Growth, Adiposity and Cardiovascular Status in Late Childhood: Relationships with Ethnicity, Maternal and Early Life Factors

Abstract

Cardiovascular disease (CVD) is a leading cause of death globally, and those of South Asian (SA) origin demonstrate a higher risk of CVD in adult life. The early origins of CVD are now recognised. but not fully understood. The best methods to use and at what age CVD risk factors in early life are detectable are not known. We therefore investigated a cohort of children for relationships of ethnicity, maternal and early life origins with growth, adiposity and CV status in late childhood to try and answer these questions. Data was collected from the cohort in late childhood, to define the children’s body fat distribution and CV status. To assess fat distribution, anthropometry and bio-impedance measurements were made. Blood pressure (BP) and aortic pulse wave velocity (aPWV) were measured to assess large vessels whilst retinal microvasculature was imaged to assess small vessels. Cardiac structure and function were determined with both traditional echocardiography measures and the newer techniques of tissue Doppler imaging and speckle tracking. Blood samples previously collected in early life were assayed for vascular growth factors (VGFs) and adiponectin. These data were used to identify associations of body fat with CV status and to determine if ethnic differences existed at this age, either in the measurements made or the relationships between these measurements. Statistical analyses, including General Linear Models were used to identify relationships between maternal and early life factors on body fat and CV health in later childhood as well as the effects of VGF Levels and adiponectin in early life on vascular status. Ethnic differences in these relationships were also identified. The results included findings of ethnic variations in some VGF levels in early life. Relationships of VGF with vascular status in early life were also identified; Fibroblast Growth Factor was negatively related to SBP, whilst Epidermal Growth Factor was positively related to both Diastolic Blood Pressure and aortic Pulse Wave Velocity. The results also demonstrated that by late childhood there are ethnic differences in CV status and body fat deposition. SA children had more body fat and lower diastolic cardiac function compared to WE children. In SA children BMI and body fat were related to cardiac structure (LV Indices). In utero and early life factors related to childhood adiposity and CV status in pre-adolescence were identified, and some of these varied by ethnicity. Maternal pregnancy BMI was positively related to body fat in late childhood, and in SA maternal pregnancy fasting glucose levels showed a negative effect on diastolic function in late childhood. These in utero and early life effects may account for individuals being set on a trajectory to a higher CVD risk profile and ultimately overt CVD. In order to further understand the relationships of ethnic, maternal and early levels of vascular growth factors with CV risk factors and disease, the relationships we have demonstrated need to be corroborated. Further research into these relationships and collection of more paediatric data using the novel methods of assessing cardiovascular status used here, could ultimately provide validated screening tools and primary preventative targets to prevent CVD.

Date of Award	31 Dec 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Leena Patel (Supervisor) & Peter Clayton (Supervisor)