British South Asian children have lower objectively measured physical activity levels than European whites and black African-Caribbeans.

Peter Whincup and colleagues carry out a cross-sectional study examining ethnic differences in precursors of of type 2 diabetes among children aged 9–10 living in three UK cities.

Background The objective of this study was to examine adiposity patterns in UK South Asian, black African–Caribbean and white European children using a range of adiposity markers. A cross-sectional survey in London, Birmingham and Leicester primary schools was conducted. Weight, height, waist circumference, skinfold thickness values (biceps, triceps, subscapular and suprailiac) were measured. Fat mass was derived from bioimpedance; optimally height-standardized indices were derived for all adiposity markers. Ethnic origin was based on parental self-report. Multilevel models were used to obtain adjusted means and ethnic differences adjusted for gender, age, month, observer and school (fitted as a random effect). A total of 5887 children aged 9–10 years participated (response rate 68%), including 1345 white Europeans, 1523 South Asians and 1570 black African–Caribbeans.Results Compared with white Europeans, South Asians had a higher sum of all skinfolds and fat mass percentage, and their body mass index (BMI) was lower. South Asians were slightly shorter but use of optimally height-standardized indices did not materially affect these comparisons. At any given fat mass, BMI was lower in South Asians than white Europeans. In similar comparisons, black African–Caribbeans had a lower sum of all skinfolds but a higher fat mass percentage, and their BMI was higher. Black African–Caribbeans were markedly taller. Use of optimally height-standardized indices yielded markedly different findings; sum of skinfolds index was markedly lower, whereas fat mass index and weight-for-height index were similar. At any given fat mass, BMI was similar in black African–Caribbeans and white Europeans.Conclusions UK South Asian children have higher adiposity levels and black African–Caribbeans have similar or lower adiposity levels when compared with white Europeans. However, these differences are not well represented by comparisons based on BMI, which systematically underestimates adiposity in South Asians, and in black African–Caribbeans it overestimates adiposity because of its association with height.

Background: Levels of physical activity and variation in physical activity and sedentary time by place and person in European children and adolescents are largely unknown. The objective of the study was to assess the variations in objectively measured physical activity and sedentary time in children and adolescents across Europe. Methods: Six databases were systematically searched to identify pan-European and national data sets on physical activity and sedentary time assessed by the same accelerometer in children (2 to 9.9 years) and adolescents (≥10 to 18 years). We harmonized individual-level data by reprocessing hip-worn raw accelerometer data files from 30 different studies conducted between 1997 and 2014, representing 47,497 individuals (2-18 years) from 18 different European countries. Results: Overall, a maximum of 29% (95% CI: 25, 33) of children and 29% (95% CI: 25, 32) of adolescents were categorized as sufficiently physically active. We observed substantial country-and region-specific differences in physical activity and sedentary time, with lower physical activity levels and prevalence estimates in Southern European countries. Boys were more active and less sedentary in all age-categories. The onset of age-related lowering or leveling-off of physical activity and increase in sedentary time seems to become apparent at around 6 to 7 years of age.

Aims/hypothesisPhysical inactivity is implicated in unfavourable patterns of obesity and cardiometabolic risk in childhood. However, few studies have quantified these associations using objective physical activity measurements in children from different ethnic groups. We examined these associations in UK children of South Asian, black African-Caribbean and white European origin.MethodsThis was a cross-sectional study of 2,049 primary school children in three UK cities, who had standardised anthropometric measurements, provided fasting blood samples and wore activity monitors for up to 7 days. Data were analysed using multilevel linear regression and allowing for measurement error.ResultsOverall physical activity levels showed strong inverse graded associations with adiposity markers (particularly sum of skinfold thicknesses), fasting insulin, HOMA insulin resistance, triacylglycerol and C-reactive protein; for an increase of 100 counts of physical activity per min of registered time, levels of these factors were 12.2% (95% CI 10.2–14.1%), 10.2% (95% CI 7.5–12.8%), 10.2% (95% CI 7.5–12.8%), 5.8% (95% CI 4.0–7.5%) and 19.2% (95% CI 13.9–24.2%) lower, respectively. Similar increments in physical activity levels were associated with lower diastolic blood pressure (1.0 mmHg, 95% CI 0.6–1.5 mmHg) and LDL-cholesterol (0.04 mmol/l, 95% CI 0.01–0.07 mmol/l), and higher HDL-cholesterol (0.02 mmol/l, 95% CI 0.01–0.04 mmol/l). Moreover, associations were broadly similar in strength in all ethnic groups. All associations between physical activity and cardiometabolic risk factors were reduced (albeit variably) after adjustment for adiposity.Conclusions/interpretationObjectively measured physical activity correlates at least as well with obesity and cardiometabolic risk factors in South Asian and African-Caribbean children as in white European children, suggesting that efforts to increase activity levels in such groups would have equally beneficial effects.

