gms | German Medical Science

Introduction: Telomeres are repetitive DNA sequences at the ends of chromosomes that protect DNA damage during cell division. Each time a cell divides, telomeres become shorter, which eventually hampers cells from successfully dividing, leading to cell death. Telomere length is used as a marker of biological age, with longer telomeres indicating a younger biological age. Recent demographic shifts have led to parents having their first child at older ages. Previous studies consistently find that older fathers tend to have children with longer telomeres, which suggests that children born to older fathers have biomarkers indicating an improved longevity. These previous studies, however, usually had limited sample sizes or were not able to control for essential family characteristics that, on one hand, are associated with the probability to becoming a father at a later age, and on the other hand with telomere length or longevity.

Methods: In our study, we utilize data from the UK Biobank, which contains information on the relative leukocyte telomere length of approximately 474,000 participants. To estimate the effect of paternal age at birth on telomere length in the offspring, we employ multiple linear regression. We control for relevant factors such as maternal age at birth, sex, year of birth, and family characteristics (birth order and number of siblings), as well as socioeconomic status (education and income) and behavioral measures (alcohol consumption and smoking habits). Using kinship coefficients and IBS0 measures, we assess the degree of relatedness among UK Biobank participants. This enables us to identify individuals belonging to a broader defined family (kinship coefficient >= 0.0442) and siblings (kinship coefficient between 0.177 – 0.354 and IBS0 > 0.001). We apply family and sibling fixed effects, which allows us to control for a common familial background and genetic factors. By leveraging the variation in father’s ages at birth, we estimate the effect on telomere length of the children within the same family or among siblings.

Results: Our results reveal that telomere length in offspring increases by 1.6% for each additional year of the father’s age at the time of birth (0.016, 95% CI: 0.013, 0.019, p-value: < 0.001). These results are consistent when analyzed separately for females and males. When controlling for family and sibling fixed effects, the pattern remains robust and becomes even more pronounced; an additional year in father’s age at birth increases telomere length by 2.5% under family fixed effects (0.025, 95% CI: 0.013, 0.037, p-value: < 0.001), and by 3.6% under sibling fixed effects (0.036, 95% CI: 0.034, 0.039, p-value: < 0.001).

Conclusion: Using data on 474,000 individuals, the results of our study confirm that offspring of older fathers have longer telomeres, even when accounting for maternal age, genetic, and behavioral factors. This confirms the idea of an epigenetic mechanism whereby children’s longevity and telomere length are influenced by their father’s age at childbirth.

The authors declare that they have no competing interests.

The authors declare that an ethics committee vote is not required.