledge of the biology of human BAT.

Establishing cross-sectional curves for height, weight, body mass index and waist circumference for 4- to 18-year-old Greek children, using the Lambda Mu and Sigma (LMS) statistical method.

BACKGROUND: We sought to establish cross-sectional curves for body weight, height, body mass index (BMI), and waist circumference for 4- to 18-year-old Greek boys and girls, using the empirical distribution and the Lambda Mu and Sigma (LMS) statistical method. METHODS: From March 2014 to May 2014, a total of 473,837 boys and girls aged 4 to 18 years who attended school in Greece were enrolled. The studied sample was representative, in terms of age-sex distribution and geographical region. Anthropometric indices measurements (i.e., height, weight and waist circumference) were performed and BMI was calculated and used to calculate normative values, using the percentiles of the empirical distributions and the LMS method. RESULTS: Updated growth references for 4- to 18-year-old Greek children tabulated as critical percentiles and LMS values from 3 to 97 (P3, P10, P25, P50, P75, P90, P97) and smoothed curves are presented. Positive secular trends of height, weight and waist circumference were observed in children and adolescents 4 to 18 years old (all p values <0.001). At all ages, boys had higher anthropometric measurements than girls (all p values <0.01). Compared to 1998 data, mean height and weight were greater in 2014 for boys and girls at all ages. CONCLUSION: Current national percentile curves for anthropometric indices could provide a more accurate estimation to assess physical growth in Greek children and adolescents. Hippokratia 2015; 19 (3): 239-248.

Role of cardiorespiratory fitness and obesity on hemodynamic responses in children.

AIM: The purpose of this study was to examine the effects of cardiorespiratory fitness (CRF) and obesity on arterial blood pressure and its determinants at rest and during isometric handgrip exercise (IHG) in children. METHODS: Fourty-eight healthy children aged 11.6±0.3 (mean ±SE) years, (24 obese or overweight [OB/OV]; 24 normal weight [NO]) participated in the study. Both groups were divided into fit or unfit subgroups according to children's performance of an exercise test (PWC170). Arterial pressure and its determinants were recorded with the use of a photoplethysmographic device (FINOMETER) during 5 minutes of rest and 3 minutes of IHG at 30% of maximum voluntary contraction. RESULTS: At rest and during IHG, unfit OB/OV children had higher systolic, mean arterial pressure, and rate pressure product (P≤0.05) than fit OB/OV children whose responses were similar to NO children, fit or unfit. Changes from rest, in cardiac output, cardiac index, and stroke volume were higher in unfit than in fit OB/OV children (P≤0.05). Unfit OB/OV children exceeded their fit counterparts in several anthropometric measures. However, CRF was found to have a main effect on systolic blood pressure (P=0.05). CONCLUSION: Unfit versus fit OB/OV children had an exaggerated systolic blood pressure response at rest and during sympathetic activation, presumably coupled with higher cardiac output and cardiac oxygen demand. These results highlight the importance of fitness for health maintenance in obese and overweight children.

Educational intervention on water intake improves hydration status and enhances exercise performance in athletic youth.

We aimed to evaluate whether an intervention program emphasizing in increased fluid intake can improve exercise performance in children exercising in the heat. Ninety-two young athletes participated in the study (age: 13.8 ± 0.4 years, weight: 54.9 ± 1.5 kg). Thirty-one (boys: 13, girls: 18) children served as the control group (CON) and 61 (boys: 30, girls: 31) as the intervention (INT). Volunteers had free access to fluids. Hydration was assessed on the basis of first morning urine. A series of field tests were used to evaluate exercise performance. All tests occurred outdoors in the morning (mean ambient temperature=28°C). After baseline testing, INT attended a lecture on hydration, and urine color charts were mounted in all bathrooms. Additionally, water accessibility was facilitated in training, dining and resting areas. Hydration status was improved significantly in the INT [USG: pre=1.031 ± 0.09, post=1.023 ± 0.012, P<0.05; urine osmolality (mOsm/kg water): pre=941 ± 30, post=782 ± 34, P<0.05], while no statistically significant changes were found in the CON [USG: pre=1.033 ± 0.011, post=1.032 ± 0.013, P>0.05; urine osmolality (mOsm/kg water) 970 ± 38 vs 961 ± 38, P>0.05]. Performance in an endurance run was improved significantly only in INT (time for 600 m: pre=189 ± 5 s, post=167 ± 4 s, P<0.05). Improving hydration status by ad libitum consumption of water can enhance performance in young children exercising in the heat.

Rates of lipid fluxes in adipose tissue in vivo after a mixed meal in morbid obesity.

