In a sense we are all at risk for obstructive sleep apnea (OSA) because we all have a potentially collapsible upper airway. Also, in all of us, the muscles responsible for holding that airway open as we take in a breath are not as active- are less powerful- during sleep. The balance can be tipped toward collapse by any condition that narrows the upper airway or impairs the activity of the dilating muscles.
You cannot do anything about some risk factors. OA is more than twice as common in men as women, although after menopause this difference between the sexes tends to disappear. You also cannot do anything about getting older, and the prevalence of OSA increases with age, at least up to the age of 65. We do not choose our parents, and studies have shown OSA can run in families. We inherit our facial structure, and small jaws, a high arched palate, and an overbite can make the airway narrow and more collapsible. In children large tonsils that narrow the airway are frequently responsible for OSA.
The culprit in most persons with OSA is something they potentially can do something about- obesity. Over 75% of persons with OSA weigh more than 120% of their ideal body weight. Another way of measuring obesity that takes into account height in called body mass index (BMI). A person with a BMI of over 30 is at increased risk for OSA. Increased neck size is a risk factor. In men a neck size of 18inches or greater (16 inches in women) is associated with an increased risk of OSA.
Habitual snorers, those who snore loudly most nights, are at increased risk. Those who have high blood pressure, especially blood pressure that is difficult to control, are at increased risk, as are those who have had a heart attack or stroke.
A fat middle aged hypertensive sleepy male who snores loudly is the poster child for OSA risk.