OBJECTIVES:Within the global context of the nutrition and physical activity transition it is important to determine the relationship between adiposity and active school transport (AST) across different environmental and socio-cultural settings. The present study assessed the association between adiposity (that is, body mass index z-score (BMIz), obesity, percentage body fat (PBF), waist circumference) and AST in 12 country sites, in the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE). METHODS: The analytical sample included 6797 children aged 9-11 years. Adiposity indicators included, BMIz calculated using reference data from the World Health Organization, obesity (BMIz ⩾ +2 s.d.), PBF measured using bioelectrical impedance and waist circumference. School travel mode was assessed by questionnaire and categorized as active travel versus motorized travel. Multilevel linear and non-linear models were used to estimate the magnitude of the associations between adiposity indicators and AST by country site and sex. RESULTS: After adjusting for age, sex, parental education and motorized vehicle availability, children who reported AST were less likely to be obese (odds ratio = 0.72, 95% confidence interval (0.60-0.87), P o0.001) and had a lower BMIz (−0.09, s.e.m. = 0.04, P = 0.013), PBF (least square means (LSM) 20.57 versus 21.23% difference − 0.66, s.e.m. = 0.22, P = 0.002) and waist circumference (LSM 63.73 cm versus 64.63 cm difference − 0.90, s.e.m. = 0.26, P = 0.001) compared with those who reported motorized travel. Overall, associations between obesity and AST did not differ by country (P = 0.279) or by sex (P = 0.571). CONCLUSIONS: AST was associated with lower measures of adiposity in this multinational sample of children. Such findings could inform global efforts to prevent obesity among school-age children.

SummaryBackground: No studies have examined if mid-upper arm circumference (MUAC) can be an alternative screening tool for obesity in an international sample of children differing widely in levels of human development.

Resting metabolic rate (RMR) and total daily energy expenditure (TDEE) were measured on a sample of 47 adults (35 males, 12 females) from two indigenous Siberian populations, the Evenki and Keto. The Douglas bag method of indirect calorimetry was used to measure the energy cost of lying, sitting, standing, and three exercise levels of the Canadian aerobic test of fitness (step test). The flex-heart rate method of heart rate monitoring (flex-HR; Spurr et al. [19881, Am. J. Clin. Nutr. 48:552-559) was utilized to predict TDEE from the measured energy costs. Measured RMR was 6.66 kJ/min (1.59 kcal/min) for males and 5.19 kJ/min (1.24 kcaymin) for the females. Subjects living in the bush in brigade work parties had significantly higher RMRs than those residing in the villages. Comparison of RMR to selected populations suggests that the elevated metabolism of the subjects living in the brigades is due to short-term environmental acclimatization to the ambient conditions of the taiga rather than long-term adaptation to living in a northern climate. TDEE was estimated at 11.8 2 3.0 MJ (2,815 kcal) for men and 8.6 ? 1.9 MJ (2,056 kcal) for women, and there were no brigade-town differences in DEE. Based on their physical activity level (PAL = TDEE: basal metabolic rate [TDEE:BMRI), which was 1.77 for males and 1.59 for females, the Evenki and The measurement of energy expenditure (EE) under free-living conditions is a central part of much research in human ecology and adaptability. Yet accurate estimates of total daily energy expenditure (TDEE) have traditionally been difficult to obtain on anthropological populations due to methodological constraints. To date, the most commonly used anthropological technique has been the factorial method (Dufour, 1984;Galvin, 1985;Hill et al., 1984;Montgomery and Johnson, 1977;Thomas, 1973). This technique estimates EE by monitoring activity patterns through direct observation, recall, or diaries. Once a time allocation profile is obtained, the time spent in each activity is then multiplied by the average energy cost for that activity to determine total EE. The energy costs are either measured by indirect calorimetry or are obtained from published sources (e.g., Durnin and Passmore, 1967;Passmore and Durnin, 1955). Although popular, the factorial method suffers from high researcher burden, disruption of habitual activity patterns, and often uses standard energy cost tables which may result in limited accuracy of the estimates.Recently, a number of new techniques have emerged for assessing EE under field conditions. The most accurate appears to be the doubly labelled water method, which involves orally enriching the body water of a subject with isotopically labelled water (2H,180). EE is estimated from CO, produc-

