Heart Disease in Men Linked to Teen Years
Normal developmental changes during the teenage years leave
young adult men at higher risk of heart disease than their female counterparts,
researchers report in the journal Circulation.
“Women’s protective advantage against heart disease starts
young,” says lead author Dr. Antoinette Moran, at the University of Minnesota
Children’s Hospital.
In adults, a set of factors increases the risk of heart
disease.
These factors include high blood pressure, smoking,
obesity, physical inactivity, abnormal cholesterol levels, and insulin
resistance (a pre-diabetic condition in which the body cannot use insulin
effectively).
To track the risk factors, researchers followed 507
Minneapolis school children from ages 11 to 19, when they had all reached sexual
maturity. Fifty-seven percent of the children were male, 80 percent were
Caucasian, and 20 percent were African American.
During the study, the researchers made 996 observations on
the group, noting blood pressure, insulin sensitivity (opposite to insulin
resistance), body mass index (BMI) and other body composition measures, blood
glucose, and cholesterol measurements.
“We wanted to see which risks emerge first and how they
relate to one another in normal, healthy school kids without diabetes or other
major illnesses,” says Dr. Moran.
At age 11, boys and girls were similar in their body
composition, lipid levels, and blood pressure, the researchers say.
Boys and girls became heavier during adolescence,
increasing in body mass index and waist size. As expected during puberty,
changes in body composition differed sharply between genders, with percentage of
body fat decreasing in boys and increasing in girls.
During the study, changes in several cardiovascular risk
factors or risk markers differed significantly between boys and girls:
- Triglycerides (a type of fat in the blood) increased in males and
decreased in females.
- High-density lipoprotein (HDL or “good”) cholesterol decreased in males
and increased in females.
- Systolic blood pressure (the first number in the blood pressure reading,
measuring the pressure when the heart contracts) increased in both, but
significantly more in the males.
- Insulin resistance, which had been lower in the boys at age 11, steadily
increased until the young men at age 19 were more insulin resistant than the
women.
Researchers found no gender difference in two other
cardiovascular risk factors, total cholesterol, and low-density lipoprotein (LDL
or “bad”) cholesterol.
“By age 19, the boys were at greater cardiovascular risk,”
notes Dr. Moran. “This is particularly surprising because we usually think of
body fat as associated with cardiovascular risk, and the increasing risk in boys
happened at the time in normal development when they were gaining muscle mass
and losing fat.”
Although girls gained cardiovascular protection when their
proportion of body fat was increasing, excess fat is still a cause for concern.
“Obesity trumps all of the other factors and erases any
gender-protective effect,” says Dr. Moran. “Obese boys and girls and men and
women all have higher cardiovascular risk.”
The researchers say further studies are needed to better
understand the development of cardiovascular protection during adolescence.
“That the protection associated with female gender starts
young is fascinating and something that we don’t understand very well,” explains
Dr. Moran.
“That this protection emerges during puberty and disappears
after menopause suggests that sex hormones give women a protective advantage,”
he says.
“There’s still a lot that needs to be sorted out in future
studies - estrogen may be protective or testosterone may be harmful,” says Dr.
Moran.
Dr. Moran says that this is normal physiology and not
something that is influenced by lifestyle factors.
Always consult your physician for more information.
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The food guide pyramid is a guideline to help you eat a
healthy diet.
The food guide pyramid can help you eat a variety of
foods while encouraging the right amount of calories and fat.
The United States Department of
Agriculture (USDA) and the US Department of
Health and Human Services have prepared a food pyramid to guide you
in selecting foods.
The food pyramid is divided into six colored bands
representing the five food groups plus oils.
Orange represents grains: Make half the grains consumed
each day whole grains.
Whole-grain foods include oatmeal, whole-wheat flour,
whole cornmeal, brown rice, and whole-wheat bread. Check the food label on
processed foods - the words “whole” or “whole grain” should be listed before
the specific grain in the product.
Green represents vegetables: Vary your vegetables.
Choose a variety of vegetables, including dark green- and orange-colored
kinds, legumes (peas and beans), starchy vegetables, and other vegetables.
Red represents fruits: Focus on fruits. Any fruit or
100 percent fruit juice counts as part of the fruit group. Fruits may be
fresh, canned, frozen, or dried, and may be whole, cut-up, or pureed.
Yellow represents oils: Know the limits on fats,
sugars, and salt (sodium).
Make most of your fat sources from fish, nuts, and
vegetable oils. Limit solid fats like butter, stick margarine, shortening,
and lard, as well as foods that contain these.
Blue represents milk: Get your calcium-rich foods. Milk
and milk products contain calcium and vitamin D, both important ingredients
in building and maintaining bone tissue. Use low-fat or fat-free milk after
the age of two years.
However, during the first year of life, infants should
be fed breast milk or iron-fortified formula.
Whole cow’s milk may be introduced after an infant’s
first birthday, but lower-fat or skim milk should not be used until the
child is at least two years old.
Purple represents meat and beans: Go lean on
protein. Choose low fat or lean meats and poultry. Vary your protein routine
- choose more fish, nuts, seeds, peas, and beans.
Activity is also represented on the pyramid by the
steps and the person climbing them, as a reminder of the importance of daily
physical activity.
Always consult your physician for more information.
(Our Organization is not responsible for the content of
Internet sites.)
American
Academy of Family Physicians
American Heart Association
Centers
for Disease Control and Prevention (CDC)
Circulation - Changes in Insulin Resistance and Cardiovascular Risk During
Adolescence
National Heart, Lung, and Blood Institute (NHLBI)
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