A fifteen year cohort based evaluation of beta 2-microglobulin as an early sign of Balkan endemic nephropathy.

The occurrence of elevated urinary beta 2-microglobulin (U beta 2m) has been established to be more common in village populations living in areas where BEN is endemic when compared to appropriate control population. In addition, beta 2-microglobulinuria is associated with BEN. It has been demonstrated that there is an increase in the U beta 2m in apparently healthy populations located in high risk areas. It is 15 years since the first systematic investigations of U beta 2m in the villages of Brod Posavina were conducted. The purpose of this study was to determine the value of a positive test for tubular proteinuria as defined by increased U beta 2m, in identifying individuals at risk to develop BEN. In these studies we followed two cohorts for 15 years: one group consisted of individuals who were positive for tubular proteinuria by U beta 2m testing in 1974; the second group was an age and sex matched group from the same village who were never positive after 12 testings in 1974. The results show that a positive test for U beta 2m is associated with 9.9 times greater relative risk of developing BEN when compared to controls that had no positive U beta 2m tests.