RT Journal Article
SR Electronic
T1 Regional variations in the prevalence and misdiagnosis of air flow obstruction in China: baseline results from a prospective cohort of the China Kadoorie Biobank (CKB)
JF BMJ Open Respiratory Research
JO BMJ Open Resp Res
FD British Thoracic Society
SP e000025
DO 10.1136/bmjresp-2014-000025
VO 1
IS 1
A1 Om P Kurmi
A1 Liming Li
A1 Margaret Smith
A1 Mareli Augustyn
A1 Junshi Chen
A1 Rory Collins
A1 Yu Guo
A1 Yabin Han
A1 Jingxin Qin
A1 Guanqun Xu
A1 Jian Wang
A1 Zheng Bian
A1 Gang Zhou
A1 Kourtney Davis
A1 Richard Peto
A1 Zhenming Chen
A1 on behalf of the China Kadoorie Biobank Collaborative Group
YR 2014
UL http://bmjopenrespres.bmj.com/content/1/1/e000025.abstract
AB Background Despite the great burden of chronic respiratory diseases in China, few large multicentre, spirometry-based studies have examined its prevalence, rate of underdiagnosis regionally or the relevance of socioeconomic and lifestyle factors. Methods We analysed data from 512 891 adults in the China Kadoorie Biobank, recruited from 10 diverse regions of China during 2004–2008. Air flow obstruction (AFO) was defined by the lower limit of normal criteria based on spirometry-measured lung function. The prevalence of AFO was analysed by region, age, socioeconomic status, body mass index (BMI) and smoking history and compared with the prevalence of self-reported physician-diagnosed chronic bronchitis or emphysema (CB/E) and its symptoms. Findings The prevalence of AFO was 7.3% in men (range 2.5–18.2%) and 6.4% in women (1.5–18.5%). Higher prevalence of AFO was associated with older age (p<0.0001), lower income (p<0.0001), poor education (p<0.001), living in rural regions (p<0.001), those who started smoking before the age of 20 years (p<0.001) and low BMI (p<0.001). Compared with self-reported diagnosis of CB/E, 88.8% of AFO was underdiagnosed; underdiagnosis proportion was highest in 30–39-year olds (96.7%) compared with the 70+ age group (81.1%), in women (90.7%), in urban areas (89.4%), in people earning 5K–10 K ¥ monthly (90.3%) and in those with middle or high school education (92.6%). Interpretation In China, the burden of AFO based on spirometry was high and significantly greater than that estimated based on self-reported physician-diagnosed CB/E, especially in rural areas, reflecting major issues with diagnosis of AFO that will impact disease treatment and management.