Smoking in other--cigars or chewing tobacco also

其他吸烟方式如雪茄及嚼咽
causes cancer because the chemicals

同样能够导致癌症
in cigarette smoke or in tobacco, in particular.

因为香烟或者烟草中的化学物质致癌
Some of the tars that are associated with smoking

尤其是一些吸烟的水手
cause cancer of the lung in particular.

会得肺部的癌症
This was first noticed by looking at epidemiological data.

这最初是由流行病学的数据中得到注意的
We talked about public health and epidemiology a few weeks ago

我们几周前讨论过公共卫生及流行病学
where you look at how diseases appear in populations

从中你们可以看到疾病在人口中的表现
and you try to figure out why things are changing.

并可以尝试指出为什么会有这样的变化
Here's as cigarettes were consumed more in the U.S.,

这里有在美国所消费的香烟的数据
you can see the trend in cigarette consumption

你可以看到自1900年到1950年来
going up over time from 1900 to 1950.

香烟消费的增长趋势