Leukocyte telomere length dynamics in women and men: menopause vs age effects.

<bold>Background: </bold>A longer leukocyte telomere length (LTL) in women than men has been attributed to a slow rate of LTL attrition in women, perhaps due to high estrogen exposure during the premenopausal period.<bold>Methods: </bold>To test this premise we performed a longitudinal study (an average follow-up of 12 years) in a subset of the population-based Danish National Twin Registry. Participants consisted of 405 women, aged 37.5 (range 18.0-64.3) years, and 329 men, aged 38.8 (range 18.0-58.5) years, at baseline examination.<bold>Results: </bold>Women showed a longer LTL [kb ± standard error(SE)] than men (baseline: 7.01 ± 0.03 vs 6.87 ± 0.04; follow-up: 6.79 ± 0.03 vs 6.65 ± 0.03; both P = 0.005). Women displayed deceleration of LTL attrition (bp/years ± SE), as they transitioned from the premenopausal period (20.6 ± 1.0) through the perimenopausal period (16.5 ± 1.3) to the postmenopausal period (15.1 ± 1.7). Age was not associated with LTL attrition in women after statistical control for menopausal status. Men, in contrast, displayed a trend for age-dependent increase in the rate of LTL attrition, which differed significantly from the pattern in women (P for interaction = 0.01).<bold>Conclusions: </bold>Results indicate that the premenopausal period is expressed in a higher rate of LTL attrition than the postmenopausal period. They further suggest that the sex gap in LTL stems from earlier ages-the period of growth and development. The higher rate of LTL attrition in premenopausal women, we propose, might relate to estrogen-mediated increased turnover of erythrocytes, menstrual bleeding or both. [ABSTRACT FROM AUTHOR]