Relationships Between Exposure to Gestational Diabetes Treatment and Neonatal Anthropometry: Evidence from the Born in Bradford (BiB) Cohort.

OBJECTIVES: To examine the relationships between gestational diabetes mellitus (GDM) treatment and neonatal anthropometry. METHODS: Covariate-adjusted multivariable linear regression analyses were used in 9907 offspring of the Born in Bradford cohort. GDM treatment type (lifestyle changes advice only, lifestyle changes and insulin or lifestyle changes and metformin) was the exposure, offspring born to mothers without GDM the control, and birth weight, head, mid-arm and abdominal circumference, and subscapular and triceps skinfold thickness the outcomes. RESULTS: Lower birth weight in offspring exposed to insulin (- 117.2 g (95% CI - 173.8, - 60.7)) and metformin (- 200.3 g (- 328.5, - 72.1)) compared to offspring not exposed to GDM was partly attributed to lower gestational age at birth and greater proportion of Pakistani mothers in the treatment groups. Higher subscapular skinfolds in offspring exposed to treatment compared to those not exposed to GDM was partly attributed to higher maternal glucose concentrations at diagnosis. In fully adjusted analyses, offspring exposed to GDM treatment had lower weight, smaller abdominal circumference and skinfolds at birth than those not exposed to GDM. Metformin exposure was associated with smaller offspring mid-arm circumference (- 0.3 cm (- 0.6, - 0.07)) than insulin exposure in fully adjusted models with no other differences found. CONCLUSIONS FOR PRACTICE: Offspring exposed to GDM treatment were lighter and smaller at birth than those not exposed to GDM. Metformin-exposed offspring had largely comparable birth anthropometric characteristics to those exposed to insulin.

Associations between maternal gestational diabetes metformin or insulin treatment and offspring growth trajectories from birth to 60 months of age: Findings from the Born in Bradford (BiB) study.

AIM: To investigate the associations between gestational diabetes mellitus (GDM) metformin or insulin treatment and offspring growth trajectories from 0 to 60 months. METHODS: Participants were from the Born in Bradford birth cohort study. Using covariate-adjusted multilevel linear spline models (4 splines: 0-1.6, 1.6-6, 6-17 and 17-60 months), we compared weight, height and body mass index (BMI) z-score trajectories of: (1) 76 offspring exposed to metformin (OGDM-Metformin) and 420 offspring exposed to insulin (OGDM-Insulin); (2) OGDM-Metformin and 9171 offspring not exposed to GDM (No-GDM); (3) OGDM-Insulin and No-GDM. RESULTS: (1) OGDM-Metformin had comparable growth trajectories to OGDM-Insulin from 0 to 60 months. (2) OGDM-Metformin had a lower mean birthweight z-score than No-GDM. OGDM-Metformin had faster changes in height z-score (0.13 [95% CI 0.026, 0.24]) from 17 to 60 months and by 60 months, had comparable mean BMI z-score to No-GDM. (3) OGDM-insulin had lower mean birthweight and height z-scores than No-GDM. OGDM-Insulin had faster changes in weight (0.32 [0.021, 0.62]) and height (0.50 [0.087, 0.91]) from 1.6 to 6 months and by 60 months, had comparable mean BMI z-score to No-GDM. CONCLUSIONS: GDM metformin treatment was not associated with differences in offspring growth trajectories compared to insulin treatment. Both metformin and insulin-exposed offspring had comparable BMI z-score to No-GDM by 60 months.

Body mass index across adulthood and the development of airflow obstruction and emphysema.

