A cheap regimen of vitamins in use for decades is seen by scientists as a way to delay the start of Alzheimer’s disease and dementia, a goal that prescription drugs have failed to achieve. / Drugmakers including Bristol-Myers Squibb Co., Pfizer Inc. (PFE) and Eli Lilly & Co. (LLY) have spent billions of dollars on ineffective therapies in a so-far fruitless effort to come up with a treatment for dementia and Alzheimer’s. / Now, in the latest of a steady drumbeat of research that suggests diet, exercise and socializing remain patients’ best hope, a study published today in the Proceedings of the National Academy of Sciences shows that vitamins B6 and B12 combined with folic acid slowed atrophy of gray matter in brain areas affected by...