Thanks for your comment on our article, Shift work and burnout in police officers: a risk assessment. We appreciate that the risk of burnout may be multi-factorial and the relative contribution of each factor may vary by occupation. We did not examine work-related stress and conflict but appreciate that such factors may contribute to burnout risk in police officers. We maintain, however, our findings that sleepiness, inadequate sleep, irregular schedules, mandatory overtime, long shifts and night shifts are factors associated with elevated burnout risk in this population. We also controlled for age in our analyses and found that age was significant in the adjusted models examining shift work, sleep and their association with Depersonalisation and Personal Accomplishment. We agree that more research into the factors contributing to burnout and programs to mitigate it in safety-sensitive shift working occupations is necessary.
Sincerely,
Scott A Peterson, Alexander P Wolkow, Steven W Lockley, Conor S O'Brien, Salim Qadri, Jason P Sullivan, Charles A Czeisler, Shantha M W Rajaratnam and Laura K Barger
Peterson et al. examined associations between shift work and burnout in 3140 police officers with special reference to sleep duration and sleepiness. The Maslach Burnout Inventory, shift schedules (irregular, rotating, fixed), shift characteristics (night, duration, frequency, work hours), sleep duration and sleepiness were used for the analysis. Adjusted odds ratios (ORs) (95% confidence intervals [CIs]) of long shifts and mandatory overtime for emotional exhaustion were 1.91 (1.35 to 2.72) and 1.37 (1.14 to 1.65), respectively. Adjusted OR (95% CI) of night shifts for depersonalisation was 1.32 (1.05 to 1.66). In addition, Adjusted ORs (95% Cis) of irregular schedules for emotional exhaustion and depersonalisation were 1.91 (1.44 to 2.54) and 1.39 (1.02 to 1.89), respectively. Furthermore, adjusted ORs (95% Cis) of sleeping <6 hours and excessive sleepiness for motional exhaustion were 1.60 (1.33 to 1.93) and 1.81 (1.50 to 2.18), respectively. I have a comment about their study.
Ogundipe et al. determined factors burnout among 204 medical doctors undergoing residency training. General Health Questionnaire (GHQ-12) and Maslach Burnout Inventory (MBI) were used for the analysis. Adjusted OR (95% CI) of call duty as being not stressful for emotional exhaustion was 0.52 (0.29, 0.97). In contrast, adjusted OR (95% CI) of emotional distress, based on GHQ score of ≥3, for emotional exhaustion was 6.97 (3.28, 14.81). In addition, adjusted OR (95% CI) of absence of doc...
Peterson et al. examined associations between shift work and burnout in 3140 police officers with special reference to sleep duration and sleepiness. The Maslach Burnout Inventory, shift schedules (irregular, rotating, fixed), shift characteristics (night, duration, frequency, work hours), sleep duration and sleepiness were used for the analysis. Adjusted odds ratios (ORs) (95% confidence intervals [CIs]) of long shifts and mandatory overtime for emotional exhaustion were 1.91 (1.35 to 2.72) and 1.37 (1.14 to 1.65), respectively. Adjusted OR (95% CI) of night shifts for depersonalisation was 1.32 (1.05 to 1.66). In addition, Adjusted ORs (95% Cis) of irregular schedules for emotional exhaustion and depersonalisation were 1.91 (1.44 to 2.54) and 1.39 (1.02 to 1.89), respectively. Furthermore, adjusted ORs (95% Cis) of sleeping <6 hours and excessive sleepiness for motional exhaustion were 1.60 (1.33 to 1.93) and 1.81 (1.50 to 2.18), respectively. I have a comment about their study.
Ogundipe et al. determined factors burnout among 204 medical doctors undergoing residency training. General Health Questionnaire (GHQ-12) and Maslach Burnout Inventory (MBI) were used for the analysis. Adjusted OR (95% CI) of call duty as being not stressful for emotional exhaustion was 0.52 (0.29, 0.97). In contrast, adjusted OR (95% CI) of emotional distress, based on GHQ score of ≥3, for emotional exhaustion was 6.97 (3.28, 14.81). In addition, adjusted OR (95% CI) of absence of doctor-to-doctor conflict for depersonalization was 0.36 (0.17, 0.76). They also clarified that aging and adequate support for the management prevented burnout with reducing personal accomplishment. I suppose that risk of burnout might not be regulated by shift of job and sleep. To prevent burnout in police officers, stress-lowering strategies should be prepared and applied comprehensively.
