FRIDAY, July 6, 2012 (HealthDay News) -- Parents are about half as likely to catch a cold as people without children, regardless of their preexisting immunity, a new study says.
The researchers said that unknown "psychological or behavioral differences between parents and nonparents" might help explain their findings.
"We found parenthood predicted a decreased probability of colds among healthy individuals exposed to a cold virus," study leader Rodlescia Sneed of Carnegie Mellon University in Pittsburgh and co-authors reported.
For the study, the researchers examined information on 795 adults from three previous studies. Volunteers in the studies were given nose drops either containing rhinovirus, which causes the common cold, or a flu virus.
After being exposed to the virus, about one-third of participants developed a cold. The study found, however, that there was a 52 percent lower rate of colds among parents compared to volunteers who didn't have any children.
This protective effect increased along with the number of children parents had. And when parents didn't live with any of their children, their risk of having a common cold dropped even more -- to 73 percent lower than nonparents.
The study is published in the July issue of the journal Psychosomatic Medicine.
Parents were less likely to catch a cold regardless of whether they had protective levels of antibodies, the study authors noted in a journal news release. Being married had no effect on the findings. However, the risk of colds was not lower for the youngest parents studied, those aged 18 to 23.
Psychological or behavioral factors could play a role in their findings, the investigators said.
The researchers also suggested that being a parent may improve the regulation of immune factors that are triggered in response to infection. More research is needed, they said, to explain how being a parent affects the body's response to the common cold.
"Our results, while provocative, have left room for future studies to pursue how various aspects of parenthood ([such as] frequency of contact with children, quality of parent/child relationships) might be related to physical health, and how parenthood could 'get under the skin' to influence physical health," the study authors concluded.
The U.S. Centers for Disease Control and Prevention has more about the common cold.