I'm not really surprised by this. Starting to smoke and continuing to smoke are bad life choices and indicate a lack of will power and long-term thinking. Yes, cigarettes are incredibly addictive and quitting is hard (I smoked for 6 years when I was a teen and young adult). The same poor life choices and lack of long-term planning also lead to a low-income existence. Not applying yourself in school because you'd rather "have fun now." Not attending college. Not eating healthy foods. Not exercising. Smoking cigarettes. The fact that these things are all related shouldn't be a mystery or revelation. Poor people smoke more because poor people make bad choices in general.