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Nevin Manimala Statistics

Area strain as prognostic factor of functional recovering in myocardial infarction

Rev Med Inst Mex Seguro Soc. 2025 Mar 3;63(2):e6591. doi: 10.5281/zenodo.14617002.

ABSTRACT

BACKGROUND: Area strain evaluates the longitudinal and circumferential deformation simultaneously. There are not estudies that support its benefit in predicting functional recovering in myocardial infarction.

OBJECTIVE: The aim was establish the prognostic value of the area strain measured within the first 7 days after succesful angioplasty to predicting functional recovering.

MATERAIL AND METHODS: A prospective cohort study was performed during 3-month follow-up. Patients with myocardial infarction treated with succesful angioplasty were enrolled. The area strain was perfomed within the first 7 days. Functional recovering was defined as an improvement of the ejection fraction ≥ 10% at 3-months follow-up.

RESULTS: A total of 52 patients were enrolled. An area strain of ≤ -24.2 % appeared in the 45.5% of the patients with functional recovering, RR 16.25 (IC 95%: 2.55-103, p = 0.003). In the multivariate analyses the area strain of ≤ -24.2 % was the only variable with statistical significance with an OR of 13.15 (IC 95%: 1.83-94, p = 0.010) when was adjusted to hypertension, OR of 12.7 (IC 95%: 1.88-85.9, p = 0.009) adjusted to reperfusion time of ≤ 120 minutes and the OR was of 11.87 (IC 95%: 1.66-84.5, p = 0.013) adjusted to smoking.

CONCLUSIONS: An area strain of ≤ – 24.2% is a prognostic factor of improvement of ejection fraction of ≥ 10% at 3-months follow-up in patients with myocardial infarction and succesful angioplasty.

PMID:40273433 | DOI:10.5281/zenodo.14617002

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Balanced Steady-State Free Precession Enables High-Resolution Dynamic 3D Deuterium Metabolic Imaging of the Human Brain at 7T

Invest Radiol. 2025 Apr 25. doi: 10.1097/RLI.0000000000001196. Online ahead of print.

ABSTRACT

OBJECTIVES: Deuterium (2H) metabolic imaging (DMI) is an emerging magnetic resonance technique to non-invasively map human brain glucose (Glc) uptake and downstream metabolism following oral or intravenous administration of 2H-labeled Glc. The achievable spatial resolution is limited due to inherently low sensitivity of DMI. This hinders potential clinical translation. The purpose of this study was to improve the signal-to-noise ratio (SNR) of 3D DMI via a balanced steady-state free precession (bSSFP) acquisition scheme combined with fast non-Cartesian spatial-spectral sampling to enable high-resolution dynamic imaging of neural Glc uptake and glutamate+glutamine (Glx) synthesis of the human brain at 7T.

MATERIALS AND METHODS: Six healthy volunteers (2 f/4 m) were scanned after oral administration of 0.8 g/kg [6,6′]-2H-Glc using a novel density-weighted bSSFP acquisition scheme combined with fast 3D concentric ring trajectory (CRT) k-space sampling at 7T. Time-resolved whole brain DMI datasets were acquired for approximately 80 minutes (7 minutes per dataset) after oral 2H-labeled Glc administration with 0.75 mL and 0.36 mL isotropic spatial resolution and results were compared to conventional spoiled Free Induction Decay (FID) 2H-MRSI with CRT readout at matched nominal spatial resolution. Dynamic DMI measurements of the brain were accompanied by simultaneous systemic Glc measurements of the interstitial fluid using a continuous Glc monitoring (CGM) sensor (on the upper arm). The correlation between brain and interstitial Glc levels was analyzed using linear mixed models.