BACKGROUND: Low body mass index (BMI) is associated with COPD, but temporal relationships between airflow obstruction (AO) development and emphysematous change are unclear. We investigated longitudinal changes in BMI, AO, and lung density throughout adulthood using data from the Framingham Offspring Cohort (FOC). METHODS: BMI trajectories were modelled throughout adulthood in 4587 FOC participants from Exam 2 (mean age = 44), through Exam 9 (mean age = 71), in AO participants and non-AO participants (AO n = 1036), determined by spirometry, using fractional polynomial growth curves. This process was repeated for low lung density (LLD) and non LLD participants (LLD n = 225) determined by Computed Tomography. Spirometry decline was compared separately between tertiles of BMI in those aged <40 years and associations between fat and lean mass (measured using Dual Energy X-ray Absorptiometry, DEXA) and development of AO and LLD were also assessed. Additional analyses were performed with adjustment for smoking volume. RESULTS: The BMI trajectory from 30 years of age was visually lower in the AO group than both non-AO smokers (non-

Associations between maternal characteristics and pharmaceutical treatment of gestational diabetes: an analysis of the UK Born in Bradford (BiB) cohort study.

OBJECTIVES: To identify the maternal characteristics associated with pharmaceutical treatment of gestational diabetes mellitus (GDM). DESIGN: Prospective birth cohort study. SETTING: Bradford, UK. PARTICIPANTS: 762 women from the Born in Bradford (BiB) cohort who were treated for GDM in a singleton pregnancy. BiB cohort participants were recruited from 2007 to 2010. All women booked for delivery were screened for GDM between 26 and 28 weeks of gestation using a 75 g 2-hour oral glucose tolerance test (OGTT). OUTCOME MEASURE: GDM treatment type: lifestyle changes advice (lifestyle changes), lifestyle changes advice with supplementary insulin (insulin) and lifestyle changes advice with supplementary metformin (metformin). RESULTS: 244 (32%) women were prescribed lifestyle changes advice alone while 518 (68%) were offered supplemental pharmaceutical treatment. The odds of receiving pharmaceutical treatment relative to lifestyle changes advice alone were increased for mothers who were obese (OR 4.6, 95% CI 2.8 to 7.5), those who smoked (OR 2.6, 95% CI 1.2 to 5.5) and had higher fasting glucose levels at OGTT (OR 2.1, 95% CI 1.6 to 2.7). The odds of being prescribed pharmaceutical treatment rather than lifestyle changes advice were lower for Pakistani women (OR 0.7, 95% CI 0.4 to 1.0)) than White British women. Relative to insulin treatment, metformin was more likely to be offered to obese women than normal weight women (relative risk ratio, RRR 3.2, 95% CI 1.3 to 7.8) and less likely to be prescribed to women with higher fasting glucose concentrations at OGTT (RRR 0.3, 95% CI 0.2 to 0.6). CONCLUSIONS: In the BiB cohort, GDM pharmaceutical treatment tended to be prescribed to women who were obese, White British, who smoked and had more severe hyperglycaemia. The characteristics of metformin-treated mothers differed from those of insulin-treated mothers as they were more likely to be obese but had lower glucose concentrations at diagnosis.

Integrating Clinical and Epidemiologic Data on Allergic Diseases Across Birth Cohorts: A Harmonization Study in the Mechanisms of the Development of Allergy Project.

The numbers of international collaborations among birth cohort studies designed to better understand asthma and allergies have increased in the last several years. However, differences in definitions and methods preclude direct pooling of original data on individual participants. As part of the Mechanisms of the Development of Allergy (MeDALL) Project, we harmonized data from 14 birth cohort studies (each with 3-20 follow-up periods) carried out in 9 European countries during 1990-1998 or 2003-2009. The harmonization process followed 6 steps: 1) organization of the harmonization panel; 2) identification of variables relevant to MeDALL objectives (candidate variables); 3) proposal of a definition for each candidate variable (reference definition); 4) assessment of the compatibility of each cohort variable with its reference definition (inferential equivalence) and classification of this inferential equivalence as complete, partial, or impossible; 5) convocation of a workshop to agree on the reference definitions and classifications of inferential equivalence; and 6) preparation and delivery of data through a knowledge management portal. We agreed on 137 reference definitions. The inferential equivalence of 3,551 cohort variables to their corresponding reference definitions was classified as complete, partial, and impossible for 70%, 15%, and 15% of the variables, respectively. A harmonized database was delivered to MeDALL investigators. In asthma and allergy birth cohorts, the harmonization of data for pooled analyses is feasible, and high inferential comparability may be achieved. The MeDALL harmonization approach can be used in other collaborative projects.

