Data for: When does early-life telomere length predict survival? A case study and meta-analysis

Suboptimal conditions during development can shorten telomeres, the
protective DNA caps on the end of chromosomes. Shorter early-life telomere
length (TL) can indicate reduced somatic maintenance, leading to lower
survival and shorter lifespan. However, despite some clear evidence, not
all studies show a relationship between early-life TL and survival or
lifespan, which may be due to differences in biology or study design
(e.g., survival period measured). In superb fairy-wrens (Malurus cyaneus),
we assessed whether early-life TL predicts mortality across different
life-history stages (fledgling, juvenile, adult). However, in contrast to
a similar study on a congener, early-life TL did not predict mortality
across any life stage in this species. We then performed a meta-analysis
including 32 effect sizes from 23 studies (15 birds and 3 mammals) to
quantify the effect of early-life TL on mortality whilst taking into
consideration potential sources of biological and methodological
variation. Overall, the effect of early-life TL on mortality was
significant, corresponding to a 15% reduction in mortality risk with each
standard deviation increase in TL. However, the effect became weaker when
correcting for publication bias. Contrary to our predictions, there was no
evidence that effects of early-life TL on mortality varied with species
lifespan or the period over which survival was measured. However, negative
effects of early-life TL on mortality risk were pervasive throughout life.
These results imply that effects of early-life TL on mortality are more
likely context-dependent rather than age-dependent, although substantial
power and publication bias issues highlight the need for more research.