Patterns of childhood body mass index (BMI), overweight and obesity in South Asian and black participants in the English National child measurement programme: effect of applying BMI adjustments standardising for ethnic differences in BMI-body fatness associations.

BACKGROUND: The National Child Measurement Programme (NCMP) records weight and height and assesses overweight-obesity patterns in English children using body mass index (BMI), which tends to underestimate body fatness in South Asian children and overestimate body fatness in Black children of presumed African ethnicity. Using BMI adjustments to ensure that adjusted BMI was similarly related to body fatness in South Asian, Black and White children, we reassessed population overweight and obesity patterns in these ethnic groups in NCMP. METHODS: Analyses were based on 2012-2013 NCMP data in 582 899 children aged 4-5 years and 485 362 children aged 10-11 years. Standard centile-based approaches defined weight status in each age group before and after applying BMI adjustments for English South Asian and Black children derived from previous studies using the deuterium dilution method. FINDINGS: Among White children, overweight-obesity prevalences (boys, girls) were 23% and 21%, respectively, in 4-5 year olds and 33% and 30%, respectively, in 10-11 year olds. Before adjustment, South Asian children had lower overweight-obesity prevalences at 4-5 years (19%, 19%) and slightly higher prevalences at 10-11 years (42%, 34%), whereas Black children had higher overweight-obesity prevalences both at 4-5 years (31%, 29%) and 10-11 years (42%, 45%). Following adjustment, overweight-obesity prevalences were markedly higher in South Asian children both at 4-5 years (39%, 35%) and at 10-11 years (52%, 44%), whereas Black children had lower prevalences at 4-5 years (11%, 12%); at 10-11 years, prevalences were slightly lower in boys (32%) but higher in girls (35%). INTERPRETATION: BMI adjustments revealed extremely high overweight-obesity prevalences among South Asian children in England, which were not apparent in unadjusted data. In contrast, after adjustment, Black children had lower overweight-obesity prevalences except among older girls. FUNDING: British Heart Foundation, NIHR CLAHRC (South London), NIHR CLAHRC (North Thames).

Body mass index adjustments to increase the validity of body fatness assessment in UK Black African and South Asian children.

BACKGROUND/OBJECTIVES: Body mass index (BMI) (weight per height2) is the most widely used marker of childhood obesity and total body fatness (BF). However, its validity is limited, especially in children of South Asian and Black African origins. We aimed to quantify BMI adjustments needed for UK children of Black African and South Asian origins so that adjusted BMI related to BF in the same way as for White European children. METHODS: We used data from four recent UK studies that made deuterium dilution BF measurements in UK children of White European, South Asian and Black African origins. A height-standardized fat mass index (FMI) was derived to represent BF. Linear regression models were then fitted, separately for boys and girls, to quantify ethnic differences in BMI-FMI relationships and to provide ethnic-specific BMI adjustments. RESULTS: We restricted analyses to 4-12 year olds, to whom a single consistent FMI (fat mass per height5) could be applied. BMI consistently underestimated BF in South Asians, requiring positive BMI adjustments of +1.12 kg m-2 (95% confidence interval (CI): 0.83, 1.41 kg m-2; P<0.0001) for boys and +1.07 kg m-2 (95% CI: 0.74, 1.39 kg m-2; P<0.0001) for girls of all age groups and FMI levels. BMI overestimated BF in Black Africans, requiring negative BMI adjustments for Black African children. However, these were complex because there were statistically significant interactions between Black African ethnicity and FMI (P=0.004 boys; P=0.003 girls) and also between FMI and age group (P<0.0001 for boys and girls). BMI adjustments therefore varied by age group and FMI level (and indirectly BMI); the largest adjustments were in younger children with higher unadjusted BMI and the smallest in older children with lower unadjusted BMI. CONCLUSIONS: BMI underestimated BF in South Asians and overestimated BF in Black Africans. Ethnic-specific adjustments, increasing BMI in South Asians and reducing BMI in Black Africans, can improve the accuracy of BF assessment in these children.

Investigating the importance of the local food environment for fruit and vegetable intake in older men and women in 20 UK towns: a cross-sectional analysis of two national cohorts using novel methods.

