US adolescent food intake trends from 1965 to 1996

AIM

To examine adolescent food consumption trends in the United States with important chronic disease implications.

METHODS

Analysis of dietary intake data from four nationally representative United States Department of Agriculture surveys of individuals 11-18 years of age (n = 12 498).

RESULTS

From 1965 to 1996, a considerable shift in the adolescent diet occurred. Total energy intake decreased as did the proportion of energy from total fat (39% to 32%) and saturated fat (15% to 12%). Concurrent increases occurred in the consumption of higher fat potatoes and mixed dishes (pizza, macaroni cheese). Lower fat milks replaced higher fat milks but total milk consumption decreased by 36%. This decrease was accompanied by an increase in consumption of soft drinks and non-citrus juices. An increase in high fat potato consumption led to an increase in vegetable intake but the number of servings for fruits and vegetables is still below the recommended five per day. Iron, folate, and calcium intakes continue to be below recommendations for girls.

CONCLUSIONS

These trends, far greater than for US adults, may compromise health of the future US population.

Cutaneous copper and zinc losses in burns

To measure the exudative cutaneous copper (Cu) and zinc (Zn) losses in burns, 10 patients, aged 36 +/- 9 years (mean +/- s.d.) with burns covering 33 +/- 10 per cent of the total body surface area, were studied from the first postburn day (D1) until D7. All intakes and losses were analysed for Cu, Zn and nitrogen (N) content. Cutaneous losses were extracted from textiles surrounding the patients. Urinary excretions were 0.12 +/- 0.06mg/24h for Cu, 0.9 +/- 0.6mg/24h for Zn, and 14.1 +/- 4.4g/24h for N. Mean daily exudative losses through wound seepage from D1 to D7 were 4.7 +/- 2.1mg/24h for Cu, 27.1 +/- 14.4mg/24h for Zn, and 8.7 +/- 3.8g/24h for N. The cumulated mean losses over 7 days were 37mg for Cu, and 212mg for Zn, representing respectively 20-40 per cent and 5-10 per cent of normal body content. Serum Cu and Zn levels were strongly depressed. The urinary Cu/N ratios correlated with clinical improvement. We conclude that the exudative Cu and Zn losses during the first week postburn contribute significantly to the increased nutrient requirements in burns.

Calcium supplementation of chocolate: effect on cocoa butter digestibility and blood lipids in humans

BACKGROUND

The digestibility of cocoa butter was reported in animal but not human studies to be low (60-70% and 89-94%, respectively). These differences could be due to the much higher ratio of calcium to fat (by wt) in the diet of rats (0.04-0.18) than in that of humans (0.01).

OBJECTIVE

We investigated whether supplementation of chocolate with 0.9% calcium (by wt), as an integral part of a Western diet, reduces absorption of cocoa butter and hence the digestible energy value of chocolate. We also assessed the effect of calcium supplementation on the blood lipid profile.

DESIGN

Ten men were fed control diets containing 98-101 g chocolate/d with or without a 0.9%-Ca supplement (0.9 g Ca/d) for 2 periods of 2 wk each. The study was conducted with use of a randomized, double-blind crossover design under free-living conditions but with strict control of food intake.

RESULTS

Calcium supplementation of chocolate increased fecal fat 2-fold (from 4.4 to 8.4 g/d; P < 0.0001) and reduced the absorption of cocoa butter by 13.0%. This was due mainly to an increase in the excretion of palmitic and stearic acids (3.4 g/d), which reduced the absorbable energy value of the chocolate by approximately 9%. This supplementation also reduced plasma LDL cholesterol by 15% (P < 0.02); HDL cholesterol was unchanged.

CONCLUSIONS

Calcium supplementation can be used as a means of reducing the absorbable energy value of chocolate. Supplementation with 2.25% CaCO3 had no effect on the taste of chocolate, was well tolerated by the subjects, and reduced LDL cholesterol in a short-term study.

Enterococcus faecium SF68 enhances the immune response to Giardia intestinalis in mice

We studied the ability of the probiotic organism Enterococcus faecium SF68 to antagonize Giardia intestinalis infection in mice. Oral feeding of E. faecium strain SF68 starting 7 d before inoculation with Giardia trophozoites significantly increased the production of specific anti-Giardia intestinal IgA and blood IgG. This humoral response was mirrored at the cellular level by an increased percentage of CD4(+) T cells in the Peyer's patches and in the spleens of SF68-fed mice. The improvement of specific immune responses in probiotic-fed mice was associated with a diminution in the number of active trophozoites in the small intestine as well as decreased shedding of fecal Giardia antigens (GSA65 protein). The ability of SF68 to stimulate the immune system at both mucosal and systemic levels highlights mechanisms by which this probiotic might antagonize pathogens in vivo. Taken together, the data demonstrate the strong potential of strain SF68 to prevent protozoa from causing intestinal infections.

