"Still and all, why bother? Here's my answer. Many people need desperately to receive this message: I feel and think much as you do, care about many of the things you care about, although most people do not care about them. You are not alone. " -- Vonnegut
I wonder how much of this phenomenon is fueled by this research and these types of articles. They don't really say what causes the early death. There are a lot of cultural assumptions that fuels that result. They only researched in high income countries. If those countries had universal health care, that might have made a difference. If those countries had universal basic income, that might have made a difference. If people are having difficulty in getting health care or minimum means of support, they're going to have a more difficult time by themselves. With others, the people around them can care for each other. There's a cultural bias from religion and because it's easier to survive with other people when resources are limited. These types of studies may just be confirming that bias and reinforcing it. I would be interested to see a study in an area where people could be self-sustaining in all ways regarding survival. If social isolation still has an effect, then I'd be interested to see what it was. At this point, it's difficult to see the relationship between social isolation and death because there are way too many factors that could be causing it. The factor may have to do more with resources than with connecting with people. I'm thinking of people like monks and people like Thoreau. With enough resources and respect for their place in society, would people like that be subject to a shorter life?
There are two aspects of mortality / demography research that I think matter a great deal here: the factors that are controlled for and the aggregation level. Reading the primary source paper reveals that they account for age, world region (so not only high income countries), gender, study length and a few other factors. They use random effects weighing to account for variability between studies. I don't know if they've accounted for income levels, but that doesn't undermine the statistical significance of the correlation between social isolation and mortality rates. Secondly, most of the research is done in an aggregated way to describe general patterns. Of course there will be (systematic) exceptions to the rule, like zen monks; this research does not imply that social isolation will necessarily lead to a shortened life, only that a large group of socially isolated people will on average have a shorter life span. Demography research is I think about general trends and patterns and not so much about individuals or small-scale groups.
I'm not necessarily doubting that there's a pattern. I'm much more interested in why that pattern exists. There's an implication that if social isolation is killing us then social networking will save us. But what is it about social networking that saves us? One of the reasons that I question studies like this is that it has the same flavor of studies that say that poor people die younger. OK, but what can be done about it? The poor people don't want to be poor and the rich people aren't going to be doing much. It's the same way with social isolation. Most of the socially isolated don't choose that. I went to Reddit to search on what other people had to say about this article. It was referenced in 8 different subs. It got almost no response, I think because there's not much to say. One of the only responses was from someone in r/foreveralone who said something along the lines of 'good, we'll die earlier and have to suffer less.' It's possible that a good portion of the suffering that people experience from social isolation is the social stigma and social approbation which articles like this one exacerbate. It's also possible that the early deaths come from lack of resources of the socially isolated. Since the studies don't really give an answer, the usefulness is dubious. The socially isolated can face more stigma. The socially networked can fear social isolation. But that's not really news. The Catholic church knew that when its biggest punishment is excommunication. Buddhist monks may be the exception to some rules, but that might be because the cultural stigma against their social isolation isn't as strong.