IndEcho study: cohort study investigating birth size, childhood growth and young adult cardiovascular risk factors as predictors of midlife myocardial structure and function in South Asians.

INTRODUCTION: South Asians have high rates of cardiovascular disease (CVD) and its risk factors (hypertension, diabetes, dyslipidaemia and central obesity). Left ventricular (LV) hypertrophy and dysfunction are features of these disorders and important predictors of CVD mortality. Lower birth and infant weight and greater childhood weight gain are associated with increased adult CVD mortality, but there are few data on their relationship to LV function. The IndEcho study will examine associations of birth size, growth during infancy, childhood and adolescence and CVD risk factors in young adulthood with midlife cardiac structure and function in South Asian Indians. METHODS AND ANALYSIS: We propose to study approximately 3000 men and women aged 43-50 years from two birth cohorts established in 1969-1973: the New Delhi Birth Cohort (n=1508) and Vellore Birth Cohort (n=2156). They had serial measurements of weight and height from birth to early adulthood. CVD risk markers (body composition, blood pressure, glucose tolerance and lipids) and lifestyle characteristics (tobacco and alcohol consumption, physical activity, socioeconomic status) were assessed at age ~30 years. Clinical measurements in IndEcho will include anthropometry, blood pressure, biochemistry (glucose, fasting insulin and lipids, urinary albumin/creatinine ratio) and body composition by dual energy X-ray absorptiometry and bioelectrical impedance. Outcomes are LV mass and indices of LV systolic and diastolic function assessed by two-dimensional and Doppler echocardiography, carotid intimal-media thickness and ECG indicators of ischaemia. Regression and conditional growth models, adjusted for potential confounders, will be used to study associations of childhood and young adult exposures with these cardiovascular outcomes. ETHICS AND DISSEMINATION: The study has been approved by the Health Ministry Steering Committee, Government of India and institutional ethics committees of participating centres in India and the University of Southampton, UK. Results will be disseminated through scientific meetings and peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN13432279; Pre-results

Maternal age at childbirth and perinatal and under-five mortality in a prospective birth cohort from Delhi

OBJECTIVE: To evaluate the relationship between maternal age at child birth and perinatal and underfive mortality.DESIGN: Prospective birth cohort.SETTING: Urban community.PARTICIPANTS: 9169 pregnancies in the New Delhi Birth Cohort resulted in 8181 live births. These children were followed for survival status and anthropometric measurements at birth (+3 days), 3, 6, 9 and 12 months (± 7 days), and every 6 months thereafter until 21 years age. Information on maternal age at child birth and socio-demographic profile was also obtained.OUTCOME MEASURES: Offspring mortality from 28 weeks gestation till 5 years age.RESULTS: Offspring mortality (stillbirths - 5 years; n=328) had a U-shaped association with maternal age (P< 0.001). Compared to the reference group (20-24 years), younger (? 19 years) and older (? 35 years) maternal ages were associated with a higher risk of offspring mortality (HR: 1.68; 95% CI 1.16, 2.43 and HR 1.48; 95% CI 1.01, 2.16, respectively). In young mothers, the increased risk persisted after adjustment for socio-economic confounders (maternal education, household income and wealth; HR 1.51; 95% CI 1.03, 2.20) and further for additional behavioural (place of delivery) and biological mediators (gestation and birth weight) (HR 2.14; 95% CI 1.25,3.64). Similar associations were documented for post-perinatal deaths but for perinatal mortality the higher risk was not statistically significant (P>0.05). In older mothers, the increased mortality risk was not statistically significant (P>0.05) after adjustment for socio-economic confounders.CONCLUSION: Young motherhood is associated with an increased risk of post-perinatal mortality and measures to prevent early childbearing should be strengthened

Weight-for-height is associated with an overestimation of thinness burden in comparison to BMI-for-age in under-5 populations with high stunting prevalence

Background: thinness at <5 years of age, also known as wasting, is used to assess the nutritional status of populations for programmatic purposes. Thinness may be defined when either weight-for-height or body-mass-index-for-age (BMI-for-age) are below –2 SD of the respective World Health Organization standards. These definitions were compared for quantifying the burden of thinness. Methods: theoretical consequences of ignoring age were evaluated by comparing, at varying height-for-age z-scores, the age- and sex-specific cut-offs of BMI that would define thinness with these two metrics. Thinness prevalence was then compared in simulated populations (short, intermediate and tall) and real-life data sets from research and the National Family Health Survey-4 (NFHS-4) in India. Results: in short (–2 SD) children, the BMI cut-offs with weight-for-height criteria were higher in comparison to BMI-for-age after 1 year of age but lower at earlier ages. In Indian research and NFHS-4 data sets (short populations), thinness prevalence with weight-for-height was lower from 0.5 to 1 years but higher at subsequent ages. The absolute difference (weight-for-height – BMI-for-age) for 0.5–5 years was 4.6% (15.9–11.3%) and 2.2% (19.2–17.0%), respectively; this attenuated in the 0–5 years age group. The discrepancy was higher in boys and maximal for stunted children, reducing with increasing stature. In simulated data sets from intermediate and tall populations, there were no meaningful differences. Conclusions: the two definitions produce cut-offs, and hence estimates of thinness, that differ with the age, sex and height of children. The relative invariance, with age and stature, of the BMI-for-age thinness definition favours its use as the preferred index for programmatic purposes

