Reference
Cohen S, Janicki-Deverts D, Turner RB, et al. Association between telomere length and experimentally induced upper respiratory viral infection in healthy adults. JAMA. 2013;309(7):699-705.
Design
Between 2008 and 2011, telomere length was measured in peripheral blood mononuclear cells (PBMCs) and T-cell subsets (CD4, CD8CD28+, CD8CD28-) in study participants who were subsequently quarantined (single rooms), exposed to a common cold virus, and monitored for 5 days for development of infection and clinical illness.
Participants
152 healthy 18- to 55-year-old residents of Pittsburgh, Penn.
Study Medication and Dosage
Nasal drops containing the common cold virus, rhinovirus 39
Outcome Measures
Infection (virus shedding or 4-fold increase in virus-specific antibody titer) and clinical illness (verified infection plus objective signs of illness) were tracked and compared with telomere length.
Key Findings
Of the 152 test subjects, 105 (69%) became infected and 33 (22%) showed symptoms of clinical illness. Shorter telomeres were associated with greater odds of infection, independent of pre-challenge virus-specific antibody, demographics, contraceptive use, season, or body mass index. The odds ratio of becoming infected increased by 71% for every standard deviation decrease in PBMC telomere length. Thus 77% of those individuals whose PBMC telomeres measured in the shortest tertile became infected, while only 66% of those in the middle tertile of length became infected, and only 57% of those with the longest telomeres succumbed to illness. Similar associations were seen in CD4 telomere length: 80% of the individuals with the shortest CD4 telomeres were infected, compared to only 54% of those with the longest. Similar associations were found with CD8CD28: 77% of the shortest became infected, while only 50% of those subjects with the longest were infected. In regard to CD8CD28 length, shorter telomere length was also associated with greater risk of clinical illness—not just infection—and this association became stronger with age.
Practice Implications
These findings suggest that telomere length is predictive of susceptibility to upper respiratory infection.
This study is consistent with a number of recent reports. A related study (Lee 2012) compared telomere length with mortality from disease in 4,271 subjects with mild to moderate chronic obstructive pulmonary disease (COPD) who participated in the Lung Health Study (LHS). All of these LHS participants had significantly shorter telomeres than healthy controls. Those LHS participants who were in the upper quartile of the group for telomere length had significantly lower risk of developing cancer during the 7.5 years of the study and lower risk of mortality compared to participants in the other 3 quartiles.1
Telomere length is looking more and more like a possible predictor of health and longevity.
In October 2012, Meng Chen from MD Anderson, presenting at the American Association for Cancer Research (AACR) Conference, reported the results of his team's analysis of data from 464 bladder cancer patients. Patients with both shorter telomere length and high scores on a depression scale had a threefold increase in cancer mortality and significantly shorter disease-free survival (31.3 months versus 199.8 months).2
In November 2012, the results were reported from what is possibly the largest study looking at telomere length and health. Researchers at Kaiser Permanente and the University of California, San Francisco measured telomere length in 110,266 people in northern California. Those people with the shortest telomeres, the lowest 10%, had a 20% higher risk of dying than people with longer telomeres.3
The implication is becoming clearer with each new study. Telomere length is looking more and more like a possible predictor of health and longevity. The question this leaves all of us with is whether interventions that change telomere length will be associated with changes in either.
In our training as naturopathic physicians we often speak of a person’s "vital force." This was and continues to be a difficult-to-define measure of vitality and the ability to heal from illness. I can’t help but wonder if telomere length is somehow a gauge by which we can assess this "force."
