Influences on childhood asthma in low-income communities in China and the United States.

For comparison of childhood asthma, the same case-finding survey and parent interview questionnaires were used to collect data from 639 children with asthma in 21 elementary schools in Beijing and 835 children with asthma in 14 elementary schools in Detroit, Michigan. Asthma prevalence in Beijing (7.3%) was more than three times lower than in Detroit (24%) despite a high level of smoking among Chinese parents. Body mass index (BMI; weight in kilograms divided by height in meters squared) levels were higher in Detroit but were not associated with persistent asthma in either country. Higher levels of past infection in Beijing and household allergens in Detroit were noted and may be associated with differences in prevalence. Despite less severe disease observed in Beijing, hospitalizations and office visits did not differ from Detroit. This may be partially associated with less use of anti-inflammatory medicine and lower levels of parental asthma management in China.