Adult diseases may be linked to childhood weight | Science News for Students

Adult diseases may be linked to childhood weight

Very overweight kids may grow up with an elevated risk of colon cancer and stroke
Jun 17, 2016 — 7:00 am EST
doctor and child

Maintaining a healthy weight in childhood is important. Being overweight early life has just been linked to cancer and stroke in adulthood

pyotr021/istockphoto

Being fat isn’t fun for anyone, especially children and teens. It’s not healthy either. Obesity that develops in childhood can set the stage for killer adult diseases, two new studies from Denmark show.

Past studies had shown that being overweight or obese boosts an adult’s risk of developing health problems affecting the heart and brain. But no one had shown that the same was true when that weight gain occurred in childhood. Now two new studies appear to do just that. Both were presented this month at the European Obesity Summit in Gothenberg, Sweden.

Researchers tend to assess obesity on the basis of more than weight alone. After all, for the same weight, a tall person will be leaner than a short person. So height, too, is key. Both height and weight go into calculating someone’s body mass index, or BMI. And the higher the BMI, the fatter a person tends to be.

Line Klingen Haugaard studies childhood obesity and how it affects health. She works at the University of Copenhagen in Denmark. Her team focused on health records for 307,000 Danes who had been born between 1930 and 1987. More than 3,500 of the women and almost 5,400 of the men at one time had suffered an ischemic (Ih-SKEEM-ik) stroke. This is where blood stops flowing to a part of the brain. Such strokes can prove deadly.

The researchers looked back at the early school records for all of the adults. They calculated the BMI for each of the men and women when they had been only 7 to 13 years old. (Denmark is one of the few nations that can do this, because its government keeps detailed, long-term health records for its citizens.)

People who had a higher BMI by age 13 faced a higher than normal risk of early stroke in adulthood, the researchers found. Early, in this case, means that a person had a stroke sometime between the ages of 25 and 55. After 55, childhood BMI appeared to play no role in stroke risk.

Consider a middle-school girl who was 156.7 centimeters (62 inches) tall and weighed 51.4 kilograms (113 pounds). Compared with a girl who was the same height but weighed 6.8 kilograms (15 pounds) less, the first girl’s adult risk of stroke would be 26 percent higher. A similar trend emerged in adult men who had been overweight as boys.

And as the BMI in childhood climbed, so did the early stroke risk that was seen in someone’s adult years, the new study found.

What might explain this? A higher BMI could cause the brain’s blood vessels to slowly harden and narrow, beginning in childhood, Haugaard suspects. And that, she worries, could disrupt the flow of blood to the brain, fostering an ischemic stroke in early to middle adulthood.

running shoe“If you have already reached the age of 55, other factors responsible for stroke become more important than any childhood factors,” says Haugaard. By other factors, she means diseases such as high blood pressure and type 2 diabetes. (High blood pressure occurs when blood flows with too much force through blood vessels. Type 2 diabetes is a condition when the body is not able to use a hormone called insulin. This hormone is important for the body to process glucose. People who have type 2 diabetes have abnormal levels of glucose in their blood, but also high risks of heart disease.)

Adult cancer risk also linked to overweight childhood

A second study also focused on Danish adults who had been overweight between the ages of 7 to 13. These people faced a heightened risk of colon cancer. This disease, which affects the biggest part of the large intestine, accounts for 8.3 percent of all U.S. cancer deaths. Any abnormal growth of cells in this part of the body might develop into a cancer.

Britt Wang Jensen works at Bispebjerg and Frederiksberg Hospital in Copenhagen. She and her colleagues gathered childhood BMI data for about 250,000 people born between 1930 and 1972. They then linked those data with national records on cancer patients.

Nearly 2,700 people from the original group developed colon cancer. And the higher their childhood BMI had been, the higher an adult’s risk of colon cancer turned out to be. Here’s another way to understand the findings: Let’s compare two boys — Jack and Tom — who were both born in the 1950s. They had the same height. Jack had an average weight. Tom weighed 5.9 kilograms (13 pounds) more than him. In adulthood, Tom had a 9 percent higher risk of colon cancer than Jack.

