Either way, it does highlight the importance of exercise for both conditions.  Inactivity leads to obesity and both problems are proven to have a negative impact on blood sugar regulation and joint functioning.  For people with diabetes, regular physical activity helps control blood sugar and helps lower the risk of cardiovascular complications.  For people with arthritis, regular exercise reduces pain and imroves joint function - contrary to the old belief that activity deteriorates the joints.  So for the people with both conditions, or who are at high risk of developing both conditions, it is extra important to try to participate in low-impact activities like walking and swimming.