Individual Variation in Hunger, Energy Intake, and Ghrelin Responses to Acute Exercise.

PURPOSE: This study aimed to characterize the immediate and extended effect of acute exercise on hunger, energy intake, and circulating acylated ghrelin concentrations using a large data set of homogenous experimental trials and to describe the variation in responses between individuals. METHODS: Data from 17 of our group's experimental crossover trials were aggregated yielding a total sample of 192 young, healthy males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69% ± 5% V˙O2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours postexercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analog scales completed at 30-min intervals, whereas ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise. RESULTS: At group level, exercise transiently suppressed hunger (P < 0.010, Cohen's d = 0.77) but did not affect energy intake. Acylated ghrelin was suppressed during exercise (P < 0.001, Cohen's d = 0.10) and remained significantly lower than control (no exercise) afterward (P < 0.024, Cohen's d = 0.61). Between participants, there were notable differences in responses; however, a large proportion of this spread lay within the boundaries of normal variation associated with biological and technical assessment error. CONCLUSION: In young men, acute exercise suppresses hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true interindividual variation from random differences within normal limits.

Maternal health inequalities and GP provision: investigating variation in consultation rates for women in the Born in Bradford cohort.

Background: The 'Five Year Forward View' (NHS England) calls for a radical upgrade in public health provision. Inequalities in maternal health may perpetuate general patterns of health inequalities across generations; therefore equitable access to general practice (GP) provision during maternity is important. This paper explores variation in GP consultation rates for disadvantaged mothers. Method: Data from the Born in Bradford cohort (around 12 000 women), combined with GP records and GP practice variables, were modelled to predict GP consultation rates, before and after adjusting for individual health and GP provision. Results: Observed GP consultation rates are higher for women in materially deprived neighbourhoods and Pakistani women. However these groups were found to consult less often after controlling for individual health. This difference, around one appointment per year, is 'explained' by the nature of GP provision. Women in practices with a low GP to patient ratio had around 09 fewer consultations over the six year period compared to women in practices with the highest ratio. Conclusions: Equitable access to GP services, particularly for women during the maternal period, is essential for tackling deep-rooted health inequalities. Future GP funding should take account of neighbourhood material deprivation to focus resources on areas of the greatest need.

ENDOGAMY, CONSANGUINITY AND THE HEALTH IMPLICATIONS OF CHANGING MARITAL CHOICES IN THE UK PAKISTANI COMMUNITY.

The biraderi (brotherhood) is a long-established, widely prevalent dimension of social stratification in Pakistani communities worldwide. Alongside consanguinity, it offers a route for cementing social solidarities and so has strong socio-biological significance. A detailed breakdown of biraderi affiliation among participants in an ongoing birth cohort study in the northern English city of Bradford is presented. There is historical resilience of intra-biraderi marriage, but with a secular decline in prevalence across all biraderi and considerable reductions in some. While a majority of marriages in all biraderi are consanguineous the prevalence varies, ranging from over 80% to under 60%. In consanguineous unions, first cousin marriages account for more than 50% in five of the fifteen biraderi and >40% in six others. Within-biraderi marriage and consanguinity enhance genetic stratification, thereby increasing rates of genomic homozygosity and the increased expression of recessive genetic disorders. The trends reported constitute putative signals of generational change in the marital choices in this community.

Ethnic and socio-economic differences in the prevalence of wheeze, severe wheeze, asthma, eczema and medication usage at 4 years of age: Findings from the Born in Bradford birth cohort.

