In virtually all parts of the world, women live longer than men. This discrepancy has been remarkably consistent for centuries, yet science has thus far been unable to determine why it exists. Now, a study reported in the multidisciplinary journal Mechanisms of Ageing and Development provides a tantalizing clue.
The study found that “natural killer” cells, a form of white blood cell that destroys aging, infected, and cancerous cells, are more active in elderly women than men, even though overall cell counts are equal between the sexes. NK cell activity protects the human body against pneumonia, cancers, and infectious diseases. Previous studies focused on comparing longevity between the sexes have not focused on NK cells specifically, which makes this study unique.
The study also found that women in general have higher B cell counts as they age. B cells are also an important white blood cell involved in immune response. Dr. Charles T. Lutz, the principal director of the study and director of molecular pathology at the University of Kentucky, suggests that other gender-related factors, such as socialization, occupation, risk-taking behaviors, and the use of hair dyes and cosmetics could also affect longevity.
While this study was quite small, involving just 50 men and women between the ages of 70 and 90 years old, it is a significant finding that merits further research.