Is Loneliness a Health Hazard?

We hear that loneliness is terrible alot and see articles like this one that say loneliness is as bad as obesity for health:

Feeling sad, lonely and useless is more than just an emotional quagmire for millions of Americans. Researchers now contend that social isolation and loneliness may represent a greater public health hazard than obesity or a near pack-a-day smoking habit.

And the problem is growing. An AARP loneliness study published in 2010 and now being updated reported that approximately 42.6 million U.S. adults ages 45 and older were suffering from loneliness. A 2018 Cigna survey indicates that Generation Z, adults between ages 18 and 22, may be the loneliest group of Americans. Additionally, census data reveal that more than one-fourth of Americans live alone and more than half are unmarried, with marriage rates and the number of children per household steadily declining.

It's clear that being alone and unhappy about it "are risk factors for early illness and death that need to be discussed more openly and for which solutions must continue to be developed," says Lisa Marsh Ryerson, president of the AARP Foundation.

I think that being alone is fine for some people, particularly those who are introverts, but the key is how one feels about being lonely.

If a person has negative thoughts about being lonely, then it can be a health concern, but if they are happy being alone or content, it is not. Half of all Americans are now unmarried and I wonder how this plays into loneliness.