After examining data from 59 countries, University of Cologne psychologist Olga Stavrova concludes that "the health and longevity benefits of religiosity are restricted to highly religious regions."
Maybe she should look into whether it is simply true of people in general who are highly religious. A purely geographic survey seems rather superficial. Presumably, people in "highly religious regions" are highly religious. But there are people in less highly religious regions who happen to be highly religious. Do they also experience health benefits therefrom?