Gender and telomere length: Systematic review and meta-analysis

Abstract

Background It is widely believed that females have longer telomeres than males, although results from studies have been contradictory. Methods We carried out a systematic review and meta-analyses to test the hypothesis that in humans, females have longer telomeres than males and that this association becomes stronger with increasing age. Searches were conducted in EMBASE and MEDLINE (by November 2009) and additional datasets were obtained from study investigators. Eligible observational studies measured telomeres for both females and males of any age, had a minimum sample size of 100 and included participants not part of a diseased group. We calculated summary estimates using random-effects meta-analyses. Heterogeneity between studies was investigated using sub-group analysis and meta-regression. Results Meta-analyses from 36 cohorts (36,230 participants) showed that on average females had longer telomeres than males (standardised difference in telomere length between females and males 0.090, 95% CI 0.015, 0.166; age-adjusted). There was little evidence that these associations varied by age group (p = 1.00) or cell type (p = 0.29). However, the size of this difference did vary by measurement methods, with only Southern blot but neither real-time PCR nor Flow-FISH showing a significant difference. This difference was not associated with random measurement error. Conclusions Telomere length is longer in females than males, although this difference was not universally found in studies that did not use Southern blot methods. Further research on explanations for the methodological differences is required.

Shortened telomere length in bipolar disorder: a comparison of the early and late stages of disease

“…A recent systematic review and metaanalysis of 36,230 participants may have clarified this problem, concluding that gender differences are detectable with Southern blot methods, but not when real-time PCR or flow-FISH are used. 48 Accordingly, in our sample there was no difference in T/S between males and females. Additionally, because of the cross-sectional nature of the study, causal associations could not be inferred.…”

Perinatal Complications and Aging Indicators by Midlife

“…Although women had somewhat longer age-38 telomeres than men (men = 1.038 T/S ratio; women = 1.059 T/S ratio, P = .351), associations between perinatal complications and aging indicators did not differ significantly between men and women, which is consistent with results of a recent meta-analysis. 32 There was no significant interaction between gender and perinatal complications predicting either TL (b = 20.044; 95% CI, 20.112 to 0.025; P = .21; the T/S ratios for men with 0, 1, and $2 perinatal complications were 1.075, 0.961, and 0.983; the comparable T/S ratios for women were 1.061, 1.103, and 0.955) or perceived age (b = 0.010; 95% CI, 20.059 to 0.078; P = .78; the standardized perceived age of men with 0, 1, and $2 perinatal complications was 20.051, 0.118, and 0.209; the comparable scores for women were 20.132, 20.055, and 0.131). The following conditions were assessed: heart disease (defined as a history of heart attack, balloon angioplasty, coronary bypass, or angina), stroke, high blood pressure, high cholesterol, diabetes, asthma, and cancer.…”

“…The cohort represents the full range of socioeconomic status (SES) in the general population of New Zealand' s South Island and is primarily white. Assessments were carried out at birth and at ages 3,5,7,9,11,13,15,18,21,26,32, and, most recently, 38 years, when 95.4% of the 1007 living study members underwent assessment in 2010 to 2012. At each assessment wave, each study member is brought to the Dunedin Research Unit for a full day of interviews and examinations.…”

Automated Assay of Telomere Length Measurement and Informatics for 100,000 Subjects in the Genetic Epidemiology Research on Adult Health and Aging (GERA) Cohort

“…Mutations that decrease telomerase and cause short telomeres in humans lead to a spectrum of premature-onset diseases and conditions collectively termed "telomere syndromes," which share many features of the common diseases of aging in the human population (Armanios and Blackburn 2012). Multiple independent studies have found impaired human telomeric DNA length maintenance to be associated with a wide range of diseases and for several age-related diseases to predict future risks and outcomes including mortality (Von Zglinicki et al 2000;Samani et al 2001;Cawthon et al 2003;Panossian et al 2003;Valdes et al 2005;Bischoff et al 2006;Harris et al 2006;MartinRuiz et al 2006;Bakaysa et al 2007;Brouilette et al 2007;Fitzpatrick et al 2007Fitzpatrick et al , 2011Aubert and Lansdorp 2008;Farzaneh-Far et al 2008;Kimura et al 2008;Epel et al 2009;Njajou et al 2009;Astrup et al 2010;Codd et al 2010Codd et al , 2013Salpea et al 2010;Willeit et al 2010a,b;Zee et al 2010;Strandberg et al 2011;Wentzensen et al 2011;Yaffe et al 2011;Honig et al 2012;Lee et al 2012;Weischer et al 2012;Bojesen 2013;Muezzinler et al 2013;Gardner et al 2014;Haycock et al 2014;Walsh et al 2014).…”