An observational study in Decompression Sickness, Barotrauma and Recreational Diving, sponsored by Medical University of Bialystok. Not yet recruiting at 2 sites in Poland. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-02.
Sponsored by Medical University of Bialystok · Observational
This cross-sectional online survey study assesses health status, physical fitness, and safety knowledge as potential determinants of diving-related adverse events among recreational divers in Poland. Recreational diving exposes participants to specific hazards, including decompression sickness (DCS) and barotrauma of the middle ear, sinuses, and lungs. To date, no Polish study has simultaneously evaluated health, physical fitness, theoretical safety knowledge, and the occurrence of adverse events in this population. Adult divers (18 years or older) who completed at least one dive in the past 24 months and reside in Poland complete an anonymous online questionnaire (about 12 to 18 minutes). Physical fitness is estimated as VO2max using the University of Houston Non-Exercise Test (physical activity rating, age, BMI, and sex). Knowledge of DCS, barotrauma, and safe-diving rules is tested at three difficulty levels. The questionnaire also captures diving exposure, certification level, chronic health conditions, and risky behaviours (smoking, alcohol use, and diving beyond certification). The primary endpoint is the proportion of divers reporting at least one diving-related adverse event. Associations with certification level, estimated VO2max, BMI, and other factors are analysed using multivariable logistic regression. The study is non-interventional, anonymous, and carries minimal risk; no clinical procedures or biological sampling are involved.
Primary objective: to assess health status, physical fitness, and safety/training knowledge in relation to the occurrence of diving-related adverse events among recreational divers in Poland.
Specific objectives: (1) estimate VO2max from the University of Houston Non-Exercise Test; (2) assess knowledge of decompression sickness, barotrauma, and safe-diving rules at basic, advanced, and emergency-medical levels; (3) determine the frequency of barotrauma and decompression sickness symptoms (clinically confirmed versus presumed); (4) identify risky behaviours (smoking, alcohol use, diving under the influence, and diving beyond certification); (5) assess associations between training level, physical activity, and health and the occurrence of adverse events using multivariable logistic regression.
Hypotheses: H1 - higher certification (Advanced Open Water Diver and above) is associated with better knowledge of diving-related health hazards; H2 - lower estimated VO2max is associated with a higher frequency of adverse events; H3 - risky behaviours are more frequent among lower-certified divers; H4 (exploratory) - decompression sickness risk factors identified in the DAN DSL 2024 dataset are present in the Polish recreational diving population.
Design: cross-sectional, observational, non-interventional study conducted as an anonymous online survey. No clinical procedures, biological sampling, or modification of medical management are involved.
Population and sampling: adults (18 years or older) residing in Poland who completed at least one dive in the past 24 months, recruited online (convenience sampling) via diving organizations, dive centers, and themed social-media communities.
Sample size: target analytic n = 384, derived by triangulation of three methods (proportion estimation n = 323; two-proportion comparison n = 304; logistic-regression events-per-variable rule n = 234), with the binding value (323) plus a 15% non-response buffer.
Data collection and privacy: anonymous online questionnaire hosted on Medical University of Bialystok infrastructure (REDCap); no identifying data and no IP address are stored; processing is GDPR-compliant; data are retained on secured university storage for 5 years and used only for aggregate scientific analysis.
22 studies on the registry are indexed under Decompression Sickness; 7 are open to participants now.
Browse Decompression Sickness studies →Medical University of Bialystok is the lead sponsor of 68 studies on the registry; 17 are open to participants now.
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Adult recreational divers residing in Poland who completed at least one dive in the past 24 months, recruited online (convenience sampling) via diving organizations (KDP/CMAS-PTTK, PADI, SSI, IANTD, RAID), dive centers, and themed social-media communities.
Exclusion Criteria:
Adults (18 years or older) residing in Poland who completed at least one dive in the past 24 months and complete the anonymous online survey. A single observational cohort assessed cross-sectionally.
Other: Anonymous online questionnaire
Anonymous online questionnaire completed once by each participant (about 12 to 18 minutes). It captures demographic data, diving exposure and certification level, chronic health conditions, risky behaviours, estimated VO2max (University of Houston Non-Exercise Test), and a diving-safety knowledge test. No clinical procedures or biological sampling are involved; this is the observational data-collection instrument for the cohort.
Prevalence of diving-related adverse events
Proportion of divers reporting at least one diving-related adverse event (barotrauma symptoms, decompression sickness symptoms, or other post-dive health problems) occurring at any time during the participant's diving history up to enrollment (lifetime recall). Reported as a percentage with 95% confidence interval.
Time frame: At enrollment (Day 1; single cross-sectional assessment)
Estimated VO2max (University of Houston Non-Exercise Test)
Estimated maximal oxygen uptake (mL/kg/min) calculated from the University of Houston Non-Exercise Test (physical activity rating, age, BMI, and sex), summarized as mean with standard deviation and as median with quartiles, stratified by sex and age.
Time frame: At enrollment (Day 1; single cross-sectional assessment)
Diving safety knowledge score
Percentage of correct answers on the diving-hazard knowledge test (decompression sickness, barotrauma, and safe-diving rules), reported overall and at three difficulty levels: basic, advanced, and emergency-medical.
Time frame: At enrollment (Day 1; single cross-sectional assessment)
Frequency of risky behaviours
Proportion of divers reporting risky behaviours: tobacco use, alcohol use before diving, diving under the influence of alcohol or other substances, and diving beyond their certification level.
Time frame: At enrollment (Day 1; single cross-sectional assessment)
Adjusted odds ratios for diving-related adverse events
Adjusted odds ratios (with 95% confidence intervals) for the occurrence of at least one diving-related adverse event, estimated by multivariable logistic regression, for certification level, estimated VO2max, BMI, and selected risk factors from the DAN DSL 2024 dataset (e.g., sex, thermal comfort, pre-dive physical activity).
Time frame: At enrollment (Day 1; single cross-sectional assessment)
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Medical University of Bialystok