As the number of children who spend time watching television or playing video games increases, a new study is revealing that children who are exposed to higher screen time have a lower bone mineral density (BMD) than those who spend time outdoors. 

Researchers at Arctic University of Norway analyzed data collected from 463 girls and 484 boys of ages 15-18 from the Tromso region of Norway. All students were a part of the Fit Future Study 2010-2011. Bone mineral density was recorded using a dual-energy Z-ray absorptiometry (DXA).

In the study, found in the journal Osteoporosis International, researchers concluded that boys spent more time in front of a screen than girls. Boys with higher screen time were linked to having a lower BMD. They also found that females who spent about four to six hours in front of the computer had higher bone mineral density than those who spent less than 1.5 hours per day in front of the screen.

Researchers analyzed the link between screen time and BMD in several regression models that included age, sexual maturation, BMI, leisure time physical activity, smoking, alcohol, cod liver oil and consumption of carbonated drinks. Lifestyle factors including how much time they spent in front of the television or computer on weekends, and their levels of physical activity, were also documented. Participant also underwent bone mineral density tests.

"Bone mineral density is a strong predictor of future fracture risk. [Our] findings for girls are intriguing and definitely merit further exploration in other studies and population groups. The findings for boys on the other hand clearly show that sedentary lifestyle during adolescence can impact on BMD and thus compromise the acquisition of peak bone mass. This can have a negative impact in terms of osteoporosis and fracture risk later in life," lead author of the study Dr. Anne Winther of the Arctic University of Norway, Tromso, said in a statement.