Vigorous physical activity and longitudinal associations with cardiometabolic risk factors in youth.

OBJECTIVE: To examine the longitudinal associations between different physical activity (PA) intensities and cardiometabolic risk factors among a sample of Canadian youth. METHODS: The findings are based on a 2-year prospective cohort study in a convenience sample of 315 youth aged 9-15 years at baseline from rural and urban schools in Alberta, Canada. Different intensities (light, moderate and vigorous) of PA were objectively assessed with Actical accelerometers. The main outcome measures were body mass index (BMI) z-score, waist circumference, cardiorespiratory fitness and systolic blood pressure at 2-year-follow-up and conditional BMI z-score velocity. A series of linear regression models were conducted to investigate the associations after adjusting for potential confounders. RESULTS: At follow-up, cardiorespiratory fitness increased (quartile 1 vs quartile 4=43.3 vs 50.2; P(trend)<0.01) and waist circumference decreased (quartile 1 vs quartile 4=79.0 vs 72.6; P(trend)=0.04; boys only) in a dose-response manner across quartiles of baseline vigorous-intensity PA. A similar trend was observed for systolic blood pressure (quartile 1 vs quartile 4=121.8 vs 115.3; P(trend)=0.07; boys only). Compared with quartile 1 of vigorous-intensity PA, BMI z-score at follow-up and conditional BMI z-score velocity were significantly lower in the quartile 2 and 3 (P<0.05). Waist circumference at follow-up also decreased (quartile 1 vs quartile 4=75.3 vs 73.8; P(trend)=0.04) across quartiles of baseline moderate-intensity PA. CONCLUSIONS: Time spent in vigorous-intensity PA was associated with several positive health outcomes 2 years later. These findings suggest that high-intensity activities in youth help to reduce the risk for several chronic diseases.

Reliability and validity of Web-SPAN, a web-based method for assessing weight status, diet and physical activity in youth.

BACKGROUND: Web-based surveys are becoming increasing popular. The present study aimed to assess the reliability and validity of the Web-Survey of Physical Activity and Nutrition (Web-SPAN) for self-report of height and weight, diet and physical activity by youth. METHODS: School children aged 11-15years (grades 7-9; n=459) participated in the school-based research (boys, n=225; girls, n=233; mean age, 12.8years). Students completed Web-SPAN (self-administered) twice and participated in on-site school assessments [height, weight, 3-day food/pedometer record, Physical Activity Questionnaire for Older Children (PAQ-C), shuttle run]. Intraclass (ICC) and Pearson's correlation coefficients and paired samples t-tests were used to assess the test-retest reliability of Web-SPAN and to compare Web-SPAN with the on-site assessments. RESULTS: Test-retest reliability for height (ICC=0.90), weight (ICC=0.98) and the PAQ-C (ICC=0.79) were highly correlated, whereas correlations for nutrients were not as strong (ICC=0.37-0.64). There were no differences between Web-SPAN times 1 and 2 for height and weight, although there were differences for the PAQ-C and most nutrients. Web-SPAN was strongly correlated with the on-site assessments, including height (ICC=0.88), weight (ICC=0.93) and the PAQ-C (ICC=0.70). Mean differences for height and the PAQ-C were not significant, whereas mean differences for weight were significant resulting in an underestimation of being overweight/obesity prevalence (84% agreement). Correlations for nutrients were in the range 0.24-0.40; mean differences were small but generally significantly different. Correlations were weak between the web-based PAQ-C and 3-day pedometer record (r=0.28) and 20-m shuttle run (r=0.28). CONCLUSIONS: Web-SPAN is a time- and cost-effective method that can be used to assess the diet and physical activity status of youth in large cross-sectional studies and to assess group trends (weight status).

Improved cardiovascular health following a progressive walking and dietary intervention for type 2 diabetes.

