Abstract
Interpretation of spirometry involves comparing lung function parameters with predicted values to determine the presence/severity of the disease. The Global Lung Function Initiative (GLI) derived reference equations for healthy individuals aged 3–95 years from multiple populations but highlighted India as a “particular group” for whom further data are needed. We aimed to derive predictive equations for spirometry in a rural Western Indian adult population.
We used spirometry data previously collected (2008–2012) from 1258 healthy adults (aged 18 years and over) by the Vadu Health and Demographic Surveillance System. We constructed sex-stratified prediction equations for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC using the Generalised Additive Model for Location, Scale and Shape (GAMLSS) method to derive the best fitting model of each outcome as a function of age and height.
When compared with GLI Ethnicity Codes 1 (White Caucasian) and 5 (Other/Mixed), the Western Indian adult population appears to have lower lung volumes on average, though the FEV1/FVC ratio is comparable. Both age and height were predictive of mean FEV1 and FVC; and for females, the variability of response was also dependent on age. FEV1/FVC appears to have a very strong age effect, highlighting the limitations of using a fixed 0.7 cut-off value.
The use of GLI normal values may result in overdiagnosis of lung disease in this population. We recommend that the values and equations generated from this study should be used by physicians in their routine practice for diagnosing disease and its severity in adults from the Western Indian population.
Abstract
The Western Indian adult population appears to have lower lung volumes compared to the Euro-American population. Use of GLI normal values may result in overdiagnosis of respiratory disease and locally derived equations should be used in clinical practice. https://bit.ly/3aMAN4s
Footnotes
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Author contributions: S. Juvekar and H. Pinnock led the development of the study. D. Agarwal wrote the first draft of the manuscript which was critically reviewed and refined by R. Parker, S. Juvekar, H. Pinnock, S. Roy, D. Ghorpade, S. Salvi, and P. Khatavkar. R. Parker performed the statistical analysis. RESPIRE UMC members provided advice and contributed to discussions. All authors approved the final version.
The RESPIRE collaboration: The University of Edinburgh, Edinburgh, UK: Harry Campbell, Harish Nair, Steve Cunningham, Monica Fletcher, Liz Grant, Aisha Holloway, Aziz Sheikh, Pam Smith; The Allergy & Asthma Institute, Islamabad, Pakistan: Osman Yusuf, Shahida Yusuf; Maternal Neonatal and Child Health Research Network, Islamabad, Pakistan: Hana Mahmood; University of Malaya, Malaysia: Wong LP; KEM Hospital Research Centre, Pune, India: Anand Kawade; Aga Khan University, Karachi, Pakistan: Sajid Bashir Soofi; Christian Medical College, Vellore, India: Rita Isaac; Victoria University of Wellington, New Zealand: Colin Simpson.
Conflict of interest: R. Parker has nothing to disclose.
Conflict of interest: H. Pinnock reports grants from NIHR Global Health Research (ref: 16/136/109, NIHR Global Respiratory Health (RESPIRE) Unit), during the conduct of the study.
Conflict of interest: S. Roy reports grants from NIHR Global Health Research (ref: 16/136/109, NIHR Global Respiratory Health (RESPIRE) Unit), during the conduct of the study.
Conflict of interest: D. Ghorpade has nothing to disclose.
Conflict of interest: S. Salvi has nothing to disclose.
Conflict of interest: P. Khatavkar has nothing to disclose.
Conflict of interest: S. Juvekar reports grants from NIHR Global Health Research (ref: 16/136/109, NIHR Global Respiratory Health (RESPIRE) Unit), during the conduct of the study.
Conflict of interest: D. Agarwal reports grants from NIHR Global Health Research (ref: 16/136/109, NIHR Global Respiratory Health (RESPIRE) Unit), during the conduct of the study.
Support statement: This study funded by the NIHR Global Health Research Unit in Respiratory Health (RESPIRE) at the Usher Institute of Population Health Sciences and Informatics. RESPIRE was commissioned by the National Institute of Health Research using Official Development Assistance (ODA) funding. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. Funding information for this article has been deposited with the Crossref Funder Registry.
- Received August 27, 2019.
- Accepted April 24, 2020.
- Copyright ©ERS 2020