139 were diagnosed with some form of cognitive impairment, including 82 with mild cognitive impairment — which may represent a transitional phase between normal age-related memory decline and Alzheimer’s disease — and 48 with Alzheimer’s.
Let’s see… 139/1432 = 9.7% and 48/1432 = 3.4%. So, out of a hundred people, about 3 people will get Alzheimer’s; 97 people will not. This are small numbers. Granted, having worked with people at the early stages of Alzheimer’s, the disease is devastating but apparently not quite as prevalent as the news coverage seems to suggest. In contrast, almost 4 times as many people have heart disease (11%). It is about as prevalent as stroke (2.6%, Table 2). And 7 out of a 100 people will get any type of cancer (Table 6)
Nevertheless, if we do want to prevent Alzheimer’s – the study claims – we just have to be married. Never mind that
The association with an increased risk of Alzheimer’s disease did not reach statistical significance.
But, okay, the difference in other cognitive impairments between singles and marrieds is statistically significant. However, there is something else that plays a role:
Having the APOE-e4 genotype — a risk factor for Alzheimer’s — was particularly damaging for those who were widowed or divorced from midlife through late life. Those who were married and had the high-risk genotype had a 3.44-fold (P<0.05) increased risk of Alzheimer's disease, compared with a 25.55-fold (P<0.001) greater risk for those who were divorced or widowed.
I have no idea what that genotype is but to me this finding that married folks have a lower risk of Alzheimer’s than divorced or widowed is, well, nice but not at all actionable. What are we to do? Ask people to get married to prevent Alzheimer’s? This would go down the (wrong) road of using marriage as a panacea, which it is not. Plus, causality – marriage prevents Alzheimer’s – cannot be established by this kind of study. It would require an experiment where people are randomly assigned to the “marriage condition.” Since that is not very ethical, we can’t conduct such a study. We can use longitudinal studies to approximate this, watching people with changing marital status. However, as the researcher pointed out, there might be other things at play here, too:
This suggested, Hakansson said, that other factors beyond cohabitation were involved in the associations. […]
Hakansson speculated that those who were widowed or divorced — and remained so — were at a greater risk than those who were single because the loss of a partner destabilized the psychobiological system, enhancing vulnerability to disease.
Maybe stress is the mediating factor, not marital status? Loosing your spouse – through death or divorce – certainly is stressful!
Now, is there anything we can do to prevent Alzheimer’s? There is apparently a “general hypothesis of social stimulation as a protective factor against dementia.” So, be social and be active! Start a walking group where you skeptically dissect news reports on what benefits marriage are supposed to bestow upon us. If nothing else, you’ll prevent heart disease through the walking…