OBJECTIVE: Although insulin resistance in obesity is established, information on insulin action on lipid fluxes, in morbid obesity, is limited. This study was undertaken in morbidly obese women to investigate insulin action on triacylglycerol fluxes and lipolysis across adipose tissue. SUBJECTS AND DESIGN: A meal was given to 26 obese (age 35+/-1 years, body mass index 46+/-1 kg m(-2)) and 11 non-obese women (age 38+/-2 years, body mass index 24+/-1 kg m(-2)). Plasma samples for glucose, insulin, triglycerides and non-esterified fatty acids (NEFAs) were taken for 360 min from a vein draining the abdominal subcutaneous adipose tissue and from the radial artery. Adipose tissue blood flow was measured with (133)Xe. RESULTS: In obese vs non-obese: (1) Arterial glucose was similar, but insulin was increased (P=0.0001). (2) Adipose tissue blood flow was decreased (P=0.0001). (3) Arterial triglycerides (P=0.0001) and NEFAs (P=0.01) were increased. (4) Lipoprotein lipase was decreased (P=0.0009), although the arteriovenous triglyceride differences were similar. (5) Veno-arterial NEFA differences across the adipose tissue were similar. (6) NEFA fluxes and hormone-sensitive lipase-derived glycerol output from 100 g adipose tissue were not different. (7) Total adipose tissue NEFA release was increased (P=0.02). CONCLUSIONS: In morbid obesity: (a) hypertriglycerinemia could be attributed to a defect in the postprandial dynamic adjustment of triglyceride clearance across the adipose tissue, partly caused by blunted BF; and (b) postprandially, there is an impairment of adipose tissue to buffer NEFA excess, despite hyperinsulinemia.

Moderate weight loss depletes intramyocellular triglycerides but has no effect on diglycerides in type II diabetes.

Intramyocellular diglycerides have been implicated in the development of insulin resistance. We aimed to evaluate the effect of weight loss, a well-known means for the improvement of insulin resistance, on intramyocellular diglycerides and triglycerides in type II diabetes. Participants were five obese women with type II diabetes (body mass index 37.5+/-1.9 kg/m(2)), who participated in a weight loss program. The aim of the program was a reduction in body weight by 10%. Muscle biopsies were obtained before and after weight loss. The intervention induced a marked reduction in intramyocellular triglycerides by 77.7+/-13.1%, whereas no significant differences were observed for diglycerides before and after weight loss. Our results indicate that weight loss due to negative energy balance depletes intramyocellular lipid storage without affecting intermediate molecules of lipid metabolism, such as intramyocellular diglycerides.

Resistance exercise plus to aerobic activities is associated with better lipids' profile among healthy individuals: the ATTICA study.

BACKGROUND: The influence of different types of exercise on risk factors for cardiovascular diseases has rarely been investigated. The aim of the present work was to evaluate the effect of adding resistance exercise to aerobic activities on lipid-lipoprotein profile, in a representative sample of men and women from the province of Attica, Greece. METHODS: We randomly enrolled 1514 and 1528 healthy men and women, respectively, stratified by city, age and gender distribution. Participants were classified as inactive (INA), sufficiently active (SA) and highly active for either aerobic activities (HAA) alone or a combination of aerobic plus resistance exercise (HAC). The main outcome measures are lipid-lipoprotein profile [total, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein-A1, apolipoprotein-B] and anthropometric indices. RESULTS: From those participating in aerobic activities, 480 (31.7%) men and 502 (32.9%) women were classified as SA, 100 men (6.6%) and 93 women (6.1%) as HAA and 90 men (5.9%) and 49 women (3.2%) as HAC. After various adjustments were made, men from the HAC group had an average of 23% lower plasma triacylglycerol concentration (P = 0.04) and 10% lower LDL-cholesterol (P = 0.01) when compared with the HAA group. Moreover, women from the HAC group had 13% lower LDL-cholesterol when compared with HAA group (P = 0.051). CONCLUSION: These data suggest that combining aerobic and resistance-type activities may confer a better effect on lipoprotein profile in healthy individuals than aerobic activities alone.

Estimated liver weight is directly related to hepatic very low-density lipoprotein-triglyceride secretion rate in men.

