Serum globulin predicts all-cause mortality for life insurance applicants

Determine the relative mortality in apparently healthy adults with various levels of serum globulin.

By use of the Social Security Death Master File, mortality in 2010 was determined for 7.7 million life insurance applicants age 20 to 89 providing blood samples with valid globulin results between 1992 and 2006. Relative mortality by Cox regression for bands of globulin values was determined by age-sex group, with age split into 20 to 59 and 60 to 89, with each grouping also including age as a covariate. Further analysis was conducted by excluding applicants with elevations of other test values associated with increased globulin levels and mortality risk.

After accounting for the mortality impact of frequently associated laboratory test abnormalities including BMI, alkaline phosphatase and albumin, relative mortality was found to increase gradually for globulin values > 3.2 g/dL. Values > 4.0 were associated with a mortality risk that was approximately doubled. There is also a small increased risk for globulin values < 1.9 g/dL.

The highest 20% of globulin levels were associated with steadily increasing mortality in life insurance applicants. In many cases, other laboratory findings were not informative of the risk.