Or could it be the Swedes are healthier in general ... less fat meaning less diabetes, less hypertension, less heart disease.
Sweden was compared to other countries, not just the U.S., including neighbors such as Norway, Finland, and Denmark. Do you think Sweden is that much healthier than any country on earth?
Also, Sweden has a risk factor that is much more of a risk than diabetes, etc. In Sweden, there is a lot less sunlight for a major part of the year, meaning potentially people with much lower Vitamin D.