Does Height Affect Life Expectancy?
There's no denying that short people tend to get the short end of the stick. In fact, studies show that short people are less likely to believe in a fair world and typically have lower life satisfaction (per Personality and Individual Differences). Their minds could change, however, if they realized some key benefits of being short.
A 2003 Life Sciences minireview analyzed a study that examined millions of deaths, finding that shorter people had lower death rates and longer lifespans on average. These findings have since been reinforced in studies examining the relationship between mortality and height in former basketball players (via PLoS ONE) and Italian soldiers (via Biodemography and Social Biology).
Some researchers (via Innovation in Aging) even believe that women's shorter heights on average may be one of the reasons they live longer than men. On average, men are 8% taller than women and have a 9% shorter life expectancy. Interestingly, Life Sciences reports that smaller animals within the same species often live longer than their larger counterparts.
This is why short people may live longer
Genes may play a role. A 2014 study in PLoS ONE found that shorter people are more likely to have a protective form of the FOX03 gene that is linked to longer lifespans. The study also discovered that taller people had higher fasting blood insulin levels, putting them at higher risk of mortality.
Another major factor is that short people's bodies have fewer cells, which provides less opportunity for cancer to develop (via Cancer Epidemiology, Biomarkers & Prevention). According to the Journals of Gerontology, every additional inch of height increases the risk of death from cancer by 7.1% in men and 5.7% in women. Short people also have shorter veins, offering less space for blood clots to occur (per American Journal of Hematology).
Despite these findings, the research isn't conclusive (per Journal of Epidemiology & Community Health), and being taller is not a death sentence. On the contrary, people of all sizes can increase their chances of living a long life if they maintain a healthy lifestyle.