Association of telomere length with general cognitive trajectories: a meta-analysis of four prospective cohort studies

To investigate the association of telomere length (TL) with trajectories of general cognitive abilities, we
used data on 5955 participants from the Sex Differences in Health and Aging Study and the Swedish
Adoption/Twin Study of Aging in Sweden, and the Mayo Clinic Study of Aging, and the Health and
Retirement Study in the United States. TL was measured at baseline, while general cognitive ability was
assessed repeatedly up to 7 occasions. Latent growth curve models were used to examine the associations.
One standard deviation increase of TL was associated with 0.021 unit increase (95% confidence
interval [CI]: 0.001, 0.042) of standardized mean general cognitive ability. After controlling for sex, the
point estimate remained similar (0.019) with a wider CI (95% CI:
0.002, 0.039). The association was
attenuated with adjustment for educational attainment (0.009, 95% CI:
0.009, 0.028). No strong evidence
was observed for the association of TL and decline in general cognitive ability. Longer TL was
associated with higher general cognitive ability levels in the age-adjusted models but not in the models
including all covariates, nor with cognitive decline.