BACKGROUND: Asthma, wheeze and eczema are common in early childhood and cause considerable morbidity. Generally rates of these conditions are higher in high income compared to low income countries. Rates in developed nations are generally higher than in less developed countries. After migration to Western countries, differences in risks of developing these conditions may between migrant and non-migrant may diminish. METHODS: A convenience sample of 1648 children of White British, Pakistani or Other ethnicity aged between 4 and 5 years were recruited from the main Born in Bradford cohort. Children's parents or guardians were asked to report on a range of potential risk factors and their associations with wheeze, asthma and eczema. Relationships between ethnicity and disease outcomes were examined using logistic regression after adjustment for other relevant risk factors and confounders. RESULTS: Ethnic differences in doctor diagnosed asthma were evident, with children of other ethnic Origin being less likely and children of Pakistani origin more likely to have a diagnosis than White British or other origin children, although after adjustment for other risk factors this difference only remained significant for the Other Ethnic group. Ethnic differences were not observed in other outcomes including wheeze in the past 12 months, severe wheeze and taking medications for breathing problems. CONCLUSIONS: In UK born children, traditional risk factors such as gender, family history, socio-economic status and child's medical history may be stronger risk factors than ethnicity or familial migration patterns.

Variation and ethnic inequalities in treatment of common mental disorders before, during and after pregnancy: combined analysis of routine and research data in the Born in Bradford cohort.

BACKGROUND: Common mental disorders (CMD) such as anxiety and depression during the maternal period can cause significant morbidity to the mother in addition to disrupting biological, attachment and parenting processes that affect child development. Pharmacological treatment is a first-line option for moderate to severe episodes. Many women prescribed pharmacological treatments cease them during pregnancy but it is unclear to what extent non-pharmacological options are offered as replacement. There are also concerns that treatments offered may not be proportionate to need in minority ethnic groups, but few data exist on treatment disparities in the maternal period. We examined these questions in a multi-ethnic cohort of women with CMD living in Bradford, England before, during and up to one year after pregnancy. METHODS: We searched the primary care records of women enrolled in the Born in Bradford cohort for diagnoses, symptoms, signs ('identification'), referrals for treatment, non-pharmacological and pharmacological treatment and monitoring ('treatment') related to CMD. Records were linked with maternity data to classify women identified with a CMD as treated prior to, and one year after, delivery. We examined rates and types of treatment during pregnancy, and analysed potential ethnic group differences using adjusted Poisson and multinomial logistic regression models. RESULTS: We analysed data on 2,234 women with indicators of CMD. Most women were discontinued from pharmacological treatment early in pregnancy, but this was accompanied by recorded access to non-drug treatments in only 15 % at the time of delivery. Fewer minority ethnic women accessed treatments compared to White British women despite minority ethnic women being 55-70 % more likely than White British women to have been identified with anxiety in their medical record. CONCLUSIONS: Very few women who discontinued pharmacological treatment early in their pregnancy were offered other non-pharmacological treatments as replacement, and most appeared to complete their pregnancy untreated. Further investigation is warranted to replicate the finding that minority ethnic women are more likely to be identified as being anxious or having anxiety and understand what causes the variation in access to treatments.

Evaluation of ethnic disparities in detection of depression and anxiety in primary care during the maternal period: combined analysis of routine and cohort data.

BACKGROUND: There are limited data on detection disparities of common mental disorders in minority ethnic women. AIMS: Describe the natural history of common mental disorders in primary care in the maternal period, characterise women with, and explore ethnic disparities in, detected and potentially missed common mental disorders. METHOD: Secondary analyses of linked birth cohort and primary care data involving 8991 (39.4% White British) women in Bradford. Common mental disorders were characterised through indications in the electronic medical record. Potentially missed common mental disorders were defined as an elevated General Health Questionnaire (GHQ-28) score during pregnancy with no corresponding common mental disorder markers in the medical record. RESULTS: Estimated prevalence of pre-birth common mental disorders was 9.5%, rising to 14.0% 3 years postnatally. Up to half of cases were potentially missed. Compared with White British women, minority ethnic women were twice as likely to have potentially missed common mental disorders and half as likely to have a marker of screening for common mental disorders. CONCLUSIONS: Common mental disorder detection disparities exist for minority ethnic women in the maternal period.

