Association of leukocyte telomere length with perceived physical fatigability.

BACKGROUND: Leukocyte telomere length (LTL) is a potential genomic marker of biological aging, but its relation to fatigability, a prognostic indicator of phenotypic aging (e.g., functional decline) is unknown. We hypothesized shorter LTL would predict greater perceived physical fatigability, but that this association would be attenuated by adjusting for chronological age. METHODS: Two generations of participants (N = 1997; 309 probands, 1688 offspring) were from the Long Life Family Study (age = 73.7 ± 10.4, range 60-108, 54.4 % women), a longitudinal cohort study of aging. LTL was assayed at baseline. Perceived physical fatigability was measured 8.0 ± 1.1 years later using the validated, self-administered 10-item Pittsburgh Fatigability Scale (PFS, 0-50, higher scores = greater fatigability). Generalized estimating equations were generated to model the association between LTL and PFS Physical scores. RESULTS: Prevalence of greater physical fatigability (PFS scores≥15) was 41.9 %. Using generalized estimating equations, a one kilobase pair shorter LTL was associated with higher PFS Physical scores (ß = 1.8, p < .0001), accounting for family structure, and adjusting for field center, follow-up time, sex, and follow-up body mass index, physical activity, and chronic health conditions. When age was included as a covariate, the association was fully attenuated (ß = 0.1, p = .78). CONCLUSION: LTL may provide an alternative method for estimating an individual's lifetime exposure to chronic stressors, but does not appear to provide additional information not captured by chronological age. Further research is needed to characterize the interaction between age, LTL, and perceived fatigability, and develop a method of identifying individuals at risk for deleterious aging.

Relationship Between Personality Measures and Perceived Mental Fatigability.

OBJECTIVE: Examine the association between personality measures and perceived mental fatigability. METHODS: We performed a cross-sectional analysis in N=1670 men, age 84.3±4.1 years. Multivariable linear regression models were used to examine the covariate adjusted association between personality measures (conscientiousness, optimism, goal reengagement, and goal disengagement) and perceived mental fatigability (measured with the validated 10-item Pittsburgh Fatigability Scale, PFS). RESULTS: One standard deviation lower conscientiousness (ß=-0.91, p<.0001) and optimism (ß=-0.63, p<.0001), and higher goal reengagement (ß=0.51, p=.01) scores were independently associated with higher PFS Mental scores adjusted for age, cognitive function, self-reported health status, depressive symptoms, sleep disturbance, physical activity, and goal disengagement. DISCUSSION: Lower conscientiousness, optimism, and higher goal reengagement were linked with more severe perceived mental fatigability in older men. Personality traits may potentially contribute to early risk assessment for fatigability in later life. Future work should be longitudinal in nature and include personality assessments to confirm the temporality of the relationships observed.