People who are neurotic — they tend to worry a lot and to have emotional ups and downs — seem to be at increased risk of developing asthma, a new study hints. Those who suffer through a divorce or other relationship conflict are also at risk for asthma, according to the study.

Animal studies have shown that chronic stress alters hormone levels, which can inflame airways making it difficult to breathe. Researchers believe that neurotic character traits may exert similar effects. If so, then helping neurotic people to calm down or "chill out" could, theoretically, reduce their risk of asthma.

Dr. Adrian Loerbroks from Heidelberg University, Germany and colleagues explored associations between neuroticism, stressful life events and asthma by surveying a sample of 5,114 men and women aged 40 to 65 years from Heidelberg and its surroundings.

Right from the start, they noticed a link between asthma and neuroticism in men, and between asthma and unemployment in both sexes. In women, having broken off a life relationship was associated with having asthma.

Among the 4,520 individuals reported to be free of asthma at the start of the study, 63 or about 2 percent, developed asthma during a median follow-up of more than 8 years, they report in the latest issue of the journal Allergy.

According to the investigators, individuals who were highly neurotic were three times more likely to develop asthma than those who were less neurotic, and breaking off a life partnership increased the risk of asthma development by more than twofold.

The link between high neuroticism and the development of asthma was present in women and men, whereas breaking off a life relationship increased asthma risk only in women.

Unemployment and death of a close person were not significantly associated with the development of asthma, the researchers note.

The researchers call for more study on personality traits, stress and asthma.

"The physiological mechanisms by which personality, stress, and emotions might influence the development or course of asthma," they note, "are still not well known."