I highly doubt anyone suffering from male pattern baldness is losing hair due to smoking, and those without male pattern baldness can smoke like chimneys and still have good hair. Look at Shane McGowan. That man is death, no teeth, his very blood is alcohol and is lungs coated in tar, yet his hair is great.
It probably doesn't help, and it's certainly bad for skin, but I seriously doubt cigarettes are the cause of male pattern baldness.
Nope, Shane Macgowan's hair is perfect, Norwood 1 at best, sub Norwood 2 at worst. He has no teeth and by all rights should be dead due to his extreme alcoholism and smoking, but he's still a 57 year old dude with NW1-2 hair. Extremely excessive alchohol and tobacco abuse hasn't made him bald.