References
1. Peterson SA, Wolkow AP, Lockley SW, et al. Associations between shift work characteristics, shift work schedules, sleep and burnout in North American police officers: a cross-sectional study. BMJ Open. 2019;9(11):e030302. Published 2019 Dec 1. doi:10.1136/bmjopen-2019-030302
2. Ogundipe OA, Olagunju AT, Lasebikan VO, Coker AO. Burnout among doctors in residency training in a tertiary hospital. Asian J Psychiatr. 2014;10:27-32. doi:10.1016/j.ajp.2014.02.010
Hopefully this will become an invaluable study. Can I alert the authors to the role of nearness to death (the nearness to death effect) in both cognitive and functional decline especially in the last year of life.
In the references you cite, the definition of multimorbidity is showed as the co-existence of two or more chronic conditions, where one is not necessarily more central than the others. But you have defined multi-morbidity comorbidity as the presence of two or more chronic health conditions in an individual. Does your definition indicate comorbidity?
To the editor:
In response to the article titled “Incidence and risk factors of retinopathy of prematurity in Korle-Bu Teaching Hospital: a baseline prospective study.” published in your esteemed journal, I would like to raise a few points regarding this study. This is a well thought of and written paper which demonstrated that birth weight less than 1.5 kg, confirmed neonatal sepsis, nasogastric tube feeding and poor pupil dilation were independently associated with increased incidence of ROP. ROP screening should be a part of the routine service for premature infants in Ghana. (1)
Retinopathy of prematurity (ROP) has a prevalence of 6 to 18% as one of the main causes of vision loss in childhood worldwide (2). Early diagnosis is of fundamental importance to avoid sequelae associated with this disease. However, we have a lack of trained professionals for the proper screening and monitoring of this disease. In addition, studies have shown that there may be a discrepancy in the diagnosis of this pathology among the specialists themselves. (3)
Due to this difficulty in monitoring, new technologies can be developed to assist in early diagnosis and monitoring, avoiding this important cause of childhood blindness. There are devices such as Retcam that can assist in telemedicine monitoring. This device has a high cost that can be compensated with the development of technologies that allow the registration of newborn images with smartphones, facilitating documen...
To the editor:
In response to the article titled “Incidence and risk factors of retinopathy of prematurity in Korle-Bu Teaching Hospital: a baseline prospective study.” published in your esteemed journal, I would like to raise a few points regarding this study. This is a well thought of and written paper which demonstrated that birth weight less than 1.5 kg, confirmed neonatal sepsis, nasogastric tube feeding and poor pupil dilation were independently associated with increased incidence of ROP. ROP screening should be a part of the routine service for premature infants in Ghana. (1)
Retinopathy of prematurity (ROP) has a prevalence of 6 to 18% as one of the main causes of vision loss in childhood worldwide (2). Early diagnosis is of fundamental importance to avoid sequelae associated with this disease. However, we have a lack of trained professionals for the proper screening and monitoring of this disease. In addition, studies have shown that there may be a discrepancy in the diagnosis of this pathology among the specialists themselves. (3)
Due to this difficulty in monitoring, new technologies can be developed to assist in early diagnosis and monitoring, avoiding this important cause of childhood blindness. There are devices such as Retcam that can assist in telemedicine monitoring. This device has a high cost that can be compensated with the development of technologies that allow the registration of newborn images with smartphones, facilitating documentation and monitoring by telemedicine (4)
In addition to telemedicine, the development of artificial intelligence algorithms can assist in the diagnosis and monitoring of ROP. Brown et al. developed and validated a fully automated deep learning system with a database of 5,511 retinography images obtained with RetCam (for the diagnosis of three disease levels (positive, pre-positive and normal) with an area under the ROC Curve of 0, 98 for the positive diagnosis of the disease with a reference standard defined by specialists.The algorithm reached 93% sensitivity and specificity of 94% for the diagnosis of disease plus and 100% sensitivity and specificity of 94% for the diagnosis pre-more or worse disease (5). Xiao et al. developed a training program with neural networks to quantify the area of neovascularization in patients with retinopathy of prematurity. (6)
The development of automated artificial intelligence systems can, therefore, help in telemedicine projects that help in tracking ROP performed by health professionals in a neonatal intensive care unit, reducing the request for eye exams. These methods can be indicated in countries with a lack of qualified professionals for adequate screening and monitoring, reducing the costs to the health system that these visually impaired children can cause, in addition to reducing one of the main causes of childhood blindness.
