Assuming we're really talking about sleep apnea, which snoring is a symptom of, and does affect your sleep in some really nasty ways. The prevalence of memory problems goes beyond what apnea would cover.

Let's talk stats for a second:

There's a buildup of fatty tissue as you age. The soft palate changes in shape, and you're more likely to gain weight. Weight is the largest component, gender is secondary, and age is tertiary. Interestingly, while sleep apnea is more likely to occur as you age, the severity goes down.

Incidence in male population goes to about 20% after the age of 75. For women, it's a bit over 10 - though that's just an estimate because women show symptoms at a different rate.

I somewhat wish apnea was the cause, for selfish reasons. There would be more drive to improve the machines, and as a bonus, these people could start getting treated.