by Patricia Shelton, MD
It’s been said that telomere length “captures the interplay between genetics, life experiences, and psychosocial and behavioral factors”1. In other words, your telomere length can be affected by nearly everything in your life.
Genetics does play an important role. People whose parents lived to be at least 100 years old have longer telomeres than those whose parents died at an average or younger age2, demonstrating the importance of genetics in determining longevity. Women also have longer telomeres than men do at the same age3, which is consistent with the longer average lifespan of women than men. Additionally, paternal age at birth is also associated with the telomere length of the children4, most likely because those men who are healthy into older age are more likely to have children when they’re older.
But while genetic factors are important, genes are certainly not the only factor that affects telomere length. Many dietary, behavioral, and psychological factors also play a major role.
The degree of inflammation in the body is one key factor. Levels of plasma homocysteine, a marker of systemic inflammation, are strongly associated with shorter telomeres5. Even in adolescents, inflammation is associated with shorter LTL6, demonstrating the importance of teaching healthy behaviors early in life. Inflammation is also linked to a number of chronic diseases, so controlling inflammation is crucial to longevity.
Smoking has been shown reliably to be associated with shorter telomeres7, and the difference is consistent with the lifespan of smokers being shorter than that of nonsmokers by about seven years8.
Longer telomeres have been shown to be associated with a moderate amount of exercise9; either too much or too little exercise leads to telomere shortening2. The association between exercise and telomeres remains after correcting for the influence of obesity (which is also associated with shorter telomeres), indicating that it is exercise specifically, rather than weight loss, that is important for telomere protection10.
Sleep also protects telomeres. Longer average sleep duration has been associated with longer telomeres11. In addition to how much you sleep, when you sleep matters; those who frequently disrupt their circadian rhythms by working night shifts have been shown to have shorter-than-average telomeres12.
In addition to the importance of physical stressors, such as smoking and inflammation, social and psychological stressors (what we usually call “stress”) are also important. Many studies have shown shorter LTL among those with increased stress in their lives1, including men who experience long-term unemployment13 and adult caregivers of children with disabilities7. LTL is shorter in adults who experienced adverse events during childhood14, and children who live in stressful situations have shorter LTL even during childhood15.
A lack of social support was associated with shorter telomeres in a study of older adults16. Multiple studies have shown that adults with depression have shorter LTL, indicating the critical importance of emotional stress17. Related to this, people with greater educational attainment have increased LTL18, which could be because they are less worried about becoming unemployed, or because they learned stress-coping mechanisms during their educational years.
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3Gardner M, Bann D, Wiley L, et al. Gender and telomere length: systematic review and meta-analysis. Exp Gerontol. 2014 Mar;51:15-27.
4Prescott J, Du M, Wong JY, et al. Paternal age at birth is associated with offspring leukocyte telomere length in the nurses’ health study. Hum Reprod. 2012 Dec;27(12):3622-31.
5Glei DA, Goldman N, Weinstein M, et al. Shorter Ends, Faster End? Leukocyte Telomere Length and Mortality Among Older Taiwanese. J Gerontol A Biol Sci Med Sci. 2014 Oct 17. pii:glu191.
6Masi S, Nightingale CM, Day IN, et al. Inflammation and not cardiovascular risk factors is associated with short leukocyte telomere length in 13- to 16-year-old adolescents. Arterioscler Thromb Vasc Biol. 2012 Aug;32(8):2029-34.
7Chen X, Velez JC, Barbosa C, et al. Smoking and perceived stress in relation to short salivary telomere length among caregivers of children with disabilities. Stress. 2014 Sep 26:1-38.
8Valdes AM, Andrew T, Gardner JP, et al. Obesity, cigarette smoking, and telomere length in women. Lancet. 2005 Aug 20-26;366(9486):662-4.
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10Du M, Precott J, Kraft P, et al. Physical activity, sedentary behavior, and leukocyte telomere length in women. Am J Epidemiol. 2012 Mar 1;175(5):414-22.
11Liang G, Schernhammer E, Qi L, et al. Associations between rotating night shifts, sleep duration, and telomere length in women. PLoS One. 2011;6(8):e23462.
12Chen WD, Wen MS, Shie SS, et al. The circadian rhythm controls telomeres and telomerase activity. Biochem Biophys Res Commun. 2014 Aug 29;451(3):408-14.
13Ala-Mursula L, Buxton JL, Ek E, et al. Long-term unemployment is associated with short telomeres in 31-year-old men: an observational study in the northern Finland birth cohort 1966. PLoS One. 2013 Nov 20;8(11):e80094.
14Chen SH, Epel ES, Mellon SH, et al. Adverse childhood experiences and leukocyte telomere maintenance in depressed and healthy adults. J Affect Disord. 2014 Dec 1;169:86-90.
15Theall KP, Brett ZH, Shirtcliff EA, et al. Neighborhood disorder and telomeres: connecting children’s exposure to community level stress and cellular response. Soc Sci Med. 2013 May;85:50-8.
16Carroll JE, Diez-Roux AV, Fitzpatrick AL, et al. Low social support is associated with shorter leukocyte telomere length in late life: multi-ethnic study of atherosclerosis. Psychosom Med. 2013 Feb;75(2):171-7.
17Verhoeven JE, Revesz D, Wolkowitz OM, et al. Cellular aging in depression: Permanent imprint or reversible process?: An overview of the current evidence, mechanistic pathways, and targets for interventions. Bioessays. 2014 Oct;36(10):968-78.
18Steptoe A, Hamer M, Butcher L, et al. Educational attainment but not measures of current socioeconomic circumstances are associated with leukocyte telomere length in healthy older men and women. Brain Behav Immun. 2011 Oct;25(7):1292-8.