Although merchants weren't exactly happy with the idea of a credit card that could be used everywhere â fewer people would be using their individual store credit cards â McNamara's cards caught on quick with customers, expanding to 20,000 users in the first year.
Smoking can cause cancer and then block your body from fighting it: 1  Poisons in cigarette smoke can weaken the bodyâs immune system, making it harder to kill cancer cells. 2  Poisons in tobacco smoke can damage or change a cell's DNA.
The incidence of lung cancer is strongly correlated with cigarette smoking, with about 90% of lung cancers arising as a result of tobacco use. The risk of lung cancer increases with the number of cigarettes smoked over time; doctors refer to this risk in terms of pack-years of smoking history (the number of packs of cigarettes smoked per day multiplied by the number of years smoked).