Reproductive history and blood cell telomere length

Abstract

Telomeres are repetitive nucleotide sequences that protect against chromosomal shortening. They are replenished by telomerase, an enzyme that may be activated by estrogen. Women have longer telomeres than men; this difference might be due to estrogen exposure. We hypothesized that reproductive histories reflecting greater estrogen exposure will be associated with longer blood cell telomeres. Among women in the Sister Study (n= 1,048), we examined telomere length in relation to self-reported data on reproductive history. The difference between age at menarche and last menstrual period was used to approximate the reproductive period. Relative telomere length (rTL) was measured using qPCR. After adjustment, rTL decreased with longer reproductive period (β= -0.019, 95% CI: -0.04, -0.00, p= 0.03). Premenopausal women had shorter rTL than postmenopausal women (β= -0.051, 95% CI: -0.12, 0.01, p= 0.13). Longer breastfeeding duration was associated with longer rTL (β= 0.027, 95% CI: 0.01, 0.05, p=0.01); increasing parity was associated with shorter rTL (β = -0.016, 95% CI: -0.03, 0.00, p=0.07). Duration of exogenous hormone use was not associated with rTL. Reproductive histories reflecting greater endogenous estrogen exposure were associated with shorter rTL. Our findings suggest that longer telomeres in women are unlikely to be explained by greater estrogen exposure.

Telomere length in individuals with early pregnancy losses

“…Аналогі-чні висновки викладені Hanna C. W. et al, 2009 [16], які обстежували жінок із репродуктивними втратами. Жінки, що перенесли втрати вагітності, зазнають стресу, через що порушуються функції цілого організму [7,9,15,16]. Вони також мають підвищений ризик кардіоваскулярних захворювань [14], які, як відомо, асоціюються із короткими теломерами [4,6].…”

“…За останнє десятиліття біологія теломер стала важливою темою у галузі репродукції людини [9]. Рання втрата вагітності (РРВ) відбувається у ~ 15 % клінічно визнаних вагітностей і є найпоширенішим ускладненням вагітності.…”

Costs of reproduction and ageing in the human female

“…Among reproductive-age women in the USA, leucocyte telomeres were shorter in parous compared with nulliparous women [59]. In young Filipino women, those with higher numbers of pregnancies had shorter telomeres [60], similarly to post-menopausal women in the USA [61] and to women participating in the Sister Study [62]. Inconsistent with the hypothesis that high costs of reproduction lead to shorter telomeres are findings in Mayan women where a higher number of surviving children was related to longer telomeres [63].…”