Both education and race link very closely with taking vitamin supplements, but they also link very closely with obesity and diabetes. For example, highly educated people are more likely to take vitamins but less likely to be overweight and have diabetes — and being overweight and having diabetes are associated with a host of health problems. This makes it virtually impossible to separate the impact of vitamins from the impact of these other variables. We know education and race are also very strongly linked to mortality rates. Given this backdrop, it is an almost insurmountable challenge to tease out any small impacts of vitamins.