Effects of probiotic bacteria in dogs with food responsive diarrhoea treated with an elimination diet*

We evaluated whether a probiotic supplementation in dogs with food responsive diarrhoea (FRD) has beneficial effects on intestinal cytokine patterns and on microbiota. Twenty-one client-owned dogs with FRD were presented for clinically needed duodeno- and colonoscopy and were enrolled in a prospective placebo (PL)-controlled probiotic trial. Intestinal tissue samples and faeces were collected during endoscopy. Intestinal mRNA abundance of interleukin (IL)-5, -10, -12p40 and -13, tumour necrosis factor-alpha, transforming growth factor-beta1 and interferon (IFN)-gamma were analysed and numbers of Lactobacillus spp., Bifidobacterium spp., Enterococcus spp. and Enterobacteriaceae and supplemented probiotic bacteria were determined in faeces. The Canine Inflammatory Bowel Disease Activity Index, a scoring system comprising general attitude, appetite, faecal consistency, defecation frequency, and vomitus, decreased in all dogs (p < 0.0001). Duodenal IL-10 mRNA levels decreased (p = 0.1) and colonic IFN-gamma mRNA levels increased (p = 0.08) after probiotic treatment. Numbers of Enterobacteriaceae decreased in FRD dogs receiving probiotic cocktail (FRD(PC)) and FRD dogs fed PL (FRD(PL)) during treatment (p < 0.05), numbers of Lactobacillus spp. increased in FRD(PC after) when compared with FRD(PC before) (p < 0.1). One strain of PC was detected in five of eight FRD(PC) dogs after probiotic supplementation. In conclusion, all dogs clinically improved after treatment, but cytokine patterns were not associated with the clinical features irrespective of the dietary supplementation.

Copper, selenium, and zinc status and balances after major trauma

To investigate the trace elements (TE) losses and status after trauma, 11 severely injured patients (Injury Severity Score: 29 +/- 6), admitted to the ICU were studied from the day of injury (D0) until D25. Balance studies were started within 24 hours after injury, until D7. Serum and urine samples were collected from D1 to D7, then on D10, 15, 20, and 25. Intravenous TE supplementation was initiated upon admission. SERUM: Selenium (Se) and zinc (Zn) levels were decreased until D7 and were normal thereafter. LOSSES: TE urinary excretions were higher than reference ranges until D20 in all patients. Fluid losses through drains contained large amounts of TE. BALANCES: Balances were slightly positive for copper (Cu) and Zn, and negative for Se from D5 to D7 despite supplements. Cu status exhibited minor changes compared to those observed with the Zn and Se status: Serum levels were decreased and losses increased. Considering the importance of Se and Zn in free radical scavenging, anabolism, and immunity, current recommendations for TE supplements in severely traumatized patients ought to be revised.

US adolescent food intake trends from 1965 to 1996

OBJECTIVE

To examine adolescent food consumption trends in the United States with important chronic disease implications.

METHODS

Analysis of dietary intake data from 4 nationally representative US Department of Agriculture surveys of persons aged 11 to 18 years (n = 12,498).

RESULTS

From 1965 to 1996, a considerable shift occurred in the adolescent diet. Total energy intake decreased, as did the proportion of energy from total fat (39%-32%) and saturated fat (15%-12%). Concurrent increases occurred in the consumption of higher-fat potatoes and mixed dishes (pizza and macaroni and cheese). Lower-fat milks replaced higher-fat milks, but total milk consumption decreased by 36%. This decrease was accompanied by an increase in the consumption of soft drinks and noncitrus juices. An increase in high-fat potato consumption led to an increase in vegetable intake, but the number of servings for fruits and vegetables is still lower than the recommended 5 per day. Iron, folic acid, and calcium intakes continue to be below those recommended for girls.

CONCLUSIONS

These trends, far greater than for US adults, may compromise the health of the future US population.

