Phoenix, Las Vegas worst for ragweed

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MADISON, N.J., May 25 (UPI) -- Phoenix; Las Vegas; Overland Park, Kan.; Riverside-San Bernardino, Calif.; and Dallas are rated highest for ragweed sensitization, researchers say.

The Quest Diagnostics Health Trends Report, Allergies Across America by Quest Diagnostics evaluated results of ImmunoCAP specific Immunoglobulin E blood testing for ragweed and ranked the worst and best cities for those with ragweed allergies.

Dr. Stanley J. Naides, medical director of immunology at Quest Diagnostics says the study is based on nearly 14 million test results from more than 2 million U.S. patient visits. Those cities at the high end of the ranking show sensitization levels nearly three times higher than those at the low end.

Miami; San Francisco; Portland, Ore.; Tampa, Fla.; and San Diego showed the lowest rate of ragweed sensitization, Naides says.

Regionally, ragweed sensitization was highest in the Southwest, Great Lakes, Mountain and Plains States. The investigators theorize the differences in ragweed sensitization regionally and in large cities may in part be due to longer and more intense ragweed pollen seasons.

However, the reasons behind these difference are unclear and deserve additional study, the researchers say.