ArticlesGlobal differences in lung function by region (PURE): an international, community-based prospective study
Introduction
The global rise in disease burden from chronic respiratory diseases1 means that more information is needed about global lung health, particularly factors that adversely affect lung function.2 Differences in lung function between ethnic groups have previously been investigated, but generally within one country or region.3 The most widely reported comparisons of lung function (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) are between white people and African Americans (decrease of 10–15%4, 5) and between white people and individuals of Asian origin (decrease of 6–12%6, 7). Few data are available for other ethnic groups and populations in different geographical regions with vastly different socioeconomic and environmental exposures that could affect lung function.8
Our aim was to document the risk factors for chronic respiratory disease burden in adults globally. We deliberately oversampled countries of low to middle income, where the disease burden is high9 and expected to rise further; little information about lung function and lung health is available for these regions. We postulated that, after adjustment for height, age, and sex, substantial global differences in lung function would be recorded, which would be a result of the complex interactions between genes and environment for each region. These differences could contribute to the baseline population risk for chronic respiratory disease and the global disparity in disease burden.
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Study design and participants
In the international, community-based prospective Population Rural Urban Epidemiology (PURE) study, we enrolled individuals aged 34–80 years from 628 urban and rural communities in 17 countries across five continents. Enrolment occurred between Jan 1, 2005, and Dec 31, 2009, except in Karnataka, India, where it began on Jan 1, 2003.
Details of the enumeration and recruitment methods are provided in the appendix and have been reported elsewhere.10 We used a multistage, convenience-sampled survey;
Results
153 996 individuals were enrolled from the 628 communities (figure 1). The countries with the highest numbers of participants were China and India (table 1). The proportion of unacceptable data was highest for South America and lowest for North America or Europe (table 2). The large amount of unacceptable data was not associated with low unadjusted lung function measurements (table 2). Healthy individuals excluded because of unacceptable data had similar baseline characteristics to individuals
Discussion
To our knowledge, we have provided the first large-scale assessment of global variation in lung function in asymptomatic non-smokers in different regions of the world (panel). We reported a significant and substantial difference in lung function between regions, with North America and Europe having the highest lung function and south Asia the lowest. These differences are not explained by variation in distribution of height, age, sex, weight, urban versus rural settings, or education levels.
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