Complex sentence: Women were 3.3 times more likely to become dependent, compared with men; and those who started using at ages 12 or 13 were four times as likely to become dependent, compared with those who started between ages 18 and 20.
Split into simpler sentences: Women were 3.3 times more likely to become dependent, compared with men. Users who started at ages 12 or 13 were four times as likely to become dependent, compared to those who started between ages 18 and 20.