Exudative mineral losses after serious burns: a clue to the alterations of magnesium and phosphate metabolism

Hypomagnesemia and hypophosphatemia are frequent after severe burns; however, increased urinary excretion does not sufficiently explain the magnitude of the mineral depletion. We measured the mineral content of cutaneous exudates during the first week after injury. Sixteen patients aged 34 +/- 9 y (mean +/- SD) with thermal burns were studied prospectively and divided in 3 groups according to the extent of their burn injury and the presence or absence of mineral supplements: group 1 (n = 5), burns covering 26 +/- 5% of body surface; group 2 (n = 6), burns covering 41 +/- 10%; and group 3 (n = 5), burns covering 42 +/- 6% with prescription of magnesium and phosphate supplements. Cutaneous exudates were extracted from the textiles (surgical drapes, dressings, sheets, etc) surrounding the patients from day 1 to day 7 after injury. Mean magnesium serum concentrations decreased below reference ranges in 12 patients between days 1 and 4 and normalized thereafter. Phosphate, normal on day 0, was low during the first week. Albumin concentrations, normal on day 0, decreased and remained low. Urinary magnesium and phosphate excretion were within reference ranges and not larger in group 3. Mean daily cutaneous losses were 16 mmol Mg/d and 11 mmol P/d (largest in group 2). Exudative magnesium losses were correlated with burn severity (r = 0.709, P = 0.003). Cutaneous magnesium losses were nearly four times larger than urinary losses whereas cutaneous phosphate losses were smaller than urinary phosphate losses. Mean daily losses of both magnesium and phosphate were more than the recommended dietary allowances. Exudative losses combined with urinary losses largely explained the increased mineral requirements after burn injury.

Effects of usual nutrient intake and vitamin D status on markers of bone turnover in Swiss adolescents

OBJECTIVE

To evaluate the effects of nutrient intake and vitamin D status on markers of type I collagen formation and degradation in adolescent boys and girls.

DESIGN

Cross-sectional study.

SETTING

Canton of Vaud, West Switzerland.

SUBJECTS

A total of 92 boys and 104 girls, aged 11-16 y. Data were collected on height, weight, pubertal status (self-assessment of Tanner stage), nutrient intake (3-day dietary record) and fasting serum concentration of 25-hydroxyvitamin D (25OHD), and markers of collagen formation (P1NP) and degradation (serum C-terminal telopeptides: S-CTX).

RESULTS

Tanner stage was a significant determinant of P1NP in boys and girls and S-CTX in girls. Of the nutrients examined, only the ratio of calcium to phosphorus (Ca/P) was positively associated with P1NP in boys, after adjustment for pubertal status. 25OHD decreased significantly at each Tanner stage in boys. Overall, 15% of boys and 17% of girls were identified as being vitamin D insufficient (serum 25OHD <30 nmol/l), with the highest proportion of insufficiency at Tanner stage 4-5 (29%) in boys and at Tanner stage 3 (24%) in girls. A significant association was not found between 25OHD and either bone turnover marker, nor was 25OHD insufficiency associated with higher concentrations of the bone turnover markers.

CONCLUSIONS

The marked effects of puberty on bone metabolism may have obscured any possible effects of diet and vitamin D status on markers of bone metabolism. The mechanistic basis for the positive association between dietary Ca/P ratio and P1NP in boys is not clear and may be attributable to a higher Ca intake per se, a critical balance between Ca and P intake or higher dairy product consumption. A higher incidence of vitamin D insufficiency in older adolescents may reflect a more sedentary lifestyle or increased utilisation of 25OHD, and suggests that further research is needed to define their requirements.

SPONSORSHIP

Nestec Ltd and The Swiss Foundation for Research in Osteoporosis.

Food habits and sport activity during adolescence: differences between athletic and non-athletic teenagers in Switzerland

OBJECTIVE

To describe food habits and dietary intakes of athletic and non-athletic adolescents in Switzerland.

SETTING

College, high schools and professional centers in the Swiss canton of Vaud.

METHOD

A total of 3,540 subjects aged 9-19 y answered a self-reported anonymous questionnaire to assess lifestyles, physical plus sports activity and food habits. Within this sample, a subgroup of 246 subjects aged 11-15 also participated in an in-depth ancillary study including a 3 day dietary record completed by an interview with a dietician.

