May 4, 2021 -- Loneliness among middle-aged men ups their risk of cancer, and being single at the time of diagnosis often leads to worse outcomes, confers a worse prognosis, a 20-year study from Finland found.
The study also found that although loneliness was associated with an increased risk of cancer, social isolation was not.
It's not clear why loneliness had a stronger association with cancer compared with social isolation, but it could be linked to satisfaction, lead author Siiri-Liisi Kraav, MSc, a PhD student at the University of Eastern Finland, said.
"For many people, their level of social contacts (social isolation) is satisfactory, and it does not necessarily cause suffering. Loneliness, however, by definition includes dissatisfaction with the situation," Kraav told Medscape.
Why loneliness might lead to a greater risk of cancer is not clear, but one possibility is inflammation, Kraav said. Loneliness may lead to inflammation itself.
The findings are a call to action, Kraav suggested. "Loneliness has a lot of adverse health effects; increased cancer incidence is only one of them. So, it would be important to prevent these negative effects by developing effective interventions for loneliness and to routinely screen for loneliness."
The study was published in May in Psychiatry Research.
There are many studies " linking both social isolation and loneliness to all-cause mortality and cardiovascular outcomes, but less specific to cancer," Julianne Holt-Lunstad, PhD, who was not involved in the study, said.
The health impact of loneliness and social isolation triggered by the pandemic may not be fully understood for "years or decades to come," Holt-Lunstad, a professor at Brigham Young University in Utah, told Medscape. "While I hope the majority of people will be resilient or recover, I suspect at least a subset of the population will have chronic effects. Thus, we need to continue to study this issue and prioritize addressing it in public health."
The Finnish study involved 2,570 men, aged 42-61 years.
After an average of 20.4 years, 649 men in the study (25.3%) had developed cancer and 283 died of the disease. They were an average of 70 years old when diagnosed, and the most common cancers were prostate (9.2%), lung (3.4%), and colorectal (3.1%).
Patients who developed cancer "were older than their healthy counterparts, drank more alcohol, and were more often smokers," the authors said.