Global differences in lung function by region (PURE): an international, community-based prospective study.
BACKGROUND
Despite the rising burden of chronic respiratory diseases, global data for lung function are not available. We investigated global variation in lung function in healthy populations by region to establish whether regional factors contribute to lung function.


METHODS
In an international, community-based prospective study, we enrolled individuals from communities in 17 countries between Jan 1, 2005, and Dec 31, 2009 (except for in Karnataka, India, where enrolment began on Jan 1, 2003). Trained local staff obtained data from participants with interview-based questionnaires, measured weight and height, and recorded forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC). We analysed data from participants 130-190 cm tall and aged 34-80 years who had a 5 pack-year smoking history or less, who were not affected by specified disorders and were not pregnant, and for whom we had at least two FEV₁ and FVC measurements that did not vary by more than 200 mL. We divided the countries into seven socioeconomic and geographical regions: south Asia (India, Bangladesh, and Pakistan), east Asia (China), southeast Asia (Malaysia), sub-Saharan Africa (South Africa and Zimbabwe), South America (Argentina, Brazil, Colombia, and Chile), the Middle East (Iran, United Arab Emirates, and Turkey), and North America or Europe (Canada, Sweden, and Poland). Data were analysed with non-linear regression to model height, age, sex, and region.


RESULTS
153,996 individuals were enrolled from 628 communities. Data from 38,517 asymptomatic, healthy non-smokers (25,614 women; 12,903 men) were analysed. For all regions, lung function increased with height non-linearly, decreased with age, and was proportionately higher in men than women. The quantitative effect of height, age, and sex on lung function differed by region. Compared with North America or Europe, FEV1 adjusted for height, age, and sex was 31·3% (95% CI 30·8-31·8%) lower in south Asia, 24·2% (23·5-24·9%) lower in southeast Asia, 12·8% (12·4-13·4%) lower in east Asia, 20·9% (19·9-22·0%) lower in sub-Saharan Africa, 5·7% (5·1-6·4%) lower in South America, and 11·2% (10·6-11·8%) lower in the Middle East. We recorded similar but larger differences in FVC. The differences were not accounted for by variation in weight, urban versus rural location, and education level between regions.


CONCLUSIONS
Lung function differs substantially between regions of the world. These large differences are not explained by factors investigated in this study; the contribution of socioeconomic, genetic, and environmental factors and their interactions with lung function and lung health need further clarification.


BACKGROUND
Full funding sources listed at end of the paper (see Acknowledgments).
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada. Electronic address: duongmy@mcmaster.ca.
MyLinh
M
Duong
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada.
Shofiqul
S
Islam
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada.
Sumathy
S
Rangarajan
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada.
Koon
K
Teo
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada.
Paul M
PM
O'Byrne
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada.
Holger J
HJ
Schünemann
School of Public Health, University of the Western Cape, Cape Town, South Africa.
Ehimario
E
Igumbor
Physiology Department, University of Zimbabwe Medical School, Harare, Zimbabwe.
Jephat
J
Chifamba
National Centre of Cardiovascular Disease, Cardiovascular Institute and Fuwai Hospital, Beijing, China.
Lisheng
L
Liu
National Centre of Cardiovascular Disease, Cardiovascular Institute and Fuwai Hospital, Beijing, China.
Wei
W
Li
Faculty of Medicine, Universiti Teknologi MARA, Shah Alam, Malaysia.
Tengku
T
Ismail
Epidemiology and Biostatistics, St John's Research Institute, Bangalore, India.
Kiruba
K
Shankar
Department of Emergency Medicine, Aga Khan University, Karachi, Pakistan.
Muhammad
M
Shahid
Health Action by People, Trivandrum, India.
Krishnapillai
K
Vijayakumar
Independent University Bangladesh, Bashundhara, Dhaka, Bangladesh.
Rita
R
Yusuf
Department of Social Medicine, Wrocław Medical University, Wrocław, Poland.
Katarzyna
K
Zatonska
Goztepe Training and Research Hospital, Istanbul, Turkey.
Aytekin
A
Oguz
Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Annika
A
Rosengren
Isfahan Cardiovascular Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Hossain
H
Heidari
Division of Cardiology, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates.
Wael
W
Almahmeed
Estudios Clínicos Latinoamérica, Rosario, Argentina.
Rafael
R
Diaz
Coronary Care Unit, Translational Epidemiology Division, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil.
Gustavo
G
Oliveira
Fundación Oftalmológica de Santander, Floridablanca, Santander, Colombia.
Patricio
P
Lopez-Jaramillo
Universidad de La Frontera, Temuco, Chile.
Pamela
P
Seron
Population Health Research Institute, Department of Medicine, Hamilton, ON, Canada.
Kieran
K
Killian
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada.
Salim
S
Yusuf
D000328:Adult; D017954:Africa South of the Sahara; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001208:Asia; D001827:Body Height; D001835:Body Weight; D002170:Canada; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008877:Middle East; D011044:Poland; D011446:Prospective Studies; D012737:Sex Factors; D013020:South America; D011795:Surveys and Questionnaires; D013548:Sweden; D014797:Vital Capacity / Q000502:physiology*