Compliance with ethical standards
Conflict of interest: The authors declare that they have no conflict of interest.
REFERENCES
1. Braimah IZ, Enweronu-Laryea C, Sackey AH, et al. Incidence and risk factors of retinopathy of prematurity in Korle-Bu Teaching Hospital: a baseline prospective study. BMJ Open. 2020;10(8):e035341. Published 2020 Aug 5. doi:10.1136/bmjopen-2019-035341
2. Fleck BW, Dangata Y. Causes of visual handicap in the Royal Blind School, Edinburgh, 1991-2. Br J Ophthalmol. 1994;78:421.
3. Chiang MF, Jiang L, Gelman R, Du YE, Flynn JT. Interexpert Agreement of Plus Disease Diagnosis in Retinopathy of Prematurity. Arch Ophthalmol. 2007;125:875-880.
4. Shanmugam MP, Mishra DK, Madhukumar R, Ramanjulu R, Reddy SY, Rodrigues G. Fundus imaging with a mobile phone: a review of techniques. Indian J Ophthalmol. 2014;62(9):960-962. doi:10.4103/0301-4738.143949
5. Brown JM, Campbell JP, Beers A, Chang K, Ostmo S, Chan RVP, Dy J, Erdogmus D, Ioannidis S, Kalpathy-Cramer J, Chiang MF, Imaging and Informatics in Retinopathy of Prematurity (i-ROP) Research Consortium. Automated Diagnosis of Plus Disease in Retinopathy of Prematurity Using Deep Convolutional Neural Networks. JAMA Ophthalmol. 2018;136:803- 810.
6. Xiao S, Bucher F, Wu Y, Rokem A, Lee CS, Marra KV, Fallon R, Diaz-Aguilar S,Aguilar E, Friedlander M, Lee AY. Fully automated, deep learning segmentationof oxygen-induced retinopathy images. JCI Insight. 2017 Dec 21;2(24). pii:97585. doi: 10.1172/jci.insight.97585.
We thank Drs Müller and Shukri(1) for their interest in our recent publication in BMJ Open entitled “Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark”(2).
We agree with the authors, that clarity and transparency are crucial when reporting research in order to interpret findings. Below we have responded to each of the two comments given by the authors.
First, while Table 2 and 3 of our publication reflects the actual, observed cost and health utilities, the incremental cost and health utilities presented in table 4 is estimated based on the regression analyses2. As such you cannot go directly from the numbers in Table 2 and 3 to the results in Table 4 without the parameters used for the regression. In order to ensure full transparency, please see the parameters used for the primary regression analyses in the new Table 1 below.
Second, during follow-up, three persons died in TKR plus non-surgical treatment group, while one person in the non-surgical treatment only group died. We decided to exclude the four persons who died from the primary analyses as we had no reason to believe that either of the treatments would be associated with an increased risk of dying and as including deaths...
We thank Drs Müller and Shukri(1) for their interest in our recent publication in BMJ Open entitled “Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark”(2).
We agree with the authors, that clarity and transparency are crucial when reporting research in order to interpret findings. Below we have responded to each of the two comments given by the authors.
First, while Table 2 and 3 of our publication reflects the actual, observed cost and health utilities, the incremental cost and health utilities presented in table 4 is estimated based on the regression analyses2. As such you cannot go directly from the numbers in Table 2 and 3 to the results in Table 4 without the parameters used for the regression. In order to ensure full transparency, please see the parameters used for the primary regression analyses in the new Table 1 below.