RESULTS: The bSSFP-CRT approach achieved SNRs that were up to 3-fold higher than conventional spoiled FID-CRT 2H-MRSI. This enabled a 2-fold higher spatial resolution. Seventy minutes after oral tracer uptake comparable 2H-Glc, 2H-Glx, and 2H-water concentrations were detected using both acquisition schemes at both, regular and high spatial resolutions (0.75 ml and 0.36 mL isotropic). The mean Areas Under the Curve (AUC) for interstitial fluid Glc measurements obtained using a CGM sensor was 509 ± 65 mM·min. This is 3.4 times higher than the mean AUC of brain Glc measurements of 149 ± 43 mM·min obtained via DMI. The linear mixed models fitted to assess the relationship between CGM measures and brain 2H-Glc yielded statistically significant slope estimates in both GM (β1 = 0.47, P = 0.01) and WM (β1 = 0.36, P = 0.03).

CONCLUSIONS: In this study we successfully implemented a balanced steady-state free precession (bSSFP) acquisition scheme for dynamic whole-brain human DMI at 7T. A 3-fold SNR increase compared to conventional spoiled acquisition allowed us to double the spatial resolution achieved using conventional FID-CRT DMI. Systemic continuous glucose measurements, combined with dynamic DMI, demonstrate significant potential for clinical applications. This could help improve our understanding of brain glucose metabolism by linking it to time-resolved peripheral glucose levels. Importantly, these measurements are conducted in a minimally invasive and physiological manner.

PMID:40273422 | DOI:10.1097/RLI.0000000000001196

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Physical activity and health-related quality of life among men with prostate cancer living in remote areas of Quebec: A cross-sectional, observational study

Can Urol Assoc J. 2025 Apr 17. doi: 10.5489/cuaj.9077. Online ahead of print.

ABSTRACT

INTRODUCTION: The majority (97.5%) of men with prostate cancer (PCa) live for at least five years after diagnosis. The health-related quality of life (HRQoL) of such men is affected by the adverse effects of treatment. Men living in remote areas of Canada have difficulty accessing specialized medical resources and psychological support. This constitutes an additional burden that weighs heavily on their HRQoL. Regular physical activity (PA) has a direct benefit, or an effect mediated by emotional distress, on the HRQoL of such individuals. In Canada, and elsewhere in the world, there is a poor uptake of PA-related recommendations.

METHOD: We conducted a cross-sectional, observational study among 85 participants between May 2023 and September 2023. We then explored, through mediation analyses, the association between PA and HRQoL, taking into account the potential mediating effect of emotional distress.

RESULTS: Most participants (61.2%) engaged in a high level of PA; however, their physical and mental HRQoL scores were low (mean scores of 41.99±6.09 and 52.40±4.86, respectively). Participants self-reported low levels of stress (mean score of 3.18±2.62). Very few participants (5.9%) displayed symptoms consistent with depression. In contrast, the majority of participants (92.9%) displayed symptoms of anxiety. No significant statistical association was observed between the level of PA and HRQoL.

CONCLUSIONS: This lack of association may be explained by the short-term, seasonal nature of certain types of PA, which prevents such PA from having a positive effect on the HRQoL.

PMID:40273413 | DOI:10.5489/cuaj.9077

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Long-term impact of posterior reconstruction urethrovesical anastomosis during robot-assisted prostatectomy: A secondary analysis of a randomized cohort

Can Urol Assoc J. 2025 Apr 17. doi: 10.5489/cuaj.9121. Online ahead of print.

ABSTRACT

INTRODUCTION: We aimed to assess early and late continence rates post-robot-assisted radical prostatectomy (RARP), comparing posterior reconstruction (PR) urethrovesical anastomosis (UVA) to conventional urethrovesical anastomosis (C-UVA).

METHODS: Consecutive patients with clinically localized prostate cancer undergoing RARP underwent simple randomization to PR-UVA or C-UVA. Return to continence outcomes were assessed using a validated questionnaire (Expanded Prostate Cancer Index Composite [EPIC] Short Form-26) at baseline, two-, three-, four-, six-, eight-, and 12-month followups. Five-year outcomes were assessed by frequency of undergoing continence-improving procedures.