RESULTS

More boys than girls reported engaging in regular sports activities (P<0.001). Adolescent food habits are quite traditional: up to 15 y, most of the respondents have a breakfast and eat at least two hot meals a day, the percentages decreasing thereafter. Snacking is widespread among adolescents (60-80% in the morning, 80-90% in the afternoon). Food habits among athletic adolescents are healthier and also are perceived as such in a higher proportion. Among athletic adolescents, consumption frequency is higher for dairy products and ready to eat (RTE) cereals, for fruit, fruit juices and salad (P<0.05 at least). Thus the athletic adolescent's food brings more micronutrients than the diet of their non-athletic counterparts. Within the subgroup (ancillary study), mean energy intake corresponds to requirements for age/gender group.

CONCLUSIONS

Athletic adolescents display healthier food habits than non-athletic adolescents: this result supports the idea that healthy behavior tends to cluster and suggests that prevention programs among this age group should target simultaneously both sports activity and food habits.

Selenium losses in 10 burned patients

To determine the selenium (Se) losses and balances, 10 patients with burns of 32 +/- 9% (mean +/- SD) of total body surface and aged 36 +/- 9 years were studied from D1 (first post-injury) unitl D7. Cutaneous losses were extracted from the textiles surrounding the patients. Serum and urine were collected until D20. Exudative losses of nitrogen decreased progressively (mean 8.7 +/- 3.8 g/24H). Se was detectable in wound seepage only during excision-grafting: mean operative loss was 342 +/- 191 mug. Mean urinary Se excretion was 41 +/- 13 mug/24H. Operative cutaneous losses led to some negative balances. Serum Se and glutathione peroxydase (GSHPx) were depressed until D20. Serum Se was related to N intake (p < 0.001). The decreased Se and GSHPx levels reflect a deficiency state, which measured losses did not explain, but limitations of the measurement methods prevented detection of Se cutaneous losses 100 mug/24H.

Malondialdehyde measurement in urine

Malondialdehyde (MDA) is an end product of lipid peroxidation and is a frequently measured index of these processes. The thiobarbituric acid (TBA) test is commonly used to measured MDA, but its specificity is questionable due to the presence of interfering chromogens. Wade and van Rij described in 1988 a method which removes these chromogens by HPLC. However, the sensitivity and the resolution of this method was not adequate for measurements of MDA in urine. We have improved this method by replacing TBA with diethylthiobarbituric acid (DETBA). The less polar MDA-DETBA complexes were isolated on Bakerbond cartridges and quantified by HPLC without interference. MDA was detectable using a fluorescence or ultraviolet detector at picomole levels. This technique was applied to urine samples obtained from ten burns patients on different days following their hospitalization. Urinary MDA in burns patients was very high and reached 18.6 mumol/mmol creatinine in one patient compared with a mean value of 0.23 mumol/mmol creatinine in healthy controls. Maximum MDA levels were attained on the third day for the majority of patients and remained, on average, much higher than normal even after 20 days. Using this method, picomole quantities of MDA can be easily and specifically detected in urine samples. This method is useful for assessing an oxidative stress.

The application of a fermented food ingredient containing 'variacin', a novel antimicrobial produced by Kocuria varians, to control the growth of Bacillus cereus in chilled dairy products

AIMS

The feasibility of applying variacin, a lantibiotic produced by Kocuria varians in the form of a spray-dried fermented ingredient to control the growth of psychrotrophic Bacillus cereus strains in chilled dairy foods, was evaluated.

METHODS AND RESULTS

A range of chilled dairy food formulations modelling commercially-available products were fabricated, to which were added varying amounts of active ingredient. These were subsequently challenged with a B. cereus spore cocktail over a range of abuse temperatures. This work was validated by the inclusion of the fermented ingredient to commercial products.

CONCLUSION

Results demonstrate the functionality of the bacteriocin at refrigeration abuse temperatures, and indicate the robust nature of the proteinaceous antimicrobial agent with regard to processing.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study indicates the applicability of fermented food ingredients containing naturally-occurring antimicrobials as additional hurdles in food preservation.

Relations between the selenium status and the low T3 syndrome after major trauma

OBJECTIVE

Thyroxine (T4) is deiodinated to triiodothyronine (T3) by the hepatic type I iodothyronine deiodinase, a selenoprotein that is sensitive to selenium (Se) deficiency. After severe injury, T4 deiodination is decreased, leading to the low T3 syndrome. Injury increases free radical production, which inactivates the iodothyronine deiodinase. The aims were to study the Se status after major trauma and to investigate its relation to the low T3 syndrome.

DESIGN

Preliminary prospective descriptive study.

SETTING

Intensive care unit at a university teaching hospital.