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In the UK, South Asian adults have increased risks of CHD, type 2 diabetes and central obesity. Black African-Caribbeans, in contrast, have increased risks of type 2 diabetes and general obesity but lower CHD risk. There is growing evidence that these risk differences emerge in early life and that nutritional factors may be important. We have therefore examined the variations in nutritional composition of the diets of South Asian, black African-Caribbean and white European children, using 24 h recalls of dietary intake collected during a cross-sectional survey of cardiovascular health in eighty-five primary schools in London, Birmingham and Leicester. In all, 2209 children aged 9-10 years took part, including 558 of South Asian, 560 of black African-Caribbean and 543 of white European ethnicity. Compared with white Europeans, South Asian children reported higher mean total energy intake; their intakes of total fat, polyunsaturated fat and protein (both absolute and as proportions of total energy intake) were higher and their intakes of carbohydrate as a proportion of energy (particularly sugars), vitamin C and D, Ca and haem Fe were lower. These differences were especially marked for Bangladeshi children. Black African-Caribbean children had lower intakes of total and saturated fat (both absolute and as proportions of energy intake), NSP, vitamin D and Ca. The lower total and saturated fat intakes were particularly marked among black African children. Appreciable ethnic differences exist in the nutritional composition of children's diets, which may contribute to future differences in chronic disease risk. KeywordsEthnicity; South Asian children; African-Caribbean children; Diet; 24-Hour recalls Compared with white Europeans, South Asians living in the UK have increased risks of CHD, type 2 diabetes and central obesity (1)(2)(3)(4)(5) . Black African-Caribbeans living in the UK have increased risks of type 2 diabetes and general obesity but have lower risks of (2,3,5,6) . Ethnic differences in the nutritional composition of diets could play an important role in these differences in disease risk, which are currently unexplained (7) . Nutrient composition is important in the aetiology of CHD, type 2 diabetes and obesity (8) . In particular, excessive consumption of energy-dense foods is associated with increased risks of overweight and obesity (8) , while high total and saturated fat intakes increase risks of insulin resistance (9) , impaired glucose tolerance (10) , raised LDL-cholesterol levels and CHD (11) . High intakes of sugars may increase serum TAG and reduce HDLcholesterol (12)(13)(14) . Low fibre (NSP) intake is associated with higher insulin resistance, raised total and LDL-cholesterol and an increased risk of obesity (15,16) and stroke (17) . Low intakes of micronutrients, including folate (8) , vitamin C (18) and vitamin D (19) , have been associated with increased risks of CVD and type 2 diabetes. The nutritional composition of adult diets differs between ethnic groups in the UK, in ways tha...

OBJECTIVEEthnic differences in type 2 diabetes risk between South Asians and white Europeans originate before adult life and are not fully explained by higher adiposity levels in South Asians. Although metabolic sensitivity to adiposity may differ between ethnic groups, this has been little studied in childhood. We have therefore examined the associations among adiposity, insulin resistance, and glycemia markers in children of different ethnic origins.RESEARCH DESIGN AND METHODSCross-sectional study of 4,633 9- to 10-year-old children (response rate 68%) predominantly of South Asian, black African-Caribbean, and white European origin (n = 1,266, 1,176, and 1,109, respectively) who had homeostasis model assessments of insulin resistance (HOMA-IR), glycemia markers (HbA1c and fasting glucose), and adiposity (BMI, waist circumference, skinfold thicknesses, and bioimpedance [fat mass]).RESULTSAll adiposity measures were positively associated with HOMA-IR in all ethnic groups, but associations were stronger among South Asians compared to black African-Caribbeans and white Europeans. For a 1-SD increase in fat mass percentage, percentage differences in HOMA-IR were 37.5% (95% CI 33.3–41.7), 29.7% (25.8–33.8), and 27.0% (22.9–31.2), respectively (P interaction < 0.001). All adiposity markers were positively associated with HbA1c in South Asians and black African-Caribbeans but not in white Europeans; for a 1-SD increase in fat mass percentage, percentage differences in HbA1c were 0.04% (95% CI 0.03–0.06), 0.04% (0.02–0.05), and 0.02% (−0.00 to 0.04), respectively (P interaction < 0.001). Patterns for fasting glucose were less consistent.CONCLUSIONSSouth Asian children are more metabolically sensitive to adiposity. Early prevention or treatment of childhood obesity may be critical for type 2 diabetes prevention, especially in South Asians.