BACKGROUND: Local neighbourhood environments can influence dietary behavior. There is limited evidence focused on older people who are likely to have greater dependence on local areas and may suffer functional limitations that amplify any neighbourhood impact. METHODS: Using multi-level ordinal regression analysis we investigated the association between multiple dimensions of neighbourhood food environments (captured by fine-detail, foot-based environmental audits and secondary data) and self-reported frequency of fruit and vegetable intake. The study was a cross-sectional analysis nested within two nationally representative cohorts in the UK: the British Regional Heart Study and the British Women's Heart and Health Study. Main exposures of interest were density of food retail outlets selling fruits and vegetables, the density of fast food outlets and a novel measure of diversity of the food retail environment. RESULTS: A total of 1124 men and 883 women, aged 69 - 92 years, living in 20 British towns were included in the analysis. There was strong evidence of an association between area income deprivation and fruit and vegetable consumption, with study members in the most deprived areas estimated to have 27% (95% CI: 7, 42) lower odds of being in a higher fruit and vegetable consumption category relative to those in the least deprived areas. We found no consistent evidence for an association between fruit and vegetable consumption and a range of other food environment domains, including density of shops selling fruits and vegetables, density of premises selling fast food, the area food retail diversity, area walkability, transport accessibility, or the local food marketing environment. For example, individuals living in areas with greatest fruit and vegetable outlet density had 2% (95% CI: -22, 21) lower odds of being in a higher fruit and vegetable consumption category relative to those in areas with no shops. CONCLUSIONS: Although small effect sizes in environment-diet relationships cannot be discounted, this study suggests that older people are less influenced by physical characteristics of neighbourhood food environments than is suggested in the literature. The association between area income deprivation and diet may be capturing an important social aspect of neighbourhoods that influence food intake in older adults and warrants further research.

Fruit, vegetable and vitamin C intakes and plasma vitamin C: cross-sectional associations with insulin resistance and glycaemia in 9-10 year-old children.

AIM: To examine whether low circulating vitamin C concentrations and low fruit and vegetable intakes were associated with insulin resistance and other Type 2 diabetes risk markers in childhood. METHODS: We conducted a cross-sectional, school-based study in 2025 UK children aged 9-10 years, predominantly of white European, South-Asian and black African origin. A 24-h dietary recall was used to assess fruit, vegetable and vitamin C intakes. Height, weight and fat mass were measured and a fasting blood sample collected to measure plasma vitamin C concentrations and Type 2 diabetes risk markers. RESULTS: In analyses adjusting for confounding variables (including socio-economic status), a one interquartile range higher plasma vitamin C concentration (30.9 µmol/l) was associated with a 9.6% (95% CI 6.5, 12.6%) lower homeostatic model assessment of insulin resistance value, 0.8% (95% CI 0.4, 1.2%) lower fasting glucose, 4.5% (95% CI 3.2, 5.9%) lower urate and 2.2% (95% CI 0.9, 3.4%) higher HDL cholesterol. HbA1c concentration was 0.6% (95% CI 0.2, 1.0%) higher. Dietary fruit, vegetable and total vitamin C intakes were not associated with any Type 2 diabetes risk markers. Lower plasma vitamin C concentrations in South-Asian and black African-Caribbean children could partly explain their higher insulin resistance. CONCLUSIONS: Lower plasma vitamin C concentrations are associated with insulin resistance and could partly explain ethnic differences in insulin resistance. Experimental studies are needed to establish whether increasing plasma vitamin C can help prevent Type 2 diabetes at an early stage.

Mild hyponatremia, hypernatremia and incident cardiovascular disease and mortality in older men: A population-based cohort study.

