It's because loneliness is much more prevalent now than in 1974. It's no longer exotic but a condition sometimes voluntarily chosen and supported by modern technologies in 2016.
Also we used to think that heart disease risk is mostly tied to diet and exercise. But it's still the #1 killer in the United States. So every protective or risk factor needs to be considered. As such, new research linking heart disease, CVD, CHD to loneliness, friendship or marriage is interesting.
My folks were Silent Generation,and I think we're a lot less lonely than they were. And face it, I like being alone. I haven't felt lonely since college, and I think that was mostly performance anxiety.
That's not to say that loneliness causes those things. I wouldn't be at all surprised to find that lonely people are more likely to be depressed and sedentary. Many diseases follow from being depressed and sedentary.
Also we used to think that heart disease risk is mostly tied to diet and exercise. But it's still the #1 killer in the United States. So every protective or risk factor needs to be considered. As such, new research linking heart disease, CVD, CHD to loneliness, friendship or marriage is interesting.
And It doesn't stop there. Loneliness is also tied to breast cancer, lymphoma and obesity : http://outcomereference.com/causes/59