AIM: To examine the impact of two different lifestyle programmes on cardiovascular health and glycaemic control among people with type 2 diabetes. METHODS: A two-phase 24-week randomized trial. During the first phase, participants were to increase daily steps using a pedometer. At week 12, participants were randomly allocated to either an enhanced lifestyle programme (ELP) targeting walking speed or a basic lifestyle programme (BLP) targeting total daily steps. Both programmes focused on increasing the intake of low glycaemic index foods but utilized different goal setting strategies. Clinical measurements were completed at baseline, week 12 and week 24. Principal outcomes were change in resting pulse rate (PR) and glycated haemoglobin A1c (A1c) between week 12 and week 24 compared between groups using analysis of covariance. RESULTS: Forty-one participants [mean +/- s.d. : age = 56.5 +/- 7.2 years, body mass index (BMI) = 32.7 +/- 6.1 kg/m(2)] were randomized. After 12 weeks, we observed an increase in average total daily steps of 1688 (95% confidence interval: 330-3040, [corrected] p = 0.02). Weight, BMI and systolic and diastolic blood pressure improved (p < 0.01 for all). No changes were observed for energy intake. At week 24, those in the ELP had a lower resting PR (71 +/- 12 b.p.m.) compared with those in the BLP (78 +/- 12 b.p.m.) (adjusted p = 0.03), while no group differences for total daily steps or glycaemic control were observed. CONCLUSIONS: Improvements in cardiovascular health can be expected following a pedometer-based lifestyle modification programme that progresses from walking more to walking faster.

Dietary carbohydrate-to-fat ratio: influence on whole-body nitrogen retention, substrate utilization, and hormone response in healthy male subjects.

The effect of a high-carbohydrate and a high-fat diet on nitrogen retention, substrate utilization, and serum hormone concentrations was assessed in six healthy male subjects. Both diets were fed at a level estimated to provide maintenance and 75% maintenance energy requirements. Urine and feces were collected and analyzed for N and energy content. Anthropometric measurements; fasting and postprandial oxygen consumption; and serum levels of glucose, triglycerides, and metabolic hormones were measured. The high-fat diet increased N retention at both energy levels with significance reached at maintenance energy intakes (p less than 0.05). The high-fat diet resulted in less weight loss (p less than 0.05) at low energy and a consistently lower respiratory quotient (p less than 0.05), indicative of increased fat oxidation. The N sparing effect of the high-fat diet did not appear to be explained by hormone levels observed but may be substrate mediated.

Metabolic assessment of female chronic dieters with either normal or low resting energy expenditures.

BACKGROUND: Chronic dieting syndrome can have negative physiologic and psychological consequences. Metabolic differences between female chronic dieters with normal and with low resting energy expenditures (REEs) have not been fully examined. OBJECTIVE: To determine whether differences existed between 2 groups (n = 15/group) of female chronic dieters aged 21-49 y with either normal (>/=100% of predicted) and with low (

Short-term changes in energy intake and serum insulin, neutral amino acids, and urinary catecholamine excretion in women.

The effect of short-term undereating (4.2 MJ [1000 kcal] for 4 d) followed by overeating (12.6 MJ [3000 kcal] for 2 d) on fasting and 2-h postprandial serum glucose, insulin, and neutral amino acids and on urinary free and total norepinephrine and dopamine excretion was studied in 12 normal women. Protein and sodium intake was constant throughout the study. Serum glucose concentration was not affected by diet but the serum total neutral amino acids (ie, sum of valine, leucine, isoleucine, and phenylalanine) tended to increase during undereating and decrease during overeating. Serum tryptophan concentration, relative to the remaining neutral amino acids, was consequently lower during undereating than overeating. The postprandial increase in serum insulin level was greater during overeating than undereating. Urinary free norepinephrine and total dopamine levels were also increased during overeating, suggesting both sympathetic and dopaminergic activation during overeating after undereating.

Changes in body composition and fat distribution after short-term weight gain in patients with anorexia nervosa.