Second, during follow-up, three persons died in TKR plus non-surgical treatment group, while one person in the non-surgical treatment only group died. We decided to exclude the four persons who died from the primary analyses as we had no reason to believe that either of the treatments would be associated with an increased risk of dying and as including deaths would have a major effect on the health utilities (death=0). Given the rather small sample size of the study, the uneven distribution of deaths between groups would carry the risk of creating spurious findings if the dead people had been included. However, to support transparency, we presented both the analyses including and excluding death, which would allow the reader to make their own interpretation.
Either way, both the analyses including and excluding the people who had died during follow-up led to the same conclusion, i.e. that TKR plus non-surgical treatment was not cost-effective as compared to non-surgical treatment alone in the 2-year time horizon. We believe that long-term analyses of our data will provide further clarity when it comes to the long-term clinical effectiveness and cost-effectiveness of TKR as treatment of moderate to severe knee osteoarthritis.
References
1. Müller D, Shukri A. Comment to ‚Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark‘ (Skou et al. BMJ Open. 2020 Jan 15;10(1):e033495)
2. Skou, ST; Roos, EM; Laursen, M; Arendt-Nielsen, L; Rasmussen, S; Simonsen, O; Ibsen, R; Larsen, AT; Kjellberg, J. Cost-effectiveness of total knee replacement in addition to non-surgical treatment: 2-year outcome from a randomized trial in secondary care in Denmark. BMJ Open 2020;10:e033495.
It is of interest to note that risk of infection is associated with population density in this study. My research indicates that weighted population density is associated with higher SARS-CoV-2 deaths in US states, in UK local authorities and sub-local authority geographies [1,2]. This is an entirely logical association.
References
1. Jones R. Would the United States have had too few beds for universal emergency care in the event of a more widespread Covid-19 epidemic? IJERPH 2020; 17: 5210. https://doi.org/doi:10.3390/ijerph17145210
2. Jones R. How many extra deaths have really occurred in the UK due to the Covid-19 outbreak? XIII. Population density and risk of Covid-19 death. DOI: 10.13140/RG.2.2.23027.35365
We read with interest the paper entitled “Efficacy and safety of the pulsed electromagnetic field in osteoarthritis: a meta-analysis”.1 This paper concluded that “PEMF could alleviate pain and improve physical function for patients with knee and hand [osteoarthritis] OA, but not for patients with cervical [osteoarthritis] OA.” We have a few concerns with their conclusion.
The first concern is that the review reports very large effect sizes for some trials,2-5 but does not alert the reader to how atypical these results are. For example, Figure 3 of the manuscript1 contains three examples of effect sizes of ~3 and 4 standardised mean difference (SMD). Effect sizes this large are usually a red flag that something is amiss, either with the results of the review or the original trial. Unfortunately, both problems are present.
The review reported a SMD for the Nelson trial5 of -3.72; but this a mistake. The authors have confused the standard deviation (SD) with the standard error (SE) and when their error is corrected the true effect size is -0.74 [95% confidence interval (CI) -1.44 to -0.04] compared with -3.72 [95% CI -4.88 to -2.56] reported in the review. The correction also changes the pooled effect to -0.33 [-0.70 to 0.04] and would support the conclusion that the treatment is not effective for knee OA.
The other two large effect sizes are driven by outcomes in the treatment group and no change in the control group.2,3 For...
We read with interest the paper entitled “Efficacy and safety of the pulsed electromagnetic field in osteoarthritis: a meta-analysis”.1 This paper concluded that “PEMF could alleviate pain and improve physical function for patients with knee and hand [osteoarthritis] OA, but not for patients with cervical [osteoarthritis] OA.” We have a few concerns with their conclusion.
The first concern is that the review reports very large effect sizes for some trials,2-5 but does not alert the reader to how atypical these results are. For example, Figure 3 of the manuscript1 contains three examples of effect sizes of ~3 and 4 standardised mean difference (SMD). Effect sizes this large are usually a red flag that something is amiss, either with the results of the review or the original trial. Unfortunately, both problems are present.
The review reported a SMD for the Nelson trial5 of -3.72; but this a mistake. The authors have confused the standard deviation (SD) with the standard error (SE) and when their error is corrected the true effect size is -0.74 [95% confidence interval (CI) -1.44 to -0.04] compared with -3.72 [95% CI -4.88 to -2.56] reported in the review. The correction also changes the pooled effect to -0.33 [-0.70 to 0.04] and would support the conclusion that the treatment is not effective for knee OA.
