[Association of age at menarche, age at menopause, and reproductive lifespan with frailty index in Chinese adult women]

Abstract

Objective: To identify individuals with accelerated aging under the frailty index (FI) as a proxy indicator of biological age, and to investigate the associations of age at menarche, age at menopause, and reproductive lifespan with frailty status and multi-timepoint FI trajectories among Chinese adult women. Methods: The current study included 302 471 women from the China Kadoorie Biobank 2004-2008 baseline survey data. Their age at menarche and menopause were self-reported, and the duration of reproductive lifespan was calculated by subtracting the two ages. The baseline FI was constructed using 28 baseline variables, including diseases, symptoms, and anthropometric measurements. Frailty status was categorized into three groups: non-frail (FI≤0.10), pre-frail (0.10<FI<0.25), and frail (FI≥0.25). For 18 157 women with the first re-survey data from June to August 2008 and the second re-survey data from August 2013 to September 2014, group-based trajectory modeling was used to characterize FI trajectories. Ordered logistic regression models were used to analyze associations between 3 reproductive factors and frailty status or FI trajectories. Results: After adjusting for potential confounders, compared to women with menarche at 15-16 years old, those with menarche ≤12, 13-14, and ≥17 years old exhibited ORs(95%CIs) for higher frailty status of 1.36 (1.31-1.41), 1.11 (1.09-1.13), and 0.92 (0.90-0.93), respectively. Compared to women with menopause at 46-50 years old, those with menopause ≤40, 41-45, and ≥51 years old had ORs (95%CIs) for higher frailty status of 1.12 (1.07-1.18), 1.04 (1.01-1.07), and 1.07 (1.04-1.10), respectively. Compared to women with a reproductive lifespan of 31-35 years, those with ≤25 and ≥36 years showed ORs (95%CIs) for higher frailty status of 1.09 (1.04-1.14) and 1.07 (1.04-1.10), respectively. Among 18 157 women, three FI trajectories were identified: low growth (60.3%), moderate growth (35.0%), and rapid growth (4.7%). Statistical associations were observed between ≤12 years old of menarche age (OR=1.35, 95%CI: 1.18-1.55) and ≥36 years of reproductive lifespan (OR=1.21, 95%CI: 1.09-1.35) with FI trajectories with higher growth rates. No statistical associations were found for other categories of menarche age, reproductive lifespan, or menopause age. Conclusion: Early menarche, premature or delayed menopause, and extremely short or long reproductive lifespans are associated with increased risks of accelerated aging in women.