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January 18, 2011

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Obese kids said to show sign of “middle-age” heart disease

Oct. 25, 2010
Courtesy of the Heart and Stroke Foundation of Canada
and World Science staff

Obese children have stiff blood ves­sels typical of much old­er adults with car­di­o­vas­cu­lar dis­ease, who are at risk of early death, ac­cord­ing to a new stu­dy.

“These obese chil­dren al­ready have stiff blood ves­sels,” said re­search­er Kev­in Har­ris of the Brit­ish Co­lum­bia Chil­dren’s Hos­pi­tal, pre­sent­ing his find­ings at this year’s Ca­na­di­an Car­di­o­vas­cu­lar Con­gress in Mont­real.

Harris explained that obese children suffer something akin to prem­a­ture ag­ing of the aor­ta, the bod­y’s larg­est ar­tery, which dis­tributes oxygen-rich blood to all oth­er ar­ter­ies. “The nor­mal aor­ta has elas­tic qual­i­ties that buff­er the flow of blood. When that elas­ticity is lost, aor­tic stiff­ness re­sults – a sign of de­vel­op­ing car­di­o­vas­cu­lar dis­ease,” Har­ris told the meet­ing. “Aor­tic stiff­ness is as­so­ci­at­ed with car­di­o­vas­cu­lar events and early death.”

Har­ris and col­leagues eval­u­at­ed 63 obese chil­dren, aged 13 on av­er­age, and com­pared them with 55 nor­mal-weight young­sters. Chil­dren un­der­went a range of tests in­clud­ing ul­tra­sound scans of the heart and blood ves­sels. These tests were to de­ter­mine the Pulse Wave Ve­locity in the aor­ta, a meas­ure of how fast blood flows and one of the meas­ures used to as­sess aor­tic stiff­ness.

Ul­tra­sounds showed that the Pulse Wave Ve­locity and oth­er meas­ures of ar­te­ri­al health were abnor­mal in obese young­sters, Har­ris said, though oth­er meas­ures of heart health such as blood li­pid lev­els and blood pres­sure were not dra­mat­ic­ally dif­fer­ent.

To see ac­tu­al changes to heart and blood ves­sel per­for­mance in obese chil­dren is ex­tremely alarm­ing, said Beth Ab­ram­son, a spokes­wom­an for the Heart and Stroke Founda­t­ion of Can­a­da, which co-hosted the con­fer­ence. “We know there is an as­socia­t­ion be­tween un­healthy lifestyles and heart dis­ease. Our kids are at risk,” she said. “Poor nu­tri­tion and in­ac­ti­vity are threat­en­ing their health and well-be­ing. We must re­think the lifestyle stan­dards we have ac­cept­ed as a so­ci­ety.”

Child­hood obes­ity rates have tripled over the last 25 years and con­tin­ue rising, warned Abram­son; over a quar­ter of Ca­na­di­an chil­dren be­tween the ages of two and 17 years are overweight or obese. She notes that the health risks in­clude heart dis­ease, high blood pres­sure, and type 2 di­a­be­tes.

Har­ris said the next step should be to de­ter­mine wheth­er these changes are re­vers­i­ble with treat­ment such as im­proved di­et and ex­er­cise. This test may even­tu­ally be help­ful in mon­i­tor­ing the pro­gres­sion of car­di­o­vas­cu­lar dis­ease in chil­dren and young adults, he added.

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The blood vessels of obese children have stiffness normally seen in much older adults with cardiovascular disease, according to a new study. “These obese children already have stiff blood vessels,” said researcher Kevin Harris of the British Columbia Children’s Hospital, presenting his findings at this year’s Canadian Cardiovascular Congress in Montreal. “Aortic stiffness is an early indicator of cardiovascular disease in obese children,” like a premature aging of the aorta, he added. The aorta, the human body’s largest artery, distributes oxygen-rich blood to all other arteries. Stiffness of the aorta is typically associated with aging and is a strong predictor of future cardiac problems and mortality in adults, Harris said. “The normal aorta has elastic qualities that buffer the flow of blood. When that elasticity is lost, aortic stiffness results – a sign of developing cardiovascular disease,” Harris told the meeting. “Aortic stiffness is associated with cardiovascular events and early death.” Harris and colleagues evaluated 63 obese children, aged 13 on average, and compared them with 55 normal-weight youngsters. Blood pressure was taken, lipids evaluated, and body mass index measured. Children then underwent ultrasound scans of the heart and blood vessels. This test was used to determine the Pulse Wave Velocity in the aorta, a measure of how fast blood flows and one of the measures used to assess aortic stiffness. Ultrasounds showed that the Pulse Wave Velocity and other measures of arterial health were abnormal in obese youngsters, Harris said, though other measures of heart health such as blood lipid levels and blood pressure were not dramatically different. To see actual changes to heart and blood vessel performance in obese children is extremely alarming, said Beth Abramson, a spokeswoman for the Heart and Stroke Foundation of Canada, which co-hosted the conference. “We know there is an association between unhealthy lifestyles and heart disease. Our kids are at risk,” she said. “Poor nutrition and inactivity are threatening their health and well-being. We must rethink the lifestyle standards we have accepted as a society.” Childhood obesity rates have tripled over the last 25 years and it continue to rise, warned Abramson, and over a quarter of Canadian children between the ages of two and 17 years are overweight or obese. She notes that the health risks include heart disease, high blood pressure, and type 2 diabetes. Harris said the next step should be to determine whether these changes are reversible with treatment such as improved diet and exercise. This test may eventually be helpful in monitoring the progression of cardiovascular disease in children and young adults, he said.