This might be a bit of an exaggeration, but Dr. Cheung's guess is that the age-related problems of the future will be a bit different than those we face today. When using your phone, try your best to keep upright!
The human head weighs about a 12 pounds. But as the neck bends forward and down, the weight on the cervical spine begins to increase. At a 15-degree angle, this weight is about 27 pounds, at 30 degrees it's 40 pounds, at 45 degrees it's 49 pounds, and at 60 degrees it's 60 pounds. Overtime, this causing compression on the joints and bones of the neck, leading to degeneration.
Next time you use your phone, take a look in the mirror to see how bad you are!