Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Department of Psychology, the University of California at Riverside.
J Gerontol A Biol Sci Med Sci. 2020 Sep 25;75(10):1943-1950. doi: 10.1093/gerona/glaa106.
Frailty is a strong predictor of adverse outcomes. However, longitudinal drivers of frailty are not well understood. This study aimed at investigating the longitudinal trajectories of a frailty index (FI) from adulthood to late life and identifying the factors associated with the level and rate of change in FI.
An age-based latent growth curve analysis was performed in the Swedish Adoption/Twin Study of Aging (N = 1,842; aged 29-102 years) using data from up to 15 measurement waves across 27 years. A 42-item FI was used to measure frailty at each wave.
A bilinear, two-slope model with a turning point at age 65 best described the age-related change in FI, showing that the increase in frailty was more than twice as fast after age 65. Underweight, obesity, female sex, overweight, being separated from one's co-twin during childhood, smoking, poor social support, and low physical activity were associated with a higher FI at age 65, with underweight having the largest effect size. When tested as time-varying covariates, underweight and higher social support were associated with a steeper increase in FI before age 65, whereas overweight and obesity were associated with less steep increase in FI after age 65.
Factors associated with the level and rate of change in frailty are largely actionable and could provide targets for intervention. As deviations from normal weight showed the strongest associations with frailty, future public health programs could benefit from monitoring of individuals with abnormal BMI, especially those who are underweight.
衰弱是不良结局的强有力预测因素。然而，衰弱的纵向驱动因素尚不清楚。本研究旨在调查从成年到老年衰弱指数（FI）的纵向轨迹，并确定与 FI 水平和变化率相关的因素。
在瑞典收养/双胞胎衰老研究（N=1842；年龄 29-102 岁）中，基于年龄的潜在增长曲线分析使用了 27 年内多达 15 次测量波的数据。使用 42 项 FI 来衡量每个波的衰弱程度。
具有转折点的双线性、两斜率模型在年龄 65 岁时最佳描述了 FI 的年龄相关变化，表明 65 岁后衰弱的增加速度快了两倍多。体重不足、肥胖、女性、超重、童年时与同卵双胞胎分离、吸烟、社会支持差和体力活动少与 65 岁时的 FI 较高有关，体重不足的影响最大。当作为时变协变量进行测试时，体重不足和较高的社会支持与 65 岁之前 FI 的增加更为陡峭相关，而超重和肥胖与 65 岁之后 FI 的增加较不陡峭相关。
与衰弱水平和变化率相关的因素在很大程度上是可操作的，可为干预提供目标。由于偏离正常体重与衰弱的关联最强，未来的公共卫生计划可能受益于监测 BMI 异常的个体，尤其是体重不足的个体。
