Here is a short extract from this American website all about Sleep Apnea, in particular OSA.
http://www.helpguide.org/life/sleep_apnea.htm
Primary causes and risk factors of obstructive sleep apnea
1. Being overweight or obese (although 50% of people with sleep apnea are not obese)
2. Large tonsils or adenoids
3. Other distinctive physical attributes (deviated septum, shape of head and neck, receding chin, enlarged tongue)
4. Nasal congestion or blockage (from cold, sinusitis, allergies, smoking, etc.)
5. Throat muscles and tongue relax more than normal during sleep (possibly due to alchohol or sedatives or age)
6. Obstructive sleep apnea does seem to run in families which may be a result of anatomic abnormalities or medical conditions that are genetic.
As some Type 2 Diabetic's may be overweight, not all, then the first comment about overwight and obesity is pretty relevant. Most of the ones I have met with it fall into that category.
Ken.