The other two large effect sizes are driven by outcomes in the treatment group and no change in the control group.2,3 For example, in the trial by Kanat et al of hand OA,3 the group mean pain score in the active PEMF group was zero at 1-month follow-up; meaning that all 25 participants completely recovered. In contrast, in the sham group, pain did not change at all. These findings are quite unlike what normally happens in trials and clinical care. For a chronic episodic condition like OA, normally there is some improvement in the placebo group due to natural history, effects of testing, and the placebo (Hawthorne)6 effect. Typically, effective treatments have small or moderate effects; but not everyone is essentially “cured”. While these unusual results are not the fault of the review authors, there is a responsibility to alert readers to how unusual these results are.
Our final concern is that a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) rating was not provided, which would have been useful to communicate to readers how confident they should be in the pooled estimate and whether further research is warranted.
We believe that this review provides a great example of the need to reflect upon large effect sizes; and to avoid simply publishing them without comment. Sometimes the problem is simply an error, and readily fixed. On other occasions there is something atypical about the trial and the reviewer is left with the challenge of what to do. At the least it would be helpful to communicate the issue to the readers. Another option may be to undertake a sensitivity analysis to see if the conclusion would change if the trial was removed. We understand that these are challenging issues, but nonetheless it is important to promote discourse in evidence-based medicine.
References
1. Wu Z, Ding X, Lei G, et al. Efficacy and safety of the pulsed electromagnetic field in osteoarthritis: a meta-analysis. BMJ Open. 2018;8(12):e022879.
2. Sutbeyaz ST, Sezer N, Koseoglu BF. The effect of pulsed electromagnetic fields in the treatment of cervical osteoarthritis: a randomized, double-blind, sham-controlled trial. Rheumatology international. 2006;26(4):320-24.
3. Kanat E, Alp A, Yurtkuran M. Magnetotherapy in hand osteoarthritis: A pilot trial. Complementary Therapies in Medicine. 2013;21(6):603-08.
4. Bagnato GL, Miceli G, Marino N, et al. Pulsed electromagnetic fields in knee osteoarthritis: a double blind, placebo-controlled, randomized clinical trial. Rheumatology. 2015;55(4):755-62.
5. Nelson FR, Zvirbulis R, Pilla AA. Non-invasive electromagnetic field therapy produces rapid and substantial pain reduction in early knee osteoarthritis: a randomized double-blind pilot study. Rheumatology International. 2013;33(8):2169-73.
6. McCambridge J, Witton J, Elbourne DR. Systematic review of the Hawthorne effect: new concepts are needed to study research participation effects. J Clin Epidemiol 2014;67(3):267-77.
Address correspondence to:
Dr Christina Abdel Shaheed
Institute for Musculoskeletal Health
P.O. Box M179, Missenden Road
Camperdown NSW 2050 Australia
Phone: +61 2 8627 6256
Fax: +61 2 8627 6262
Email: Christina.abdelshaheed@sydney.edu.au
Altschul et al. conducted a prospective study to investigate the association between blood pressure (BP) and cognitive functions across the eighth decade (1). Women with higher early-life cognitive function had lower BP during the eighth decade. In addition, prescribed antihypertensive medication was closely associated with lower BP, but antihypertensive medication had no effect on better cognitive function. Regarding no relationship between BP and cognitive decline, I have some concerns.
First, Ou et al. conducted a meta-analysis regarding the association between BP and cognitive impairment/dementia in prospective studies (2). The significant relationship of BP with cognitive impairment/dementia was observed in different BP variables, which were classified into midlife and late-life periods. In addition, prescribed antihypertensive medications exhibited a 21% reduction in dementia risk, which was different from data by Altschul et al. I suspect that long-term follow-up might change the relationship between BP and cognitive functions. Long survivors’ effect on BP and cognitive functions should be specified by further study.
Second, visit-to-visit variability in blood pressure was a significant predictor of subsequent cognitive decline in old subjects (3,4). But the association between BP variability and cognitive impairment was not mediated by BP lowering medication (5). As BP variables such as high systolic BP, low diastolic BP, excessive BP variability, and...
