Apr 29, 2026
Version 1
Association Between Adiposity, Hyperglycaemia and Pulmonary Function Tests in Adults: Protocol for a Systematic Review V.1
- Sucheera Samarasinghe1,
- Shamini Prathapan2,
- Niroshini Adikaram3,
- Lakmali Amarasiri4,
- Sujanthi Wickramage1,
- Prasad Katulanda4
- 1University of Moratuwa;
- 2University of Sri Jayewardenepura;
- 3Post graduate institute of Medicine;
- 4University of Colombo
Protocol Citation: Sucheera Samarasinghe, Shamini Prathapan, Niroshini Adikaram, Lakmali Amarasiri, Sujanthi Wickramage, Prasad Katulanda 2026. Association Between Adiposity, Hyperglycaemia and Pulmonary Function Tests in Adults: Protocol for a Systematic Review. protocols.io https://dx.doi.org/10.17504/protocols.io.4r3l2dk94g1y/v1Version created by Sucheera Samarasinghe
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: April 28, 2026
Last Modified: April 29, 2026
Protocol Integer ID: 315920
Keywords: Adiposity, BMI, Body Plethysmography, Diabetes, Diffusion capacity of CO, DLCO, Hyperglycaemia, Lung function tests, Lung volumes, Obesity, Overweight, Pre-diabetes, Pulmonary function tests, Spirometry, TLCO, Transfer factor for carbon monoxide, Underweight, pulmonary function tests in adult, pulmonary function parameters in adult, pulmonary function test, lung function test, objective measure of lung function, assessment of respiratory physiology, pulmonary function parameter, lung function, pulmonary function, association between adiposity, associations between adiposity measure, respiratory health, adiposity measure, lung volume, relationship between adiposity, adiposity, excess adiposity, respiratory physiology, major metabolic abnormality, systematic review background obesity, prevalence of obesity, impaired glucose metabolism, hyperglycaemia, spirometry, metabolic, obesity, glucose metabolism, diabetes
Disclaimer
No disclaimers
Abstract
Background
Obesity and hyperglycaemia are major metabolic abnormalities contributing significantly to the global burden of non‑communicable diseases. The prevalence of obesity and diabetes has increased dramatically over the past decades, with substantial implications for cardiovascular, metabolic and respiratory health. Pulmonary function tests (PFTs) provide an objective measure of lung function and are
widely used in the assessment of respiratory physiology and disease. Increasing evidence suggests that excess adiposity and impaired glucose metabolism may influence pulmonary function through mechanical, inflammatory and metabolic pathways. However, findings across studies remain inconsistent.
Methods
This systematic review will be conducted following the PRISMA‑P guidelines. Electronic databases including PubMed, Scopus, Web of Science, EMBASE and the Cochrane Library will be searched. Observational and interventional studies assessing associations between adiposity measures, hyperglycaemia and pulmonary function parameters in adults will be included. Two independent reviewers will screen studies, extract data and assess methodological quality.
Discussion
This review will synthesize evidence regarding the relationship between adiposity, hyperglycaemia and pulmonary function and may inform clinical practice and future research. As this constitutes a protocol of a systematic review, ethical approval has not been secured. This is registered on PROSPERO 2023 CRD420250646626
Available from: https://www.crd.york.ac.uk/PROSPERO/view/CRD420250646626
Keywords:
Adiposity, BMI, Body Plethysmography, Diabetes, Diffusion capacity of CO, DLCO,
Hyperglycaemia, Lung function tests, Lung volumes, Obesity, Overweight,
Pre-diabetes, Pulmonary function tests, Spirometry, TLCO, Transfer factor for
carbon monoxide, Underweight
Corresponding authors’ name: Sucheera Samarasinghe; Email address: [email protected] ; ORCID ID: 0000-0002-9760-4622
Guidelines
Safety warnings
No warnings
Ethics statement
This is a protocol for a systematic review.
Search strategy
The relevant keywords under the main themes listed in Table 1 in the Attachment will be used to create a comprehensive search strategy.
