High incidence of idiopathic nephrotic syndrome in East Asian children: a nationwide survey in Japan (JP-SHINE study)

Little is known regarding the epidemiology of idiopathic nephrotic syndrome (INS) in East Asia. Previous studies have suggested higher incidence of INS in Asian children, though decreasing trend of its incidence has also been shown. We conducted a nationwide study of Japanese children aged 6 months to 15 years with INS. Children who were newly diagnosed with INS between 1 January 2010 and 31 December 2012 were eligible. Children with congenital nephrotic syndrome or nephrotic syndrome secondary to nephritis were excluded. A total of 2099 children were initially diagnosed with INS and were followed for up to 4 years. The estimated incidence of INS was 6.49 cases/100,000 children per year, without clear correlation with geographical region. The male:female ratio was 1.9 and approximately 50 % of children were