Maternal psychological distress in primary care and association with child behavioural outcomes at age three.

Observational studies indicate children whose mothers have poor mental health are at increased risk of socio-emotional behavioural difficulties, but it is unknown whether these outcomes vary by the mothers' mental health recognition and treatment status. To examine this question, we analysed linked longitudinal primary care and research data from 1078 women enrolled in the Born in Bradford cohort. A latent class analysis of treatment status and self-reported distress broadly categorised women as (a) not having a common mental disorder (CMD) that persisted through pregnancy and the first 2 years after delivery (N = 756, 70.1 %), (b) treated for CMD (N = 67, 6.2 %), or (c) untreated (N = 255, 23.7 %). Compared to children of mothers without CMD, 3-year-old children with mothers classified as having untreated CMD had higher standardised factor scores on the Strengths and Difficulties Questionnaire (d = 0.32), as did children with mothers classified as having treated CMD (d = 0.27). Results were only slightly attenuated in adjusted analyses. Children of mothers with CMD may be at risk for socio-emotional and behavioural difficulties. The development of effective treatments for CMD needs to be balanced by greater attempts to identify and treat women.

Linear spline multilevel models for summarising childhood growth trajectories: A guide to their application using examples from five birth cohorts.

Childhood growth is of interest in medical research concerned with determinants and consequences of variation from healthy growth and development. Linear spline multilevel modelling is a useful approach for deriving individual summary measures of growth, which overcomes several data issues (co-linearity of repeat measures, the requirement for all individuals to be measured at the same ages and bias due to missing data). Here, we outline the application of this methodology to model individual trajectories of length/height and weight, drawing on examples from five cohorts from different generations and different geographical regions with varying levels of economic development. We describe the unique features of the data within each cohort that have implications for the application of linear spline multilevel models, for example, differences in the density and inter-individual variation in measurement occasions, and multiple sources of measurement with varying measurement error. After providing example Stata syntax and a suggested workflow for the implementation of linear spline multilevel models, we conclude with a discussion of the advantages and disadvantages of the linear spline approach compared with other growth modelling methods such as fractional polynomials, more complex spline functions and other non-linear models.

The relationship between early life modifiable risk factors for childhood obesity, ethnicity and body mass index at age 3 years: findings from the Born in Bradford birth cohort study.

BACKGROUND: Many modifiable risk factors in early infancy have been shown to be associated with childhood overweight and obesity. These risk factors have not been studied within children of South Asian origin in the UK. The aims of this paper are to describe differences in the prevalence of modifiable risk factors for childhood obesity between children of White British and Pakistani origin and investigate the association between these risk factors and childhood BMI measured at age 3 years. We used data from a sub-study of the Born in Bradford birth cohort with detailed follow-up visits throughout early childhood. 987 participants with a BMI measurement at age 3 were included; 39% were White British, 48% were of Pakistani origin and 13% were of other ethnicities. Linear and Poisson regression models were used to assess the association between risk factors and two outcomes at age 3; BMI z-scores and child overweight. RESULTS: Compared to Pakistani mothers, White British mothers were more likely to smoke during pregnancy, have higher BMI, breastfeed for a shorter duration and wean earlier, while Pakistani mothers had higher rates of gestational diabetes and were less active. There was no strong evidence that the relationship between risk factors and BMI z-score differed by ethnicity. There were associations between BMI z-score and maternal smoking (mean difference in BMI z-score 0.33 (95% CI 0.13, 0.53)), maternal obesity (0.37 (0.19, 0.55)), indulgent feeding style (0.15 (-0.06, 0.36)), lower parental warmth scores (0.21 (0.05, 0.36)) and higher parental hostility scores (0.17 (0.01, 0.33)). Consistent associations between these risk factors and child overweight were found. Mean BMI and the relative risk of being overweight were lower in children of mothers with lower parental self-efficacy scores and who watched more hours of TV. Other risk factors (gestational diabetes, child diet, child sleep, child TV viewing and maternal physical activity) were not associated with BMI. CONCLUSIONS: Whilst the prevalence of risk factors that have been associated with childhood greater BMI differ between White British and Pakistani the magnitude of their associations with BMI are similar in the two groups.

