They had 1567 participants. Compared to control (HIIT-like), HIIT reduced risk by 1.7% while moderate intensity training increased it by 1.2%. The overall mortality in the control group was 4.7%. For a controlled trial, that seems like a large number of participants (correct me if I'm wrong), they just were too healthy ;-)
I assume the significance problem is inherent to studies looking at mortality as the outcome is very binary and can take a long time to manifest. As an effect on all-cause mortality can be seen as the ultimate metric of how healthy something is, it's probably still worth it to investigate. In this case, they made it quite difficult for themselves by comparing active people to other active people.
It's also possible that they made other observations during the study that are or will be published separately.
Also, just adding some sugar to this, don't forget that this study was in Norway. Overall health levels would be higher than in, say, USA. I'm talking about weight specifically.
Assuming healthy / not overweight would be a very big assumption to make for the US (as a Norwegian I went to the the USA, once, in 1999, and what I saw there shocked me), where another study could be to monitor mortality outcome of getting weight under control and exercising vs not.
I'd also love to see impact of weight resistance training added to the mix surveyed.
And not just Norway, but specifically Trondheim. Correct me if I am wrong, but I expect their lifestyle to be even less sedentary than the average Oslo resident. I expect the results to have slim pickings (pun intended)!
Roger that. But even by e.g. Australian standards (which are a lot closer to the US ones), Oslo is far from sedentary; I didn't even think about buying a car in Norway before I left it, being happy to walk/run, ride or PT it everywhere. Bad diet, alcohol use etc is a lot more common than in Norway too.
I read that wrong. I thought that the overall mortality rate in the groups was 1.2% and 1.7%. Didn't realize those were both differences from the control.
Because running a large enough study is expensive and it's cost-effective to perform a smaller study to determine an approximate size of the effect. Then, you can design the next study to have enough power to distinguish the expected effect size from the null hypothesis.
Additionally, these results could be aggregated with comparable results to yield a stronger result.
I assume the significance problem is inherent to studies looking at mortality as the outcome is very binary and can take a long time to manifest. As an effect on all-cause mortality can be seen as the ultimate metric of how healthy something is, it's probably still worth it to investigate. In this case, they made it quite difficult for themselves by comparing active people to other active people.
It's also possible that they made other observations during the study that are or will be published separately.