Risk factors such as insulin resistance and high blood pressure begin to take their toll on the body as early as age 14, say researchers according to a recent study. The study was
In adults, high blood pressure is linked to an increased risk of heart attack, stroke and kidney disease. Researchers wanted to determine if high blood pressure is related to other heart disease risk factors seen in adolescents, such as insulin resistance, obesity and high cholesterol.
Insulin resistance is a condition in which the body's cells are less responsive to insulin,the hormone that helps the body's tissues absorb nourishment (glucose). Unlike diabetes, in which the body cannot create enough insulin, people with insulin resistance have plenty of insulin but their bodies do not use it properly. Glucose levels therefore remain high, which causes more insulin to be released by the pancreas. As a result, people with insulin resistance often end up having too much insulin circulating in the blood. Insulin resistance may lead to diabetes and a cluster of factors including insulin resistance (called Metabolic Syndrome X) has been linked to an increased risk of heart disease.
Researchers measured obesity, insulin resistance, blood pressure and cholesterol levels of 324 boys and girls. Measurements were taken when the young people were 14 and again when they were 16. Obesity levels were measured using a body mass index (BMI) calculation. BMI is the person's weight in kilograms divided by their height in meters squared (wt/ht2). Researchers classified those with a BMI of 25 or greater as overweight while those with a BMI of 30 or greater were considered obese. Cholesterol and triglycerides were measured with a total cholesterol blood test, including levels of HDL (good) cholesterol, LDL (bad) cholesterol and triglycerides.
Insulin resistance was measured through a process called an insulin clamp study. Participants were given a steady infusion on insulin through an IV, along with enough glucose to maintain safe body levels. The dose of the insulin was "clamped," meaning that it was held at a certain amount. Researchers then measured the amount of glucose needed. Lower amounts of glucose processed by the body indicated insulin resistance.
At the time of the second measurements, researchers found a significant correlation between insulin resistance and systolic blood pressure in the boys. Systolic blood pressure is the top number in a blood pressure reading. This measurement represents the highest level of the blood's pressure within the artery walls and corresponds to the contraction of the heart's main pumping chambers (ventricles). Higher insulin resistance was related to a higher systolic blood pressure in the the15-year-old boys.
Researchers also found that insulin resistance in adolescents was linked to a decrease of "good" HDL cholesterol and an increase of triglycerides. In addition, the correlation between high blood pressure and insulin resistance was directly affected by levels of obesity.
While researchers were unable to determine the reason why the boys' data differed from the girls', they speculated that it may relate to an overall early risk, which is higher in males than females. Researchers also noted that the ages of 14 to 16 is a time span when many boys go through puberty. They went on to suggest that a healthy diet, regular exercise and weight control in adolescents can help to postpone or prevent serious health problems as adults.