Oh the classical correlation != causation meme! Read the f***ing paper first and understand the arguments!
You should understand WHICH 4 biomarkers they are testing: VLDL, Albumin, Citrate, and Alpha-1 acid glycoprotein. If these four are high, chances are the metabolism behind these four indicators has been wrong for DECADES and is hardly reversible. It makes sense, therefore, to predict 5-y mortality rate with these 4 biomarkers. Sure the prediction isn't perfect, but boy are they good indicators of someone health just as fasting blood glucose, blood pressures, cholesterols and other measurements!
So, just quit this kneejerk correlation != causation reaction already and understand the science behind it!