Katelyn Jetelina, an epidemiologist at the University of Texas, Houston, says that age is the biggest personal risk factor, followed by having certain comorbidities or being immunocompromised.

Katelyn Jetelina 是休斯顿德州大学的流行病学家，她说最大的个人风险因素是年龄，其次是有某些合并症或免疫受损。

Personal factors also affect whether a person will begin to smoke. People with tendencies toward risk-taking behaviour are more likely to start smoking than people who tend not to take risks.

个人因素也会影响一个人是否会开始抽烟。有冒险倾向的人比不愿冒险的人开始抽烟的可能性要大。