What causes arthritis?

To begin with, arthritis takes many forms, each of which is set on by different factors. Osteorarthritis is the most common and least severe. It triggers a gradually degenerating process in the affected joints and surrounding bone and cartilage.

It's a common misconception that arthritis is caused by the wear we put on our joints daily. It develops over time and is brought on early by a number of underlying factors aside from age, including abnormal joint development.
The best way to avoid it is to take care of your joints throughout your lifetime. Glucosamine and omega 3 acids are both known to help slow the progression of osteoarthritis, but regular exercise, rest, and a balanced diet are all going to help your cause, just as it seems to be beneficial preventive measure to almost every avoidable ailment out there.

But be careful with the way you exercise. I was in Tae Kwon Do and Soccer at the same time for about three years. Now I hate to run because after about half a mile my knees start to hurt really bad. They also crack any time I bend them. Only 15 :(

May not be directly attributed to arthritis though.

Another cause could be mal-nutrition during joint development, or chemical compounds wearing at the joint cushions.