OBJECTIVE: To compare Canadians of Aboriginal (First Nation, FN) and European ancestry (EA), with respect to obesity, subcutaneous fatness and relative subcutaneous fat distribution. DESIGN: Cross-sectional comparison. SUBJECTS: 118 First Nation and 472 European ancestry Canadians from Northern Ontario, youth (5 ± 19 y) and adults (20 ± 75 y). MEASUREMENTS: Stature, mass and skinfold thicknesses at the triceps, biceps, medial calf, subscapular, suprailiac and abdominal sites. ANALYSIS: Prevalence of obesity was determined using the 85 th percentile of body mass index (BMI) from NHANES II as the cut-off. Principal components (PC) analyses were performed on the six skinfolds. The ®rst component (PC1) represented a trunk-extremity skinfold contrast. Differences in mean component scores between FN and EA were assessed using independent samples t-tests. RESULTS: Prevalence of obesity among FN was high, ranging from 29% in youth to 60% in adult females. FN demonstrated greater subcutaneous adiposity and greater values for PC1, with the exception of adult males, where the difference is in the expected direction, but is not signi®cant. The direction of the differences indicates that the FN have a greater centralization of subcutaneous fat. CONCLUSIONS: FN Canadians generally have a greater prevalence of obesity, greater subcutaneous fatness and a more centralized distribution of body fat than those of European ancestry.

OBJECTIVE: To examine the growth status, prevalence of risk of overweight and of overweight, and secular changes in growth status in Navajo youth from 1955 to 1997. SUBJECTS: 526 (256 males, 270 females) Navajo children 6 ± 12 y of age. MEASUREMENTS: Stature and mass were measured and the body mass index (BMI) was calculated. ANALYSIS: All three variables were plotted relative to age-and sex-speci®c US reference data and the prevalence rates for risk of overweight and of overweight were estimated using the BMI as the criterion. The cut-off for the risk of overweight was the age-and sex-speci®c 85th and 95th percentiles of NHANES I, while the cut-off for overweight was a BMI 95th percentiles. Age-speci®c sex differences were compared using independent samples t-tests. Secular changes for body size were estimated by comparing age-and sex-speci®c means for stature, mass, and the BMI in the present study and two previous studies in 1955 and 1989. RESULTS: No statistically signi®cant differences were observed between sexes within age groups. In both sexes, mean age-speci®c stature appeared to be relatively stable around the 50th percentile of US reference values. Mean age-speci®c mass appeared to be relatively stable between the 50th and 90th percentiles of the reference values, while the mean BMI tended to¯uctuate about the 85th percentile. Approximately 41% of the Navajo boys and girls 6 ± 12 y of age had BMIs 85th percentiles of US reference data. Compared to corresponding data on Navajo youth in 1955 and 1989, the current sample was larger in mass and the BMI. The estimated rate of secular change in mass was about 1.5 kgadecade in younger boys and girls, and about 3 kgadecade in older boys and girls between 1955 and 1997. The estimated rate of secular change in the BMI was about 0.5 ± 1.0 unitsadecade between 1955 and 1997, while that for stature was about 2 cmadecade between 1955 and 1997. CONCLUSIONS: The results are consistent with recent ®ndings on the Navajo Health and Nutrition Survey that overweight is a serious public health concern across the lifespan in the Navajo, and that the problem begins in childhood. Furthermore, Navajo children appear to be heavier than about a decade ago.

No abstract

This study examines physical growth and nutritional status in a sample of 478 (247 males; 231 females) Evenki herders of Central Siberia. The Evenki display slow growth in stature and body weight, particularly during late childhood and adolescence. Adult males fall below the U.S. 5th percentiles for both stature and body weight. Adult females are below the 5th percentile for stature and approximate the 15th percentile for weight. Despite their diminutive size, the Evenki appear to have adequate energy reserves, as indicated by their skinfold measurements, which range between the U.S. 15th and 50th percentiles. Among adults, women are relatively heavier and fatter than men and tend to increase in weight and fatness with age. Poor growth in the Evenki does not appear to be directly attributable to limited food availability. Rather, it is hypothesized that elevated metabolic requirements, associated with adaptation to a high latitude ecosystem, are responsible for limiting the amount of energy that is allocated to growth. Relatively high levels of adiposity in adult females appear to be the product of changes in activity patterns and fertility levels that resulted after the collectivization of the Evenki. © 1994 Wiley-Liss, Inc.

These variables extend the potential of field-based 24-h waist-worn accelerometry to distinguish and categorize the underlying robust patterns of movement/non-movement signals conveying magnitude, duration, frequency and periodicity during the nocturnal sleep period.