Seven-year-old Edward Saldana was diagnosed with asthma at age 1, said his mother, Martha Saldana of Riverbank.

"He just hates all this medication," Martha Saldana said. "He says, 'I've been on medication all my life.'"

Her son uses two kinds of inhalers and a machine called a nebulizer that helps open his bronchial tubes so he can breathe, she said. Sometimes, such as last month over Christmas vacation, he uses the machine twice a day. He used to take it to school, she said.

A report released today by the Great Valley Center concludes that Central Valley children are more likely than other people in the state to be diagnosed with asthma or exhibit asthma-related symptoms.

Adults in the valley are no less affected by this chronic lung disease, according to the report. People 18 and older in all valley counties have higher prevalence of asthma than the state average, and more than 80 percent of the counties have higher rates than the San Francisco Bay Area, the report states.

The report and its findings on asthma are based on responses to last year's California Health Interview Survey, involving 55,428 households and touted as the largest health survey ever conducted in the United States.

Physicians, such as Dr. Robert Tanaka, are not surprised asthma rates are high in the valley.

Experts think chronic exposure to irritants, such as air pollution and allergens, could cause someone to develop airway inflammation, which leads to asthma, said Tanaka, who treats adults with asthma at Sutter Gould Medical Foundation.

On the other hand, Dr. Robert Donovan, medical director of the emergency room at Doctors Medical Center, said he takes the report with a grain of salt, particularly when valley rates of asthma are not that different than rates in the Bay Area and Los Angeles.

"I'm concerned that the real number difference may not really be of clinical significance," he said.

The Central Valley has the highest prevalence of asthma among children ages 0 to 17 (11 percent) when compared with the Bay Area (10 percent), the state (8 percent), and the Los Angeles region (8 percent), the report concludes.

For adults, that's 10 percent for the valley, 9 percent for the Bay Area and the state, and 8 percent for the Los Angeles region.

Within the Central Valley, the eight-county San Joaquin Valley has the highest rate of childhood asthma, at 12 percent. Fresno and Kings lead valley counties for childhood asthma rates, at 16.4 percent and 14.7 percent, respectively.

Stanislaus County has the lowest rate in the San Joaquin Valley, at 9.3 percent. That's slightly above the statewide average of 8 percent for childhood asthma.

Plenty of people who suffer from allergies and asthma say they feel better when they leave the valley, which often has high levels of ozone and dust.

Ozone pollution, which results when sunlight bakes chemicals emitted primarily from cars, can trigger asthma attacks and irritate other lung problems. Dust also can cause people with asthma to suffer attacks or wheezing.

Born in Oakdale, Martha Saldana has lived in the valley all her life. Two years ago, her family moved to the coast for a time. While there, Edward didn't have to use his nebulizer, she said.

"I noticed when he's here in the valley he starts coughing. He gets that croupy cough," she said. "As soon as he goes back to the coast, he's fine."

Asthma on the rise nationwide

Asthma prevalence has more than doubled in the country in the past 15 years, the report states.

"Hands down, it is a fact that the incidence of asthma and all allergic diseases is increasing in the United States," said Dr. Gregory Bensch with the Allergy, Immunology and Asthma Medical Group, which has offices in Stockton, Modesto, Manteca and elsewhere.

"We have high levels of certain allergens in the valley and we tend to have poor air quality in the valley," he said. "Both are known to be pretty potent stimuli for exacerbating asthma."

Bensch said asthma often goes unrecognized, but it's better to start treatment early. Children with other allergic problems, such as eczema or hay fever, are at increased risk for asthma, he said.

The American Lung Association, with Bensch and another physician, is conducting a pilot program in the Stockton Unified School District to conduct breathing tests in schools, just as vision and hearing tests are conducted.

"We're trying to identify people earlier," he said, adding that parents and teachers should be on the lookout for kids who are coughing or wheezing or get exhausted easily.

Stanislaus County Supervisor Paul Caruso said there should be a concerted effort to clean up the air, but said he doubts it would completely relieve the suffering for asthmatics.

"It's an ag community, and people who relocate to this area need to understand that," he said.

Bee staff writer Melanie Turner can be reached at 578-2366 or mturner@modbee.com.

Reprinted by permission of Modesto Bee.