Left-handed people seemingly die 6 to 9 years sooner than right-handed people. No one has a good explanation for why
According to psychologist Stanley Coren, lefties live less long for a variety of reasons. Lefties tend to have a lower immunity to disease, as well as a higher accident rate, Coren says.
A survey taken of a thousand recently deceased claimed that the average left handed person died nine years sooner than the right handed counterpart. While the average age of death for righties was 75, the average age of death for lefties was apparently 66.
Many were quick to question this, because in other similar experiments there was either a much smaller difference in the age of death or no notable difference at all. In addition, nine years is a larger age gap than even the gap between smokers' and non-smokers' projected lifespans.
A study of right and left handed cricket players showed only a two year gap, while a study of right and left handed baseball players showed only an eight month gap. Those who dispute the nine-year gap argue that if it were so, life insurance companies would have caught on much sooner and would be slower to insure lefties.
A 1992 article in the Atlantic notes that lefties have higher frequencies of depression, substance abuse, bed wetting, suicide and attempted suicide, low birth weight, sleeping disorders, and autoimmune diseases. This is argued as an explanation for why they live shorter lifespans.
Yet another explanation is that there's simply a generational gap between lefties and righties. That is, that some of the older generation of lefties was forced to become right-handed. It wasn't until later generations that people were free to be left- or right-handed.