Children born with a higher birth weight are on average heavier at 7 years of age, having a higher cardiovascular risk. The conclusion is of a study by the Instituto de Saúde Pública da Universidade do Porto (ISPUP), published in the “International Journal of Obesity”.
“Adverse exposures, when they occur at certain critical periods early in life, can lead to a higher cardiometabolic risk at an early age and later in adulthood. Following this logic, we know that birth weight is a major determinant of cardiometabolic complications in the future”, says Maria João Fonseca, first author of the study, coordinated by the researcher Ana Cristina Santos.
“The literature describes two mechanisms by which birth weight may lead to greater cardiovascular risk”, the researcher says. On the one hand, there is the so-called “tracking effect”, which refers to the stabilization of weight over time. “According to this model, children who are born with a higher weight tend to maintain a high body mass index (BMI) during childhood and also fatness throughout life, which translates into greater cardiovascular risk”, she adds.
Another mechanism, so-called “programming“, argues that the body of a child with low birth weight is not as well adapted to cope with extrauterine life, namely the obesogenic environment in which we live, and therefore has a higher cardiovascular risk.
Given these two contradictory mechanisms, this study sought to understand why birth weight influences cardiovascular risk later in life, using a sample of 4881 children from the Generation XXI cohort – a longitudinal study that has followed since 2005, 8600 participants who were born in public maternity hospitals in the Porto Metropolitan Area.
The researchers obtained birth weight through clinical records at the time of birth, and measured cardiometabolic risk indicators (systolic and diastolic blood pressure, LDL cholesterol, glucose and triglycerides) and the BMI of the participants when they were 4 and 7 years old.
They found that children born with a higher weight have a higher BMI at 7 years and, consequently, have worse cardiometabolic indicators. Participants who had a lower birth weight were also found to have higher blood pressure, which was the only cardiometabolic indicator that was directly altered via low birth weight.
According to Maria João Fonseca, “this article shows that both birth weight and children’s BMI during childhood are important for future cardiometabolic risk. We were able to show that a higher weight seems to be associated with cardiometabolic changes as early as 7 years of age”.
The article, developed within the ISPUP Epidemiology Research Unit (EPIUnit), is entitled Direct and BMI-mediated effect of birth weight on childhood cardiometabolic health — a birth cohort study. The researchers Milton Severo, Debbie A. Lawlor and Henrique Barros also participated in the study.
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