Sleep apnea may increase risk of brain tumor

Obstructive sleep apnea (OSA) can cause repetitive dips in blood oxygen levels, which can then cause chronic inflammation. Some researchers think this chronic inflammation may increase risk of cardiovascular disease, lowered immunity, and increased risk of tumors. This study showed an increase risk of brain tumors in patients with sleep apnea. The article does not describe the OSA severity - is it only in severe OSA sufferers? Or is there risk increased even with mild OSA? Does it depend on how the researchers defined apnea events - with oxygen level dip and/or arousal in brain wave monitoring? More questions than answers at this point.