High serum isoflavone concentrations are associated with the risk of precocious puberty in Korean girls

Summary Objective The gradual decrease in the age of onset of puberty raises concerns about the contribution of phytoestrogen intake on sexual maturation. However, no data are available on the association between serum isoflavone (genistein, daidzein) concentration and central precocious puberty (CPP). The aim of the study was to test the association between serum isoflavone concentrations and the risk of CPP in Korean girls. Study design A case‐control study was conducted at Inje University Hospital in Korea. One‐hundred and eight girls with CPP (aged 8·6 ± 0·8 year) and 91 age‐matched controls (aged 8·5 ± 0·8 year) were examined. Results Serum concentrations of daidzein (P = 0·0202), genistein (P = 0·0021) and total isoflavones (P = 0·0009) were higher in children with CPP than in normal children. When the children were categorized into three groups according to total serum isoflavone as follows: