Shape change and obesity prevalence among male UK offshore workers after 30 years: New insight from a 3D scanning study.

OBJECTIVES: In 1984, male UK offshore workers had greater overweight and obesity prevalence and fat content than the general population. Since then, body weight has increased by 19%, but, without accompanying anthropometric measures, their size increase, current obesity, and fatness prevalence remain unknown. This study therefore aimed to acquire contemporary anthropometric data, profile changes since the original survey, and assess current obesity prevalence in the male offshore workforce. METHODS: A total of 588 men, recruited via quota sampling to match the workforce weight profile, underwent stature, weight, and 3D photonic scanning measurements from which anatomical girths were extracted, enabling computation of body mass index (BMI), total fat, and visceral adipose tissue (VAT). RESULTS: On average, UK male offshore workers are now 8.1 y older, 3.1 cm taller, 13.9 kg heavier, and have greater girths than in 1984, which are >97% attributable to increased weight, and <3% to age difference. Mean BMI increased significantly from 24.9 to 28.1 kg/m2 and of the contemporary sample, 18% have healthy weight, 52% are overweight, and 30% obese, representing an increase in overweight and obesity prevalence by 6% and 24%, respectively. Waist cutoffs identify 39% of the contemporary sample as healthy, 27% at increased health risk, and 34% at high risk. CONCLUSIONS: UK offshore workers today have higher BMI than Scottish men, although some muscular individuals may be misclassified by BMI. Girth data, particularly at the waist, where dimensional increase was greatest, together with predictions of total and visceral fatness, suggest less favorable health status in others.

Defying geometric similarity: Shape centralization in male UK offshore workers.

OBJECTIVES: Applying geometric similarity predictions of body dimensions to specific occupational groups has the potential to reveal useful ergonomic and health implications. This study assessed a representative sample of the male UK offshore workforce, and examined how body dimensions from sites typifying musculoskeletal development or fat accumulation, differed from predicted values. METHODS: A cross sectional sample was obtained across seven weight categories using quota sampling, to match the wider workforce. In total, 588 UK offshore workers, 84 from each of seven weight categories, were measured for stature, mass and underwent 3D body scans which yielded 22 dimensional measurements. Each measurement was modeled using a body-mass power law (adjusting for age), to derive its exponent, which was compared against that predicted from geometric similarity. RESULTS: Mass scaled to stature 1.73 (CI: 1.44-2.02). Arm and leg volume increased by mass0.8 , and torso volume increased by mass1.1 in contrast to mass 1.0 predicted by geometric similarity. Neck girth increased by mass 0.33 as expected, while torso girth and depth dimensions increased by mass0.53-0.72 , all substantially greater than assumed by geometric similarity. CONCLUSIONS: After controlling for age, offshore workers experience spectacular "super-centralization" of body shape, with greatest gains in abdominal depth and girth dimensions in areas of fat accumulation, and relative dimensional loss in limbs. These findings are consistent with the antecedents of sarcopenic obesity, and should be flagged as a health concern for this workforce, and for future targeted research and lifestyle interventions.

Survival suit volume reduction associated with immersion: implications for buoyancy estimation in offshore workers of different size.

RATIONALE: It is currently unknown how body size affects buoyancy in submerged helicopter escape. METHOD: Eight healthy males aged 39.6 ± 12.6 year (mean ± SD) with BMI 22.0-40.0 kg m-2 wearing a standard survival ('dry') suit undertook a normal venting manoeuvre and underwent 3D scanning to assess body volume (wearing the suit) before and after immersion in a swimming pool. RESULTS: Immersion-induced volume loss averaged 14.4 ± 5.4 l, decreased with increasing dry density (mass volume-1) and theoretical buoyant force in 588 UK offshore workers was found to be 264 ± 46 and 232 ± 60 N using linear and power functions, respectively. Both approaches revealed heavier workers to have greater buoyant force. DISCUSSION: While a larger sample may yield a more accurate buoyancy prediction, this study shows heavier workers are likely to have greater buoyancy. Without free-swimming capability to overcome such buoyancy, some individuals may possibly exceed the safe limit to enable escape from a submerged helicopter. Practitioner Summary: Air expulsion reduced total body volume of survival-suited volunteers following immersion by an amount inversely proportional to body size. When applied to 588 offshore workers, the predicted air loss suggested buoyant force to be greatest in the heaviest individuals, which may impede their ability to exit a submerged helicopter.

The effect of time on CPR and automated external defibrillator skills in the Public Access Defibrillation Trial.

BACKGROUND: The time to skill deterioration between primary training/retraining and further retraining in cardiopulmonary resuscitation (CPR) and automated external defibrillation (AED) for lay-persons is unclear. The Public Access Defibrillation (PAD) trial was a multi-center randomized controlled trial evaluating survival after CPR-only versus CPR+AED delivered by onsite non-medical volunteer responders in out-of-hospital cardiac arrest. AIMS: This sub-study evaluated the relationship of time between primary training/retraining and further retraining on volunteer performance during pretest AED and CPR skill evaluation. METHODS: Volunteers at 1260 facilities in 24 North American regions underwent training/retraining according to facility randomization, which included an initial session and a refresher session at approximately 6 months. Before the next retraining, a CPR and AED skill test was completed for 2729 volunteers. Primary outcome for the study was assessment of global competence of CPR or AED performance (adequate versus not adequate) using chi(2)-test for trends by time interval (3, 6, 9, and 12 months). Confirmatory (GEE) logistic regression analysis, adjusted for site and potential confounders was done. RESULTS: The proportion of volunteers judged to be competent did not diminish by interval (3, 6, 9, and 12 months) for either CPR or AED skills. After adjusting for site and potential confounders, longer intervals to further retraining was associated with a slightly lower likelihood of performing adequate CPR but not with AED scores. CONCLUSIONS: After primary training/retraining, the CPR skills of targeted lay responders deteriorate nominally but 80% remain competent up to 1 year. AED skills do not deteriorate significantly and 90% of volunteers remain competent up to 1 year.

Variability in body size and shape of UK offshore workers: A cluster analysis approach.

Male UK offshore workers have enlarged dimensions compared with UK norms and knowledge of specific sizes and shapes typifying their physiques will assist a range of functions related to health and ergonomics. A representative sample of the UK offshore workforce (n = 588) underwent 3D photonic scanning, from which 19 extracted dimensional measures were used in k-means cluster analysis to characterise physique groups. Of the 11 resulting clusters four somatotype groups were expressed: one cluster was muscular and lean, four had greater muscularity than adiposity, three had equal adiposity and muscularity and three had greater adiposity than muscularity. Some clusters appeared constitutionally similar to others, differing only in absolute size. These cluster centroids represent an evidence-base for future designs in apparel and other applications where body size and proportions affect functional performance. They also constitute phenotypic evidence providing insight into the 'offshore culture' which may underpin the enlarged dimensions of offshore workers.

The ability of UK offshore workers of different body size and shape to egress through a restricted window space.

404 male offshore workers aged 41.4 ± 10.7 y underwent 3D body scanning and an egress task simulating the smallest helicopter window emergency exit size. The 198 who failed were older (P < 0.01), taller (P < 0.05) and heavier (P < 0.0001) than the 206 who passed. Using all extracted dimensions from the scans, binary logistic regression identified a model (refined using backward elimination) which predicted egress outcome with 75.2% accuracy. Using only weight, bideltoid breadth and maximum chest depth, the model achieved ∼70% accuracy. When anatomical dimensions categorise individuals for small window egress, 25% or more will be misclassified, with false positives (those predicted to fail, but pass) slightly outnumbering false negatives (those predicted to pass, but fail), highlighting the limitations of a predictive approach which treats the body as a rigid object. Differences in flexibility and technique may explain these observations, which may be important considerations for future research.

A comparison of the AVID and DAVID trials of implantable defibrillators.

