UK-born Pakistani-origin infants are relatively more adipose than white British infants: findings from 8704 mother-offspring pairs in the Born-in-Bradford prospective birth cohort
KeywordREF 2014; Birth weight; Pakistani-origin infants; South Asian infants; White British infants; Adiposity; Skinfold thickness; Cord leptin
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AbstractBACKGROUND: Previous studies have shown markedly lower birth weight among infants of South Asian origin compared with those of White European origin. Whether such differences mask greater adiposity in South Asian infants and whether they persist across generations in contemporary UK populations is unclear. Our aim was to compare birth weight, skinfold thickness and cord leptin between Pakistani and White British infants and to investigate the explanatory factors, including parental and grandparental birthplace. METHODS: We examined the differences in birth weight and skinfold thickness between 4649 Pakistani and 4055 White British infants born at term in the same UK maternity unit and compared cord leptin in a subgroup of 775 Pakistani and 612 White British infants. RESULTS: Pakistani infants were lighter (adjusted mean difference -234 g 95% CI -258 to -210) and were smaller in both subscapular and triceps skinfold measurements. The differences for subscapular and triceps skinfold thickness (mean z-score difference -0.27 95% CI -0.34 to -0.20 and -0.23 95% CI -0.30 to -0.16, respectively) were smaller than the difference in birth weight (mean z-score difference -0.52 95% CI -0.58 to -0.47) and attenuated to the null with adjustment for birth weight (0.03 95% CI -0.03 to 0.09 and -0.01 95% CI -0.08 to 0.05, respectively). Cord leptin concentration (indicator of fat mass) was similar in Pakistani and White British infants without adjustment for birth weight, but with adjustment became 30% higher (95% CI 17% to 44%) among Pakistani infants compared with White British infants. The magnitudes of difference did not differ by generation. CONCLUSIONS: Despite being markedly lighter, Pakistani infants had similar skinfold thicknesses and greater total fat mass, as indicated by cord leptin, for a given birth weight than White British infants. Any efforts to reduce ethnic inequalities in birth weight need to consider differences in adiposity and the possibility that increasing birth weight in South Asian infants might inadvertently worsen health by increasing relative adiposity.
CitationWest, J., Lawlor, D. A., Fairley, L., Bhopal, R., Cameron, N., McKinney, P. A., Sattar, N., Wright, J. (2013) UK-born Pakistani-origin infants are relatively more adipose than white British infants: findings from 8704 mother-offspring pairs in the Born-in-Bradford prospective birth cohort. Journal of Epidemiology and Community Health, 67 (7), 544-551.
Link to publisher’s versionhttp://dx.doi.org/10.1136/jech-2012-201891
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Cohort Profile: the Born in Bradford multi-ethnic family cohort studyWright, J.; Small, Neil A.; Raynor, P.; Tuffnell, D.J.; Bhopal, R.S.; Cameron, N.; Fairley, L.; Lawlor, D.A.; Parslow, Roger C.; Petherick, E.S.; et al. (2013)The Born in Bradford cohort study was established in 2007 to examine how genetic, nutritional, environmental, behavioural and social factors impact on health and development during childhood, and subsequently adult life in a deprived multi-ethnic population. Between 2007 and 2011, detailed information on socio-economic characteristics, ethnicity and family trees, lifestyle factors, environmental risk factors and physical and mental health has been collected from 12 453 women with 13 776 pregnancies (recruited at ∼28 weeks) and 3448 of their partners. Mothers were weighed and measured at recruitment, and infants have had detailed anthropometric assessment at birth and post-natally up to 2 years of age. Results of an oral glucose tolerance test and lipid profiles were obtained on the mothers during pregnancy at ∼28 weeks gestation, and pregnancy serum, plasma and urine samples have been stored. Cord blood samples have been obtained and stored and Deoxyribonucleic acid (DNA) extraction on 10 000 mother–offspring pairs is nearly completed. The study has a biobank of over 250 000 samples of maternal blood, DNA and urine, cord blood and DNA and paternal saliva. Details of how scientists can access these data are provided in this cohort profile.