Can different primary care databases produce comparable estimates of burden of disease: results of a study exploring venous leg ulceration.

BACKGROUND: Primary care databases from the UK have been widely used to produce evidence on the epidemiology and health service usage of a wide range of conditions. To date there have been few evaluations of the comparability of estimates between different sources of these data. AIM: To estimate the comparability of two widely used primary care databases, the Health Improvement Network Database (THIN) and the General Practice Research Database (GPRD) using venous leg ulceration as an exemplar condition. DESIGN OF STUDY: Cross prospective cohort comparison. SETTING: GPRD and the THIN databases using data from 1998 to 2006. METHOD: A data set was extracted from both databases containing all cases of persons aged 20 years or greater with a database diagnosis of venous leg ulceration recorded in the databases for the period 1998-2006. Annual rates of incidence and prevalence of venous leg ulceration were calculated within each database and standardized to the European standard population and compared using standardized rate ratios. RESULTS: Comparable estimates of venous leg ulcer incidence from the GPRD and THIN databases could be obtained using data from 2000 to 2006 and of prevalence using data from 2001 to 2006. CONCLUSIONS: Recent data collected by these two databases are more likely to produce comparable results of the burden venous leg ulceration. These results require confirmation in other disease areas to enable researchers to have confidence in the comparability of findings from these two widely used primary care research resources.

Ambient Air Pollution and Newborn Size and Adiposity at Birth: Differences by Maternal Ethnicity (the Born in Bradford Study Cohort).

BACKGROUND: Exposure to ambient air pollution has been associated with reduced size of newborns; however, the modifying effect of maternal ethnicity remains little explored among South Asians. OBJECTIVES: We investigated ethnic differences in the association between ambient air pollution and newborn's size. METHOD: Pregnant women were recruited between 2007 and 2010 for the Born in Bradford cohort study, in England. Exposures to particulate matter (≤ 10 µm, PM10; ≤ 2.5 µm, PM2.5), PM2.5 absorbance, and nitrogen oxides (NOx, NO2) were estimated using land-use regressions models. Using multivariate linear regression models, we evaluated effect modification by maternal ethnicity ("white British" or "Pakistani origin," self-reported) on the associations of air pollution and birth weight, head circumference, and triceps and subscapular skinfold thickness. RESULTS: A 5-µg/m3 increase in mean third trimester PM2.5 was associated with significantly lower birth weight and smaller head circumference in children of white British mothers (-43 g; 95% CI: -76, -10 and -0.28 cm; 95% CI: -0.39, -0.17, respectively), but not in children of Pakistani origin (9 g; 95% CI: -17, 35 and -0.08 cm; 95% CI: -0.17, 0.01, respectively) (p(int) = 0.03 and < 0.001). In contrast, PM2.5 was associated with significantly larger triceps and subscapular skinfold thicknesses in children of Pakistani origin (0.17 mm; 95% CI: 0.08, 0.25 and 0.21 mm; 95% CI: 0.12, 0.29, respectively), but not in white British children (-0.02 mm; 95% CI: -0.14, 0.01 and 0.06 mm; 95% CI: -0.06, 0.18, respectively) (p(int) = 0.06 and 0.11). Patterns of associations for PM10 and PM2.5 absorbance according to ethnicity were similar to those for PM2.5, but associations of the outcomes with NO2 and NOx were mostly nonsignificant in both ethnic groups. CONCLUSIONS: Our results suggest that associations of ambient PM exposures with newborn size and adiposity differ between white British and Pakistani origin infants. CITATION: Schembari A, de Hoogh K, Pedersen M, Dadvand P, Martinez D, Hoek G, Petherick ES, Wright J, Nieuwenhuijsen MJ. 2015. Ambient air pollution and newborn size and adiposity at birth: differences by maternal ethnicity (the Born in Bradford study cohort). Environ Health Perspect 123:1208-1215; http://dx.doi.org/10.1289/ehp.1408675.

