Weekend Screen Time=Bad Bones for Teen Boys

Bad to the bone, those electric screens…A new observational study from Norway has found that when boys spend too much time in front of a screen on the weekends it could very well result in poorer bone health. In a collaboration between UiT The Arctic University of Norway, the University Hospital of North Norway and the Norwegian Institute of Public Health, researchers analyzed data from the 961 individuals involved in the Tromsø Fit Futures Study in Norway; the participants were 15-17 year old school students.

According to the June 10, 2015 news release, the team found that boys had about five hours a day of screen time on the weekend; girls had four hours a day on the weekend. It turned out that 2-4, or more than 6 hours, “in front of a screen were linked to statistically significant reductions of bone mineral density at the femoral neck compared with boys clocking fewer than 2 hours of screen time daily on the weekend. But boys who spent 4 to 6 hours in front of a screen tended to have higher than expected bone mineral density levels. The opposite was true of girls among whom 4-6 hours of weekend screen time daily was associated with higher bone mineral density, even though they took less exercise than those who said they spent less time in front of a screen.”

The researchers indicated that the lack of impact of screen time on girls’ bone health may be explained by their different body fat distribution.

Anne Winther, a study author and Ph.D. candidate, told OTW, “We were surprised at gender difference, so that screen time at weekends was negatively associated with bone mass density levels in boys and positively in girls. This was after adjustments of several confounders known to affect bone, including age, puberty, physical activity levels and weekday screen time.”

Winther added, “As results from a cross section study, our findings are relationships only. But these contrasting patterns persisted two years later, and indicate stronger relationships. Screen time during weekends may be a possible indicator of lifestyle factors that may have detrimental effect on bone health. As participation in recreational sports or performing sports at a competitive level seems to exert significant beneficial effect on bone, the best way to promote good bone health in this age group is to encourage such activity. In addition physical activity during adolescence promotes physical activity practice in later life.”