Intergenerational change in anthropometry of children and adolescents in the New Delhi Birth Cohort

Background: A comparison of the anthropometry of children and adolescents with that of their parents at the same age may provide a more precise measure of intergenerational changes in linear growth and body mass index (BMI). Methods: New Delhi Birth Cohort participants (F1), born between 1969 and 1972, were followed up for anthropometry at birth and at 6-monthly intervals until 21 years of age. At variable intervals 1447 children, aged 0-19 years (F2) and born to 818 F1 participants, were measured (weight and height), providing 2236 sets of anthropometries. Intergenerational changes (F2-F1) in height and BMI [absolute and standard deviation (SD) units] were computed by comparing children with their parents at corresponding ages. Results: F2 children were taller (P &lt; 0.001) than their parents at corresponding ages; the increase {mean [95% confidence interval (CI)] World Health Organization SD units} was 0.97 (0.83, 1.11), 1.21 (1.10, 1.32), 1.09 (0.98, 1.19), 1.10 (1.00, 1.21) and 0.75 (0.65, 0.85) for age categories of 0-5, 5-7.5, 7.5-10, 10-12.5 and &gt;12.5 years, respectively. In absolute terms, this increase ranged from 3.5 cm (0-5-year-olds) to 7.5 cm (10-12.5-year-olds). The corresponding increases in BMI SD scores were 0.32 (0.18, 0.47), 0.60 (0.45, 0.75), 1.13 (0.99, 1.27), 1.30 (1.15, 1.45) and 1.00 (0.85, 1.15), respectively. The absolute BMI increase ranged from 1-3 kg/m2 at &gt;5 years age to ∼3 kg/m2 at &gt;10-years of age. The intergenerational increases were comparable in both sexes, but were greater in children born and measured later. A positive change in socioeconomic status was associated with an increase in height across the generations. Conclusions: Children and adolescents, throughout the ages 0-19 years, have become considerably taller and have a higher BMI than their parents at corresponding ages in an urban middle-class Indian population undergoing socioeconomic improvements.</p

Longitudinal Growth and Undernutrition Burden Among Term Low Birth Weight Newborns Reared in Adverse Socioeconomic Conditions in Delhi

BACKGROUND: There is limited data in term low birth weight neonates from urban poor settings on the incidence of and recovery from undernutrition and co-existence of its different forms, under conditions of appropriate health and nutrition care counselling. OBJECTIVES: To determine the longitudinal growth and undernutrition burden among term low birth weight newborns reared in adverse conditions, but with appropriate counselling. METHODS: The study reports follow-up data from DIVIDS trial. 2079 term low birth weight (1800-2499 grams) newborns from an urban poor setting were followed-up for growth from 0 to 26 weeks (n=1282) and at 2.8-6.8 years (n=912). Using Cole LMS approach, age- and sex-specific internal z scores were computed and subsequently adjusted for the effect of a vitamin D intervention and potential bias due to attrition. Back-transformed measurements were then used to compute WHO z scores for height for age (HAZ), weight for age (WAZ), and BMI for age (BMIZ). RESULTS: HAZ remained fairly stable: mean changes from birth till 6 weeks, 26 weeks and 3-7 years were 0.07, 0.04 and 0.2 SD, respectively. BMIZ and WAZ showed considerable catch-up; 0.69 SD, 1.84 SD and 1.38 SD for BMIZ, and 0.25 SD, 0.89 SD and 0.60 SD for WAZ, respectively. 60-92% had at least one form of undernutrition and co-existence was frequent. Half the children remained stunted till 5 years, while underweight and wasting declined considerably from 0-6 months. CONCLUSION: With appropriate counselling of parents, term low birth weight infants reared under adverse socioeconomic conditions show substantial catch-up growth in BMIZ and WAZ but not in HAZ. The long-term consequences of this excess weight over length gain need focused evaluation

Waist Circumference, Waist-to-Height Ratio and BMI percentiles in children aged 5 to 19 years in India: A population-based study

