Link between low birth weight and heart disease in later life
Link between low birth weight and heart disease in later life
28 July 2008
Children who are small at birth already have changes to their heart and blood vessel function in early childhood that may help to explain why they are more likely to develop heart disease in later life. This link between low birth weight and heart disease was established in a study of 140 children aged eight and nine. The results suggest that the way heart and blood vessels function under stress can reveal whether a person has a higher risk of developing high blood pressure. It also revealed differences in the way boys and girls respond to stress.
The research was led by Dr Alexander Jones, clinician scientist at the UCL Institute of Child Health in London, in his previous post as a clinical research fellow at the University of Southampton’s MRC Epidemiology Resource Centre. The results are published in the European Heart Journal.
The children had been healthy babies, born in Southampton, and were within the normal birth weight range. They were asked to perform a public-speaking task involving story telling, followed by mental arithmetic. During this, the performance of their heart and circulation was recorded using sensors. The tests found that changes in the heart and circulation differed between boys and girls.
Dr Jones explained:
“In boys we found that the lower their birth weight was, the more likely they were to have a higher vascular resistance, that is the resistance to flow that has to be overcome to push blood around the circulatory system, and higher blood pressure, particularly 25-30 minutes after the start of the stress test. In contrast, girls who were smaller at birth did not demonstrate a specific response to stress. They consistently, whether under stress or at rest, showed evidence of greater activity in the sympathetic nervous system, the part of the nervous system that controls involuntary actions and becomes more active during stress contributing to the ‘fight or flight’ response.’’
“This is the first evidence of relationships between size at birth and the function of the heart and blood vessels in childhood. The sex differences in these relationships were striking and may eventually lead to a better understanding of why men and women tend to develop high blood pressure and heart or vascular disease at different times in their lives. It suggests that different underlying mechanisms for developing the same disorder may exist in the two sexes but have the same eventual result,” he concluded.
Though the changes in the children’s responses to stress did not show that they had any early indications of disease, Dr Jones said:
“We have strong reasons to believe that children with more exaggerated stress responses are more likely to become adults who develop hypertension and go on to develop heart or vascular disease earlier in life than those who do not demonstrate these greater responses.”
Original research paper: Sex-specific programming of cardiovascular physiology in children is published in the European Heart Journal.
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