This question [about whether religious people live longer] can be asked in two different ways. One can ask whether religious people live longer than their non religious compatriots. Or one can ask whether people living in religious countries enjoy longer lives than people in secular countries. Oddly, the answers to these questions are very different.
Countries with very low life expectancy are mostly very religious. The nations of sub-Saharan Africa are a good example. There plagues of malaria, parasites, dengue fever, cholera, diarrheal diseases, HIV/AIDS, etc., lop decades off life expectancy that is below 60 years for most of these countries. The presence of many serious chronic illnesses, and the expectation of an early death, predicts universal belief in God and the importance of religion.
With economic development, health improves, but religion declines. This means that developed countries are both healthier and more secular. Developed countries reap the benefits of improved healthcare, sanitation, and public health programs like vaccination for measles and smallpox. As a result, average life expectancy has literally doubled from what it was a century ago.
So secular populations definitely live much longer than residents of highly religious countries. Examples include Sweden (life expectancy of 81 years) and Japan (life expectancy of 82 years) where residents outlive more religious Americans (78.5 years).