A new study has found a link between loss of a father—through death, imprisonment or parental separation—and reduced telomere length.

Telomeres are repetitive DNA sequences at the ends of chromosomes. Reduced telomere length has been linked to aging and also to disease and exposure to stress, for example, smoking, mental illness, obesity, poor sleep and poverty. As a marker of stress, reduced telomere length may manifest itself long before health consequences are discernible, especially in children.

The researchers used data on 2,420 children from the Fragile Families and Child Wellbeing Study, which is following a cohort of children born in 20 large American cities at the turn of the 21st century. The children gave the saliva samples that were tested for telomere length at age 9.

Colter Mitchell and his team at the University of Michigan, USA, found that children who had lost their fathers tended to have shorter telomeres. The results were visible for all types of father loss, in both girls and boys, and in children of different races and ethnicities and irrespective of when the loss had taken place in the child’s life.

Two findings stand out because they are inconsistent with previous research.

Previous research has found that parents’ separation or divorce has a greater the impact on children than the death of a father. But, in this study, a father’s death was associated with the largest reduction in telomere length. The telomeres of children whose father had died were 16% shorter than other children’s, on average, compared to 10% shorter for children whose father was incarcerated and 6% shorter for children whose for parents had separated. This finding may be due to something about the sample, which is urban and disadvantaged, or it may indicate that for some outcomes (e.g., health), the negative consequences of a father’s death are underestimated in studies that rely exclusively on survey questions to measure health and disease, especially in children.

Second, other studies have found that when a  father dies, income loss is a significant factor in the effect his death has on his children. In this study, the researchers controlled for income loss and found that it accounted for only 19% of the lower telomere length of children who experienced the death of a father. Perhaps the difference is that the fathers in this sample were more disadvantaged than the fathers in most studies, making the economic impact of losing a father less consequential.

The link between father loss and telomere length reduction was 40% larger for boys than for girls, mainly because of a large correlation between telomere length and boys’ losing their fathers before the age of 5. Other research has found that children who lose their fathers in early childhood are more likely to live with a stepfather, which has been shown to be especially stressful for boys.

The authors also found that the association between father loss and telomere length was 90% larger for children with certain variants of the serotonin transporter, which is known to affect depression and mood. This finding is consistent with previous research that shows that children with the more ‘reactive variants’ of this gene respond more negatively to stressful environments than other children do.

The study shows a clear potential for a biological connection between father loss and later health problems.

References

Mitchell C, McLanahan S, Schneper L, Garfinkel I & Brooks-Gunn J, Notterman D (2017), Father Loss and Child Telomere Length, Pediatrics