a specific population. It differs from species
to species. The maximum recorded lifespan
for humans, reported in 2010, was 122.5 years
for females and 116 years for males.
Lifespan is a common measurement in
aging research. That’s because it is clear-cut
and easy to measure—an organism is either
Researchers are finding that lifespan
alive or dead. Scientists look for factors such
may be influenced by external factors, as well.
as genes, environment, and behavioral traits
This has been demonstrated in animal stud-
(including diet) that may contribute to an
ies. NIA’s Interventions Testing Program (ITP)
organism’s lifespan. Altering a factor to see if
examines a variety of compounds for their
it changes lifespan can provide evidence about
effects on the lifespan of mice. Compounds
whether or not that specific factor is impor-
studied include dietary supplements,
tant for aging. For instance, when researchers
hormones, and anti-inflammatory drugs.
suspect that a specific gene has an effect on
In one ITP study, male mice treated with
lifespan, they may test their hypothesis by
aspirin, an anti-inflammatory drug, displayed
modifying the activity of that gene (perhaps
a moderately increased lifespan. In another
lower its activity by deleting the gene or
ITP study, masoprocol, an anti-inflammatory
increase its activity by adding an extra copy
drug that has antioxidant properties, was
of it). If the life of the animal with the modified found to increase longevity of male, but not gene activity is longer or shorter, then the gene
female, mice. These and other findings may
probably does play a role in lifespan.
help scientists identify compounds to test in
BIOLOGY OF AGING: RESEARCH TODAY FOR A HEALTHIER TOMORROW 7