This bad habit affects nearly every organ in your body. It can lead to heart disease, cancer, diabetes, stroke, bronchitis, emphysema, and other health problems. It also raises your risk of tuberculosis, eye problems, and immune disorders like rheumatoid arthritis. And if you spend a lot of time around someone who smokes, you’re more likely to have asthma, heart disease, lung cancer, or a stroke. Talk to your doctor about quitting smoking.