RESULTS: A total of 163 patients were randomized 1:1 to PR-UVA or C-UVA from April 2014 to July 2015, and 140 patients completed followup. There were no significant clinical or functional differences between groups preoperatively. Using a continence definition of 0-1 pads/day, the continence rates for PR-UVA vs. C-UVA were 39% vs. 38% at two months, respectively (p=1.0), and 93% vs. 86%, respectively, at 12 months (p=0.3). Frequency of urine leak, quantity of pad use, subjective urinary control, and overall bother improved significantly in all patients during the 12-month study period (p<0.001); however, no difference was demonstrated between groups. Five-year results showed no statistically significant difference in the number of patients undergoing a continence-improving procedure (hazard ratio 1.21, 95% confidence interval 0.40-3.65, p=0.7).

CONCLUSIONS: PR-UVA failed to show a benefit in short-term return to urinary continence or need for an incontinence-improving procedure five years post-RARP.

PMID:40273410 | DOI:10.5489/cuaj.9121

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Analyzing Satellite Imagery to Target Tuberculosis Control Interventions in Densely Urbanized Areas of Kigali, Rwanda: Cross-Sectional Pilot Study

JMIR Public Health Surveill. 2025 Apr 24;11:e68355. doi: 10.2196/68355.

ABSTRACT

BACKGROUND: Early diagnosis and treatment initiation for tuberculosis (TB) not only improve individual patient outcomes but also reduce circulation within communities. Active case-finding (ACF), a cornerstone of TB control programs, aims to achieve this by targeting symptom screening and laboratory testing for individuals at high risk of infection. However, its efficiency is dependent on the ability to accurately identify such high-risk individuals and communities. The socioeconomic determinants of TB include difficulties in accessing health care and high within-household contact rates. These two determinants are common in the poorest neighborhoods of many sub-Saharan cities, where household crowding and lack of health-care access often coincide with malnutrition and HIV infection, further contributing to the TB burden.

OBJECTIVE: In this study, we propose a new approach to enhance the efficacy of ACF with focused interventions that target subpopulations at high risk. In particular, we focus on densely inhabited urban areas, where the proximity of individuals represents a proxy for poorer neighborhoods with enhanced contact rates.

METHODS: To this end, we used satellite imagery of the city of Kigali, Rwanda, and computer-vision algorithms to identify areas with a high density of small residential buildings. We subsequently screened 10,423 people living in these areas for TB exposure and symptoms and referred patients with a higher risk score for polymerase chain reaction testing.

RESULTS: We found autocorrelation in questionnaire scores for adjacent areas up to 782 meters. We removed the effects of this autocorrelation by aggregating the results based on H3 hexagons with a long diagonal of 1062 meters. Out of 324 people with high questionnaire scores, 202 underwent polymerase chain reaction testing, and 9 people had positive test results. We observed a weak but statistically significant correlation (r=0.28; P=.04) between the mean questionnaire score and the mean urban density of each hexagonal area.

CONCLUSIONS: Nine previously undiagnosed individuals had positive test results through this screening program. This limited number may be due to low TB incidence in Kigali, Rwanda, during the study period. However, our results suggest that analyzing satellite imagery may allow the identification of urban areas where inhabitants are at higher risk of TB. These findings could be used to efficiently guide targeted ACF interventions.

PMID:40273403 | DOI:10.2196/68355

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Long-term Fine Particulate Matter Exposure and Coronary Artery Disease: Unraveling Cardiometabolic Pathways and Modification of Genetic Susceptibility

Eur J Prev Cardiol. 2025 Apr 24:zwaf239. doi: 10.1093/eurjpc/zwaf239. Online ahead of print.

ABSTRACT

AIMS: Which cardiometabolic risk factors (CMRFs) primarily mediate the association between long-term fine particulate matter (PM2.5) exposure and coronary artery disease (CAD) incidence, and whether participants with high genetic risks of CMRFs are more susceptible remains unclear.

METHODS: This study was based on the project of Prediction for Atherosclerotic Cardiovascular Disease Risk in China. Long-term PM2.5 concentration was assessed by satellite-based spatiotemporal model at 1km resolution. Mediation analyses were conducted to assess the mediating contribution of CMRFs for PM2.5 and CAD, and then stratified by genetic risk of CMRFs. Additive interaction was additionally evaluated on modification of genetic risk for PM2.5 and CAD.

RESULTS: During a median follow-up of 11.15 years, 941 CAD cases of 34,481 participants were recorded. Each 10 μg/m3 increase in PM2.5 exposure was associated with a 28% increased risk of CAD (hazard ratio: 1.28; 95% confidence interval [CI]: 1.19, 1.37). Systolic blood pressure (SBP) and low-density lipoprotein cholesterol (LDL-C) emerged as the primary mediators, with mediating proportions of 13.02% (95%CI:4.63,21.42) and 9.23% (95%CI:0.34,18.12), respectively. Notably, individuals with high genetic risk exhibited greater mediating proportions at 18.99% (95%CI:6.43,31.55) and 16.30% (95%CI:5.11,27.52) then those with low genetic risk at 2.42% (95%CI: -16.80,21.64) and 6.15% (95%CI: -8.13,20.43). Meanwhile, the genetic risks of SBP and LDL-C also significantly exacerbated CAD risk related to PM2.5 exposure, demonstrating additive interaction (P<0.05).

CONCLUSIONS: This study provided a combination of conventional and genetic evidence to underscore the importance of integrated management targeting BP and blood cholesterol to mitigate CAD burden when PM2.5 exposure is unavoidable.

PMID:40273389 | DOI:10.1093/eurjpc/zwaf239

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Efficacy of Mediterranean Diet vs. Low-FODMAP Diet in Patients With Nonconstipated Irritable Bowel Syndrome: A Pilot Randomized Controlled Trial

Neurogastroenterol Motil. 2025 Apr 24:e70060. doi: 10.1111/nmo.70060. Online ahead of print.

ABSTRACT

INTRODUCTION: Mediterranean diet (MD) has been proposed as a dietary therapy for irritable bowel syndrome (IBS) but its efficacy remains unclear. We compared the efficacy of MD to a diet low in fermentable oligo-, di-, monosaccharides, and polyols (LFD).

METHODS: In this pilot-feasibility, randomized controlled trial (RCT), adult patients with diarrhea-predominant IBS (IBS-D) or mixed bowel pattern (IBS-M) were randomized to MD versus LFD for 4 weeks. Meals were provided for both groups (ModifyHealth, GA). Daily variables included abdominal pain intensity (API) and bloating, while IBS symptom severity score (IBS-SSS) and IBS adequate relief (IBS-AR) were scored weekly. The primary endpoint was the proportion of patients with ≥ 30% decrease in API for ≥ 2/4 weeks.

RESULTS: Of 26 randomized patients, 20 finished the study (10 per group). Seventy-three percent of the MD group met the primary endpoint compared to 81.8% of the LFD group (p = 1.0). Although not statistically significant, a numerically higher proportion of the LFD group reported adequate relief and met the responder endpoint for IBS-SSS (50-point reduction) compared to the MD group (54.6% vs. 27.3% for IBS-AR and 81.8% vs. 45.5% for IBS-SSS, p = 0.39 and 0.18, respectively). The LFD group also had a significantly greater reduction in IBS-SSS score over the 4-week treatment period compared to the MD group (-105.5 vs. -60, p = 0.02).

CONCLUSION: MD provides symptom relief in IBS-D and IBS-M; however, the magnitude of relief was higher with the LFD. Larger diet comparison studies in real-world settings are needed before MD can be routinely recommended to IBS patients.

TRIAL REGISTRATION: Clinicaltrials.gov: NCT05807919.

