Studies have found that a person's risk for acquiring certain diseases and disorders, including hypertension, asthma, and depression, can increase from living with an affected partner. These researchers applied that idea to the most common allergy in adults, hay fever.

What the researchers wanted to know: In their words, "Does my partner cause my allergy?" So if you live with someone who has hay fever, does that increase your risk of getting the allergy?

What they did: Researchers randomly selected 6,640 people ages 25-74 from a city in Germany to recruit for the study; 4,261 subjects participated. Qualified interviewers questioned the subjects on whether the subjects had a history of hay fever, whether they were married or lived with a partner and for how long, and whether their partner had hay fever. Subjects also answered questions such as whether they smoked and whether their parents had a history of allergy, to account for other things that could affect the results. The researchers then analyzed subjects' responses.

What they found: In this study, the risk of getting hay fever doubled when a person lived with someone who had the allergy. The risk seemed to increase further the longer a person lived with their S.O., the Sneezing One.

What this study means to you: Moving in together isn't all fun and games.

Caveats: It's not clear that the partner's allergy causes the other person to develop it as well. It may just be that because people are drawn to those near them in social status, ethnicity, etc., both partners tend to have a similar predisposition to the disease.

Find out more: http://www.medicinenet.com/Hay_Fever/article.htm

Read the article: Schafer, T., Merkl, J., Klemm, E., Wichmann, H.E., and J. Ring. "Does My Partner Cause My Allergy?" Allergy. July 2004, Vol. 59, No. 7, pp. 781-85.