Pay attention to that under-the-weather feeling

Seemingly healthy people who say they don’t feel so hot are prone to developing colds, a new study finds.

Having a weakened immune system prompts individuals to rate their general health as relatively poor, even if they don’t display illness symptoms, say psychologist Sheldon Cohen of Carnegie Mellon University in Pittsburgh and his colleagues. Fatigue, reduced appetite and other signs of feeling off-kilter, which may be related to a weakened immune system, possibly spur reports of middling or worse health in people who then get sick when exposed to the cold virus, the researchers propose in the November/December Psychosomatic Medicine.

Previous studies have reported that people judge themselves as healthier if they exercise, eat a good diet, avoid alcohol and cigarettes, feel at ease and cheerful, and have close friends and relatives. These characteristics lower one’s near-term chances of getting sick and dying.

But in the new study, the presence or absence of these commendable traits could not account for the elevated likelihood of catching the common cold among young and middle-aged adults reporting less-than-excellent health, Cohen’s team says. Neither could volunteers’ past sensitivity or resistance to catching colds.

Cohen’s group analyzed data from 360 healthy U.S. adults, ages 18 to 55. These volunteers had participated in one of two previous studies in which they were asked to rate their health as excellent, very good, good, fair or poor. Nobody reported being in poor health and only eight people said they were in fair health. That’s not surprising since the researchers recruited relatively young adults who had no severe medical or psychological ailments.

Participants received nasal drops containing a virus that causes the common cold. They then spent that day and the next five quarantined in separate rooms. Daily blood tests determined that 289 volunteers became infected with the cold virus. Sneezing, throat soreness, congestion and other cold symptoms appeared in 117 individuals.

Participants who rated their health as good or fair were almost three times as likely to develop cold symptoms as those who cited excellent health. Even those citing very good health were more than twice as likely to come down with a cold relative to excellent-health reporters. Self-health ratings offered no clues to who would become infected but remain free of cold symptoms.

The study’s results suggest that physicians can gain quick insights into patients’ risk for infectious disease by asking them to rate their health. “People without any obvious, detectable health troubles but low self-reported health are at risk for a range of problems, including infections,” Cohen says.

Poor self-rated health may be an especially accurate marker of a susceptibility to infections in older adults, speculates UCLA psychoneuroimmunologist Hyong Jin Cho, who did not participate in the new study. As people age, the immune system generally becomes less able to defend against infection.

For now, Cohen’s study offers a rare biological explanation for the power of self-rated health to predict disease and even death, Cho and UCLA colleague Michael Irwin write in an editorial published with the new study.

Cohen’s findings raise the possibility that immunity-boosting medications can prevent infectious illnesses in people who rate their health as lukewarm or worse, Cho says.