PMID:40273380 | DOI:10.1111/nmo.70060

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Functional Lumen Imaging Probe Measurement Post-Pneumatic Dilation in Clinically Relevant Esophagogastric Junction Outlet Obstruction

Neurogastroenterol Motil. 2025 Apr 24:e70053. doi: 10.1111/nmo.70053. Online ahead of print.

ABSTRACT

BACKGROUND: Pneumatic dilation (PD) is an effective treatment for disorders of reduced esophageal opening. Functional lumen impedance planimetry (FLIP) can effectively measure lower esophageal sphincter (LES) physiology compared to esophageal standards. The aim of this retrospective cohort analysis was to evaluate if FLIP measurements and esophageal opening classifications changed consistently with symptom improvement post-PD. Also, the aim was to determine if post-PD FLIP measurement correlated with the need for repeat dilation.

METHODS: Patients with clinically significant esophagogastric junction outlet obstruction (EGJOO) with reduced esophageal opening (REO) or borderline REO (BrEO) based on FLIP, timed barium esophagram (TBE), and manometry who underwent PD were included. Post-PD FLIP measurements were taken immediately after PD during the same endoscopy encounter.

RESULTS: After PD, average distensibility index (DI) increased from 1.5 mm2/mmHg to 4.7 mm2/mmHg (p < 0.001) and diameter changed from 8.9 mm to 15.9 mm (p < 0.001). Average post-dilation Eckardt score was 1.2, decreasing from an average pre-dilation score of 6.25. Of those requiring repeat dilations, average post-dilation DI was 4.5 mm2/mmHg and diameter 16.4 mm, not statistically different from those that did not undergo repeat procedure (p = 0.79, 0.67, respectively). Post-dilation esophageal openings were all NEO or BnEO. Average Eckardt score at 6-8 week follow-up was not significantly different from those who did not require repeat dilation (1.4, p = 0.112).

CONCLUSIONS: PD appears to be associated with improved esophageal opening and a significant change in both DI and diameter, consistent with an improved Eckardt score. Post-dilation DI, diameter, esophageal opening pattern, and Eckardt score did not reveal a trend indicating the need for repeat dilation.

PMID:40273370 | DOI:10.1111/nmo.70053

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Response to Drs. Igor Burstyn and George Luta’s letter: Advice on better utilization of validation data to adjust odds ratios for differential exposure misclassification (recall bias)

Scand J Work Environ Health. 2025 Apr 24:4232. doi: 10.5271/sjweh.4232. Online ahead of print.