The most commonly described psychologic abnormality associated with anorexia nervosa is a distorted perception of body weight and shape. This perception may contribute to the anorexic patient's resistance to gaining weight even when it is a medical necessity. The purpose of this study was to assess body-composition and fat-distribution changes after short-term weight gain in 26 female anorexia nervosa patients 27.6 +/- 6.6 (mean +/- SD) y of age, with a body mass index (BMI; in kg/m2) of 16.5 +/- 1.9. They participated in a refeeding protocol both as inpatients (n = 21) and as outpatients (n = 5) until they achieved maximum weight gain. Body-composition and fat-distribution changes were measured by using dual-energy X-ray absorptiometry (DXA) and skinfold thickness and circumference measurements. A mean weight gain of 6.7 +/- 5.3 kg (P < 0.001) was observed, which included significant increases in body fat (P < 0.001), lean body mass (P < 0.05), and bone mineral content (P < 0.01), with body fat being the component that increased the most. When measured by DXA, fat gain was not significantly different among the three central regions: subscapular, 1.7 +/- 1.2 kg; waist, 1.8 +/- 1.3 kg; and thigh, 1.5 +/- 1.0 kg (P = 0.10). Thus, although fat was the largest component of the weight gained, there was no preferential fat deposition in any one area and the female gynoid body shape was maintained.

Accuracy of subcutaneous fat measurement: comparison of skinfold calipers, ultrasound, and computed tomography.

OBJECTIVE: The purpose of this study was to compare skinfold caliper and ultrasound measurement of subcutaneous body fat at three abdominal sites with computed tomography, which is considered to be the gold standard. DESIGN: This was a cross-sectional study in which computed-tomography, ultrasound, and skinfold caliper measurements were made at three distinct abdominal sites. All body composition and anthropometric measurements were performed on each subject on one occasion. SUBJECTS: Twenty-two subjects were recruited (13 men and 9 women). Mean ages (+/- standard deviation) were 43 +/- 4 years for the women and 51 +/- 18 years for the men. All subjects had been previously scheduled for an abdominal or pelvic computed-tomography scan at the Department of Radiology, St Paul's Hospital, Vancouver, British Columbia, Canada, and participated in the study on a volunteer basis. MAIN OUTCOME MEASURES: A better agreement was found between the skinfold calipers and computed-tomography methods than between the ultrasound and computed-tomography method for the measurement of subcutaneous body fat. This was observed when the data were analyzed for both correlational agreement and for graphical interpretation. STATISTICAL ANALYSES PERFORMED: The relationships among skinfold, ultrasound, and computed-tomography measurements were analyzed by determining Pearson correlation coefficients. A graphical method described by Bland and Altman was also used to assess agreement among the three methods. RESULTS: Significant correlation coefficients were observed between skinfold calipers and computed tomography at all three abdominal sites (site 1, r = .60, P = .003; site 2, r = .70, P = .0001; site 3, r = .73, P = .0001). Ultrasound and computed-tomography methods only showed a significant correlation at site 3 (r = .54; P = .009). The graphical method revealed that the variation in the ultrasound measurements was much greater than that of the skinfold measurements when compared to computed-tomography values. APPLICATIONS/CONCLUSIONS: The results of this study indicated that relative agreement in the measurement of subcutaneous body fat between skinfold and computed-tomography measurements was superior to that exhibited between ultrasound and computed-tomography measurements. This finding enhances the potential use of skinfold calipers in the clinical setting, particularly in view of the fact that measurement of subcutaneous body fat at different body sites is becoming increasingly important for the characterization of risk of certain disease states.

Effectiveness of two training methods to improve the quality of foodservice in small facilities for adult care.

OBJECTIVE: Community-based adult-care facilities (ACFs) with fewer than 25 beds provide homes for persons with disabilities who cannot live independently. The staff in these facilities are not required to have any formal foodservice training, yet they provide meals for the residents. The objective of this study was to evaluate the quality of foodservices before and after a foodservice training program. DESIGN: Forty-six ACFs from six health-unit areas throughout the province of British Columbia were enrolled in the study, which involved a pretest-posttest design over a 5-month period. The health units were randomly assigned to one of three programs. INTERVENTION: The ACFs received either a training workshop plus foodservice manual developed specifically for ACFs, the manual only, or no intervention. MAIN OUTCOME MEASURES: Facilities were audited on performance in food purchasing, menu planning, food safety, and food storage. These areas were rated according to established minimum government regulations and other foodservice standards. Differences between the two audit scores (postintervention score minus preintervention score) were analyzed for each program section. Group comparisons were done using analysis of covariance procedures, with the initial score being the covariable. RESULTS: No treatment effect was found on performance for food purchasing and food storage. Training via workshop plus manual resulted in a significant improvement in audit scores for menu planning and food safety compared with training via the manual alone. APPLICATION: Dietitians should consider providing foodservice training workshops for similar types of facilities. The benefits of providing a manual alone are negligible.