The comprehensive search will be executed in the selected databases (PubMed, Scopus, Web of Science, EMBASE and the Cochrane Library) as a single line by combining words using ‘Boolean operators (‘AND’ or ‘OR’), and asterisk search operations will also be applied. The search strategy will be tailored to each database. Controlled vocabulary terms will be used where applicable, includingMedical Subject Headings (MeSH) in PubMed and Emtree terms in EMBASE, in combination
with relevant free-text keywords to ensure a sensitive and comprehensive search. Additional eligible studies will be identified by, reference list checking (backward citation searching) of important included studies and checking relevant systematic reviews. The number of results retrieved from each database will be recorded and stored in Mendeley to avoid duplication and for citation purposes.
Condition
and domain being studied
The condition of interest includes adiposity and hyperglycaemia (prediabetes and diabetes) across their full clinical spectrum in adults. Studies assessing these metabolic conditions in relation to pulmonary function test parameters will be included to examine their association with respiratory function.
Population
Adults assessed for adiposity and/or hyperglycaemia in relation to pulmonary function will be taken as the study population. Inclusion criteria are all adults (≥18 years) of any sex, studies examining the combined effect of adiposity andhyperglycaemia (prediabetes or diabetes) on pulmonary function, individuals assessed for adiposity using validated measures (e.g., BMI, waist circumference, body fat percentage, visceral fat percentage, muscle mass, basal metabolic rate, resting metabolic rate), individuals with hyperglycaemia, including prediabetes or diabetes, diagnosed using clinical or laboratory criteria (e.g.FBS, HbA1C, PPBS), studies reporting pulmonary function assessed using standardized methods (e.g., spirometry, body plethysmography, diffusion capacity of CO) and participants from any country or geographic region. The exclusion criteria are non-human populations (e.g., animal or experimental laboratory studies), adults with comorbidities (eg., connective tissue diseases, COVID) that may affect pulmonary function outcomes, pulmonary function not clearly assessed or not reported and the study population limited only to special subgroups (e.g., pregnant women, elite athletes, or patients with established chronic respiratory diseases) without representation of the general adult population. However, studies with mixed populations of adults and children, or mixed hyperglycaemic status, will be included only if adult-specific data can be separately extracted for the eligible population. Studies where such separation is not possible will be excluded. A sensitivity analysis will be conducted to evaluate the impact of including studies with partially available data.
Intervention(s)/
exposure(s)
The primary exposures of interest are adiposity (e.g., body mass index (BMI), waist circumference, body fat percentage, visceral fat percentage, waist circumference, muscle mass, basal metabolic rate, resting metabolic rate) and hyperglycaemia (fasting glucose, HbA1c, random blood glucose, PPBS, diabetes diagnosis; diabetes/ prediabetes). The review will only include studies evaluating the combined or interactive effect of these exposures on pulmonary function outcomes.
Comparator
Individuals without adiposity and without hyperglycaemia (i.e., normal body composition and normoglycaemia status) will serve as the reference group. Where applicable, studies comparing combined exposure groups with single-exposure or unexposed groups will also be considered.
Context
Studies conducted in any healthcare or community setting and in any country or geographic region will be considered.
Main Outcome(s)
The main outcome would be the pulmonary function parameters, namely FEV1, FVC, FEV1/FVC ratio, DLCO, KCO, total lung capacity, residual volume, specific airway resistance, spirometry and their reported association (e.g., regression coefficients, mean differences, odds ratios, relative risks) with combined adiposity and hyperglycaemia.
