Fetal programming of health and disease; follow-up of children whose mothers took part in a pre-conceptional nutrition trial in Mumbai, India

The Mumbai Maternal Nutrition Project was a randomised controlled trial which took place in a slum community in the city of Mumbai, India. The participants were women planning to have children. They had diets low in vitamins and minerals (micronutrients) and their newborns were at high risk of low birth weight. The aim of the trial was to test whether improving the micronutrient quality of their diet for a sustained period of time before conception, and throughout pregnancy, increases birth weight and improves the children's long-term health. Women were offered, in addition to their usual diet, a specially designed daily snack made from (treatment group) micronutrient-rich foods including green leafy vegetables, fruit and milk, or (controls) low micronutrient vegetables such as potato and onion. On average the treatment snacks contained 10-23% of the WHO recommended Reference Nutrient Intake for beta-carotene, folate, vitamins B2 and B12, calcium and iron.

The trial was unusual in two ways: (a) in supplementing women before pregnancy and (b) in using local micronutrient-rich foods rather than pharmaceutical micronutrient supplements. The primary outcome was birth weight, but it was powered to enable the study of longer term outcomes in the children. We pre-specified that we planned to test the effect of starting the intervention at least three months before conception, and we expected greater effects on birth weight among thinner women. The first women were recruited in January 2006 and the last baby was born in May 2012. We enrolled 6513 women, of whom 2291 became pregnant, resulting in 1962 singleton live births; 1826 of the 2291 women started the supplement at least three months before becoming pregnant and had 1562 live births.

Among all the women who gave birth, the intervention had a positive but non-significant effect on birth weight (+26 g [95% CI -15, 68 g], p=0.22). There was a greater effect among women who started supplementation at least three months before pregnancy (+48g [95% CI 1, 96 g], p=0.046). In these women, the intervention reduced the rate of low birth weight babies (Treatment: 34%, Controls 41%; OR 0.76 [95% CI 0.59, 0.98], p=0.03). The birth weight effect increased with maternal pre-pregnant body mass index: -8g, +79g and +113g in the lowest, middle and highest thirds of maternal BMI respectively (p for interaction=0.001). An unexpected benefit of the intervention was that it reduced the prevalence of diabetes in the mothers during pregnancy (Treatment: 7%, Controls: 13%, p<0.01).

In the proposed study, we now aim to assess the effect of the intervention on outcomes in the children (N~1800) at the age of 6 years. We will measure a range of growth, functional and health outcomes, including height, body composition, risk markers for later diabetes and heart disease, and brain function.

The study has already started (from Sept 2013) in order assess children in a narrow age window. Ethical approval was obtained from the JJ Hospital, Mumbai. Families are visited by a health worker to explain the study. As close as possible to the child's 6th birthday, the child and both parents are asked to attend a research clinic at the Centre for the Study of Social Change in Bandra, Mumbai, after an overnight fast. Detailed body measurements of the parents and child are performed. A fasting blood sample is taken from the child for glucose, insulin and lipids. Further blood samples are drawn at 30 and 120 minutes after an oral glucose load. Blood pressure and hand grip strength are measured. Cognitive (intelligence) testing is carried out using tests validated for Indian children. The children have fat, lean and bone mass measured using dual X-ray absorptiometry at a local hospital. In parents, a full blood count and fasting glucose are measured. DNA and RNA samples for future genetic and epigenetic analyses are collected from the children and parents and frozen. The study will take 3 years to complete.

As described above, the Mumbai Maternal Nutrition Project was a randomised controlled trial in Mumbai, India, which aimed to test whether improving the micronutrient quality of a women's diet before conception and throughout pregnancy increases birth weight and improves the long-term health of the child. The intervention reduced the incidence of gestational diabetes, and among women of normal or high BMI, increased birth weight. The aim of the study proposed here is to determine whether it has improved the health and capacity of the children at the age of 6 years.

The study has already started (from Sept 2013) so as not to miss the age window in the earliest-born children. Ethical approval was obtained from JJ Hospital, Mumbai. Families are visited by health workers to explain the study. As close as possible to their 6th birthday, the child and both parents attend a research clinic at the Centre for the Study of Social Change in Bandra, Mumbai, after an overnight fast. Detailed body measurements of the parents and child are performed. A fasting blood sample is taken from the child for glucose, insulin and lipids, and further samples drawn at 30 and 120 minutes after an oral glucose load. Blood pressure and hand grip strength are measured. Fat, lean and bone mass are measured using DXA. Cognitive function is measured using the Kaufman Assessment Battery and other tests validated for Indian children and designed to measure multiple domains. Parents' fasting glucose is measured. DNA and RNA samples for future genetic/epigenetic analyses are collected from children and parents, and frozen.

110 children have been studied so far, and over 3 years we expect to study ~1500 (80%) of the surviving children from the original 1962 births. We will have 80% power to detect a difference of 0.14 SDs in continuous outcomes between treatment and control groups at 5% significance. This equates, for example, to approximately 1.4 mmHg of systolic blood pressure.

Our findings have enormous public health potential as they offer a primordial prevention strategy to control and prevent the rising burden of non-communicable disease. The research will benefit the public by improving health and reducing chronic disease in the current and future generations. In the longer term, this will enhance human capital in India; translating the findings to other populations will benefit the wider population.

The beneficiaries of our research include colleagues working in the field of DOHaD, other clinicians, nutritionists, epidemiologists, public health practitioners and policy makers; the findings will add to the existing knowledge base on the influence of maternal nutrition on offspring health in young childhood. We know from earlier work in India and elsewhere that the measurements we are planning at the age of 6 years (cardiovascular risk factors, body composition, cognitive function) track into adult life, and our findings will therefore provide evidence of the importance of maternal nutrition for adult health.

Our work has resulted in a network of scientists and researchers who work closely together and share learning and skills. This enables young researchers in both India and the UK to develop transferable research skills and contributes to capacity building. Our work in India has led to the development of research infrastructure, skilled teams and independent researchers.

A better understanding of the relationships between maternal nutrition and chronic disease risk factors in childhood, as well as an improved understanding of optimal childhood growth patterns will have significant impact for other scientists and policy makers. It will help guide the development of further interventions in infancy and early childhood and address translation of evidence into practice. Our work has influenced research strategy in India and the UK with major funders such as the Indian Council of Medical Research, Department of Biotechnology, the Medical Research Council and the Wellcome Trust funding and prioritising early life origins research. The DOHaD work has also influenced policy. Recent evidence of impact includes the adoption by the International Diabetes Federation of a 'life circle' approach to diabetes prevention; the emphasis by international agencies on better nutrition in the 'first 1000 days' (conception to age 2 years); and the World Health Assembly declaration on chronic disease, recognising the importance of early life factors. The Lancet series on maternal and child nutrition in 2008 and 2013 have included the DOHaD concept and highlighted the wider nutrition-sensitive issues in tackling maternal and child undernutrition. This will in turn feed into the high level panel which will consider the next set of Millenium Development Goals and possibly lead to the inclusion of targets for maternal health and child stunting.