INS and Alzheimer disease: The HR (95% CI) for AD was 0.92 (0.59 to 1.45) for those on metformin alone, 1.08 (0.84 to 1.38) for those on sulfonylurea alone, and 0.40 (0.32 to 0.50) for the combined treatment, and the decrease was not related to sequence or insulin usage.