Reference
Wojcicki JM, Heyman MB, Elwan D, et al. Telomere length is associated with oppositional defiant behavior and maternal clinical depression in Latino preschool children. Transl Psychiatry. 2015 Jun 16;5:e581.
Design
Longitudinal study
Participants
Two hundred low-income Latino children and their mothers (108 4-year-olds and 92 5-year-olds): The children and their mothers were recruited prenatally at 2 hospitals in San Francisco, California, between in 2006 and 2007, and at the time of enrollment, maternal sociodemographic and health history was collected, including data on maternal depression.
Outcome Measures
The role of maternal depression on presence of oppositional behavior in the children was assessed for their associations with telomere length (TL). Telomere length (TL) was examined using quantitative polymerase chain reaction from dried blood spots of the 108 4-year-old Latino children and the 92 5-year-old non-Latino children.
Depressive symptoms in the mothers were assessed prenatally, at 4 to 6 weeks postpartum, and annually for 5 years thereafter using the Edinburgh Postpartum Depression Scale and the Center for Epidemiologic Studies Depression Scale. Current major depressive episodes were evaluated using the Mini International Neurophyschiatric Interview.
This study suggests that environmental factors may influence telomere length, potentially affecting the longevity of offspring.
At birth, at 6 months, and annually thereafter, each child’s weight and height, along with maternal body mass index, were measured. Child psychiatric and behavioral problems were assessed at 3, 4, and 5 years of age (specifically internalizing and externalizing behaviors) using the Child Behavior Checklist (CBCL/1½-5).
Key Findings
The percentage of infants with mothers who had depressive symptoms ranged from 32.1% in the prenatal period to 12.0% at 12 months postpartum. There was no significant association between child TL and maternal depressive symptoms. Additionally, there was no relationship between maternal depressive symptoms and TL in children—meaning the children with short TL did not have mothers with a higher rate of depressive symptoms, and the cohort of mothers with depressive symptoms did not have children with shorter TL, respectively.
There were statistically significant associations between child behavior and TL at 3, 4, and 5 years of age. Child anxiety at 5 years was associated with reduced TL by about 350 base pairs. (P<0.01). Children with oppositionally defiant behavior at 3, 4, or 5 years had shorter TL by about 450 base pairs (P<0.01). Multivariate analysis showed that independent predictors for shorter TLs at age 4 or 5 years also included exposure to maternal clinical depression (but not just depressive symptoms) at 3 years of age (P=0.01), shorter maternal TL, and younger paternal age at the child’s birth.
Practice Implications
This study is the first to link maternal clinical depression and oppositional defiant behavior in children with shorter TL in the preschool years in a population of low-income Latino children. Previous studies in adults have demonstrated a link between major depressive disorder and TL in adults,1 but in this study, maternal clinical depression was linked with shorter TL in offspring only at 5 years of age. Prenatal maternal depressive symptoms were not associated with a shortening in TL in offspring.
TL has been associated with prolonged health and healthy aging. Telomeres naturally shorten with each cell division, with the exception of a few cell types that express the enzyme telomerase, which preserves this protective DNA when cells divide. Telomere shortening has been correlated with decreased longevity, dementia, and other age-related processes.2 This study suggests that environmental factors may influence TL, potentially affecting the longevity of offspring.
Limitations
This study was relatively small, and the number of mothers with chronic depression was too small (n=3) to draw any strong conclusions. Further studies with larger cohorts are required to verify the findings observed in this study. Additionally, it is unknown whether the results seen in Latino children would also apply across other cultural groups. Finally, this study evaluated TL only twice over a short time period. If these studies are repeated, TL measurement should begin at birth and be evaluated more often to better understand changes over time.
