Telomere length and telomerase activity have received increased attention
as markers of cellular aging, but the determinants of inter-individual variation
in these markers are incompletely understood. Cytomegalovirus (CMV) infection
may be particularly important for telomere and telomerase dynamics due to its
dramatic impact on peripheral blood lymphocyte composition, i.e., increasing the
number and proportions of highly differentiated T cells that are characterized
by shorter telomere length (TL) and lowered telomerase activity (TA). However,
the possible relationship between CMV infection and leukocyte TL and TA has not
been well-examined in vivo. This study examined the
associations of CMV seropositivity and CMV IgG antibodies with leukocyte (TL)
and (TA) in a sample of 434 healthy individuals (ages 53–76) from the
Whitehall II cohort. Positive CMV serostatus was significantly associated with
lower TA among women, and higher CMV IgG antibody levels were associated with
lower TA in the overall sample. However, neither CMV seropositivity nor CMV IgG
antibody levels (reflecting subclinical reactivation) among the seropositive
were significantly associated with TL. These associations were robust to
adjustment for age, employment grade, BMI, and smoking status. The results
demonstrate that CMV seropositivity and subclinical reactivation predict lower TA. Future longitudinal studies should test whether the association of CMV
with lower TA contributes to accelerated telomere shortening over time.