Stephen Daniels is a doctor who treats kids at the University of Colorado School of Medicine in Aurora. He was not involved with either study. He says the new findings are important and fit with what might be expected.

“The major strengths of the two studies are the large populations and the lengths of the follow-ups,” says Daniels. Some of the people in these studies were followed until they died. Daniels explains that it’s hard for scientists to track people for such a long time. That’s why these studies are important.

Both studies point to why it’s important to maintain a healthy weight at every age. Indeed, says Daniels, eating well in childhood and maintaining healthy levels of exercise are some of “the most important things for kids and their parents to think about.”

Power Words

(for more about Power Words, click here)

body mass index    (BMI) A person’s weight in kilograms divided by the square of his or her height in meters. BMI can be used to evaluate if someone is overweight or obese. However, because BMI does not account for how much muscle or fat a person has, it is not an accurate measure.

blood pressure    The force exerted against vessel walls by blood moving through the body. Usually this pressure refers to blood moving specifically through the body’s arteries. That pressure allows blood to circulate to our heads and keeps the fluid moving so that it can deliver oxygen to all tissues. Blood pressure can vary based on physical activity and the body’s position. High blood pressure can put someone at risk for heart attacks or stroke. Low blood pressure may leave people dizzy, or faint, as the pressure becomes too low to supply enough blood to the brain.

cancer    Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.

colon    (in biology) The majority of the large intestine, it runs between the cecum (a pouch below the small intestine) and the rectum. Foods are not digested in the colon, although this tissue lubricates wastes that will be excreted. Some liquids and salts, however, will be removed from materials stored in the colon before excretion.

glucose    A simple sugar that is an important energy source in living organisms. It is half of the molecule that makes up table sugar (also known as sucrose).

hormone    (in zoology and medicine)  A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.

insulin    A hormone produced in the pancreas (an organ that is part of the digestive system) that helps the body use glucose as fuel.

ischemia    (adj. ischemic) A blockage of blood flow, especially from an artery, to some part of the body. The condition can lead to death of the affected tissue.

obesity    Extreme overweight. Obesity is associated with a wide range of health problems, including type 2 diabetes and high blood pressure.

overweight    A medical condition where the body has accumulated too much body fat. People are not considered overweight if they weigh more than is normal for their age and height, but that extra weight comes from bone or muscle.

risk   The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.

stroke    (in biology and medicine) A condition where blood stops flowing to part of the brain or leaks in the brain.

type 2 diabetes   A disease caused by the body’s inability to effectively use insulin, a hormone that helps the body process and use sugars. Unless diabetes is controlled, a person faces the risk of heart disease, coma or death.

NGSS: 

  • MS-LS1-5
  • HS-LS1-2
  • HS-LS1-3
  • HS-ETS1-1

Citation

L. Haugaard et al. High child BMI and gain in BMI increases the risk of early stroke in adulthood. European Obesity Summit 2016. June 1, 2016. Gothenberg, Sweden.

B. Jensen et al. Higher body mass index at age 13 years increases risk of colon cancer in adulthood. European Obesity Summit 2016. June 1, 2016. Gothenberg, Sweden. 

Further Reading

T. Haelle. “To control overeating: Slow down!” Science News for Students. February 8, 2016.

A. Yeager. “Heart damage linked to obesity in kids.” Science News for Students. December 3, 2015.

J. Raloff. “Fat becomes a disease.” Science News for Students. June 21, 2013.

S. Ornes. “Kids with ‘adult’ problems.” Science News for Students. July 2, 2012.

S. Ornes. “Obesity linked to location.” Science News for Students. May 11, 2012.

S. Ornes. “Fat weights heavy on the brain.” Science News for Students. April 13, 2011.

S. Ornes. “Obesity and the common cold.” Science News for Students. October 5, 2010.