ABSTRACT

We want to thank Drs. Burstyn & Luta (1) for their recognition of our recent study (2) suggesting that estimates of breast cancer risk following retrospective self-reported night shift work are inflated by recall bias. The main strength of the study was a gold standard based on individual, prospective, objective and detailed information on night shift work that allowed validation of self-reported night shift work obtained after breast cancer was diagnosed – the usual situation for case-control studies (3). The study confirmed what textbooks have long taught but rarely documented empirically (4-6). We also want to thank Drs. Burstyn & Luta for their advice on how we could have utilized this precious dataset not only for simple but also probabilistic and Bayesian quantitative bias analyses. Even if highly instructive, this may still require strong statistical involvement. Using data provided in our paper, Drs. Burstyn & Luta’s bias-corrected odds ratio (OR) estimate of breast cancer following night shift work was centered around 1.0 (95% credible interval 0.3-1.7) and suggests that recall bias could completely, and not only partly as in our analysis (OR 1.05; correctly computed 95% confidence interval 0.88-1.27), explain the observed associations between night shift work and breast cancer found in case-control studies with retrospective self-reported exposure information. This finding strengthens our concern that breast cancer studies based on retrospective self-reports of night shifts may not provide convincing evidence. The gold standard of this validation study was based on a cohort of healthcare workers with day-by-day night shift information from a pay roll register and has earlier been used for breast cancer risk assessment showing no increased risk (7). A recent Swedish study using comparable data neither showed an overall increased risk (8). However, these studies included only information on recent night shift work. The next step should be a follow up of the cohorts when information on more distant night shift work becomes available with an emphasis on analyses that explore the timing of shift work on breast cancer risk. References 1. Burstyn I, Luta G. Advice on better utilization of validation data to adjust odds ratios for differential exposure misclassification (recall bias). Scand J Work Environ Health – online first. https://doi.org/10.5271/sjweh.4226 2. Vestergaard JM, Haug JN, Dalbøge A, Bonde JP, Garde AH, Hansen J et al. Validity of self-reported night shift work among women with and without breast cancer. Scand J Work Environ Health. 2024;50(3):152-7. https://doi.org/10.5271/sjweh.4142. 3. Cordina-Duverger E, Menegaux F, Popa A, Rabstein S, Harth V, Pesch B et al. Night shift work and breast cancer: a pooled analysis of population-based case-control studies with complete work history. Eur J Epidemiol. 2018; 33(4):369-79. https://doi.org/10.1007/s10654-018-0368-x. 4. Berrington de González A, Richardson DB, Schubauer-Berigan MK. Statistical methods in cancer research, Volume V. Bias assessment in case-control and cohort studies for hazard identification. Lyon, France: International Agency for Research on Cancer; 2024. 5. Checkoway H, Pearce N, Kriebel D. Research Methods in Occupational Epidemiology. New York: Oxford University Press 2004. p372. 6. Rothman KJ. Modern Epidemiology. Boston/Toronto: Little, Brown and Company; 1986. p358. 7. Vistisen HT, Garde AH, Frydenberg M, Christiansen P, Hansen AM, Hansen J et al. Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data. Scand J Work Environ Health. 2017;43(1):59-67. https://doi.org/10.5271/sjweh.3603. 8. Gustavsson P, Bigert C, Andersson T, Kader M, Härmä M, Selander J et al. Night work and breast cancer risk in a cohort of female healthcare employees in Stockholm, Sweden. Occup Environ Med. 2023;80(7):372-6. https://doi.org/10.1136/oemed-2022-108673. Henrik Albert Kolstad, MD,1, 2 Jesper Medom Vestergaard, MIT,1 Jens Peter Bonde, MD,3 Sadie Costello, PhD,4 Annett Dalbøge, PhD,1 Åse Marie Hansen, PhD,5, 6 Ann Dyreborg Larsen, PhD,6 Anne Helene Garde, PhD 5, 6 1 Occupational and Environmental Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark. 2 Department of Clinical Medicine, Aarhus University, Denmark. 3 Department of Occupational and Environmental Medicine, Bispebjerg and Frederiksberg Hospital, Denmark. 4 Environmental Health Science, School of Public Health, University of California, Berkeley, USA. 5 The National Research Centre for the Working Environment, Denmark. 6 Department of Public Health, University of Copenhagen, Denmark. Correspondence to: Henrik Kolstad, Occupational and Environmental Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark. [E-mail: kolstad@clin.au.dk].

PMID:40273368 | DOI:10.5271/sjweh.4232

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Advice on better utilization of validation data to adjust odds ratios for differential exposure misclassification (recall bias)

Scand J Work Environ Health. 2025 Apr 24:4226. doi: 10.5271/sjweh.4226. Online ahead of print.

