Decreasing hypocomplementemia and membranoproliferative glomerulonephritisin Japan

The number of patients with mernbranoproliferative glomerulonephritis(MPGN) diagnosed in our institution and the incidence of hypocomplementemia as de termined by school urinary screening programs in Japan were investigated re trospectively. Fifty-seven children were diagnosed as having MPGN between 1 974 and 1997. Of these, 13 patients were diagnosed during period 1 (1974-19 79) and 25 during period 2 (1980-1985). A decreasing trend was observed dur ing periods 3 (1986-1991) (12 patients) and 4 (1992-1997) (7 patients) comp ared with period 2 (P<0.05 and P<0.01, respectively). A significant differe nce was also noted when MPGN was compared between periods 1 and 2 (1974-198 5) and periods 3 and 4 (1986-1997) (P<0.01). Serum C3 was measured in 1,282 school children with abnormal urinary findings between 1980 and 1997. Thir ty children had hypocomplementemia. The incidence of hypocomplementemia was significantly lower in period 3 (1986-1991) (9 children) and period 4 (199 2-1997) (2 children compared with period 2 (1980-1985) (19 children) (P<0.0 5 and P<0.01, respectively). New cases of MPGN in our institution and the i ncidence of hypocomplementemia as determined by school urinary screening pr ograms are decreasing in Japan. The reason for this trend is unknown.