AIM: To examine the association between serum sodium concentration and incident major cardiovascular disease (CVD) outcomes and total mortality in older men. METHODS AND RESULTS: A prospective study of 3099 men aged 60-79 years without a history of cardiovascular disease followed up for an average 11 years during which there were 528 major CVD events (fatal coronary heart disease [CHD] and non-fatal MI, stroke and CVD death) and 873 total deaths. A U shaped relationship was seen between serum sodium concentration and major CVD events and mortality. Hyponatremia (<136 mEq/L) and low sodium within the normal range (136-138 mEq/L) showed significantly increased risk of major CVD events and total mortality compared to men within the upper normal range (139-143 mEq/L) after adjustment for a wide range of confounders and traditional risk factors [adjusted HRs 1.55 (1.13,2.12) and 1.40 (1.14,1.72) for major CVD events respectively and 1.30 (1.02,1.66) and 1.30 (1.11,1.53) respectively for total mortality]. Hyponatremia was associated with inflammation, NT-proBNP, low muscle mass and alkaline phosphatase; these factors contributed to the increased total mortality associated with hyponatremia but did not explain the increased risk of CVD events associated with hyponatremia or low normal sodium concentration. Hypernatremia (≥145 mEq/L) was associated with significantly increased risk of CVD events and mortality due to CVD causes. CONCLUSION: Mild hyponatremia even within the normal sodium range and hypernatremia are both associated with increased total mortality and major CVD events in older men without CVD which is not explained by known adverse CV risk factors.

Socio-demographic characteristics, lifestyle factors and burden of morbidity associated with self-reported hearing and vision impairments in older British community-dwelling men: a cross-sectional study.

BACKGROUND: Hearing and vision problems are common in older adults. We investigated the association of self-reported sensory impairment with lifestyle factors, chronic conditions, physical functioning, quality of life and social interaction. METHODS: A population-based cross-sectional study of participants of the British Regional Heart Study aged 63-85 years. RESULTS: A total of 3981 men (82% response rate) provided data. Twenty-seven per cent (n = 1074) reported hearing impairment including being able to hear with aid (n = 482), being unable to hear (no aid) (n = 424) and being unable to hear despite aid (n = 168). Three per cent (n = 124) reported vision impairment. Not being able to hear, irrespective of use of hearing aid, was associated with poor quality of life, poor social interaction and poor physical functioning. Men who could not hear despite hearing aid were more likely to report coronary heart disease (CHD) [age-adjusted odds ratios (ORs) 1.89 (95% confidence interval 1.36-2.63)]. Vision impairment was associated with symptoms of CHD including breathlessness [OR 2.06 (1.38-3.06)] and chest pain [OR 1.58 (1.07-2.35)]. Vision impairment was also associated with poor quality of life, poor social interaction and poor physical functioning. CONCLUSIONS: Sensory impairment is associated with poor physical functioning, poor health and poor social interaction in older men. Further research is warranted on pathways underlying these associations.

Overweight across the life course and adipokines, inflammatory and endothelial markers at age 60-64 years: evidence from the 1946 birth cohort.

BACKGROUND/OBJECTIVES: There is growing evidence that early development of obesity increases cardiovascular risk later in life, but less is known about whether there are effects of long-term excess body weight on the biological drivers associated with the atherosclerotic pathway, particularly adipokines, inflammatory and endothelial markers. This paper therefore investigates the influence of overweight across the life course on levels of these markers at retirement age. SUBJECTS/METHODS: Data from the Medical Research Council National Survey of Health and Development (n=1784) were used to examine the associations between overweight status at 2, 4, 6, 7, 11, 15, 20, 26, 36, 43, 53 and 60-64 years (body mass index (BMI)⩾25 kg m(-2) for adult ages and gender-specific cut-points for childhood ages equivalent to BMI⩾25 kg m(-2)) and measurements of adipokines (leptin and adiponectin), inflammatory markers (C-reactive protein (CRP), interleukin-6 (IL-6)) and endothelial markers (E-selectin, tissue plasminogen activator (t-PA) and von Willebrand factor) at 60-64 years. In addition, the fit of different life course models (sensitive periods/accumulation) were compared using partial F-tests. RESULTS: In age- and sex-adjusted models, overweight at 11 years and onwards was associated with higher leptin, CRP and IL-6 and lower adiponectin; overweight at 15 years and onwards was associated with higher E-selectin and t-PA. Associations between overweight at all ages earlier than 60-64 with leptin, adiponectin, CRP and IL-6 were reduced but remained apparent after adjustment for overweight at 60-64 years; whereas those with E-selectin and t-PA were entirely explained. An accumulation model best described the associations between overweight across the life course with adipokines and inflammatory markers, whereas for the endothelial markers, the sensitive period model for 60-64 years provided a slightly better fit than the accumulation model. CONCLUSIONS: Overweight across the life course has a cumulative influence on adipokines, inflammatory and possibly endothelial markers. Avoidance of overweight from adolescence onwards is likely important for cardiovascular disease prevention.