ABSTRACT

We were delighted by the publication in your journal of the results of a validation study on self-reported night shift work by Vestergaard et al (1). Such exquisite validation studies that compare self-report to employment records are rare and sorely needed if we are to draw appropriate inferences from epidemiologic studies, both in characterization the degree of risk and – as recently argued by IARC – hazard identification (2). However, we have strong reasons to believe that the validation data which Vestergaard et al obtained could (and should) have been better used to “correct” odds ratios (OR) for differential exposure misclassifications. [NB: Our use of the Excel spreadsheet of Lash et al (3) cited in Vestergaard et al (1) leads to the same “corrected” point estimate but a different, wider, 95% confidence interval (CI) 0.88-1.27. The corrected 95% CI reported in table 3 of (1) is obtained if we use rounded-up counts after adjustment. This is incorrect because expected counts “do not have to be integers”, as stated for the Excel spreadsheet that Vestergaard et al used. This illustrates the importance of the use of tools as intended and the unexpected impact on their results of apparently small changes to the input values for their calculations.] First, we must note that quantitative bias analysis does not correct for exposure misclassification in general. In the case of using fixed values of sensitivities and specificities, it provides a corrected estimate only under the assumption that misclassification probabilities are known with absolute certainty. However, it is obvious from table 2 of Vestergaard et al (1) that misclassification probabilities are estimated with uncertainty. When there is uncertainty about sensitivities and specificities, the textbook they quote recommends (urges!) that probabilistic bias analysis should be carried out to account simultaneously for uncertainty in misclassification probabilities and random sampling errors (3). When this is done, probabilistic bias analysis does not guarantee the correction or adjustment for misclassification of exposure, but it merely produces a collection of alternative estimates via a Monte-Carlo simulation. An alternative adjustment approach for this case of uncertain exposure probabilities, which does involve theoretical assurance of correcting the OR for misclassification of exposure, is a Bayesian methodology (4, 5). Probabilistic bias analysis and Bayesian methods are not guaranteed to produce identical numerical results, and only Bayesian methods produce results that can be interpreted as distributions of true values given data, model and priors (6). Second, it is known to be risky to adjust for exposure misclassification using fixed values of sensitivities and specificities if these are not known exactly (4). Small deviations from true misclassification probabilities can have a dramatic impact on the resulting adjustment. Thus, the corrected OR in Vestergaard et al (1) of 1.05 (95% CI 0.95-1.16) is just one of many such adjusted estimates that is consistent with the presented validation data as we show below. Bayesian methods yet again come to the rescue here because they are designed to account for uncertainty in misclassification parameters by using prior probability distributions. Third, we are puzzled by Vestergaard et al`s choice of using the bootstrap to estimate distributions of sensitivities and specificities when there is a far simpler accepted approach to expressing uncertainty about proportions in quantitative bias analyses (Bayesian or probabilistic). When the validation study estimates a proportion k/N, the uncertainty about the true value of the proportion is typically expressed by using a Beta distribution, defined on [0,1] and is a conjugate prior of the Bernoulli distribution. For an observed proportion k/N, given that before performing the validation study we were completely ignorant about the value of the proportion, the Beta(α,β) distribution that captures this information has shape parameters α=k+1 and β=N-k+1, eg, see (7). We calculated these shape parameters for the misclassification probabilities from table 2 of Vestergaard et al (1) (this is partially reproduced in table 1) and presented them in our table 2, which also shows the corresponding means and variances. Fourth, we observe that the Bayesian adjustment for differential exposure misclassification yields what may be considered as qualitatively different results compared to Vestergaard et al`s adjustment of using fixed values. We followed the implementation from Singer et al (8). The Bayesian approach imposed no correlation between the misclassification parameters. We used a vague prior on the OR, null centered with 95% CI 0.02-50, as recommended for a sparse data problem (9). We also specified a