Metabolic and anthropometric changes in female weight cyclers and controls over a 1-year period.

OBJECTIVE: Women who diet to lose weight often regain the weight over time, and the cycle repeats itself. The objective of this study was to identify a group of female weight cyclers and to match them with a control group who had never consciously tried to lose weight. For 1 year, weight patterns, eating habits, metabolic parameters, and body composition were assessed to determine whether there was a relationship between weight cycling and these variables. DESIGN: Measurements were done at baseline and at 6 and 12 months. Changes in weight, diet, and exercise were monitored throughout the year. SETTING: All testing was done at a university physiology laboratory. SUBJECTS/SAMPLES: Nine weight cyclers with a notable history of dieting and food restriction were recruited. Subsequently, nine control subjects were selected and matched for age, height, weight, lean body mass, and exercise habits. MAIN OUTCOME MEASURE: The observational study included measures of 3-day diet records, skinfold and girth, serum glucose, insulin and triiodothyronine, and resting energy expenditure. STATISTICAL ANALYSES PERFORMED: The main variables were analyzed using a 2 x 3 (diet group x time) analysis of variance with repeated measures on the time factor. Comparison of the means was done by Tukey post hoc test. RESULTS: A 7-point satisfaction scale indicated that the weight cyclers were dissatisfied with their weight compared with the noncyclers (P = .03). Otherwise, there were no differences between groups in dietary intakes or the physiologic variables. APPLICATIONS/CONCLUSIONS: In the parameters measured, a history of weight cycling did not affect the metabolic profiles of the weight cyclers compared with the noncyclers.

Energy balance in women with breast cancer during adjuvant treatment.

OBJECTIVE: To compare weight, body composition, and major determinants of energy balance of women treated with adjuvant chemotherapy (n = 8) using Adriamycin and cyclophosphamide (AC), or radiation therapy (n = 10). DESIGN: The study used a nonrandomized prospective design. Pretreatment and posttreatment measurements, obtained at baseline and 12 weeks, respectively, included weight, body composition (determined using dual-energy x-ray absorptiometry), energy intake (determined using 3-day food records), resting energy expenditure (determined in indirect calorimetry), and physical activity (determined using 3-day physical activity records). Poststudy follow-up weights were obtained for 13 women. SUBJECTS/SETTING: Eighteen premenopausal women with breast cancer in the early stage, recruited from outpatient clinics, participated in and completed the study. STATISTICAL ANALYSES PERFORMED: Unpaired Student t tests or X2 tests were used to test for differences in baseline subject characteristics, and repeated measures analysis of variance was used to compare groups before and after treatment. RESULTS: Body weight was unchanged in both treatment groups during the study, although poststudy follow-up weights (n = 13) suggested a tendency for weight gain in both groups. Significant changes in body composition for both groups included a mean loss of 0.8 kg total lean body mass (LBM), a mean loss of 0.4 kg LBM in the leg region, and a mean 1.3% increase in percent body fat, from 40.0% to 41.3%. Overall, no between-group differences were observed in any factors associated with energy balance. APPLICATIONS: In this short-term study, AC chemotherapy using fewer antineoplastic agents and number of treatments than most chemotherapy protocols for breast cancer, did not result in weight gain during treatment. Regardless of weight gain, changes in body composition may occur in women with breast cancer during or after treatment. These potential changes have important implications for preventive nutrition counseling.

Metabolic and anthropometric changes with weight cycling in wrestlers.

