Loneliness increases cancer risk among middle-aged men, longitudinal study shows

Middle-aged men who are lonely had increased risk for cancer, regardless of the social network size, according to results of a longitudinal study published in Psychiatry Research.

“Previous studies have suggested a link between psychological factors and cancer onset, as well as cancer progression,” Siiri-Liisi Kraav, MSc, a PhD student at the University of Eastern Finland’s Institute of Clinical Medicine/Psychiatry, told Healio Psychiatry. “The knowledge about linkage between loneliness and cancer was scarce. Loneliness studies are often carried out in older patients and the follow-up times are not long enough to uncover all the negative effects. In the current study we were able to observe the connection between loneliness and cancer incidence during a long follow-up time (20 years) in a cohort sample of middle-aged men.”

Kraav and colleagues assessed baseline levels of loneliness, social isolation and health-related factors among 2,570 men aged 42 to 61 years at baseline. They evaluated the link between cancer incidence, loneliness and social isolation using Cox proportional hazards analysis. Further, they used the Kaplan-Meier method to assess the impact of relationship status on cancer mortality among cancer patients.

Results showed a link between loneliness and total cancer incidence after the researchers adjusted for tested lifestyle and health-related covariates. They observed an association between social isolation and total cancer incidence; however, they did not observe this association when adjusting for lifestyle, diet or Human Population Laboratory (HPL) Depression Scale scores. Further, loneliness appeared linked to lung cancer incidence, except for when the researchers adjusted for HPL Depression Scale scores. They reported that social isolation was not significantly associated with lung cancer. Moreover, there was no apparent connection between neither loneliness nor social isolation and prostate or colorectal cancer. Study participants with cancer who were single at baseline exhibited worse survival outcomes.

“This study emphasizes the link between loneliness and adverse health effects,” Kraav said. “Even though we cannot draw any conclusions on how to prevent cancer based on this study, it is one step further towards uncovering the mechanisms underlying the connections between psychological factors and cancer onset. In the future, it will hopefully help develop approaches in personalized health care.”