To examine the individual and interpersonal factors that are associated with or influence cardiorespiratory fitness among the general adult population worldwide.
The following literature databases will be searched for articles published in journals: MEDLINE, EMBASE, and Cochrane Library. A grey literature search will be conducted in the following databases: Scopus and Google Scholar.
No date, language, article type, text availability, or species restrictions or filters will be applied for any of the searches.
Types of study to be included
Quantitative observational studies (cohort studies, case-control studies, and cross-sectional surveys) and experimental studies that investigate correlates and/or determinants of CRF in the general adult population.
Condition or domain being studied
Our review will include studies that report on correlates and/or determinants of CRF among adults aged 18-65 years of age in non-symptomatic, non-institutionalized populations. Participants who are not representative of the general population, such as physically trained military personnel, will be excluded.
Any individual factors (non-modifiable biological risk factors, behavioural risk factors, and socioeconomic risk factors) or interpersonal factors will be included.
Adults with lower levels of cardiorespiratory fitness.
CRF that is measured through maximal, or estimated through submaximal, treadmill or cycle ergometer tests.
Risk of bias (quality) assessment
A customized version of the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies by the National Heart, Lung, and Blood Institute at the National Institutes of Health, USA, will be utilized to assess the risk of bias and methodological quality for all observational studies. The studies will be assessed based on questions addressing the following major criteria: Risk of selection bias, Precision, Risk of information bias, Adequate assessment of association between exposure and outcome, and Risk of investigator bias. Studies will be given a cumulative quality rating of Low, Medium, or High based on responses to the questions. While studies of all qualities will be included in the review, the limitations of studies rated Low will be discussed and a sensitivity analysis will be conducted to assess their impact on any pooled analyses.
The risk of bias in all experimental studies included in the review will be assessed using the Downs and Black “Checklist for Measuring Study Quality”, which is a 27-item numerical checklist designed to assess the quality of both randomized and non-randomized studies. Each study will receive a total numerical score out of a maximum of 30 points and any studies that receive a total score of less than 15 will be specified and a sensitivity analysis would once again be performed in order to assess their impact on pooled analyses, if such analyses are conducted.
Strategy for data synthesis
We plan to first conduct a narrative synthesis of the data from all included studies and synthesize our results separately for men and women. We expect to find a fair number of differences between the included studies and will qualitatively assess the studies for heterogeneity. A meta-analysis will only be conducted if more than two included studies are homogenous with regards to exposure, population characteristics, and study design. If data are pooled, inverse variance weighting will be applied for the pooling method.
Analysis of subgroups or subsets
If sufficient data are available from the included studies, we further plan to present our narrative results stratified by different types of exposures, by study design, and by region or country of study.
Contact details for further information
Organisational affiliation of the review
Department of Epidemiology and Health Monitoring, Robert Koch Institute
Ms Nita Perumal, Robert Koch Institute Dr Jonas Finger, Robert Koch Institute Dr Gert Mensink, Robert Koch Institute Dr Thomas Keil, Charité University Medical Center
Anticipated or actual start date
01 June 2016
Anticipated completion date
30 April 2017
This project is internally funded by the Robert Koch Institute. The Robert Koch Institute is a Federal Institute within the portfolio of the Federal Ministry of Health, Germany
Conflicts of interest
Subject index terms status
Subject indexing assigned by CRD
Subject index terms
Adult; Cardiorespiratory Fitness; Health Status; Humans; Physical Fitness
Stage of review
Date of registration in PROSPERO
17 January 2017
Date of publication of this revision
08 May 2017
Stage of review at time of this submission
Piloting of the study selection process
Formal screening of search results against eligibility criteria
Risk of bias (quality) assessment
PROSPERO This information has been provided by the named contact for this review. CRD has accepted this information in good faith and registered the review in PROSPERO. CRD bears no responsibility or liability for the content of this registration record, any associated files or external websites.