Frailty can be viewed as a state of physiological decline that increases susceptibility to adverse health outcomes. This loss of physiological reserve means that even small stressors can lead to disability and death in frail individuals. Frailty can be measured with various clinical tools; the two most popular are the frailty index and the frailty phenotype. Clinical studies have used these tools to show that women are frailer than men even though they have longer lifespans. Still, factors responsible for this frailty-mortality paradox are not well understood. This review highlights evidence for male-female differences in frailty from both the clinical literature and in animal models of frailty. We review evidence for higher frailty levels in female animals as seen in many preclinical models. Mechanisms that may contribute to sex differences in frailty are highlighted. In addition, we review work that suggests frailty may play a role in susceptibility to chronic diseases of aging in a sex-specific fashion. Additional mechanistic studies in preclinical models are needed to understand factors involved in male-female differences in frailty in late life.

虚弱可以被视为一种生理衰退状态，增加了对不良健康结果的敏感性。这种生理储备的丧失意味着即使是很小的压力也可能导致体弱者的残疾和死亡。可以用各种临床工具测量虚弱；最流行的两个是衰弱指数和衰弱表型。临床研究使用这些工具表明女性比男性更虚弱，尽管她们的寿命更长。尽管如此，造成这种虚弱死亡率悖论的因素还没有被很好地理解。这篇综述强调了临床文献和虚弱动物模型中男女虚弱差异的证据。我们回顾了许多临床前模型中发现的雌性动物虚弱程度较高的证据。强调了可能导致脆弱性性别差异的机制。此外，我们回顾了表明虚弱可能以特定性别的方式在对衰老慢性疾病的易感性中起作用的工作。需要在临床前模型中进行额外的机制研究，以了解导致晚年体弱的男女差异的因素。