Association Strength of Three Adiposity Measures with Autonomic Nervous System Function in Apparently Healthy Employees

OBJECTIVES

To investigate the association of different measures of central (abdominal) and overall adiposity with autonomic nervous system (ANS) function, indexed by heart rate variability (HRV), in apparently healthy human adults.

DESIGN AND MEASUREMENTS

Cross-sectional data of 8,538 participants (20% female, age: 41 ± 11 years, body mass index (BMI): 24 ± 4 kg/m2, waist circumference (WC): 91 ± 12 cm, waist-to-height ratio (WHtR): 0.45 ± 0.08) were available for analysis.

RESULTS

All measures of adiposity were inversely correlated with vagally-mediated HRV indexed by RMSSD (all p<0.001). Strongest associations were found with WC and RMSSD (r = -0.29). Associations were stronger in males (WC r = -0.32) than in females (WC r = -0.23). Partial correlations revealed the same pattern for RMSSD (WC all pcc = -0.12 p<0.001; WC male pcc = -0.14 p<0.001; WC female pcc = -0.06 p<0.05). Correlation strength of BMI and WHtR with RMSSD were similar and significantly weaker compared to WC (p < .001) in unadjusted analysis. Overall, nonparametric Kendall's τb led to the same conclusions.

CONCLUSION

The present data supports previous findings, that HRV is related to measures of adiposity in healthy individuals. In line with previous research, we found that WC is more strongly related to measures of HRV, indicating that WC best captures adiposity related risk.

[Work-related Stress and the Allostatic Load Index - A Systematic Review]

OBJECTIVES

Work-related stress is a growing social challenge and has been associated with reduced employee health, well-being, and productivity. One tool to measure the stress-related wear and tear of the body is the Allostatic Load Index (ALI). This review summarizes recent evidence on the association between work-related stress and ALI in working adults.

METHODS

A systematic literature search following the PRISMA-Statement was conducted in 21 databases including Medline, PubPsych, MedPilot, and Cochrane Register. Publications addressing work related-stress and medical parameters using ALI were considered. Data on study population, analytic techniques, and results were tabulated. Methodological quality was evaluated using a standardized checklist.

RESULTS

9 articles were identified with a total of 3 532 employees from 5 countries reporting cross-sectional data from the years 2003-2013. Overall, 7 studies reported a positive and significant association between work-related stress and ALI, while 2 studies showed no or an insignificant association. Substantial heterogeneity was observed in methods applied and study quality.

CONCLUSIONS

This systematic review provides evidence that work-related stress is associated with ALI in cross-sectional studies. This association needs to be demonstrated by future studies using longitudinal data on working populations.

A software tool for prediction of prosthesis failure at the carpometacarpal joint of the thumb

Early recognition of prosthesis failure is difficult. A tool that helps to identify faulty prosthesis - a cause of early implant loosening - is needed. The aim of this study was to detect early implant loosening by applying a software program EBRA (Ein-Bild-Röntgen-Analyse). EBRA was applied to the radiographs of a series of 76 patients, with a total of 102 thumb carpometacarpal joint de la Caffinière prostheses, with an average follow-up of 14.5 months (range 0.5-24). The data were used to draw graphs of cup migration and inclination over time. Corresponding regression lines of migration and inclination in relation to time were made up to the point of loosening. The gradient of regression was calculated for all implants. The gradient of regression on the x and y axes differed significantly between stable and loose implants. Loose and stable implants showed significantly different cup migration on the x and y axes over time. EBRA proved to be a reliable tool to visualize cup migration in the trapeziometacarpal joint and to predict implant failure.

Is the adiposity-associated FTO gene variant related to all-cause mortality independent of adiposity? Meta-analysis of data from 169,551 Caucasian adults

Previously, a single nucleotide polymorphism (SNP), rs9939609, in the FTO gene showed a much stronger association with all-cause mortality than expected from its association with body mass index (BMI), body fat mass index (FMI) and waist circumference (WC). This finding implies that the SNP has strong pleiotropic effects on adiposity and adiposity-independent pathological pathways that leads to increased mortality. To investigate this further, we conducted a meta-analysis of similar data from 34 longitudinal studies including 169,551 adult Caucasians among whom 27,100 died during follow-up. Linear regression showed that the minor allele of the FTO SNP was associated with greater BMI (n = 169,551; 0.32 kg m(-2) ; 95% CI 0.28-0.32, P < 1 × 10(-32) ), WC (n = 152,631; 0.76 cm; 0.68-0.84, P < 1 × 10(-32) ) and FMI (n = 48,192; 0.17 kg m(-2) ; 0.13-0.22, P = 1.0 × 10(-13) ). Cox proportional hazard regression analyses for mortality showed that the hazards ratio (HR) for the minor allele of the FTO SNPs was 1.02 (1.00-1.04, P = 0.097), but the apparent excess risk was eliminated after adjustment for BMI and WC (HR: 1.00; 0.98-1.03, P = 0.662) and for FMI (HR: 1.00; 0.96-1.04, P = 0.932). In conclusion, this study does not support that the FTO SNP is associated with all-cause mortality independently of the adiposity phenotypes.

Lower heart rate variability predicts increased level of C-reactive protein 4 years later in healthy, nonsmoking adults

BACKGROUND

Inflammation and vagally mediated heart rate variability (vmHRV) have been implicated in a number of conditions including diabetes and cardiovascular disease. Consistent with the inflammatory reflex termed the 'cholinergic anti-inflammatory pathway', numerous cross-sectional studies have demonstrated negative associations between vmHRV and inflammatory markers such as C-reactive protein (CRP). The only prospective study, however, showed the opposite: higher CRP at baseline predicted higher high-frequency heart rate variability (HF-HRV) at follow-up. Thus, additional studies are needed to examine the prospective association between vmHRV and CRP.

