HSD17B1 and Alzheimer disease: We found that an increase in the number of rare alleles of the HSD17B1 SNP (rs598126 and rs2010750) was associated with a decrease in AD among women who ever used hormonal derivatives (Ptrend = 0.04 and Ptrend = 0.08, respectively), but with an increase in AD among women who never used them (Ptrend = 0.06; Pi = 0.02 and Ptrend = 0.04; Pi = 0.01, respectively).