A study of patients in 30 hospitals in six big cities, including Beijing and Shanghai, found that worsening environmental conditions are causing a rise in the incidence of chronic lung diseases, state media reported. Researchers also said increasing numbers of urban youths are suffering from emphysema and chronic bronchitis, diseases normally associated with the elderly. About 9% of sufferers in the study were aged under 40, while 73% of those surveyed with chronic lung disease were male. Around 43 million people in China have chronic lung disease, with about one million of them dying each year.