TJ: "Consistent with" LNT does not mean that LNT is proven. It merely means that the cited papers do not *disprove* LNT.
There is some work which specifically set out to test it. A physicist at the University of Pittsburgh in the US studied lung cancer rates as a function of radon levels throughout the US. He found that cancer rate declines with radon level for very low exposures, then rises, which contradicts LNT.
You can download the full study if you're interested:
Bernard L. Cohen, Health Physics, Feb. 1995, Vol. 68, No. 2, pp 157-174
http://www.phyast.pitt.edu/~blc/LNT-1995.PDF
This has been criticized as an "ecological" study, meaning specific individual exposures for radon are not known. But LNT is an ecological hypothesis. If it is correct, then by definition each increment of exposure results in the same increment of risk. If one person has twice the exposure, they have twice the risk; the total number of cancers induced in a population should be the average exposure times the population times the (linear) risk per unit exposure. We don't need to know the exposure distribution. To my knowledge, this study falsifying LNT has never been successfully rebutted.
About 1.3 million people die of cancer in Europe annually. The random fluctuation in that number, twice its square root for the 95% confidence interval, is about +/- 2300. Multiply that by a 70-year lifespan, and you can generate 160,000 "model deaths" that aren't statistically detectable and thus can't be disproven. Plus, other factors affecting cancer deaths (new treatments, changes in diet, etc. etc.) further confuse any effort to tease out the effects of low-level radiation.
Of course, with equal statistical (in)validity, I claim that the hormesis hypothesis is right, and the radiation released by Chernobyl will prevent 160,000 deaths over 70 years. Nobody can prove me wrong.
The only clearly detectable cancer from Chernobyl was thyroid cancer, because the background incidence is so small. And the worst-case annual risk of developing it, 15 years after the accident, was 1 chance in 9000 (11 cases per 100,000 population in Belarus).
Coincidentally, the annual death risk from driving a car in the US is also about 1 in 9000 (40,000 deaths, 360 million people). The difference is thyroid cancer has a 98% cure rate.
The take-home message is the worst directly attributable excess risk from Chernobyl to the general population was much less than an ordinary risk we take every day, for the worst accident ever. That makes nuclear power comparatively safe.