Neighborhood Deprivation and Changes in Oral Health in Older Age: A Longitudinal Population-Based Study.

The aim of this study was to examine the extent to which neighborhood-level socioeconomic factors (objective and perceived) are associated with poor oral health in older adults over time, independent of individual socioeconomic position. Data for this cross-sectional and longitudinal observation study came from a socially and geographically representative cohort of men aged 71 to 92 y in 2010-12 (n = 1,622), drawn from British general practices, which was followed up in 2018-19 (aged 78-98 y; N = 667). Dental measures at both times included number of teeth, periodontal pocket depth, self-rated oral health, and dry mouth. Neighborhood deprivation was based on Index of Multiple Deprivation (IMD) and a cumulative index measuring perceptions about local environment. Individual-level socioeconomic position was based on longest-held occupation. Multilevel and multivariate logistic regressions, adjusted for relevant sociodemographic, behavioral, and health-related factors, were performed to examine the relationships of dental measures with IMD and perceived neighborhood quality index, respectively. Cross-sectionally, risks of tooth loss, periodontal pockets, and dry mouth increased from IMD quintiles 1 to 5 (least to most deprived); odds ratios (ORs) for quintile 5 were 2.22 (95% confidence interval [CI], 1.41-3.51), 2.82 (95% CI, 1.72-4.64), and 1.51 (95% CI, 1.08-2.09), respectively, after adjusting for sociodemographic, behavioral, and health-related factors. Risks of increased pocket depth and dry mouth were significantly greater in quintile 5 (highest problems) of perceived neighborhood quality index compared to quintile 1. Over the 8-y follow-up, deterioration of dentition (tooth loss) was significantly higher in the most deprived IMD quintiles after full adjustment (OR for quintile 5 = 2.32; 95% CI, 1.09-4.89). Deterioration of dentition and dry mouth were significantly greater in quintile 5 of perceived neighborhood quality index. Neighborhood-level factors were associated with poor oral health in older age, both cross-sectionally and longitudinally, particularly with tooth loss, and dry mouth, independent of individual-level socioeconomic position.

The Relationships of Dentition, Use of Dental Prothesis and Oral Health Problems with Frailty, Disability and Diet Quality: Results from Population-Based Studies of Older Adults from the UK and USA.

OBJECTIVES: This study examined the relationships of dental status, use and types of dental prothesis and oral health problems, individually and combined, with diet quality, frailty and disability in two population-based studies of older adults. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: Men form the British Regional Heart Study (BRHS) (aged 85±4 years in 2018; n=1013) and Men and Women from the Health, Aging, and Body Composition (HABC) Study (aged 75±3 years in 1998-99; n=1975). MEASUREMENTS: Physical and dental examinations and questionnaires were collected with data available for dental status, oral problems related to eating, diet quality, Fried frailty phenotype, disability based on mobility limitations, and activities of daily living (ADL). The associations of dental status and oral health problems, individually and combined, with risk of frailty and disability were quantified. The relationship with diet quality was also assessed. RESULTS: In the BRHS, but not HABC Study, impaired natural dentition without the use of dentures was associated with frailty independently. This relationship was only established in the same group in those with oral problems (OR=3.24; 95% CI: 1.30-8.03). In the HABC Study, functional dentition with oral health problems was associated with greater risk of frailty (OR=2.21; 95% CI: 1.18-4.15). In both studies those who wore a full or partial denture in one or more jaw who reported oral problems were more likely to have disability. There was no association with diet quality in these groups. CONCLUSION: Older adults with impaired dentition even who use dentures who experience self-report oral problems related to eating may be at increased risk of frailty and disability. Further research is needed to establish whether improving oral problems could potentially reduce the occurrence of frailty and disability.

Do women exhibit greater differences in established and novel risk factors between diabetes and non-diabetes than men? The British Regional Heart Study and British Women's Heart Health Study.