PATIENTS AND METHODS

11 patients aged 41 +/- 4 years (mean +/- SEM), with severe multiple injuries (Injury Severity Score 29 +/- 2 points). A balance study was performed from day 1 to day 7. Serum and urine samples were collected from the time of admission until day 7, then on days 10, 15, 20, 25 and 30. Non-parametric tests and Pearson's correlation coefficients were used for analysis.

RESULTS

Cumulated Se losses were 0.88 +/- 0.1 mumol/24h. Serum Se was decreased from admission to day 7. T3, free T3, and the T3/T4 ratio were low until day 5, being lowest on day 2; T4 and thyroid stimulating hormone were normal. Serum Se was correlated with T3 (r = 0.55, p = 0.0001), and with free T3 (r = 0.35).

CONCLUSION

Se status is altered after trauma, with decreased Se serum levels upon admission to the ICU but with no major Se losses. Se is probably redistributed to the tissues. The correlation between Se and T3, along with the parallel decrease in T4 deiodination, indicates that reduced deiodination might be related to the transient decrease in serum Se.

Application of lysostaphin-producing lactobacilli to control staphylococcal food poisoning in meat products

The potential of lysostaphin-producing strains of Lactobacillus curvatus (Lys+) to prevent food-borne illness by Staphylococcus aureus was investigated under practical conditions. A response surface model was developed to estimate the effect of pH, temperature, and salt concentration on the lysostaphin activity. The model was applied to fermenting sausages, and a 90% reduction of lysostaphin activity at ripening was predicted. The residual was sufficiently high to reduce staphylococcal counts by 10(4) to 10(5) CFU/g within 2 to 3 days to below the level of detection. These results were obtained in pilot scale experiments with L. curvatus (Lys+) as a starter culture and S. aureus as well as Staphylococcus carnosus as model contaminants. The applicability of L. curvatus (Lys+) as a protective culture was studied in a mayonnaise-based meat salad. Upon incubation at 25 degrees C the staphylococci were rapidly killed within 24 h, whereas in the presence of the isogenic Lys(-) strain the staphylococci grew up to numbers of 10(7) CFU/g.

Food and nutrient intakes in a group of 11 to 16 year old Swiss teenagers

Better knowledge of the dietary intake of teenagers is necessary to help health professionals to provide better advice on an individual and data for prevention and health programme. We carried out a dietary survey by 3-day records technique in a group of adolescents living in the Canton of Vaud, Switzerland. Food habits were traditional but rich in refined products and poor in plant food. Mean daily energy intake, which was 8025 kJ for the girls and 9350 kJ for boys, was lower than the recommended dietary allowances, especially for girls. Independently of the gender, breakfast represented 19% of the total daily energy intake, lunch 31% and dinner 29%. Total energy provided by snacks was 23.0% for girls and 20.4% for boys. The percentage of energy supplied by the afternoon snack was 15.8% for the girls and 13.3% for the boys. The source of energy was 14% from protein, 37% from fat and 49% from carbohydrates. A high percentage of adolescents had low micronutrient intakes (vitamins A, E, B1, B6, C, folates and for minerals magnesium, calcium and iron). An increase intake of vegetables and fruit should thus be strongly encouraged; snacking could offer a target vector to improve dietary nutritional quality.

Assessment of adolescent food habits in Switzerland

Several physical, psychological and behavioural changes may affect food habits during adolescence and have long-term consequences on adult health status. Also, as food habits are related to lifestyle and physical activity, all should be assessed together. This paper describes a self-administered food frequency questionnaire (FFQ) designed to assess semi-quantitatively food habits of adolescents, and evaluates its use in a study of lifestyle and physical activity. A FFQ was developed, tested in 20 adolescents and compared with a modified version of the diet history method (a combination of a 3-day dietary record and an interview with a dietitian). This validated semi-quantitative questionnaire was later included in a larger questionnaire on lifestyle and physical activity in a study of 3540 adolescents aged 9-19 years. In the validation study with 20 adolescents, the FFQ showed a good agreement with the modified version of the diet history. During the survey several consumption frequencies were found to be low. In the group of adolescents aged 14-19 years old, dairy products were consumed daily by less than 50% of the sample. About 53% girls but only 33% boys consumed one fruit daily. For one vegetable portion, these proportions were 17 and 8%, respectively. The self-administered food frequency questionnaire correctly describes food consumption in adolescents. Moreover, it was well accepted by the target group, easily understood and completed with very few problems. The results show that a significant proportion of adolescents didn>>t consume milk, fruit and vegetable on a daily basis.