Repeated cycles of weight loss and regain have come to be known as weight cycling. This phenomenon is frequently observed in athletes who must meet specific weight categories to qualify for competition. The purpose of this study was to determine the metabolic and anthropometric changes that occur with rapid weight loss/regain cycles in competitive wrestlers. Collegiate wrestlers were divided into two groups, "cyclers" (N = 8) and "noncyclers" (N = 6), based on their reported dieting history. Measurements included a 3-d diet record, resting energy expenditure (REE), skinfold and girth measures, and biochemical tests at three time points: preseason, peak season, and off-season. All anthropometric measures changed with time, and a diet group by time interaction was observed for the trunk to extremity skinfolds ratio (T/E) (P < 0.05), with greater fat loss and regain from the trunk area of the cyclers. There were no differences in REE within or between groups. Serum triiodothyronine (T3) values decreased over time (P < 0.01). Large weight losses appear to have occurred due to both dieting and short-term dehydration, and although physiological changes were observed, a training effect may have overridden any metabolic influence of weight cycling.

Benefits of exercise training for men with insulin-dependent diabetes mellitus.

Twelve healthy men with IDDM participated in a 12-week walking/jogging exercise program. Pre- and postexercise assessment of dietary intakes, body composition, biochemical measures, and exercise performance indicators were completed. Subjects exercised either 3 or 5 days per week for 1 hour at 60% to 80% of estimated maximal heart rate. Dietary intakes showed a voluntary reduction in fat intake as a percent of total energy from 40% +/- 7% (mean +/- SD) to 37% +/- 8% (P = .053). No change occurred over time in body composition measures except for a significant reduction in the waist-to-hip ratio from 0.87 +/- 0.04 to 0.86 +/- 0.04 (P = .007). Fasting serum glucose and lipid levels did not change over time. Exercise capacity improved, as shown by an increased time to exhaustion on a treadmill run from 7.9 +/- 3.7 minutes to 9.7 +/- 3.8 minutes (P less than .001); and a lower heart rate at a constant work load--from 183 +/- 18 beats per minute preexercise to 175 +/- 20 beats per minute postexercise (P = .022). The study showed that healthy male subjects with IDDM can benefit from regular exercise with a redistribution of body fat and improved exercise capacity.

The in-vitro porcine adhesion model is not predictive of the esophageal transit of risedronate tablets in humans.

Mucosal damage due to esophageal adhesion of pharmaceuticals is a continued concern to both health care providers and drug manufacturers. As a result of this concern, dosage forms are now being designed to exhibit minimal esophageal adhesion. Previous researchers have used an in-vitro porcine esophageal model to determine the propensity for formulations to adhere to the esophagus as an alternative to human scintigraphy studies. This study used a porcine esophageal adhesion model similar to that used previously to determine the adhesiveness of placebo bisphosphonate formulations. Results are analogous to those obtained by previous researchers, with film-coated tablets showing greater adhesiveness than uncoated tablets. These same tablet formulations were also evaluated previously by a human scintigraphy study, and the results were exactly opposite of those obtained using the in-vitro porcine model. In the human scintigraphy study, the film-coated placebo risedronate tablet had a faster transit time than an uncoated round placebo tablet. In conclusion, the in-vitro porcine esophageal model is not predictive of esophageal transit in man and gamma scintigraphy is the preferred method to evaluate esophageal transit.

Physiological effects of bulimia nervosa on the gastrointestinal tract.

Bulimia nervosa is an eating disorder characterized by frequent bouts of binge eating accompanied by compensatory behaviour for preventing weight gain (purging). It is estimated that 3% to 5% of young women are affected by bulimia nervosa, and its prevalence is increasing. Bulimia nervosa afflicts both sexes and all races. It can lead to serious medical complications. The expression of the disease in the gastrointestinal tract may have a critical role in the diagnosis of bulimia nervosa. Physiological effects of bulimia nervosa on the gastrointestinal tract include dental caries and enamel erosion; enlargement of the parotid gland; esophagitis; changes in gastric capacity and gastric emptying; gastric necrosis; and alterations of the intestinal mucosa. Identification of any of these factors may aid in establishing an early diagnosis, which has been shown to increase the likelihood of recovery.

