Feeling lonely at multiple times throughout life leads to more serious illness and higher mortality risk in mid to later life, a new study shows.

“Cumulative loneliness in mid- to later-life may be a mortality risk factor with a notable impact on excess mortality,” according to the research, published in the Proceedings of the National Academy of Sciences.

“The focus on cumulative loneliness brings a new contribution to the field of loneliness research,” says senior author Lindsay Kobayashi, professor of epidemiology and global health and director of the Social Epidemiology of Global Aging Lab at the University of Michigan.

The researchers found that participants who reported more periods of feeling lonely had significantly greater mortality risk, compared to participants who reported no or fewer periods of loneliness. The researchers used data from more than 9,000 participants aged 50 and older in the US Health and Retirement Study, considered the most authoritative data source on aging in the United States.

The data on loneliness covered an eight-year period from 1996-2004 and was categorized into four groups: never experienced loneliness and experienced loneliness at one, two, or three points. Responses were cross-referenced with participants’ health and lifestyle, and objectively measured social isolation at baseline in 1996 and subsequent mortality risk through 2019.

The results surprised even the researchers: They observed 106 excess deaths when loneliness was reported one time, 202 excess deaths when loneliness was reported two times, and 288 excess deaths when loneliness was reported three or more times over the eight-year exposure period.

“Loneliness is not a static experience, it is dynamic. So, the eight-year duration of our data on loneliness was a unique part of this study that allowed us to look into cumulative loneliness over time,” Kobayashi says.

‘”The numbers surprised me. They strike me as very high because loneliness is preventable. Anytime there are excess deaths due to a modifiable risk factor it’s too many.”

With life expectancy in the US still at historic lows and loneliness being treated as a global health crisis by the US Surgeon General and the World Health Organization, the study urges prevention: “Loneliness may be an important target for interventions to improve life expectancy in the United States.”

Read the full article about loneliness in older adults by Kim North Shine at Futurity.