Telomere length: population epidemiology and concordance in Australian children aged 11-12 years and their parents.

OBJECTIVES: To (1) describe the epidemiology of child and adult telomere length, and (2) investigate parent-child telomere length concordance. DESIGN: Population-based cross-sectional study within the Longitudinal Study of Australian Children. SETTING: Assessment centres in seven major Australian cities and eight selected regional towns; February 2015 to March 2016. PARTICIPANTS: Of 1874 participating families, telomere data were available for analysis for 1206 children and 1343 parents, of whom 1143 were parent-child pairs. There were 589 boys and 617 girls; 175 fathers and 1168 mothers. OUTCOME MEASURES: Relative telomere length (T/S ratio), calculated by comparing telomeric DNA (T) level with the single copy (S) beta-globin gene in venous blood-derived genomic DNA by quantitative real-time PCR. RESULTS: Mean T/S ratio for all children, boys and girls was 1.09 (SD 0.56), 1.05 (SD 0.53) and 1.13 (SD 0.59), respectively. Mean T/S ratio for all parents, fathers and mothers was 0.81 (SD 0.37), 0.82 (SD 0.36) and 0.81 (SD 0.38), respectively. Parent-child T/S ratio concordance was moderate (correlation 0.24). In adjusted regression models, one unit higher parent T/S ratio was associated with 0.36 (estimated linear regression coefficient (ß); 95% CI 0.28 to 0.45) higher child T/S ratio. Concordance was higher in the youngest parent-age tertile (ß 0.49; 95% CI 0.34 to 0.64) compared with the middle (ß 0.35; 95% CI 0.21 to 0.48) and oldest tertile (ß 0.26; 95% CI 0.11 to 0.41; p-trend 0.04). Father-child concordance was 0.34 (95% CI 0.18 to 0.48), while mother-child was 0.22 (95% CI 0.17 to 0.28). CONCLUSIONS: We provide telomere length population values for children aged 11-12 years and their mid-life parents. Relative telomere length was shorter in adults than children, as expected. There was modest evidence of parent-child concordance, which diminished with increasing parent age.