FRIDAY, Nov. 9 (HealthDay News) -- Children in more affluent families are more likely to develop peanut allergy, a preliminary study suggests.

The researchers said their findings support the theory that a lack of exposure to germs during early childhood increases the future risk of allergies. This so-called "hygiene hypothesis" suggests that living in an overly clean home may suppress the natural development of a child's immune system.

For the study, the investigators looked at more than 8,300 people and found that nearly 800 had an elevated antibody level to peanuts, according to the study presented Friday at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI), in Anaheim, Calif.

"Overall household income is only associated with peanut sensitization in children aged 1 to 9 years," study lead author Dr. Sandy Yip said in an ACAAI news release. "This may indicate that development of peanut sensitization at a young age is related to affluence, but those developed later in life are not."

The study authors also found that peanut allergy was generally higher in males and racial minorities regardless of age, and that peanut-specific antibody levels peaked in adolescence (ages 10 to 19), but tapered off after middle age.

"While many children can develop a tolerance to food allergens as they age, only 20 percent will outgrow a peanut allergy," Dr. Stanley Fineman, ACAAI president, said in the news release. "It's important that children remain under the care of a board-certified allergist to receive treatment."

Peanut allergy affects about 400,000 children in the United States and is one of the food allergies most commonly associated with sudden and severe allergic reactions, including potentially deadly anaphylaxis, according to the ACAAI.

Although the study found an association between household income and peanut sensitization in young children, it did not prove a cause-and-effect relationship. The data and conclusions of research presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The Food Allergy and Anaphylaxis Network has more about peanut allergy.