Figure 2. DR has more favorable effects on the lifespan of non-inbred mice compared to inbred mice (1934 – present; excluding ILSXISS strains).

A literature review identified 72 laboratory experiments that evaluated the effects of DR-type diets on survival in mice (Supplemental Table 2). Of these 72 experiments, 24 were performed using non-inbred mouse genotypes, including F₁ offspring derived from inbred line crosses, F₂ offspring derived from a four-way cross of inbred lines, or wild-derived genetically heterogeneous mice. The height of each bar corresponds to the average effect of DR on median or maximum lifespan among n experiments for which the necessary information was available (non-inbred strains, grey bars; inbred strains, white bars). The average effect and associated standard error were calculated by assigning greater weight to studies that used larger sample sizes. For a given category, asterisk symbols are used to denote cases in which the average effect of DR on the lifespan of inbred strains is significantly different from the average effect of DR on the lifespan of non-inbred strains (P < 0.05; two-sample t-test and Wilcoxon rank sum test).