I'm advocating that people do studies with randomized interventions—an approach that is capable of proving causation—and not being satisfied with purely observational studies that look at correlations, which are often hopelessly confounded and can't distinguish between "X causes Y" and "Z causes both X and Y". I was pleasantly surprised to find that this study was of the first type rather than the second.
While this take seems popular, this isn't a good way of looking at it because, in my experience, it seems to lead to the dismissal of good evidence or it suggests that we can't build confident causal inferences without a certain study. For example, RCTs are also observational, and it's incorrect to say they can uniquely detect causation.
I think a more helpful way to look at research is to look for a convergence of outcomes across the evidence, like a bunch of needles of various sizes pointing in the same direction (or not) on a gauge. And where there are divergences, and there always will be, which differences in methodology can explain them.
I completely agree that randomized intervention studies have enormous value when compared to observational studies.
In this example, it would be particularly hard to establish a causative relationship that said "hearing aids inhibit dementia" or "hearing loss causes dementia" if instead all you had was a population, some of whom used hearing aids, and some of whom had varying levels of hearing abilities, and some of whom developed dementia. In all the noise, you'd be very fortunate to find that a control group of people with undiagnosed (how would you ever measure that!) hearing loss who failed to get hearing aids had cognitive decline in excess of that experienced by those who did get hearing aids. Here, instead, the intervention is "the coin flip said you're in the hearing aid group/you're in the health education group."
Of course, the murky ethical issue here is that this randomized intervention resulted in some people having poorer hearing, perhaps permanently (use it or lose it!) and some people having more rapid cognitive decline. This randomized intervention directly caused real suffering. Nearly 125 people in the heart-health group with increased risk of dementia onset were assigned to a study that just received health education. For at least three years, they had reduced hearing and a reduced ability to communicate, and after three years, they had significantly greater cognitive decline.
Caution is good, but in general I have no problem personally with the 'shut up and multiply' application of ethics in this case. There are 8 billion people all getting old, and more being born every day who will eventually get older. It's very important as a species to know that hearing aids slow cognitive decline, and if that meant that 119 people were placed at a slightly increased medical risk, 119 divided by 8 billion is a pretty small number, and 7.999999881 billion who are now more likely to get hearing aids and have slower cognitive decline is a lot of positive utility. But it wasn't me or my mom who can no longer hear and who is suffering from dementia, and some will draw a hard line and say that you can't perform studies that will put even a small number of people at increased risk.
We should be careful to evaluate merit and limit harm, but we should perform more randomized intervention studies.
waterhouse|2 years ago
hombre_fatal|2 years ago
I think a more helpful way to look at research is to look for a convergence of outcomes across the evidence, like a bunch of needles of various sizes pointing in the same direction (or not) on a gauge. And where there are divergences, and there always will be, which differences in methodology can explain them.
LeifCarrotson|2 years ago
In this example, it would be particularly hard to establish a causative relationship that said "hearing aids inhibit dementia" or "hearing loss causes dementia" if instead all you had was a population, some of whom used hearing aids, and some of whom had varying levels of hearing abilities, and some of whom developed dementia. In all the noise, you'd be very fortunate to find that a control group of people with undiagnosed (how would you ever measure that!) hearing loss who failed to get hearing aids had cognitive decline in excess of that experienced by those who did get hearing aids. Here, instead, the intervention is "the coin flip said you're in the hearing aid group/you're in the health education group."
Of course, the murky ethical issue here is that this randomized intervention resulted in some people having poorer hearing, perhaps permanently (use it or lose it!) and some people having more rapid cognitive decline. This randomized intervention directly caused real suffering. Nearly 125 people in the heart-health group with increased risk of dementia onset were assigned to a study that just received health education. For at least three years, they had reduced hearing and a reduced ability to communicate, and after three years, they had significantly greater cognitive decline.
Caution is good, but in general I have no problem personally with the 'shut up and multiply' application of ethics in this case. There are 8 billion people all getting old, and more being born every day who will eventually get older. It's very important as a species to know that hearing aids slow cognitive decline, and if that meant that 119 people were placed at a slightly increased medical risk, 119 divided by 8 billion is a pretty small number, and 7.999999881 billion who are now more likely to get hearing aids and have slower cognitive decline is a lot of positive utility. But it wasn't me or my mom who can no longer hear and who is suffering from dementia, and some will draw a hard line and say that you can't perform studies that will put even a small number of people at increased risk.
We should be careful to evaluate merit and limit harm, but we should perform more randomized intervention studies.