Leukocyte Telomere Length and All-Cause Mortality: A Between-Within Twin Study With Time-Dependent Effects Using Generalized Survival Models. Issue 10 (29th June 2018)

• Record Type: Journal Article
• Authors: Zhan, Yiqiang; Liu, Xing-Rong; Reynolds, Chandra A; Pedersen, Nancy L; Hägg, Sara; Clements, Mark S
• Is Part Of: American journal of epidemiology. Volume 187:Issue 10(2018)
• Page Start: 2186
• Page End: 2191
• Publication Date: 2018-06-29
• Subjects: between-within model -- generalized survival model -- mortality -- shared frailty -- telomere; Epidemiology -- Periodicals; Public health -- Periodicals; 614.4
• DOI: 10.1093/aje/kwy128
• Languages: English
• ISSNs: 0002-9262

Abstract

Abstract: Although previous studies examining leukocyte telomere length (LTL) and all-cause mortality controlled for several confounders, the observed association could be biased due to unmeasured confounders, including familial factors. We aimed to examine the association of LTL with all-cause mortality in a Swedish twin sample while adjusting for familial factors and allowing for time-dependent effects. A total of 366 participants (174 twin pairs and 18 individuals) were recruited from the Swedish Twin Registry. LTL was assessed using the Southern blot method. All-cause mortality data were obtained through linkage with the Swedish Population Registry, updated through November 15, 2017. To control for familial factors within twin pairs, we applied a between-within shared frailty model based on generalized survival models. Overall, 115 (31.4%) participants were men and 251 (68.6%) were women. The average age of the study participants when blood was drawn was 79.1 years, and follow-up duration ranged from 10 days to 25.7 years (mean = 10.2 years). During the follow-up period, 341 (93.2%) participants died. Shorter LTL was associated with higher mortality rates when controlling for familial factors in the between-within shared frailty model. We found significant time-dependent effects of LTL on all-cause mortality, where the mortality rate ratios were attenuated with increasing age.