Telomere length among Chinese aged 75+ years

Telomere length (TL) is generally regarded as a biomarker of aging. TL, which is influenced by sociodemographic factors, has been shown to be inversely associated with morbidity. However, most studies examined the youngest old and whether the findings can be extended to older individuals is less clear. Further, few studies have examined these questions in Chinese older adults. This cross-sectional study examined TL and its associated factors in Chinese aged 75+ years in Hong Kong.Participants were from the Mr. and Ms. Osteoporosis cohort. A structured interview on sociodemographic factors and physical measurement was conducted. Frailty and sarcopenia status were respectively determined by Fried's criteria and Asian Working Group for Sarcopenia definition. TL was measured by a molecular inversion probe - quantitative PCR (MIP-qPCR) assay and expressed as a novel telomere / a single copy reference gene (T/S) ratio. Adjusted binary logistic regressions were used to examine the associations between TL and the presence of multimorbidity, age-related diseases, frailty and sarcopenia.Among 555 participants (mean age 83.6±3.8 years, 41.3% women), the mean T/S ratio was 1.01±0.20. Males had a lower T/S ratio (0.97±0.20) compared with females (1.07±0.18) (p<0.001). A lower education level was related to a longer TL (p=0.016). Being a current smoker was related to a shorter TL (p=0.007). TL was not significantly different across categories of age, subjective socioeconomic status, drinking status, physical activity level and body mass index (p>0.05). There were no associations between TL and the presence of multimorbidity, diabetes, stroke, cardiovascular diseases, cognitive impairment, frailty and sarcopenia.Among Chinese aged 75+ years, males had shorter TL compared with females. TL was not associated with age-related diseases, frailty and sarcopenia in this age group. TL may not be a biological marker of aging among older individuals.