WP 2- Baseline Data
How do lifestyle and nutrition affect pregnancy and foetal outcomes relevant to metabolic disease in the various settings?
The link between suboptimum foetal growth and a higher risk of cardio-metabolic disease such as cardiovascular disease, hypertension, insulin resistance syndrome or type 2 diabetes have been demonstrated in several populations and age groups. The factors that modulate the growth of the foetus and permanently program its metabolism may be the key to effective prevention of these chronic diseases in adult life. Thus there is an urgent need to assess the potential contribution of impaired foetal growth and growth in early infancy to cardiometabolic risk in adults, and to identify in what ways this increased risk can be mitigated; this is particularly pertinent to South Asian populations. The aim of WP2 was to explore the range of reversible lifestyle and nutritional risk factors in pregnant mothers and their newborns, relevant to future metabolic diseases in South Asians living in Europe and in their home countries.
Data analysis and results
Baseline data were collected on South Asian women and their newborns in Dhaka, Karachi, Bangladesh, London and Oslo (Oslo data is still to be processed). The data included:
· Routine clinical data and measurements.
· Foetal measurements and cord blood and placenta sampling.
· Biochemical assays of metabolic and nutritional status.
· Health, lifestyle and dietary questionnaires.
The primary analysis in WP2 has been to characterise the metabolic and nutritional status of women recruited and the phenotypes of their offspring at birth.
Baseline characteristics of the pregnant women
Women recruited to the GIFTS study varied between study sites with regard to age and BMI, with the oldest women with highest BMI being in the UK and the youngest with lowest BMI in Bangladesh. Systolic blood pressure differences also existed between the 3 study groups and were higher in the UK, consistent with the age and BMI of the women. In the Bangladeshi study group, nearly 1/3rd of women were underweight, compared to 21.9% of the Pakistani group and only 3% in the UK study.
Metabolic and nutritional parameters
Women studied in WP2 had varied nutritional and metabolic parameters, with women in Bangladesh having the highest levels of serum folate and vitamin B12. Further investigation is ongoing to determine whether this is due to differences in dietary intake, supplementation, or assay variation. Women in the UK had the highest levels of vitamin D and were more hyperglycaemic.
Characteristics of the offspring born to women
Babies born to women in the UK were delivered earlier (at 38.5 weeks gestation) compared to those in Bangladesh, likely reflecting variation in obstetric practice. Despite these deliveries being at an earlier gestational age, babies born in the UK were heavier than their Bangladeshi and Pakistani counterparts, with higher birth length and skinfolds compared to Pakistani babies. Interestingly, the abdominal circumference of Pakistani babies was higher than that in the UK, suggesting greater central adiposity.
Analysis of the data from WP2 is ongoing and includes biochemical assay comparison, correction of birth measurements for gestational age at delivery and the identification of maternal determinants of birth weight and anthropometric measures. Evaluation of the observational data is also underway. The characteristics of the mothers and offspring recruited and studied have been characterised using simple descriptive statistics, and analysis is currently being performed to make comparisons between those recruited in Pakistan, Bangladesh and London.
This work package has enabled us to identify the prevalence of nutritional deficiencies and adverse metabolic health in people of South Asian origin in the UK, Bangladesh and Pakistan. It has also informed the subsequent intervention in WP3 and provided an important test of the recruitment, sample collection and analysis protocols. The high prevalence of micronutrient deficiencies provides an important insight to feed back to those delivering healthcare to women in pregnancy so that strategies to prevent and treat them can be implemented.
The data from WP2 will also be integrated into the WP6 and WP7 studies, in which genomic and epigenomic associations with micronutrient status and metabolic health are being investigated. These studies should, through Mendelian randomisation, identify causal pathways in determining birthweight, and identify potential epigenetic signatures of fetal programming.
We are currently preparing the feasibility of 4 manuscripts for publication from WP2: three manuscripts describing country-specific prevalence of micronutrient deficiencies and adverse metabolic health in pregnancy; and one manuscript combining the data collected from all 3 WP2 sites that analyse the combined dataset to identify nutritional and metabolic determinants of birth phenotype in babies of South Asian ethnicity.