Head and neck squamous cell carcinoma is a common type of cancer that develops in the outer layer of the skin. Now, new study findings published in JAMA Otolaryngology suggest that people with head and neck cancers who smoke and drink are at a higher risk for death, reports Reuters.

For the study, researchers assessed 463 patients with head and neck cancers. Participants were diagnosed and treated between 1997 and 2012. About half of the participants were examined for at least seven years, and 254 people (55 percent) died over the course of the study.

Study results showed that those who smoked at the time of diagnosis were twice as likely to die than nonsmokers and those who reported alcohol use of any kind were 68 percent more likely to die.

Unmarried people were 87 percent more likely to die from head and neck cancers than married people; smokers were less likely to be married. According to the study’s authors, about 60 percent of smokers were unmarried, and 64 percent were drinkers; meanwhile, 40 percent of nonsmokers were unmarried, and 38 percent were drinkers.

What’s more, about half of the smokers lived for only about seven years after their diagnosis compared with half of the nonsmokers who survived for at least 17 years.

Study limitations included the lack of data on how changes in marital status may have played a role in smoking or drinking status and the inability of researchers to distinguish nonsmokers who recently quit from those who never smoked.

“A patient’s response to this cancer and healing from the very invasive treatment of the disease will be greatly diminished in a patient already compromised by dealing with the untoward effects of smoking,” said Karl Kelsey, MD, MOH, director of the Center for Environmental Health and Technology at Brown University in Providence, Rhode Island, who was not involved in the study. “Quitting smoking at any time reduces your risk of poor outcomes.”

According to Kelsey, a large number of these particular cancer cases are caused by the common sexually transmitted infection known as human papilloma virus (HPV), which may explain the connection between marriage and cancer risk in this study.

Click here to learn about how HPV is linked to head and neck cancers.