BACKGROUND: Animal studies suggest that liver weight is directly related to hepatic very low-density lipoprotein-triglyceride (VLDL-TG) secretion, independently of body size. This relationship has never been examined in humans. MATERIALS AND METHODS: We measured VLDL-TG secretion rate by using stable isotope-labelled tracers in 21 healthy, non-obese men (age: 25 +/- 3 years; body mass index: 24.8 +/- 1.6 kg m(-2)), and evaluated the relationship between VLDL-TG secretion and indices of total and regional adiposity (body mass index, total body fat, trunk fat), metabolic parameters (free fatty acid, glucose, and insulin concentrations, homeostasis model assessment index of insulin resistance, resting energy expenditure), and estimated liver weight. RESULTS: Correlation analysis showed that estimated liver weight was positively associated with total VLDL-TG secretion rate (r = 0.722, P < 0.001), VLDL-TG secretion rate per liter of plasma (r = 0.562, P = 0.008), VLDL-TG secretion rate per kilogram of body weight (r = 0.555, P = 0.009), and VLDL-TG secretion rate per kilogram of liver weight (r = 0.620, P = 0.003). In multiple regression analysis, estimated liver weight was the only significant predictor of VLDL-TG secretion rate regardless of units of expression, explaining 31-52% of total variance; none of the metabolic parameters and indices of body fatness entered the regression models. CONCLUSIONS: We conclude that estimated liver weight is directly related to hepatic VLDL-TG secretion rate in healthy non-obese men; this relationship is likely not mediated by interindividual variation in body size.

The type and intensity of exercise have independent and additive effects on bone mineral density.

Previous research on the effects of running and swimming on areal bone mineral density (aBMD) is inconclusive. This study examined the putative roles of the type and intensity of exercise in this respect, by measuring aBMD (adjusted for age, weight, and height) of the total body and of various subregions in 52 males aged 17 - 30 yr (21 runners, 16 swimmers, 15 controls). The athletes were competing at either long-distance ("endurance", n = 17) or short-distance ("sprint", n = 20) events. Compared with controls, runners had significantly higher leg aBMD (+ 6.7 %, p < 0.05), while swimmers had significantly lower leg and total body aBMD (- 9.8 % and - 7.0 %, respectively, p < 0.05). Endurance athletes had significantly lower total body aBMD than controls (- 4.9 %, p < 0.05). Sprint athletes did not differ significantly from controls at any site, but they had significantly higher aBMD than endurance athletes throughout the skeleton (p < 0.05). Compared with controls, endurance swimmers had significantly lower aBMD at the legs and total body (- 14.8 % and - 10.4 %, respectively, p < 0.05), while sprint runners had significantly higher values for the legs, trunk, and total body (+ 8.0 %, + 10.0 %, and + 6.3 %, respectively, p < 0.05). Sprint swimmers and endurance runners did not differ from controls at any site or the total body. These results suggest that the type and intensity of exercise have independent and additive effects on bone density.

Effect of eating frequency on body composition in 9-11-year-old children.

The aim of this study was twofold: a) to examine the association between eating frequency and body composition in children, and b) to identify possible factors that may explain this relationship. Body composition (anthropometry) and dietary intake (3-day food records) were assessed in a cohort of 151 children. After excluding the underreporters (n = 20), data from 131 children (66 boys and 65 girls) aged 9.9 +/- 0.1 yr with a BMI of 19.6 +/- 0.4 kg/m (2) (means +/- se) were used for further analysis. Children were categorized in tertiles based on the daily number of eating episodes. Physical activity was assessed in a subgroup of 48 volunteers with 4-day accelerometry (RT3, Stayhealthy Inc., Monrovia, CA, USA). The number of eating episodes was inversely associated (p < 0.05) with the sum of skinfolds (r = - 0.17) and % body fat (r = - 0.18) after controlling for age and sex. Frequent eaters presented lower total (p < 0.05) and central adiposity (p < 0.01) compared with the infrequent ones. This was despite the fact that energy intake was higher for the frequent eaters (2077.0 +/- 64.3 vs. 1813.0 +/- 37.8 kcals/day for the frequent and the infrequent eaters, respectively, p < 0.05). Actually, frequent eaters devoted more time to physical activity than infrequent ones (624.7 +/- 13.5 vs. 559.2 +/- 23.1 min/day, p < 0.05). In conclusion, high eating frequency was associated with more favorable body composition in this cohort of school children. Increased energy expenditure due to physical activity may, at least in part, explain the favorable body composition of children who eat frequently.

Differences in the quantitative and qualitative performance of a calcium-specific food frequency questionnaire across age and sex.