Altschul et al. conducted a prospective study to investigate the association between blood pressure (BP) and cognitive functions across the eighth decade (1). Women with higher early-life cognitive function had lower BP during the eighth decade. In addition, prescribed antihypertensive medication was closely associated with lower BP, but antihypertensive medication had no effect on better cognitive function. Regarding no relationship between BP and cognitive decline, I have some concerns.
First, Ou et al. conducted a meta-analysis regarding the association between BP and cognitive impairment/dementia in prospective studies (2). The significant relationship of BP with cognitive impairment/dementia was observed in different BP variables, which were classified into midlife and late-life periods. In addition, prescribed antihypertensive medications exhibited a 21% reduction in dementia risk, which was different from data by Altschul et al. I suspect that long-term follow-up might change the relationship between BP and cognitive functions. Long survivors’ effect on BP and cognitive functions should be specified by further study.
Second, visit-to-visit variability in blood pressure was a significant predictor of subsequent cognitive decline in old subjects (3,4). But the association between BP variability and cognitive impairment was not mediated by BP lowering medication (5). As BP variables such as high systolic BP, low diastolic BP, excessive BP variability, and orthostatic hypotension would interact with each other for increased dementia risk in later life (1), comprehensive analyses are needed to understand the effect of BP variables on subsequent cognitive decline.
Finally, Rajan et al. reported a U-shaped relationship between BP and Alzheimer disease (AD) (6), which was in agreement with data by Ou et al (2). These study present that non-linear relationships between BP and subsequent cognitive impairment/dementia might be existed.
References
1. Altschul D, Starr J, Deary I. Blood pressure and cognitive function across the eighth decade: a prospective study of the Lothian Birth Cohort of 1936. BMJ Open. 2020;10(7):e033990. doi:10.1136/bmjopen-2019-033990
2. Ou YN, Tan CC, Shen XN, et al. Blood pressure and risks of cognitive impairment and dementia: A systematic review and meta-analysis of 209 prospective studies. Hypertension. 2020;76:217-225. doi: 10.1161/HYPERTENSIONAHA.120.14993
3. Sabayan B, Wijsman LW, Foster-Dingley JC, et al. Association of visit-to-visit variability in blood pressure with cognitive function in old age: prospective cohort study. BMJ. 2013;347:f4600. doi: 10.1136/bmj.f4600
4. Qin B, Viera AJ, Muntner P. Visit-to-visit variability in blood pressure is related to late-life cognitive decline. Hypertension. 2016;68:106-113. doi: 10.1161/HYPERTENSIONAHA.116.07494
5. Wijsman LW, de Craen AJ, Muller M. Blood pressure lowering medication, visit-to-visit blood pressure variability, and cognitive function in old age. Am J Hypertens. 2016;29:311-318. doi: 10.1093/ajh/hpv101
6. Rajan KB, Barnes LL, Wilson RS, Weuve J, McAninch EA, Evans DA. Blood pressure and risk of incident Alzheimer's disease dementia by antihypertensive medications and APOE ε4 allele. Ann Neurol. 2018;83(5):935-944. doi:10.1002/ana.25228
We would like to thank RJ Aitken for presenting his basic scientist view on our clinical trial.
His first comment addresses the fact that we include “idiopathic infertility patients irrespective of their redox status “. He suggests that we should only include patients with proven oxidative stress. We would like to respond that, of course, we would prefer to follow his advice, on the condition that validated test are available to differentiate between men that do suffer (constantly) from oxidative stress and those that do not, or that are even at risk for reductive stress. If we could all agree on the reliability of such tests, then it would certainly be worthwhile to try and get additional funding for pre- and post-therapy testing in (a subset of) our patients, then analyze them separately according to their redox status. Such an addition might provide a more solid basis for the antioxidant therapy. However, sperm DNA fragmentation tests are very costly and there is as yet no international consensus on which sperm DNA fragmentation test should be used as becomes obviously clear when reading the extensive review of the literature composed by Agarwal et al and the extensive discussion it awakened with more than 50 commentary letters published.(1,2) As to the danger of causing reductive stress, we think this is limited, as Impryl does not contain direct and strong scavenging antioxidants such as vitamin C and E, but rather focuses on the homocysteine pathway and the 1...
We would like to thank RJ Aitken for presenting his basic scientist view on our clinical trial.
