Single People Face Higher Cancer Rates, Study Finds

Adults who have never married are significantly more likely to develop cancer than those who are married or have been, according to a major new study in the United States.

Researchers at the University of Miami analysed more than four million cancer cases recorded across 12 US states between 2015 and 2022. They found that cancer incidence rates were 68% higher among never-married men and 85% higher among never-married women, compared with those who were or had previously been married.

The scientists are quick to point out, however, that marriage itself does not protect against cancer. Rather, they believe a range of lifestyle and social factors are at work.

"It means that if you're not married, you should be paying extra attention to cancer risk factors, getting any screenings you may need, and staying up to date on health care," said clinical psychologist Frank Penedo, one of the study's authors.

Known cancer risk factors such as smoking, chronic stress and reproductive history are all linked to marital status. There is also the possibility that healthier people are simply more likely to marry in the first place. For the purposes of the research, unmarried couples living together were classified as single.

Some of the starkest differences appeared in cancers associated with the human papillomavirus (HPV). Never-married men developed anal cancer at roughly five times the rate of married or previously married men, while never-married women were nearly three times as likely to develop cervical cancer. Having a partner who encourages medical check-ups may play a meaningful role in earlier detection, the team suggested. For cancers with well-established screening programmes, such as breast and prostate cancer, the gaps were considerably smaller.

The study was observational and did not track individuals over time, and it treated all married or previously married people as a single group regardless of the length or quality of their relationship.

Epidemiologist Paulo Pinheiro said the findings pointed to social circumstances as a meaningful signal of cancer risk at the population level, and called for screening and prevention efforts to take marital status into account.

Other research has found advantages to single life, including stronger social networks beyond a partner and greater personal autonomy. Separate evidence has also linked marriage to an increased risk of dementia, underlining that neither relationship status is straightforwardly healthier than the other.

The research was published in the journal Cancer Research Communications.