Researchers have known people who live farther from the equator are more likely to develop multiple sclerosis (MS) and have often attributed that to vitamin D exposure. But countries farther from the equator are also more likely to be wealthier than countries nearer to the equator. A new analysis shows that the amount a country spends on health care may help explain the link between MS and latitude. This new research is published in the August 24, 2022, online issue of Neurology.