Department of Animal Ecology, Ageing Research Group, Evolutionary Biology Centre, Uppsala University, Sweden.
Department of Mathematics and Computer Sciences, Max Planck Odense Center on the Biodemography of Aging, University of Southern Denmark.
J Gerontol A Biol Sci Med Sci. 2014 Jun;69(6):666-74. doi: 10.1093/gerona/glt158. Epub 2013 Oct 29.
Diet effects on age-dependent mortality patterns are well documented in a large number of animal species, but studies that look at the effects of nutrient availability on late-life mortality plateaus are lacking. Here, we focus on the effect of dietary protein content (low, intermediate, and high) on mortality trajectories in late life in the fruit fly Drosophila melanogaster. According to the two theories that are mainly implicated in explaining the deceleration of mortality rate in late life (the heterogeneity/frailty theory and the Hamiltonian theory), we predict, in general, the occurrence of late-life mortality deceleration under most circumstances, independent of sex and dietary regime. However, the heterogeneity theory of late life is more flexible in allowing no mortality deceleration to occur under certain circumstances compared with the Hamiltonian theory. We applied a novel statistical approach based on Bayesian inference of age-specific mortality rates and found a deceleration of late-life mortality rates on all diets in males but only on the intermediate (standard) diet in females. The difference in mortality rate deceleration between males and females on extreme diets suggests that the existence of mortality plateaus in late life is sex and diet dependent and, therefore, not a universal characteristic of large enough cohorts.
大量动物物种的研究充分证明了饮食对与年龄相关的死亡率模式的影响，但缺乏研究关注营养素供应对生命后期死亡率平台的影响。在这里，我们专注于饮食蛋白质含量（低、中、高）对黑腹果蝇生命后期死亡率轨迹的影响。根据主要用于解释生命后期死亡率减速的两个理论（异质性/脆弱性理论和哈密顿理论），我们预测，在大多数情况下，无论性别和饮食制度如何，通常都会出现生命后期死亡率减速。然而，与哈密顿理论相比，晚期生命的异质性理论在某些情况下允许不发生死亡率减速，更为灵活。我们应用了一种基于贝叶斯推断年龄特定死亡率的新统计方法，发现雄性在所有饮食中生命后期死亡率减速，但雌性仅在中等（标准）饮食中减速。极端饮食下雄性和雌性死亡率减速的差异表明，生命后期死亡率平台的存在取决于性别和饮食，因此，不是足够大的群体的普遍特征。