AIMS/HYPOTHESIS: Type 2 diabetes is associated with greater relative risk of CHD in women than in men, which is not fully explained by conventional cardiovascular risk factors. We assessed whether cardiovascular risk factors including more novel factors such as markers of insulin resistance, inflammation, activated coagulation and endothelial dysfunction differ more between diabetic and non-diabetic women than between diabetic and non-diabetic men, and the role of insulin resistance. METHODS: A cross-sectional study of non-diabetic and diabetic men and women (n = 7,529) aged 60-79 years with no previous myocardial infarction who underwent an examination was conducted. Measurements of anthropometry, blood pressure and fasting measurements of lipids, insulin, glucose and haemostatic and inflammatory markers were taken. RESULTS: Non-diabetic women tended to have more favourable risk factors and were less insulin resistant than non-diabetic men, but this was diminished in the diabetic state. Levels of waist circumference, BMI, von Willebrand factor (VWF), WBC count, insulin resistance (HOMA-IR), diastolic blood pressure, HDL-cholesterol, tissue plasminogen activator (t-PA) and factor VIII differed more between diabetic and non-diabetic women than between diabetic and non-diabetic men (test for diabetes × sex interaction p < 0.05). The more adverse effect of diabetes on these risk markers in women was associated with, and thereby largely attenuated by, insulin resistance. CONCLUSIONS/INTERPRETATION: The greater adverse influence of diabetes per se on adiposity and HOMA-IR and downstream blood pressure, lipids, endothelial dysfunction and systemic inflammation in women compared with men may contribute to their greater relative risk of coronary heart disease.

Statin use after first myocardial infarction in UK men and women from 1997 to 2006: Who started and who continued treatment?

BACKGROUND AND AIMS: To examine trends in initiation and continuation of statin treatment after myocardial infarction (MI) and their determinants, during a period of increasing usage. METHODS AND RESULTS: 9367 patients aged 30-84 with a first Myocardial Infarction (MI) in 1997-2006 were identified in DIN-LINK, an anonymised, UK primary care database. We assessed statin initiation (prescription within 6 months of MI) and continued therapy (% covered by a prescription on a given day of those prescribed a statin within 6 months). The influences of co-morbidities and socio-economic deprivation (Index of Multiple Deprivation) were examined. Statin initiation increased from 37% for MIs in 1997 to 92% in 2006. Continuation at 1 year remained stable over successive cohorts at approximately 80%, settling to about 76% in patients with 5-10 years follow up. Younger age, affluence, revascularisation in 6 months after MI, and absence of congestive heart failure, predicted higher initiation and continuation; a diagnosis of hypertension or diabetes predicted higher initiation, while smoking was associated with poorer continuation. Men had higher initiation and continued therapy, but these effects were largely explained by their younger age. Type of statin initially prescribed did not influence continued usage. CONCLUSION: Statin use after MI increased markedly between 1997 and 2006, whilst continued therapy remained high and stable. Importantly, first choice of statin had no effect on continuation. Whilst the high current levels of initiation may have reached a ceiling, increasing continuation rates among smokers, older patients and those from lower socio-economic groups, should remain a priority.

The potential for a two-stage diabetes risk algorithm combining non-laboratory-based scores with subsequent routine non-fasting blood tests: results from prospective studies in older men and women.

AIM: To develop strategies based on simple clinical assessment and blood markers to identify older individuals at high risk for Type 2 diabetes. METHODS: A prospective study of non-diabetic men (n = 3523) and women (n = 3404) aged 60-79 years followed for 7 years, during which there were 297 incident cases of Type 2 diabetes. Logistic regression was used to develop scores to predict incident cases, starting with clinical predictors and adding blood markers that predicted the incidence of diabetes. Receiving operating characteristic analyses were used to assess improvement in prediction. RESULTS: The area under the curve for a simple clinical assessment score, which included age, sex, family history of diabetes, smoking status, BMI, waist circumference, hypertension and recall of doctor diagnosis of coronary heart disease was 0.765 (0.740, 0.791); sensitivity and specificity in the top quintile of the score were 50.3 and 81.4%, respectively. Addition of simple fasting blood markers HDL cholesterol, triglyceride and glucose improved prediction [area under the curve = 0.817 (0.793, 0.840), P < 0.0001; sensitivity 63.8%; specificity 82.0%]. An alternative model adding blood markers not dependent on fasting yielded similar results. Further addition of C-reactive protein made no improvement. Blood measurements made small differences to reclassification of risk in those in the lowest three quintiles of the non-laboratory score. CONCLUSION: In large population settings, simple clinical assessments could be used in the first instance to identify older adults who would benefit from further testing with routine (non-fasting) blood markers to identify those at most likely to be at elevated diabetes risk.