Growth patterns of white British and Pakistani children in the Born in Bradford cohort: a latent growth modelling approach.

BACKGROUND: Childhood growth patterns have been proposed as a key predictor of health during childhood and adult life. In earlier studies, however, the statistical methodologies employed failed to uncover the more subtle patterns in growth trajectories. METHODS: Study participants were 1364 singleton term children (602 white British and 762 Pakistani origin) drawn from the Born in Bradford (BiB) prospective cohort. Weights were measured at 0, 1, 3, 6, 12, 18, 24 and 36 months. Age-specific and sex-specific standardised weight scores were derived based on the World Health Organisation growth standards. Missing growth data were estimated using Full Information Maximum Likelihood (FIML) method. Growth Mixture Model was used to analyse growth patterns of children from birth until 36 months. RESULTS: On average, Pakistani children were 190 g lighter than white British children at birth. Based on our Growth Mixture Model results, the study children had three distinct growth patterns: 'normal growers' (95.9%), 'fast growers' (2.5%) and 'slow growers' (1.6%). The Pakistani children were more likely to be in either the 'fast' (OR=2.90; 95% CI 0.91 to 9.25) or 'slow' (OR=15.63; 95% CI 1.06 to 230) grower class than the white British. Pakistani children showed faster growth than the white British between 3 and 36 months of age. CONCLUSIONS: In this growth study we have identified that the study children have three distinct growth patterns. These growth patterns may provide greater insight in predicting the risk of childhood or early adulthood diseases in life-course studies.

Experiences and outcomes of maternal Ramadan fasting during pregnancy: results from a sub-cohort of the Born in Bradford birth cohort study.

BACKGROUND: Observing the fast during the holy month of Ramadan is one of the five pillars of Islam. Although pregnant women and those with pre-existing illness are exempted from fasting many still choose to fast during this time. The fasting behaviours of pregnant Muslim women resident in Western countries remain largely unexplored and relationships between fasting behaviour and offspring health outcomes remain contentious. This study was undertaken to assess the prevalence, characteristics of fasting behaviours and offspring health outcomes in Asian and Asian British Muslim women within a UK birth cohort. METHODS: Prospective cohort study conducted at the Bradford Royal Infirmary UK from October to December 2010 comprising 310 pregnant Muslim women of Asian or Asian British ethnicity that had a live singleton birth at the Bradford Royal Infirmary. The main outcome of the study was the decision to fast or not during Ramadan. Secondary outcomes were preterm births and mean birthweight. Logistic regression analyses were used to investigate the relationship between covariables of interest and women's decision to fast or not fast. Logistic regression was also used to investigate the relationship between covariables and preterm birth as well as low birth weight. RESULTS: Mutually adjusted analysis showed that the odds of any fasting were higher for women with an obese BMI at booking compared to women with a normal BMI, (OR 2.78 (95% C.I. 1.29-5.97)), for multiparous compared to nulliparous women(OR 3.69 (95% C.I. 1.38-9.86)), and for Bangladeshi origin women compared to Pakistani origin women (OR 3.77 (95% C.I. 1.04-13.65)). Odds of fasting were lower in women with higher levels of education (OR 0.40 (95% C.I. 0.18-0.91)) and with increasing maternal age (OR 0.87 (95% C.I. 0.80-0.94). No associations were observed between fasting and health outcomes in the offspring. CONCLUSIONS: Pregnant Muslim women residing in the UK who fasted during Ramadan differed by social, demographic and lifestyle characteristics compared to their non-fasting peers. Fasting was not found to be associated with adverse birth outcomes in this sample although these results require confirmation using reported fasting data in a larger sample before the safety of fasting during pregnancy can be established.

Using latent class analysis to develop a model of the relationship between socioeconomic position and ethnicity: cross-sectional analyses from a multi-ethnic birth cohort study.

