Most previous research on the relationship between body mass index
(BMI) - a measure of weight adjusted for height - and cardiovascular
events like heart attacks has focused on older adults
Researchers looked the relationship between BMI and routinely
collected cardiovascular data, such as blood pressure and heart
rate, in more than 3000 17-year-olds born in the 1990s. They also
examined cardiovascular scans from 400 21-year-olds who were at
higher genetic risk for an unhealthy BMI.
"Our results suggested that having a higher BMI likely causes higher
blood pressure," said lead study author Kaitlin Wade of the
University of Bristol in the UK. The results also suggest that a
higher BMI causes so-called left ventricular mass index to be
higher, reflecting enlargement of the left ventricle in the heart,
which pumps blood around the body, she said.
"These findings suggest that BMI is likely to have an adverse causal
impact on cardiac structure even in young adults," Wade said by
email. "Our results support efforts to reduce BMI to within a
normal, healthy range from a young age to prevent later
cardiovascular disease."
A BMI of 18.5 to 24.9 is considered healthy, 25 to 29.9 is
overweight, 30 or above is obese and 40 or higher is morbidly or
extremely obese. (The U.S. Centers for Disease Control and
Prevention has a free online BMI calculator here: http://bit.ly/2ylWKJC.)
In the current study, the 17-year-olds with weight data available
had an average BMI of about 23, in the healthy range, and average
blood pressure readings of about 119 mmHG over 64 mmHG, also within
a healthy range.
The American Heart Association defines hypertension, or high blood
pressure, as a systolic reading of 130 mmHg or higher and diastolic
readings of 80 mmHg or higher. Systolic pressure reflects the
pressure blood exerts against artery walls when the heart beats.
Diastolic pressure indicates the pressure when the heart rests
between beats.
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Among the young adults in the current study, higher BMIs were
associated with an increased risk of high blood pressure,
researchers report in Circulation.
The study wasn't a true controlled experiment designed to prove
whether or how excess weight might directly cause heart problems.
Still, the results suggest that heavier young adults had hearts that
pumped a greater volume of blood each minute, which over time can
lead to high blood pressure and thickening of the heart muscle,
noted Dr. Holly Gooding, a researcher at Harvard Medical School in
Boston who wasn't involved in the study.
"Whether this is due to the increased metabolic demands of their
higher weight, or increased inflammation generated by the fat cells
themselves, or something else is unclear, as these mechanisms
weren't addressed in this study," Gooding said by email. "What we do
know is that it is not simply due to lower physical activity or less
optimal dietary patterns in these individuals, as these lifestyle
factors were not associated with the genes for BMI."
No matter what they weigh, young people can still take steps to
minimize their risk of heart attacks and other cardiovascular
problems, Gooding added.
"Everyone can protect their heart by staying physically active,
eating a diet rich in fruits and vegetables and whole grains and low
in sodium and added sugars, and avoiding smoking," Gooding said.
"These health behaviors are important regardless of one's weight
status."
SOURCE: http://bit.ly/2mU6Vgb Circulation, online July 30, 2018.
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