We compared 2 studies of implantable cardiac defibrillators (ICDs) to determine the effects of device mode on outcomes. The Antiarrhythmics Versus Implantable Defibrillators (AVID) trial (1993 to 1997) demonstrated improved survival with the ICD compared with antiarrhythmic drug therapy. The Dual-chamber And VVI Implantable Defibrillator (DAVID) trial (2000 to 2002) showed that VVI pacing at 40 beats/min in patients with ICDs reduced the combined end point of death and hospitalization for congestive heart failure compared with DDDR pacing at 70 beats/min. Patients in the AVID trial (631 of 1,016) and the DAVID trial (221 of 506) meeting common inclusion and all exclusion criteria were studied. The major end points were the time to death, and the composite end point of time to death or hospitalization for congestive heart failure. Patients in the AVID and DAVID trials were similar, but more AVID patients had coronary artery disease (p = 0.04), history of myocardial infarction (p = 0.005), and previous ventricular arrhythmias (p = 0.03). DAVID patients underwent more previous revascularization procedures (coronary artery bypass surgery, p = 0.03; percutaneous coronary intervention, p = 0.001), and were more often taking beta-blocking drugs at hospital discharge (p <0.001). The backup VVI ICD groups in both studies had similar outcomes (p = 0.4), even when corrected for the previous demographic differences. The time-to- composite end point was similar in AVID patients treated with antiarrhythmic drugs and DAVID patients treated with DDDR ICDs (p = 0.6). Despite improved pharmacologic therapy and revascularization, outcomes have not improved with backup VVI pacing ICDs. If DDDR ICDs had been used in the AVID trial, benefit from ICDs for patients with serious ventricular arrhythmias could have been missed.

Body size and ability to pass through a restricted space: Observations from 3D scanning of 210 male UK offshore workers.

Offshore workers are subjected to a unique physical and cultural environment which has the ability to affect their size and shape. Because they are heavier than the UK adult population we hypothesized they would have larger torso dimensions which would adversely affect their ability to pass one another in a restricted space. A sample of 210 male offshore workers was selected across the full weight range, and measured using 3D body scanning for shape. Bideltoid breadth and maximum chest depth were extracted from the scans and compared with reference population data. In addition a size algorithm previously calculated on 44 individuals was applied to adjust for wearing a survival suit and re-breather device. Mean bideltoid breadth and chest depth was 51.4 cm and 27.9 cm in the offshore workers, compared with 49.7 cm and 25.4 cm respectively in the UK population as a whole. Considering the probability of two randomly selected people passing within a restricted space of 100 cm and 80 cm, offshore workers are 28% and 34% less likely to pass face to face and face to side respectively, as compared with UK adults, an effect which is exacerbated when wearing personal protective equipment.

Comparison of arrhythmia recurrence in patients presenting with ventricular fibrillation versus ventricular tachycardia in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial.

Because many episodes of ventricular fibrillation (VF) are believed to be triggered by ventricular tachycardia (VT), patients who present with VT or VF are usually grouped together in discussions of natural history and treatment. However, there are significant differences in the clinical profiles of these 2 patient groups, and some studies have suggested differences in their response to therapy. We examined arrhythmias occurring spontaneously in 449 patients assigned to implantable cardioverter-defibrillator (ICD) therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial to determine whether patients who receive an ICD after VT have arrhythmias during follow-up that are different from patients who present with VF. ICD printouts were analyzed both by a committee blinded to the patients' original presenting arrhythmia and by the local investigator. During 31 +/- 14 months of follow-up, 2,673 therapies were reported. Patients who were enrolled in the AVID trial after an episode of VT were more likely to have an episode of VT (73.5% vs 30.1%, p <0.001), and were less likely to have an episode of VF (18.3% vs 28.0%, p = 0.013) than patients enrolled after an episode of VF. Adjustment for differences in ejection fraction, previous infarction, and beta-blocker and antiarrhythmic therapy did not appreciably change the results. Ventricular arrhythmia recurrence during follow-up is different in patients who originally present with VT than in those who originally present with VF. These findings suggest there are important differences in the electrophysiologic characteristics of these 2 patient populations.

How well are cardiopulmonary resuscitation and automated external defibrillator skills retained over time? Results from the Public Access Defibrillation (PAD) Trial.