uniform prior (0-1) on the exposure prevalence among controls. The Bayesian model converged and none of its diagnostics appear anomalous; implementation details that center around R (10) packages rjags (11) can be found in the supplementary material (www.sjweh.fi/article/4226) appendix A. Summaries of the posterior distributions are presented in table 3. The posterior OR adjusted for recall bias had a mean of 0.98, median of 0.97 and a credible interval of 0.30-1.71. As an added benefit, we have learned about the distributions of misclassification parameters and true prevalences, which can be used further if one is to update the study in question or use similar exposure assessment tools in a setting where similar exposure misclassification is suspected. Lastly, we carried out our probabilistic bias analysis using the same Beta distributions as in table 2, assuming that the correlation of sensitivities and specificities is weak (ie, 0.1). Details of the implementation of probabilistic bias analysis using the R package episensor (12) are available in supplementary appendix B. The resulting simulated OR had a median of 1.00 and a 95% simulation interval of 0.48-1.31. Thus, Vestergaard et al (1) is an example of a study where using fixed values of misclassification probabilities leads to a rather different estimate of 1.05 (and corresponding 95% CI 0.95-1.16) compared to both probabilistic bias analysis and Bayesian adjustment method that use the same validation data. Distributions of OR obtained after probabilistic and Bayesian adjustments are illustrated in figure 1, which shows that the Bayesian method (in red) favors lower true values of the OR compared to the probabilistic one (in gray). When faced with numerically different results of adjustment for exposure misclassification, we advise our colleagues to rely on the results that arise from the more theoretically justified methodology. In the case of adjustment from Vestergaard et al (1), we think that the Bayesian results are more defensible, yielding an adjusted OR centered around 1.0 (95% credible interval 0.3-1.7). This result appears to us to be a rather more convincing estimate for the association of breast cancer with report of ever having worked night shifts than Vestergaard et al`s “corrected” estimate. We urge epidemiologists who collect precious validation data to collaborate with statisticians who can help them fully utilize it, arriving at more defensible effect estimates and, ultimately, better risk assessments. References 1. Vestergaard JM, Haug JN, Dalbøge A, Bonde JP, Garde AH, Hansen J et al. Validity of self-reported night shift work among women with and without breast cancer. Scand J Work Environ Health 2024 Apr;50(3):152-7. https://doi.org/10.5271/sjweh.4142. 2. IARC. Statistical Methods in Cancer Research Volume V: Bias Assessment in Case-Control and Cohort Studies for Hazard Identification. IARC Scientific Publication No. 171. 1 ed. Lyon, France: International Agency for Research on Cancer; 2024. 3. Lash TL, Fox MP, Fink AK. Applying Quantitative Bias Analysis to Epidemiologic Data: Springer; 2021. 4. Gustafson P, Le ND, Saskin R. Case-control analysis with partial knowledge of exposure misclassification probabilities. Biometrics 2001 Jun;57(2):598-609. https://doi.org/10.1111/j.0006-341X.2001.00598.x. 5. Gustafson P. Measurement Error and Misclassification in Statistics and Epidemiology: Chapman & Hall/CRC Press; 2004. 6. MacLehose RF, Gustafson P. Is probabilistic bias analysis approximately Bayesian? Epidemiology 2012 Jan;23(1):151-8. https://doi.org/10.1097/EDE.0b013e31823b539c. 7. Luta G, Ford MB, Bondy M, Shields PG, Stamey JD. Bayesian sensitivity analysis methods to evaluate bias due to misclassification and missing data using informative priors and external validation data. Cancer Epidemiol 2013 Apr;37(2):121-6. https://doi.org/10.1016/j.canep.2012.11.006. 8. Singer AB, Daniele Fallin M, Burstyn I. Bayesian Correction for Exposure Misclassification and Evolution of Evidence in Two Studies of the Association Between Maternal Occupational Exposure to Asthmagens and Risk of Autism Spectrum Disorder. Curr Environ Health Rep 2018 Sep;5(3):338-50. https://doi.org/10.1007/s40572-018-0205-0. 9. Greenland S, Mansournia MA, Altman DG. Sparse data bias: a problem hiding in plain sight. BMJ 2016 Apr;352:i1981. https://doi.org/10.1136/bmj.i1981. 10. Team RD. A language and environment for statistical computing. ISBN 3-900051-07-0. Vienna, Austria: R Foundation for Statistical Computing; 2006. 11. Plummer M. rjags: Bayesian Graphical Models using MCMC. R package version 4-16 ed2024. 12. Haine D. The episensr package: basic sensitivity analysis of epidemiological results. R package version 1.3.0. 2023 Available from: https://dhaine.github.io/episensr/.

PMID:40273363 | DOI:10.5271/sjweh.4226