"The association between cumulative dose, lagged 10 years, and solid cancer mortality was reasonably well described by a linear model (fig 1); inclusion of a parameter describing the linear association between cumulative dose and solid cancer contributed substantially to model goodness of fit (supplementary table B). The addition of a parameter for the square of cumulative dose led to only a modest improvement in model goodness of fit compared with the linear model (likelihood ratio test =2.51, df=1; P=0.11), suggesting some downward curvature (that is, a negative estimated coefficient for the quadratic term). The addition of a parameter for an exponential term in the model led to a modest improvement in model goodness of fit for a linear-exponential model compared with the linear model (likelihood ratio test =3.17, df=1; P=0.08), again suggesting some downward curvature. To assess the trend over the lower cumulative dose range, we estimated associations between cumulative dose and solid cancer mortality over restricted ranges of 0-400 mGy cumulative dose (excess relative rate 0.63 (0.34 to 0.92) per Gy), 0-200 mGy cumulative dose (0.97 (0.55 to 1.39) per Gy), 0-100 mGy cumulative dose (1.12 (0.45 to 1.80) per Gy), 0-50 mGy cumulative dose (1.38 (0.20 to 2.60) per Gy), and 0-20 mGy cumulative dose (1.30 (−1.33 to 4.06) per Gy) (supplementary table C). Over the restricted range of 0-200 mGy cumulative dose, the association between cumulative dose and solid cancer mortality was well described by a linear model, and the addition of a parameter for the square of cumulative dose led to minimal improvement in model goodness of fit compared with the linear model (likelihood ratio test=0.54, df=1; P=0.46)."
They say over and over that linear model (with relative risk = 1 at 0 dose) is a good fit! this is LNT. They say the improvements of adding the other fit are marginal. The error bounds here are large, and the deviation is small but apparently systematic or real below 200mGy. The authors, as far as I can tell, are just reporting the figures without claiming LNT is wrong.