There are many features that influence a left-handed person’s life expectancy. First, everyday tools adapted to left-handed people are less common and this is the first risk factor that left-handed people are subjected to. Indeed, using the wrong tools increases the risk of injury. Moreover, it is believed that the rate of exposure to sexual hormones is more pronounced for left-handed people during pregnancy and that is why they have an approximately 4% greater risk of developing certain cancers (genetic effect). also, even though left-handed people have a life expectancy that is shorter by about 10 years*, several factors that are more or less understood do play a role in this.
* some studies suggest this is closer to 3-5 years rather than 10.