Lack of exercise is also a risk factor for heart disease but it's relatively small when compared with the others.

缺乏锻炼也是导致心脏病的一个因素。但和其他因素相比，这种危险较小。

Q: is this a risk factor?

问：这是风险因素的一类吗？

Obesity is an important risk factor.

肥胖是一种重要的危险因素。

Stress is a risk factor for depression.

压力是导致沮丧的一个危险因素。

Poor oral hygiene is also a risk factor.

口腔卫生不良也是一个危险因素。