Maternal age at last birth and leukocyte telomere length in a nationally representative population of perimenopausal and postmenopausal women.
Level 4 - case-series / case-control
Cross-sectional survey analysis
PubMed 33110040 · doi:10.1097/GME.0000000000001669
What was done
The authors conducted a cross-sectional analysis using 1999–2002 NHANES data from 1,232 perimenopausal and postmenopausal women aged 40 years and older. Maternal age at last live birth was self-reported, and leukocyte telomere length was measured via quantitative polymerase chain reaction (qPCR). Multivariable least-squares geometric mean telomere lengths were calculated across maternal age categories (<25, 25–29, 30–34, 35–39, and ≥40 years), adjusting for chronological age, race/ethnicity, number of live births, survey cycle, and history of hysterectomy or oophorectomy.
What was found
Older maternal age at last birth was positively associated with leukocyte telomere length: adjusted least-squares geometric mean telomere lengths across age categories (<25, 25–29, 30–34, 35–39, ≥40 y) were 0.90, 0.93, 0.93, 0.95, and 0.96, respectively (P for trend = 0.04). Exploratory analyses suggested this association was restricted to women with one or two live births or those who reported ever using oral contraceptives (P for interaction < 0.10 for both).
Why it matters
This study provides population-level evidence linking later reproductive timing to longer leukocyte telomeres in middle-aged and older women, suggesting potential intersections between reproductive span and cellular aging.
Limits
The study is cross-sectional, preventing causal inference or determination of whether later childbearing slows cellular aging versus slower biological aging enabling later reproduction. Maternal age at last birth was self-reported. Residual confounding by socioeconomic, lifestyle, or unmeasured health factors remains possible.
Cited by
- supports Women whose last childbirth occurs later in life, such as in their 30s rather than their 20s, have longer telomeres.