BACKGROUND: The current standard for cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) retraining for laypersons is a four-hour course every two years. Others have documented substantial skill deterioration during this time period. OBJECTIVES: To evaluate 1) the retention of core CPR and AED skills among volunteer laypersons and 2) the time required to retrain laypersons to proficiency as a function of time since initial training. METHODS: This was an observational follow-up study evaluating CPR and AED skill retention and testing/retraining time up through 17 months after initial training. The study took place at 1,260 facilities recruited by 24 North American clinical research centers, and included 6,182 volunteer laypersons participating in the Public Access Defibrillation (PAD) Trial. Training to proficiency in either CPR only (N = 2,426) or CPR+AED (N = 3,756) was followed by testing/retraining provided three to 17 months later. Retraining was done in brief, one-on-one, individualized, interactive sessions. The outcome studied was instructors' global assessments of performance of CPR and AED skill adequacy, i.e., whether CPR actions would likely result in perfusion (yes/no) and whether AED actions would result in a shock through the heart (yes/no). RESULTS: For global CPR performance, 79%, 73%, and 71% of volunteers tested for the first time since initial training three to five, six to 11, and 12 to 17 months after initial training, respectively, were judged by their instructors as having adequate performance (p < 0.001, chi-square for linear trend). For global AED performance, 91%, 86%, and 84% of volunteers, respectively, were judged as having adequate performance (p < 0.001). The mean (+/- standard deviation) times required to test and retrain volunteers to proficiency were 5.7 (+/- 4.0) minutes for CPR skills and 7.7 (+/- 4.6) minutes for CPR+AED skills. CONCLUSIONS: Among PAD Trial volunteer laypersons participating in a simulated resuscitation, the proportions of volunteers judged by instructors to have adequate CPR and AED skills demonstrated small declines associated with longer intervals between initial training and subsequent testing. However, based on instructors' judgment, large majorities of volunteers still retained both CPR and AED core skills through 17 months after initial training. Furthermore, individual testing and retraining for CPR and AED skills were usually accomplished in less than 10 minutes per volunteer. Additional research is essential to identify training and evaluation techniques that predict adequate CPR and AED skill performance of laypersons when applied to an actual cardiac arrest.

Lower observed versus expected (based on U.S. age and gender specific rates) survival in patients treated for near-fatal ventricular arrhythmias.

Implantable cardioverter defibrillators (ICDs) have improved survival for patients with ventricular fibrillation (VF) or sustained vertricular tachycardia (VT). However, the survival of these patients compared to the general population has not been assessed. Observed survival rates for patients randomized to either antiarrhythmic drug therapy (mainly amiodarone) arm or ICD arm were compared to expected rates, calculated using age and sex-specific survival rates derived from the 1989-1991 US population life tables and applied to the age and sex distribution of patients in each arm. Consistent with the results of the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, patients randomized to receive ICDs experienced significantly higher survival than those in the drug arm; however, both groups experienced significantly lower survival than expected using age and gender matched U.S. survival rates. Within arms, the difference between the observed and expected rates increased over 3 years of follow-up from 7.7% to 15.3% for the ICD arm, and from 14.6% to 26.4% for the drug arm. These results quantify the improvements in survival that can be expected for VF or VT patients using drug or ICD therapies and underscore the need for continued research into methods for further improving the overall level of health of these patients.

Analysis of implantable cardioverter defibrillator therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial.

INTRODUCTION: The implantable cardioverter defibrillator (ICD) is commonly used to treat patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia recurrence rates in these patients are high, but which patients will receive a therapy and the forms of arrhythmia recurrence (VT or VF) are poorly understood. METHODS AND RESULTS: The therapy delivered by the ICD was examined in 449 patients randomized to ICD therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. Events triggering ICD shocks or antitachycardia pacing (ATP) were reviewed for arrhythmia diagnosis, clinical symptoms, activity at the onset of the arrhythmia, and appropriateness and results of therapy. Both shock and ATP therapies were frequent by 2 years, with 68% of patients receiving some therapy or having an arrhythmic death. An appropriate shock was delivered in 53% of patients, and ATP was delivered in 68% of patients who had ATP activated. The first arrhythmia treated in follow-up was diagnosed as VT (63%), VF (13%), supraventricular tachycardia (18%), unknown arrhythmia (3%), or due to ICD malfunction or inappropriate sensing (3%). Acceleration of an arrhythmia by the ICD occurred in 8% of patients who received any therapy. No physical activity consistently preceded arrhythmias, nor did any single clinical factor predict the symptoms of the arrhythmia. CONCLUSION: Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided.