RH of all-cause mortality for GHb levels compared with the referent of 4.8% (the 12.5th percentile, as indicated by the vertical line) among adults aged ≥20 years and older overall (A) and with diagnosed diabetes (B) in the U.S. NHANES III Linked Mortality File (19). Age was the time scale, adjusted for sex, race/ethnicity (non-Hispanic white, non-Hispanic black, Mexican American, or other), education (less than high school, high school graduate, or some college or higher), smoking status (current, past, or never), BMI (continuous), systolic blood pressure (continuous), and HDL cholesterol (continuous). ——, Fitted three-knot spline relationship; – – –, pointwise upper and lower 95% CI limits.