Early development of obesity and the metabolic syndrome
Instituto de Saúde Pública da Universidade do Porto, Faculdade de Medicina da Universidade do Porto, Unidade de Investigação e Desenvolvimento Cardiovascular
Rates of overweight and obesity (including central adiposity), are increasing in children to epidemic proportions, and may even reverse the present decline trends in adult rates of cardiovascular diseases.
Overweight or obesity in childhood is associated with higher blood pressure, fasting lipids, glucose, insulin and markers of non-alcoholic fatty liver disease.
Type 2 diabetes, a disease previously considered to occur only in adults is increasingly seen in obese children. Obese children are more likely to become obese adults and it was recently shown that greater body mass index in childhood is associated with increased risk of cardiovascular disease later in adulthood.
These associations highlight the need to prevent childhood obesity, but as yet effective interventions for achieving this are unknown. A better understanding of the determinants of childhood obesity might lead to more effective preventive interventions.
A well-recognized cluster of cardiovascular risk factors among adults, the metabolic syndrome, has been associated with an increased risk of cardiovascular diseases and type 2 diabetes, and currently reaches remarkable proportions in our population. Also, there is growing evidence on the increasing prevalence of metabolic syndrome components in obese children and adolescents.
During the last decades, a large body of evidence has emerged describing the association between growth patterns in early life and the development of later health outcomes. It seems that early life exposures are crucial factors for a variety of health outcomes such as body size, body composition and the risk of diseases, such as type 2 diabetes and cardiovascular disease.
Thus, this project was designed to provide new insights on the determinants of early growth patterns and to estimate the association between intrauterine characteristics, fast early postnatal growth and other infant characteristics on the risk of developing the childhood overweight/obesity and adverse metabolic and vascular profiles, namely the metabolic syndrome components.
This project will use data from Geração XXI, a previously assembled cohort of 8654 babies born in Porto, Portugal, between May 2005 and August 2006.
For the establishment of this birth cohort, all mothers resident in the metropolitan area of Porto who delivered a live born baby during the assembling period in one of the five public hospitals serving the area were invited to participate.
In this project we aim to
a) determine which intrauterine (including maternal hypertensive disorder of pregnancy, gestational diabetes, weight gain in pregnancy, smoking and alcohol intake and socioeconomic position) and postnatal (including infant feeding and exposure to passive parental tobacco) exposures are associated with the amount and pattern of weight gain 0-2 years;
b) study the association of adipokines levels in the cord blood with the amount and pattern of post natal growth;
c) evaluate the association of intrauterine and postnatal exposures (as listed in (a)) with overweight/obesity, lipids, insulin and blood pressure levels at four years of age;
d) evaluate the associations of the amount and pattern of postnatal growth with overweight/obesity, lipids, insulin and blood pressure levels at four years of age and determine the extent to which any associations in (c) are mediated via postnatal growth.
Data were collected 24 to 72 hours after delivery by trained interviewers using a structured questionnaire to obtain information on mothers demographic and lifestyle variables, past medical history, complications and use of medication during pregnancy.
Newborn clinical registries were used to collect information on delivery, post-partum complications, anthropometrics and feeding during hospital stay. A blood sample of the mother and blood from the umbilical cord were collected at birth. Childhood growth and infant exposures have been monitored since birth via questionnaires and health data.
This existing information will be used to address objectives (a) and (b). The entire cohort will be invited to a follow-up assessment that is planned to begin in 2009. Both mother and child (at four years of age) will be evaluated.
A structured questionnaire will be applied and anthropometrics (child: weight, height, and waist, hip, arm, thigh and thoracic circumferences; mother: weight, waist, hip and arm circumferences) and blood pressure measured. Also, a blood sample from both mother and child will be collected. Data from this new evaluation, together with existing data willbe used to address all objectives (c) and (d).
Ethical approval for the study was obtained from relevant institutional ethics committees and all ethical procedures regarding informed consent were followed.