Effectiveness of a group psychoeducation program for the treatment of subclinical disordered eating in women with type 1 diabetes.

The coexistence of type 1 diabetes mellitus and disordered eating is associated with poor metabolic control, poor adherence to diabetes treatment regimens, and increased risk of long-term diabetic complications. This study assessed whether a six-session group psychoeducation program would improve metabolic control, diabetes treatment adherence, eating disorder symptomatology, and general psychopathology in women with coexisting type 1 diabetes and subclinical disordered eating. Fourteen women were assigned to the treatment group (n=8) or wait-list control group (n=6). Measurements were taken at baseline, post-intervention, and one month post-intervention. There were no significant differences in how the treatment group and wait-list control group changed over time. Between the first and second measurements, both groups demonstrated significant improvements in depression and general emotional distress. The results suggest that a six-session group psychoeducation program is no more effective than a wait-list control group for treating subclinical disordered eating in women with type 1 diabetes. Further research is required to determine the most effective treatment for this population.

Infant body composition in the PEA POD® era: what have we learned and where do we go from here?

The availability of clinically feasible infant body composition assessment can inform current questions regarding the developmental origins of chronic disease. A strategic approach will facilitate more rapid advancement in knowledge. The objective of this study was to summarize published evidence and ongoing research activity in infant body composition using the PEA POD® infant body composition system. All published studies using the PEA POD® were identified and grouped according to study population and question. All centers with PEA POD® units were invited to participate in an online survey regarding past, current and future PEA POD® use, and results were analyzed using descriptive statistics. The resulting information was used to identify gaps or limitations in existing knowledge, thus highlighting potential research priorities. Twenty-seven published articles were identified and grouped into six research themes. Although the number of infants studied is significant in some areas, interpretation of data is limited by methodological differences. Survey responses were received from 16 of ∼60 centers. Research themes echoed those identified from the published literature. Controlling for or reporting potential confounding variables is essential for understanding infant body composition data. Measurement of health outcome variables would be helpful in identifying associations.

Early markers of adult obesity: a review.

The purpose of this review was to evaluate factors in early childhood (≤5 years of age) that are the most significant predictors of the development of obesity in adulthood. Factors of interest included exposures/insults in the prenatal period, infancy and early childhood, as well as other socio-demographic variables such as socioeconomic status (SES) or birth place that could impact all three time periods. An extensive electronic and systematic search initially resulted in 8,880 citations, after duplicates were removed. Specific inclusion and exclusion criteria were set, and following two screening processes, 135 studies were retained for detailed abstraction and analysis. A total of 42 variables were associated with obesity in adulthood; however, of these, only seven variables may be considered as potential early markers of obesity based on the reported associations. Possible early markers of obesity included maternal smoking and maternal weight gain during pregnancy. Probable early markers of obesity included maternal body mass index, childhood growth patterns (early rapid growth and early adiposity rebound), childhood obesity and father's employment (a proxy measure for SES in many studies). Health promotion programmes/agencies should consider these factors as reasonable targets to reduce the risk of adult obesity.

Weight gain in breast cancer survivors: prevalence, pattern and health consequences.

Weight gain is a common and persistent problem for many breast cancer survivors and is associated with adverse health consequences. A comprehensive review of the English language literature was conducted to investigate the frequency, magnitude and pattern of weight gain among breast cancer survivors, to identify factors that are associated with these changes and to review the clinical significance of weight gain on disease free survival and overall health. While there appears to be a general trend toward a reduction in the magnitude of weight gain in recent years, as many as 50-96% of women experience weight gain during treatment and many, including some women who remain weight stable during treatment, report progressive weight gain in the months and years after diagnosis. Weight gain is more common in women receiving adjuvant chemotherapy, especially for women receiving longer duration treatments and seems to be especially pronounced in premenopausal women. With or without weight gain, unfavourable changes in body composition including fat gain and loss of lean tissue are prevalent. This unique pattern of weight gain and change in body composition is distressing for most women, poses significant risk for the development of co-morbid conditions and may impact on long term disease-free survival.