BACKGROUND: Almost all studies in health research control or investigate socioeconomic position (SEP) as exposure or confounder. Different measures of SEP capture different aspects of the underlying construct, so efficient methodologies to combine them are needed. SEP and ethnicity are strongly associated, however not all measures of SEP may be appropriate for all ethnic groups. METHODS: We used latent class analysis (LCA) to define subgroups of women with similar SEP profiles using 19 measures of SEP. Data from 11,326 women were used, from eight different ethnic groups but with the majority from White British (40%) or Pakistani (45%) backgrounds, who were recruited during pregnancy to the Born in Bradford birth cohort study. RESULTS: Five distinct SEP subclasses were identified in the LCA: (i) "Least socioeconomically deprived and most educated" (20%); (ii) "Employed and not materially deprived" (19%); (iii) "Employed and no access to money" (16%); (iv) "Benefits and not materially deprived" (29%) and (v) "Most economically deprived" (16%). Based on the magnitude of the point estimates, the strongest associations were that compared to White British women, Pakistani and Bangladeshi women were more likely to belong to groups: (iv) "benefits and not materially deprived" (relative risk ratio (95% CI): 5.24 (4.44, 6.19) and 3.44 (2.37, 5.00), respectively) or (v) most deprived group (2.36 (1.96, 2.84) and 3.35 (2.21, 5.06) respectively) compared to the least deprived class. White Other women were more than twice as likely to be in the (iv) "benefits and not materially deprived group" compared to White British women and all ethnic groups, other than the Mixed group, were less likely to be in the (iii) "employed and not materially deprived" group than White British women. CONCLUSIONS: LCA allows different aspects of an individual's SEP to be considered in one multidimensional indicator, which can then be integrated in epidemiological analyses. Ethnicity is strongly associated with these identified subgroups. Findings from this study suggest a careful use of SEP measures in health research, especially when looking at different ethnic groups. Further replication of these findings is needed in other populations.

Ethnic differences in infant feeding practices and their relationship with BMI at 3 years of age - results from the Born in Bradford birth cohort study.

The present study aimed to explore previously unreported ethnic differences in infant feeding practices during the introduction of solid foods, accounting for maternal and birth factors, and to determine whether these feeding patterns are associated with BMI at 3 years of age. An observational study using Poisson regression was carried out to investigate the relationship between ethnicity and infant feeding practices and linear regression was used to investigate the relationship between feeding practices and BMI at 3 years of age in a subsample of 1327 infants in Bradford. It was found that compared with White British mothers, mothers of Other ethnicities were less likely to replace breast milk with formula milk before introducing solid foods (adjusted relative risk (RR) - Pakistani: 0·76 (95 % CI 0·64, 0·91), Other South Asian: 0·58 (95 % CI 0·39, 0·86), and Other ethnicities: 0·50 (95 % CI 0·34, 0·73)). Pakistani and Other South Asian mothers were less likely to introduce solid foods early ( < 17 weeks) (adjusted RR - Pakistani: 0·92 (95 % CI 0·87, 0·96) and Other South Asian: 0·87 (95 % CI 0·81, 0·93)). Other South Asian mothers and mothers of Other ethnicities were more likely to continue breast-feeding after introducing solid foods (adjusted RR - 1·72 (95 % CI 1·29, 2·29) and 2·12 (95 % CI 1·60, 2·81), respectively). Pakistani and Other South Asian infants were more likely to be fed sweetened foods (adjusted RR - 1·18 (95 % CI 1·13, 1·23) and 1·19 (95 % CI 1·10, 1·28), respectively) and Pakistani infants were more likely to consume sweetened drinks (adjusted RR 1·72 (95 % CI 1·15, 2·57)). No association between infant feeding practices and BMI at 3 years was observed. Although ethnic differences in infant feeding practices were found, there was no association with BMI at 3 years of age. Interventions targeting infant feeding practices need to consider ethnicity to identify which populations are failing to follow recommendations.