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Being overweight may cause higher blood pressure and thicken heart muscle, leading to heart disease. Researchers used data on healthy 17-year-olds and 21-year-olds who have participated in the ongoing Children of the 90s study-Avon Longitudinal Study of Parents and Children since they were born in the Bristol area of the United Kingdom.
The researchers’ findings suggest that higher BMI caused higher systolic and diastolic blood pressure; and caused enlargement of the left ventricle, the heart’s main pumping chamber. Thickening of vessel walls is widely considered to be the first sign of atherosclerosis, a disease in which fatty plaques build up within the arteries and lead to heart disease. Higher BMIs cause changes in the heart structure of the young that may precede changes in blood vessels.
Two of the analyses used in the study-Mendelian randomization and recall-by-genotype take advantage of the properties of genetic variation. Recall-by-genotype is novel and exploits the random allocation of genes at conception. This provides a natural experiment analogous to a randomized trial compare differences in an outcome -such as heart structure and function with differences in BMI, without the relationship being skewed by other lifestyle and behavioral factors.