Objective: Nationally representative percentiles for Waist Circumference (WC), Waist‐to‐Height‐Ratio (WHtR) and Body Mass Index (BMI) are not available for children and adolescents in India. Methods: Using LMS method, age‐ and gender‐specific reference growth charts were constructed for WC (n = 68,261), WHtR (n = 68,261) and BMI (n = 67,741) from children/adolescents aged 5‐19 years who participated in a nationally representative survey. General obesity, indicating overall obesity, was defined as age‐sex‐specific BMI z‐scores ≥ 95th percentile. Central obesity was defined in three ways: WC ≥ 90th percentile, WHtR ≥ 0.5 and both WC ≥ 90th percentile and WHtR ≥ 0.5. Findings: WC and BMI percentiles for boys and girls are lower than those previously reported from India and several other countries. The BMI percentiles are lower than the WHO 2007 reference population. The prevalence of general obesity using India specific BMI centiles was 2.9% (95%CI: 2.6,3.2). The prevalence of central obesity was 6.1% (95%CI: 5.7,6.6) using WC ≥ 90th percentile, 5.3% (95%CI: 5.0,5.7) using WHtR ≥ 0.5 and 3.6% using both criteria. Three‐fourth of children with general obesity also had central obesity based on WC ≥ 90th. Conclusions: Indian children are thinner than Caucasian and other Asian children, and the global WHO reference population. Using India specific reference, the prevalence of central obesity is higher than general obesity, with a significant overlap between the two

Longitudinal growth and undernutrition burden among term low birth weight newborns reared in adverse socioeconomic conditions in Delhi

Background: there is limited data in term low birth weight neonates from urban poor settings on the incidence of and recovery from undernutrition and co-existence of its different forms, under conditions of appropriate health and nutrition care counselling.Objectives: to determine the longitudinal growth and undernutrition burden among term low birth weight newborns reared in adverse conditions, but with appropriate counselling.Methods: the study reports follow-up data from DIVIDS trial. 2079 term low birth weight (1800-2499 grams) newborns from an urban poor setting were followed-up for growth from 0 to 26 weeks (n=1282) and at 2.8-6.8 years (n=912). Using Cole LMS approach, age- and sex-specific internal z scores were computed and subsequently adjusted for the effect of a vitamin D intervention and potential bias due to attrition. Back-transformed measurements were then used to compute WHO z scores for height for age (HAZ), weight for age (WAZ), and BMI for age (BMIZ).Results: HAZ remained fairly stable: mean changes from birth till 6 weeks, 26 weeks and 3-7 years were 0.07, 0.04 and 0.2 SD, respectively. BMIZ and WAZ showed considerable catch-up; 0.69 SD, 1.84 SD and 1.38 SD for BMIZ, and 0.25 SD, 0.89 SD and 0.60 SD for WAZ, respectively. 60-92% had at least one form of undernutrition and co-existence was frequent. Half the children remained stunted till 5 years, while underweight and wasting declined considerably from 0-6 months.Conclusion: with appropriate counselling of parents, term low birth weight infants reared under adverse socioeconomic conditions show substantial catch-up growth in BMIZ and WAZ but not in HAZ. The long-term consequences of this excess weight over length gain need focused evaluation

Echocardiography protocol and cardiometabolic phenotyping in Indian birth cohorts - the IndEcho study

Background: Asian Indians are at higher risk of cardiometabolic disease compared to other ethnic groups, and the age of onset is typically younger. Cardiac structure and function are poorly characterized in this ethnic group. In this study, we describe image-acquisition methods and the reproducibility of measurements and detailed echocardiography characteristics in two large Indian population-based cohorts (the New Delhi and Vellore Birth Cohorts) from India.Methods: the IndEcho study captured transthoracic echocardiographic measurements of cardiac structure and function from 2,322 men and women aged 43–50 years. M-mode measurements in the parasternal long axis (PLAX) and 2-dimensional (2D) short axis recordings at the mitral valve, mid-papillary and apical level were recorded. Apical 2D recordings of two- three- and four-chamber (2C, 3C and 4C) views and Doppler images (colour, pulsed and continuous) were recorded in cine-loop format. Left ventricular (LV) mass, LV hypertrophy, and indices of LV systolic and diastolic function were derived.Results: echocardiographic measurements showed good/excellent technical reproducibility. Hetero-geneity across sites, sex and rural/urban differences in cardiac structure and function were observed. Overall, this cohort of South Asian Indians had smaller LV mass and normal systolic and diastolic function when compared with published data on other Asian Indians and the West, (LV mass indexed for body surface area: Delhi men: 68 g/m2, women 63.9; Vellore men: 65.8, women 61.6) but were within ethnic-specific reference ranges. The higher prevalence of obesity, diabetes and hypertension is reflected by the higher proportion of LV remodelling and lesser hypertrophy.Conclusions: our study adds to scarce population-based echocardiographic data for mid-life Asian Indians. Compared to published literature on other ethnic groups, the Asian Indian heart is characterised by smaller cardiac dimensions and normal range systolic and diastolic function on a background of a high prevalence of hypertension, diabetes and cardiac disease at a relatively young age. This data will form the basis for further analyses of lifecourse, metabolic and body composition predictors of cardiac structure and function, and echocardiographic predictors of future mortality.ISRCTN registration number: 1343227