Isoflavones have been suggested to have protective effects on certain cancers. However, the association of soya foods or dietary isoflavones with the risk of myelodysplastic syndromes (MDS) has not been examined. Thus, the aim of this hospital-based case–control study undertaken in China in 2012–2013 was to investigate the association between dietary isoflavone intake and MDS risk. The analysis included 208 cases aged 19–85 years with MDS and 208 controls individually matched to the cases by sex, birth quinquennium and residential locality. Information on habitual food intakes, including nine items of soya foods, was sought from in-person interviews using a validated 107-item FFQ. Dietary intakes of daidzein, genistein, glycitein and total isoflavones were estimated using the 2008 US Department of Agriculture Isoflavone Database. OR were calculated from conditional logistic regression after adjustment for potential confounding by demographics, lifestyle and dietary factors. The mean daily intake of total isoflavones was 19·0 mg in cases and 23·0 mg in controls. Dietary intake of isoflavones was inversely associated with the risk of MDS. The adjusted OR in the highest tertile compared with the lowest tertile of intake were 0·43 (95 % CI 0·21, 0·85) for daidzein, 0·36 (95 % CI 0·18, 0·74) for genistein, 0·49 (95 % CI 0·25, 0·97) for glycitein and 0·40 (95 % CI 0·20, 0·81) for total isoflavones. The findings suggest that higher dietary intake of isoflavones is associated with a reduced risk of MDS in a Chinese population.