Agreement between routine and research measurement of infant height and weight.Bryant, M.; Santorelli, G.; Fairley, L.; Petherick, E.S.; Bhopal, R.S.; Lawlor, D.A.; Tilling, K.; Howe, L.D.; Farrar, D.; Cameron, N.; et al. (2015)In many countries, routine data relating to growth of infants are collected as a means of tracking health and illness up to school age. These have potential to be used in research. For health monitoring and research, data should be accurate and reliable. This study aimed to determine the agreement between length/height and weight measurements from routine infant records and researcher-collected data. Methods Height/length and weight at ages 6, 12 and 24 months from the longitudinal UK birth cohort (born in Bradford; n=836–1280) were compared with routine data collected by health visitors within 2 months of the research data (n=104–573 for different comparisons). Data were age adjusted and compared using Bland Altman plots. Results There was agreement between data sources, albeit weaker for height than for weight. Routine data tended to underestimate length/height at 6 months (0.5 cm (95% CI −4.0 to 4.9)) and overestimate it at 12 (−0.3 cm (95% CI −0.5 to 4.0)) and 24 months (0.3 cm (95% CI −4.0 to 3.4)). Routine data slightly overestimated weight at all three ages (range −0.04 kg (95% CI −1.2 to 0.9) to −0.04 (95% CI −0.7 to 0.6)). Limits of agreement were wide, particularly for height. Differences were generally random, although routine data tended to underestimate length in taller infants and underestimate weight in lighter infants. Conclusions Routine data can provide an accurate and feasible method of data collection for research, though wide limits of agreement between data sources may be observed. Differences could be due to methodological issues; but may relate to variability in clinical practice. Continued provision of appropriate training and assessment is essential for health professionals responsible for collecting routine data.
Risk factors for congenital anomaly in a multiethnic birth cohort: an analysis of the Born in Bradford studySheridan, E.; Wright, J.; Small, Neil A.; Corry, P.C.; Oddie, S.J.; Whibley, C.; Petherick, E.S.; Malik, T.; Pawson, Nicole; McKinney, P.A.; et al. (2013)Background: Congenital anomalies are a leading cause of infant death and disability and their incidence varies between ethnic groups in the UK. Rates of infant death are highest in children of Pakistani origin, and congenital anomalies are the most common cause of death in children younger than 12 in this ethnic group. We investigated the incidence of congenital anomalies in a large multiethnic birth cohort to identify the causes of the excess of congenital anomalies in this community. Methods: We obtained questionnaire data from the mothers of children with one or more anomalies from the Born in Bradford study, a prospective birth cohort study of 13 776 babies and their families in which recruitment was undertaken between 2007 and 2011. Details of anomalies were prospectively reported to the study and we cross checked these details against medical records. We linked data for anomalies to maternal questionnaire and clinical data gathered as part of the Born in Bradford study. We calculated univariate and multivariate risk ratios (RRs) with 95% CIs for various maternal risk factors. Findings: Of 11 396 babies for whom questionnaire data were available, 386 (3%) had a congenital anomaly. Rates for congenital anomaly were 305·74 per 10 000 livebirths, compared with a national rate of 165·90 per 10 000. The risk was greater for mothers of Pakistani origin than for those of white British origin (univariate RR 1·96, 95% CI 1·56–2·46). Overall, 2013 (18%) babies were the offspring of first-cousin unions. These babies were mainly of Pakistani origin—1922 (37%) of 5127 babies of Pakistani origin had parents in first-cousin unions. Consanguinity was associated with a doubling of risk for congenital anomaly (multivariate RR 2·19, 95% CI 1·67–2·85); we noted no association with increasing deprivation. 31% of all anomalies in children of Pakistani origin could be attributed to consanguinity. We noted a similar increase in risk for mothers of white British origin older than 34 years (multivariate RR 1·83, 95% CI 1·14–3·00). Maternal education to degree level was protective (0·53, 95% CI 0·38–0·75), irrespective of ethnic origin. Interpretation: Consanguinity is a major risk factor for congenital anomaly. The risk remains even after adjustment for deprivation, and accounts for almost a third of anomalies in babies of Pakistani origin. High levels of educational attainment are associated with reduced risk in all ethnic groups. Our findings will be valuable in health promotion and public health, and to those commissioning antenatal, paediatric, and clinical genetic services. Sensitive advice about the risks should be provided to communities at increased risk, and to couples in consanguineous unions, to assist in reproductive decision making. Funding: National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care programme.