Does telomere length predict decline in physical functioning in older twin sisters during an 11-year follow-up?

Abstract

Leukocyte telomere length (LTL) is known to be associated with mortality, but its association with age-related decline in physical functioning and the development of disability is less clear. This study examined the associations between LTL and physical functioning, and investigated whether LTL predicts level of physical functioning over an 11-year follow-up. Older mono-(MZ) and dizygotic (DZ) twin sisters (n = 386) participated in the study. Relative LTL was measured by qPCR at baseline. Physical functioning was measured by 6-min walking distance and level of physical activity (PA). Walking distance was measured at baseline and at 3-year follow-up. PA was assessed by questionnaire at baseline and at 3-and 11-year follow-ups. The baseline analysis was performed with path models, adjusted with age and within-pair dependence of twin pairs. The longitudinal analysis was performed with a repeated measures linear model adjusted for age and longitudinal within-pair dependence. A nonrandom missing data analysis was utilized. At baseline, in all individuals, LTL was associated with PA (est. 0.14, SE 0.06, p = 0.011), but not with walking distance. Over the follow-up, a borderline significant association was observed between LTL and walking distance (est. 0.14, SE 0.07, p = 0.060) and a significant association between LTL and PA (est. 0.19, SE 0.06, p = 0.001). The results suggest that LTL is associated with PA and may, therefore, serve as a biomarker predicting the development of disability. Longitudinal associations between LTL and PA were observed only when nonrandom data missingness was taken into account in the analysis.

Resistance training and redox homeostasis: Correlation with age-associated genomic changes

“…Contradictory findings exist with respect the association between LTL and specific indicators of physical functioning [27] , [28] , [61] , [73] , primarily in elderly population. However, most of the data support the hypothesis that this sensitive chromosome region may be considered a biomarker of age-related changes in functional capacity.…”

Resistance Training and Redox Homeostasis: Correlation with Age-Associated Genomic Changes

“…Contradictory findings exist with respect the association between LTL and specific indicators of physical functioning [27,28,73,61], primarily in elderly population. However, most of the data support the hypothesis that this sensitive chromosome region may be considered a biomarker of age-related changes in functional capacity.…”

Short Telomere Length Is Related to Limitations in Physical Function in Elderly European Adults

“…A novel finding in this study was that the influence of LTL on functional limitation was driven by the detrimental effect of having short telomeres, rather than reflecting a linear dose-response relationship. Previous investigations into the links between LTL and health outcomes have commonly reported weak to modest linear associations ( Harris et al, 2006 , 2012 , 2016 ; Risques et al, 2010 ; Bendix et al, 2011 ; Lee et al, 2013 ; Woo et al, 2014 ; Sillanpää et al, 2016 ). The existence of a large inter-individual variability in LTL across study samples, together with a hypothesized non-linear relationship between LTL and function, may mask the true impact of having short telomeres on the development of age-related diseases ( Scheinberg et al, 2010 ; Cui et al, 2012 ; Ye et al, 2013 ).…”

“…Interestingly, while short LTL is associated with the higher likelihood of having functional limitation, a corresponding link between LTL and handgrip strength was not observed. Previous studies based on single markers of physical function have yielded controversial results ( Harris et al, 2006 , 2012 , 2016 ; Lee et al, 2013 ; Woo et al, 2014 ; Loprinzi and Loenneke, 2016 ; Sillanpää et al, 2016 ). As the use of single physical functioning markers may not fully capture the inability to perform activities of daily living, our data support the use of a composite construct of self-reported limitations in activities of daily living as an instrument that is more able to accurately reflect physical functioning.…”

“…Previous investigations of links between leucocyte telomere length (LTL) and physical functioning during old age have yielded inconclusive results ( Harris et al, 2006 , 2012 , 2016 ; Risques et al, 2010 ; Bendix et al, 2011 ; Lee et al, 2013 ; Woo et al, 2014 ; Sillanpää et al, 2016 ), where between-study inconsistencies may be related to the use of different approaches in assessing physical functioning. Notably, some of the previous studies have used single tests of muscle function whereas others have used constructs based on self-reported abilities in the assessment of physical functioning ( Harris et al, 2006 , 2012 , 2016 ; Risques et al, 2010 ; Bendix et al, 2011 ; Lee et al, 2013 ; Woo et al, 2014 ; Sillanpää et al, 2016 ). It can be hypothesized that in contrast to a composite construct of self-reported abilities, single tests of muscle function may not fully capture the inability to perform daily activities.…”