Additional outcome(s)
I. Presence of restrictive or obstructive patterns
II. Reported effect modifiers or confounders influencing the association (e.g., age, sex, smoking status, physical activity, socioeconomic status, comorbidities)
III. Risk of bias and methodological quality assessment scores of included studies using an appropriate appraisal tool
Data extraction
A comprehensive search will be conducted by all reviewers using the specified search terms across the mentioned electronic databases. All studies retrieved from the initial search will be uploaded into Rayyan software, and duplicates will be removed. The imported studies will then be shared among reviewers for independent screening. A three-stage screening process will be applied: title screening, abstract screening, and full-text screening. During the title and abstract screening, two reviewers will independently assess studies for relevance and eligibility based on predefined criteria. Studies for which both reviewers agree will move to the full-text review stage. The full text of all eligible studies will then be reviewed independently by two reviewers, and those meeting inclusion criteria will be retained for the final synthesis. Any discrepancies between reviewers at any stage of screening will be resolved by discussion or by consulting a third reviewer. Then the data will be extracted from the selected studies using a structured data extraction form by two reviewers. The data extraction form consists of the details of include author, year, country, study design, sample size, participant characteristics, comparator, adiposity measures, glycaemic measures, pulmonary function parameters, and their associations, associated factors and other relevant findings.
A Microsoft Excel spreadsheet format will be used for data extraction from each included study by two reviewers independently to minimize potential bias and to ensure accuracy. Any discrepancies or disagreements in data extraction will be resolved through discussion or, if necessary, by consulting a third reviewer.
During the data extraction process, quality assessment will be conducted for each included study. Then the extracted data will be double checked and verified by another reviewer. Then collected data will be synthesized and analyzed including synthesis of data through meta-analysis.
Risk of bias assessment
The methodological quality and risk of bias of included studies will be assessed independently by two reviewers. During the synthesis of results, the selected articles will be assessed by a standardized tool (according to the study type) to ensure methodological quality by two reviewers independently (using Cochrane Collaboration's Risk of Bias Tool- ROB-2, ROBINS-I, Newcastle-Ottawa, JBI checklist). Any disagreement will be resolved by discussions and considering the opinions of other reviewers.
Data synthesis
A narrative synthesis will be conducted for all included studies, organized by key themes including study design, population characteristics, exposure assessment, and pulmonary function outcomes. Findings will be summarized in tables and text to describe the association between combined adiposity and hyperglycaemia and pulmonary function. Where appropriate, meta‑analysis will be conducted. Pooled effect estimates (e.g., mean differences, regression coefficients, or odds ratios) with 95% confidence intervals will be calculated using a random-effects model to account for variability between-studies. For studies with missing or incomplete data, attempts will be made to contact the corresponding authors. If the required data cannot be obtained, the study will be included in the narrative synthesis but excluded from meta-analysis. The potential impact of missing data on the review findings will be discussed. If sufficient studies are available for meta-analysis and substantial heterogeneity is observed, meta-regression will be conducted to explore potential sources of heterogeneity, such as age, sex, study design, and measurement of exposures.
Protocol references
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Goldman, M. D. (2003). Lung dysfunction in diabetes. In Diabetes Care (Vol. 26, Number 6). https://doi.org/10.2337/diacare.26.6.1915
Hayfron-Benjamin, C. F., Tei, R. K., Osei-Tutu, J. K., Amo-Nyarko, T., Vormatu, P., Ackam, J. N., Asante, G. O., Musah, L., Bruce, A. N. K., & Obeng, K. A. (2023). Pulmonary Function in Adults With Type 2 Diabetes With and Without Obesity. CHEST Pulmonary, 1(3). https://doi.org/10.1016/j.chpulm.2023.100014
Jeon, Y. K., Shin, M. J., Kim, M. H., Mok, J. H., Kim, S. S., Kim, B. H., Kim, S. J., Kim, Y. K., Chang, J. H., Shin, Y. B., & Kim, I. J. (2015). Low pulmonary function is related with a high risk of sarcopenia in community-dwelling older adults: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008–2011. Osteoporosis International, 26(10). https://doi.org/10.1007/s00198-015-3152-8
Leone, N., Courbon, D., Thomas, F., Bean, K., Jégo, B., Leynaert, B., Guize, L., & Zureik, M. (2009). Lung function impairment and metabolic syndrome the critical role of abdominal obesity. American Journal of Respiratory and Critical Care Medicine, 179(6). https://doi.org/10.1164/rccm.200807-1195OC
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