Originally Posted by Barty
No, but light in the blue spectrum is known to affect your melatonin level and disturbs your sleep, which is why it is recommended that you not use things like tablets before sleep. Reading with the front light before bed is just the kind of thing that people use the front light for, so it matters whether the light tints blue or yellow.
Or it might not, really. The oft-quoted research showing that tablet use at night-time disrupted melatonin production showed that you needed to use an LCD tablet, no night mode, on full brightness (!!!) for two full hours before there was any disruption. Even at that rather massive level of light exposure, one hour didn't disrupt things.
The current LED-lit ereaders put out a whole lot less light (using sensible settings) at a far less blue level than these experimental conditions used. I suspect that our concerns should be more aesthetic than health-based.