Physical activity, obesity and cardiometabolic risk factors in 9- to 10-year-old UK children of white European, South Asian and black African-Caribbean origin: the Child Heart And health Study in England (CHASE).

AIMS/HYPOTHESIS: Physical 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. METHODS: This 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. RESULTS: Overall 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/INTERPRETATION: Objectively 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.

Assessing prediction of diabetes in older adults using different adiposity measures: a 7 year prospective study in 6,923 older men and women.

AIMS/HYPOTHESIS: The aim of this study was to examine whether waist circumference (WC) or WHR improve diabetes prediction beyond body mass index in older men and women, and to define optimal cut-off points. METHODS: In this prospective study, non-diabetic men (n = 3,519) and women (n = 3,404) aged 60-79 years were followed up for 7 years. There were 169 and 128 incident cases of type 2 diabetes in men and women, respectively. RESULTS: BMI, WC and WHR all showed strong associations with incident type 2 diabetes independent of potential confounders. In men, the adjusted relative risks (top vs lowest quartile) were 4.71 (95% CI 2.45-9.03) for BMI, 3.53 (95% CI 1.92-6.48) for WC and 2.76 (95% CI 1.58-4.82) for WHR. For women, the corresponding relative risks were 4.10 (95% CI 2.16-7.79), 12.18 (95% CI 4.83-30.74) and 5.61 (95% CI 2.84-11.09) for BMI, WC and WHR, respectively. Receiver-operating characteristic curve analysis revealed similar associations for BMI and WC in predicting diabetes in men (AUC = 0.726 and 0.713, respectively); WHR was the weakest predictor (AUC = 0.656). In women, WC was a significantly stronger predictor (AUC = 0.780) than either BMI (AUC = 0.733) or WHR (AUC = 0.728; p < 0.01 for both). Inclusion of both WC and BMI did not improve prediction beyond BMI alone in men or WC alone in women. Optimal sensitivity and specificity for the prediction of type 2 diabetes was observed at a WC of 100 cm in men and 92 cm in women. CONCLUSIONS/INTERPRETATION: In older men, BMI and WC yielded similar prediction of risk of type 2 diabetes, whereas WC was clearly a superior predictor in older women.

Insufficient evidence to support separate BMI definitions for obesity in children and adolescents from south Asian ethnic groups in the UK.

Re-evaluation of adult obesity thresholds in some ethnic groups has led to the questioning of childhood obesity thresholds. An expert group was convened to examine the representativeness of childhood obesity definitions, evidence for ethnic differences in body composition in UK children and the extent of misclassification of adiposity by current body mass index (BMI) thresholds in south Asian and black groups. The group concluded that the current International Obesity Task Force (IOTF) definitions remained the most appropriate for use in the United Kingdom, but further research was needed on the relationship of body shape, fat mass, metabolic markers and ethnicity in children and adolescents.

Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables.

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

Nutritional composition of the diets of South Asian, black African-Caribbean and white European children in the United Kingdom: the Child Heart and Health Study in England (CHASE).

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.

Chronic exposure to outdoor air pollution and lung function in adults.