METHODS

Healthy employees participated in a voluntary on-site health assessment. Blood samples and ambulatory heart rate recordings were obtained, and night-time HF-HRV was calculated. Useable heart rate data were available in 2007 for 106 nonsmoking employees (9% women; age 44.4 ± 8 years), all of whom returned for an identical follow-up health assessment in 2011. Bootstrapped (500 replications) bivariate (r) and partial Pearson's correlations (ppc) adjusting for sex, age and body mass index at baseline (2007) were calculated.

RESULTS

Zero-order correlations indicated that higher HF-HRV was associated with lower levels of CRP at both time-points (2007: r = -0.19, P < 0.05; 2011: r = -0.34, P < 0.001). After adjustment, HF-HRV remained a significant predictor of CRP (ppc = -0.20, P < 0.05).

CONCLUSION

In this study, we have provided in vivo support for the cholinergic anti-inflammatory pathway in humans. Cardiac vagal modulation at baseline predicts level of CRP 4 years later. Our findings have important implications for the role of vmHRV as a risk factor for cardiovascular disease morbidity and mortality. Interventions targeted at vmHRV might be useful in the prevention of diseases associated with elevated systemic inflammation.

[Caesarean section in german hospitals: validity of hospital quality report data for monitoring C-section rates]

OBJECTIVE

It is not known if "hospital quality reports" (HQR) document Caesarean (C-) section rates at the hospital level accurately enough for use as a reliable data source when it comes to explaining regional variations of C-sections in Germany by factors at the hospital level. We aimed to answer this question using HQR from hospitals in Baden-Württemberg as data source.

METHOD

Diagnostic and procedure codes from HQR for the year 2008 (HQRdata), were used to calculate numbers of births, numbers of C-sections, and rates of births by C-section (CSR) for 94 of 97 hospitals in Baden-Württemberg. These numbers were compared to internal hospital (IH) data delivered upon request by 80 of 97 hospitals and stemming from vital statistics, birth registry forms, or external quality assurance datasets.

RESULTS

There was no difference in the number of births between HQR data and IH data, but the number of C-sections and the CSR differed significantly (p<0.05; Wilcoxon rank sum test). CSR calculated using HQR data was 4.9 ± 17.9% higher than CSR from IH data (absolute difference 1.5 ± 5.8%). The correlation between the 2 data sources was moderate (r=0.73). Only 55% of the variance in IH data-based CSR was explained by HQR data. The proportion between highest and lowest CSR in hospitals in Baden-Württemberg was 4.9 for HQR data and 3.6 for IH data.

CONCLUSION

There are significant and relevant differences between C-section rates based on ei-ther HQR or IH data. This questions routine data from HQR for 2008 as a reliable data source for research work.

Body mass index is related to autonomic nervous system activity as measured by heart rate variability--a replication using short term measurements

OBJECTIVES

The present analysis is a replication of previous findings presenting first evidence of an association between body mass index (BMI) and autonomic nervous system (ANS) activity as measured by heart rate variability (HRV), in healthy non-obese adults.

DESIGN

A total of fifty-nine apparently healthy male (M) and female (F) individuals (M/F = 15/44) were included in the trial. HRV data for analysis was derived from 5 minutes of baseline recordings, while the subject was sitting on a comfortable chair. Subjects' body measures (weight and height) were taken and BMI was obtained according to common calculation (kg/m²).

RESULTS

BMI was inversely related to pNN50 and RMSSD components of HRV. Statistically significant differences between stratified groups (BMI<20, BMI 20-25, BMI >25) only occurred for analysis of pNN50 components. The pNN50 components and RMSSD are strongly associated with cardiac vagal influence, and thus represents parasympathetic activity.

CONCLUSIONS

The present data supports previous findings, that sympatho-vagal balance is related to BMI in non-obese, healthy individuals, providing evidence for a prominent role of the vagus nerve in the modulation of the energy expenditure of the human organism. Furthermore, this relation can be observed in short term recordings of HRV of 5 minutes in length.

Process analysis to reduce MRI access time at a German University Hospital

QUALITY PROBLEM OR ISSUE

Long access times for magnetic resonance imaging (MRI) can negatively impact the quality of care provided to patients. We investigated improving access by reducing MRI processing time.

INITIAL ASSESSMENT

Data were collected for scans (n= 360) performed over 3 weeks (April-May 2008) at the University Hospital of Mannheim, Germany. Average access time, excluding emergencies, was 44 (±44) days for outpatients and 3 (±5) days for inpatients. Factors influencing total MRI processing time were identified using multivariate linear regression. In addition to region scanned, the total MRI processing time was significantly related to performing multiple scans (β = 33.57, P< 0.01), using oral contrast media (β = 13.58, P< 0.01), placing an intravenous (IV) catheter (β = 5.00, P= 0.04) and scanning patients ≤8 years old (β = 0.41, P= 0.03). Contrary to prior perceptions, emergency cases (5.6%) and late arrivals (12.8% >5 min late) were less than expected.

CHOICE OF SOLUTION

Increasing scheduling flexibility to address non-modifiable process variation and completing preparatory activities outside the scanner room were identified as process improvement targets.

IMPLEMENTATION

Scheduling was adapted to utilize three expected total MRI processing times and IV placement was moved outside the scanner room.

EVALUATION

Planned hardware and software upgrades were completed concurrent to the process improvements. As a result, it was not possible to accurately measure the effect of implementing the scheduling and preparatory activity changes.

LESSONS LEARNED

Clinical study team members' prior perceptions of workflow obstacles did not match the study findings. Utilizing insiders and outsiders during process analysis may limit bias in identification of process improvement opportunities.