(Newser) – A booming economy would seem to be good news all around, but a new study finds a strange thing: More middle-aged people and seniors tend to die in a strong economy than in a weak one, reports Medical News Today. Specifically, Netherlands researchers found that death rates in developed countries rose for people 40-44 and 70-74 as the GDP ticked up. Every 1% rise in the GDP translated into an increase in the death rate for both groups of about 0.36%.

So what's going on? The scientists aren't sure, but they float a number of theories rounded up by LiveScience. A strong economy means more people are schlepping out to work in the morning, which theoretically raises the risk of traffic accidents and work-related stress, at least for the 40-somethings. As for the older group, they might be getting less care from adult children tied to their jobs. The researchers say these are just best guesses, however, and say the topic needs more study. (Read more death rates stories.)

