IgA level is associated with risk for mortality in an eighty-year-old population

Immunoglobulin levels are elevated in the older people. However, it is unknown whether these levels are related to mortality.

To evaluate the association between immunoglobulin levels and mortality.

The study population included 697 individuals (277 males and 420 females) of 1,282 eighty-year-old individuals residing in the Fukuoka prefecture, Japan. The participants were followed for 4 years after the baseline examination.

The hyper-IgA group, defined as a serum IgA level >400 mg/dl, had high mortality using Kaplan-Meier analysis (log rank, p=0.037). Multivariate Cox regression analyses revealed a high risk of mortality (hazard rate=1.233, 95% confidence interval 1.109-1.491, p=0.031) after adjusting for covariates. The high risk of mortality in the hyper-IgA group was significant in males, but not in females. Moreover, Kaplan-Meier analysis revealed that IgA was related to cancer mortality in males (log rank, p=0.031), but not to pneumonia or cardiovascular disease. IgM and IgG levels were not related to high risk of mortality.

Serum IgA levels appear to be a predictor of mortality, especially cancer mortality in males.