Department of Anthropology, Pennsylvania State University, 421 Carpenter Building, University Park, PA, 16802, USA.
Department of Biobehavioral Health, Pennsylvania State University, University Park, PA, USA.
Sci Rep. 2020 Nov 25;10(1):20522. doi: 10.1038/s41598-020-77082-2.
Understanding factors contributing to variation in 'biological age' is essential to understanding variation in susceptibility to disease and functional decline. One factor that could accelerate biological aging in women is reproduction. Pregnancy is characterized by extensive, energetically-costly changes across numerous physiological systems. These 'costs of reproduction' may accumulate with each pregnancy, accelerating biological aging. Despite evidence for costs of reproduction using molecular and demographic measures, it is unknown whether parity is linked to commonly-used clinical measures of biological aging. We use data collected between 1999 and 2010 from the National Health and Nutrition Examination Survey (n = 4418) to test whether parity (number of live births) predicted four previously-validated composite measures of biological age and system integrity: Levine Method, homeostatic dysregulation, Klemera-Doubal method biological age, and allostatic load. Parity exhibited a U-shaped relationship with accelerated biological aging when controlling for chronological age, lifestyle, health-related, and demographic factors in post-menopausal, but not pre-menopausal, women, with biological age acceleration being lowest among post-menopausal women reporting between three and four live births. Our findings suggest a link between reproductive function and physiological dysregulation, and allude to possible compensatory mechanisms that buffer the effects of reproductive function on physiological dysregulation during a woman's reproductive lifespan. Future work should continue to investigate links between parity, menopausal status, and biological age using targeted physiological measures and longitudinal studies.
了解导致“生物年龄”变化的因素对于理解疾病易感性和功能下降的变化至关重要。可能加速女性生物衰老的一个因素是生殖。怀孕的特点是在许多生理系统中发生广泛的、能量消耗大的变化。这些“生殖成本”可能随着每次怀孕而积累，从而加速生物衰老。尽管有使用分子和人口学措施证明生殖成本的证据，但尚不清楚生育次数是否与生物衰老的常用临床测量指标有关。我们使用 1999 年至 2010 年期间从全国健康和营养检查调查（n=4418）收集的数据来测试生育次数（活产数）是否预测了之前验证过的四种综合生物年龄和系统完整性测量指标：Levine 方法、内稳态失调、Klemera-Doubal 方法生物年龄和全身负荷。在控制了绝经后妇女的年龄、生活方式、与健康相关的和人口统计学因素后，生育次数与加速的生物衰老呈 U 形关系，但在绝经前妇女中则没有，生育次数在报告生育 3 至 4 次的绝经后妇女中最低。我们的发现表明生殖功能与生理失调之间存在联系，并暗示了可能的补偿机制，这些机制在女性生殖寿命期间缓冲了生殖功能对生理失调的影响。未来的工作应该继续使用靶向生理测量和纵向研究来调查生育次数、绝经状态和生物年龄之间的联系。