OBJECTIVE: To examine putative differences in the quantitative and qualitative performance of a food frequency questionnaire (FFQ) for assessing dietary calcium intake across age and sex in the Greek population. MATERIALS AND METHODS: A total of 351 children (189 girls and 162 boys, aged 11.9 +/- 1.2 years), 260 adults (192 women and 68 men, aged 29.6 +/- 2.7 years) and 390 elderly individuals (317 women and 73 men, aged 68.6 +/- 4.6 years) were recruited. Estimates of calcium intake from the 30-item FFQ were compared with those from a multi-pass 24-h recall. RESULTS: The FFQ significantly underestimated mean calcium intake in all age groups and both sexes (P < 0.05). The magnitude of underestimation, however, was greater in adults (-207 +/- 344 mg day(-1)), less in the elderly (-137 +/- 310 mg day(-1)) and even less in children (-74 +/- 340 mg day(-1); P < 0.025), with no differences between sexes. Calcium intakes by the two methods were positively and significantly correlated in all study groups (r = 0.536-0.739, P < 0.001). Cohen's weighted kappa statistic ranged from 0.39 to 0.57, indicating moderate agreement between the two methods. The 95% limits of agreement were comparably wide across age and sex (boys: -762, 585 mg day(-1); girls: -747, 624 mg day(-1); adult men: -972, 505 mg day(-1); adult women: -867, 412 mg day(-1); elderly men: -858, 486 mg day(-1); elderly women: -732, 480 mg day(-1)). A significant association between age, sex and the classification of individuals as true/false positive/negative was detected (P < 0.001), implying that sensitivity, specificity, positive and negative predictive values of the FFQ were not independent of the age and sex of the participants. Gross misclassification by the FFQ ranged from 0% to 4.2%, whereas 75.3-87.3% of the subjects were correctly classified. In this respect, the FFQ performed similarly across the study groups (P = 0.065). Without controlling for age, however, gross misclassification appeared to be higher in females than in males (3.2% versus 0.7%, respectively, P = 0.048). CONCLUSIONS: There may be several significant differences in the quantitative and qualitative performance of a calcium-specific FFQ across age and sex. This should be taken into account when attempting to evaluate dietary calcium intake in men and women or in different age groups, as some of the differences between study groups may actually be due to the different response of these groups to the FFQ.

Central and total adiposity are lower in overweight and obese children with high cardiorespiratory fitness.

OBJECTIVE: To examine the influence of cardiorespiratory fitness on total and truncal fatness in children. It was hypothesised that high cardiorespiratory fitness would result in lower total and central obesity. DESIGN: Observational cohort study. SETTING: Primary and secondary schools in Athens, Greece. SUBJECTS: A total of 1362 healthy children aged 6-13 y (742 boys and 620 girls). METHODS: Anthropometric data (height, body mass, four skinfolds thickness) were collected and per cent body fat was calculated. Body mass index (BMI) sex- and age-specific cutoff points were used for overweight and obesity definition and children were placed in two groups: overweight/obese and nonoverweight. Cardiorespiratory fitness (CRF) was assessed with the endurance shuttle-run test. Participants were grouped into high (upper two quintiles) and low (lower two quintiles) CRF based on age and sex distributions. T-test and Mann-Whitney test were used for comparisons between fit and unfit children within each BMI category. RESULTS: Sum of skinfolds, subscapular and truncal skinfold thickness, BMI and per cent body fat were lower in overweight and obese youths with high CRF in comparison with youths at the same BMI category with low CRF (P<0.01). The beneficial effect of high CRF was also presented in nonoverweight children (P<0.01). The influence of CRF on body composition remained even after correcting body fatness for BMI. CONCLUSIONS: Central and total obesity were lower in overweight and obese children with high CRF. This is the first study to show that a high CRF may reduce the hazards of obesity in children.

Nutrition-related habits of Greek adolescents.

OBJECTIVE: To investigate nutrition-related habits of Greek school-aged adolescents. DESIGN: Epidemiological survey. SETTING AND SUBJECTS: The study was part of the Health Behavior in School Aged Children (HBSC) survey. A representative sample of school-aged adolescents aged 11.5, 13.5, and 15.5 y was obtained. The final sample consisted of 4211 students (51.6% girls and 48.4% boys). They were asked to complete a translated form of the international HBSC questionnaire, including several thematic entities. The Unhealthy Food Choices Score (UFCS) was devised in order to evaluate the overall quality of reported eating habits of respondents; the higher the score, the lower the diet quality. RESULTS: Among all students surveyed, 14.7% were reported to be on a diet to lose weight (girls: 19.5%; boys: 9.7%; P<0.001), and 22.9% were dissatisfied with their body weight but not on a diet. Girls were found to have lower UFCS values compared to boys (24.7 +/- 4.6 vs 24.1 +/- 4.5, P<0.001). Girls dissatisfied with their weight, but not on a diet, showed the highest UFCS values compared to both those on a diet and those not on a diet. TV viewing was positively associated with the consumption of sodas, crisps, cakes and pastries, and sweets and chocolates. CONCLUSIONS: Dieting is becoming a major problem, especially among older girls. The findings of this study suggest that eating habits of Greek school-aged adolescents are in the process of changing from more traditional to more Westernized ones.