Physical fitness and sport activity of children and adolescents: methodological aspects of a regional survey

Measurement of physical fitness and physical activity in children and adolescents raise a lot of methodological issues, explaining the scarcity of surveys in European countries and in Switzerland. This article exposes the design and the methods used in a survey on physical fitness, physical activity and health conducted in a region of Switzerland, and discuss the choice of the instruments and the quality control procedure selected to measure physical activity and physical fitness. The survey was conducted in a sample of 3540 students 9-19 years-old and included a battery of physical fitness tests, anthropometrics measurements and a self-report questionnaire on physical activity, sports activity and life styles. An ancillary study in a sub sample assessed daily physical activity with a pedometer, dietary intake with a 3-day dietary record, serum lipids and nutritional status. Some results are displayed as example. Quality control techniques are exposed and the choice of the instrument to assess physical fitness, physical activity, sports, and dietary intake are discussed. Local reference tables are now available for fitness tests and the practicability of fitness testing has been demonstrated in physical education. The research process has induced the sensitisation of schools toward health promotion through physical activity.

[Unrecognised intake of trace elements in polytraumatized and burnt patients]

Recommended trace element doses during parenteral nutrition have been revised many times and increased, especially in surgical patients. Blood products are known to provide significant amounts of trace elements under certain circumstances. In intensive care patients crystalloids and colloids are also given in large amounts. This study aimed at determining the magnitude of the unrecognized trace element administrations after major burns and/or trauma. Fifteen patients burnt 36 +/- 11% (mean +/- SD) of body surface area, aged 34 +/- 8 years, admitted to the Burns Centre and 11 trauma patients with an Injury Severity Score of 29 +/- 6 points, aged 40 +/- 13 years, admitted to the surgical Intensive Care Unit in a Swiss University Hospital. Prospective study of intakes and urinary excretion from the first post-injury day (D1) to D7. Copper and zinc were analyzed by flame atomic absorption spectrophotometry, and selenium by fluorimetry. The actual trace element administrations were much larger than those prescribed in the 3 groups of patients, and were significantly above the most recent parenteral recommended daily allowance = RDA (2.3 times RDA for copper, 5 times for selenium and zinc in Group 2, which received the largest i.v. supplements). There greatest provision of the 3 elements was by the blood products (packed red cells and frozen plasma) and by the albumin solutions (0.5 mg.L-1 Cu, 90 micrograms.L-1 Se and 2.1 mg.L-1 Zn in the 20% solutions). During the resuscitation phase, crystalloids provided a significant amount of copper (0.14 mg.L-1 NaCl 0.9%, none in dextrose) and zinc (0.3 mg.L-1 of any crystalloid), whereas selenium was not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Sports activity, physical activity and fitness of 9- to 19-year-old teenagers in the canton of Vaud (Switzerland)

BACKGROUND

The protective effects of physical activity and fitness on cardiovascular health have clearly been shown among adults and, to a lesser extent, among children and adolescents. However, data are currently lacking pertaining to children and adolescents living in Switzerland.

OBJECTIVES

To gather data on the physical fitness and physical/sports activity of children and adolescents aged 9 to 19 years.

METHODS

From September 1996 until March 1997, 3540 subjects (1778 girls, 1762 boys) from the canton of Vaud were enrolled in a multifaceted study which included a battery of 7 tests measuring different components of fitness, anthropometric measures and a self-administered questionnaire assessing physical activity, health and lifestyles.

RESULTS

Most of the respondents practise sports on a regular basis but boys engage in physical and sports activities much more often than girls: 75% of boys versus 56% of girls spent at least one hour a day in activities inducing sweating, an index of moderate to vigorous physical activity (p < 0.001). Depending on the grade, 56 to 74% of girls and 62 to 88% of boys reported participation in sports clubs (p < 0.01); current participation ranges from 33 to 46% among girls and 64 to 69% among boys (p < 0.001). Participation in physical and sports activities was lower after age 15 than before, and also lower among girls than among boys. As far as fitness is concerned, girls exhibit greater flexibility than boys, while the latter exhibit greater strength and endurance, especially after age 15. Calculated values for the BMI and VO2max are within the ranges published in the international literature for both sexes.

CONCLUSION

Programmes and strategies which aim to increase physical activities should be gender-specific and should especially target adolescents aged over 15. Physical/sports activities and fitness could and should be monitored using both a battery of tests and self-administered questionnaires.