BACKGROUND: The extent to which chronic exposure to outdoor air pollutants influences lung function in adults is unclear. The aim of this study was to measure the association between chronic exposure to outdoor air pollutants and adult lung function. METHODS: The relationship between measures of lung function (forced expiratory volume in 1 s (FEV(1)) and FEV(1) as a percentage of forced vital capacity (FVC)) and average exposure to particulate matter <10 microm in diameter, nitrogen dioxide, sulfur dioxide and ozone was examined in four representative cross-sectional surveys of the English population aged > or =16 in 1995, 1996, 1997 and 2001. Year-specific estimates were pooled using fixed effects meta-analysis. RESULTS: Greater exposure to particulate matter <10 microm in diameter, nitrogen dioxide and sulfur dioxide was associated with lower adult FEV(1). The size of the effect on population mean FEV(1) was about 3% for particulate matter <10 microm, and 0.7% for nitrogen dioxide and sulfur dioxide, for a 10 microg/m(3) increase in pollutant concentration. The effects were most marked in men, older adults and ex-smokers. FEV(1) was not associated with ozone concentration. No associations were found between the pollutants and FEV(1) as a percentage of FVC. CONCLUSIONS: Chronic exposure to outdoor air pollution is associated with modestly reduced FEV(1) in adults.

Is body mass index before middle age related to coronary heart disease risk in later life? Evidence from observational studies.

OBJECTIVE: Although obesity beginning early in life is becoming more common, its implications for coronary heart disease (CHD) risk in later life remain uncertain. We examined the relationship of body mass index (BMI) before 30 years of age to CHD risk in later life. DESIGN: Systematic review of published studies relating BMI between age 2 and 30 years to later CHD risk. Studies were identified using Medline (1950 onwards), Embase (1980 onwards) and Web of Science (1970 onwards) databases (to November 2007). MEASUREMENTS: Relative risks (RR) of CHD associated with a 1 standard deviation (s.d.) higher BMI (most based on a narrow age range at measurement) were extracted by two authors independently, and combined using random-effect models. RESULTS: A total of 15 studies provided 17 estimates (731 337 participants, 23 894 CHD events) of the association of early BMI to later CHD outcome. BMI in early childhood (2-6 years, 3 estimates) showed a weak inverse association with CHD risk (RR 0.94, 95% CI 0.82-1.07). BMI in later childhood (7 to <18 years, 7 estimates) and BMI in early adult life (18-30 years, 7 estimates) were both positively related to later CHD risk (RR 1.09, 95% CI 1.00-1.20; RR 1.19, 95% CI 1.11-1.29 respectively). However, there was considerable statistical heterogeneity between study estimates. Results were unaffected by adjustment for social class and/or cigarette smoking, blood pressure and/or total cholesterol, in studies with available data. Gender and year of birth (1900-1976) had little effect on the association. CONCLUSIONS: BMI is positively related to CHD risk from childhood onwards; the associations in young adults are consistent with those observed in middle age. Long-term control of BMI from childhood may be important to reduce the risk of CHD.

Evidence of an accelerating increase in prevalence of diagnosed Type 2 diabetes in British men, 1978-2005.

BACKGROUND: The prevalence of Type 2 diabetes is increasing worldwide; predictions suggest that the disease will reach epidemic proportions this century. This study aims to estimate the extent of the increase in prevalence of diagnosed Type 2 diabetes in British men between 1978 and 2005. METHODS: A representative cohort of 7722 British men aged 40-59 years at entry in 1978-1980 were selected from general practices in 24 British towns. Seven sequential questionnaire surveys were carried out between 1978 and 2005, recording recall of a doctor diagnosis of diabetes at each time point. Logistic regression models with generalized estimating equations were fitted to provide age-adjusted estimates of the calendar year increases in odds of Type 2 diabetes, both overall and for consecutive periods, each of approximately 5 years. RESULTS: The crude prevalence of Type 2 diabetes increased from 1.2% in 1978-1980 to 12.1% in 2005. The age-adjusted average annual increase in Type 2 diabetes prevalence for the 27-year study period was 7.0% [95% confidence interval (CI) 5.4%, 8.6%]. However, the age-adjusted annual rate of increase increased over time, from 4.3% (95% CI 0.4%, 8.2%) between 1979 and 1984 to 11.8% (95% CI 8.4%, 15.4%) between 2003 and 2005; P (trend) = 0.01. The highest annual increases occurred in subjects with higher mean body mass index levels and in towns in Scotland. CONCLUSIONS: The prevalence of Type 2 diabetes has risen substantially in Britain during the last three decades; the recent rate of increase has been almost three times greater than that in the early 1980s.