His first comment addresses the fact that we include “idiopathic infertility patients irrespective of their redox status “. He suggests that we should only include patients with proven oxidative stress. We would like to respond that, of course, we would prefer to follow his advice, on the condition that validated test are available to differentiate between men that do suffer (constantly) from oxidative stress and those that do not, or that are even at risk for reductive stress. If we could all agree on the reliability of such tests, then it would certainly be worthwhile to try and get additional funding for pre- and post-therapy testing in (a subset of) our patients, then analyze them separately according to their redox status. Such an addition might provide a more solid basis for the antioxidant therapy. However, sperm DNA fragmentation tests are very costly and there is as yet no international consensus on which sperm DNA fragmentation test should be used as becomes obviously clear when reading the extensive review of the literature composed by Agarwal et al and the extensive discussion it awakened with more than 50 commentary letters published.(1,2) As to the danger of causing reductive stress, we think this is limited, as Impryl does not contain direct and strong scavenging antioxidants such as vitamin C and E, but rather focuses on the homocysteine pathway and the 1 carbon cycle.(3,4)
His second comment addresses the fact that our primary outcome measure is pregnancy and that we do not search for increased mutational load or cancer-causing mutations in the offspring. Of course, we agree that preventing such mutations might be another important benefit of antioxidant therapy. However, for now we will adhere to pregnancy as our “real world situation” outcome measurement. Epigenetic changes in offspring are not within the scope of the SUMMER study.
We thank RJ Aitkin for presenting these critical notes and also for his positive comments. We surely hope that basic scientists will someday provide us with the technologies that reliably measure oxidative stress and more insight into the occurrence of cancer-causing mutations in offspring.
References
1. Agarwal A, Majzoub A, Esteves SC, Ko E, Ramasamy R, Zini A. Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios. Transl Androl Urol. 2016;5(6):935-950. doi:10.21037/tau.2016.10.03
2. Ward WS. Eight tests for sperm DNA fragmentation and their roles in the clinic. Transl Androl Urol. 2017;6(Suppl 4):S468-S470. doi:10.21037/tau.2017.03.78
3. Mohammadi, P., Hassani‐Bafrani, H., Tavalaee, M., Dattilo, M. and Nasr‐Esfahani, M.H. (2018), One‐carbon cycle support rescues sperm damage in experimentally induced varicocoele in rats. BJU Int, 122: 480-489. doi:10.1111/bju.14385
4. Gallo, A., Menezo, Y., Dale, B. et al. Metabolic enhancers supporting 1-carbon cycle affect sperm functionality: an in vitro comparative study. Sci Rep 8, 11769 (2018). https://doi.org/10.1038/s41598-018-30066-9
Dear Dr. Kawada,
Thanks for your comment on our article, Shift work and burnout in police officers: a risk assessment. We appreciate that the risk of burnout may be multi-factorial and the relative contribution of each factor may vary by occupation. We did not examine work-related stress and conflict but appreciate that such factors may contribute to burnout risk in police officers. We maintain, however, our findings that sleepiness, inadequate sleep, irregular schedules, mandatory overtime, long shifts and night shifts are factors associated with elevated burnout risk in this population. We also controlled for age in our analyses and found that age was significant in the adjusted models examining shift work, sleep and their association with Depersonalisation and Personal Accomplishment. We agree that more research into the factors contributing to burnout and programs to mitigate it in safety-sensitive shift working occupations is necessary.
Sincerely,
Scott A Peterson, Alexander P Wolkow, Steven W Lockley, Conor S O'Brien, Salim Qadri, Jason P Sullivan, Charles A Czeisler, Shantha M W Rajaratnam and Laura K Barger
Peterson et al. examined associations between shift work and burnout in 3140 police officers with special reference to sleep duration and sleepiness. The Maslach Burnout Inventory, shift schedules (irregular, rotating, fixed), shift characteristics (night, duration, frequency, work hours), sleep duration and sleepiness were used for the analysis. Adjusted odds ratios (ORs) (95% confidence intervals [CIs]) of long shifts and mandatory overtime for emotional exhaustion were 1.91 (1.35 to 2.72) and 1.37 (1.14 to 1.65), respectively. Adjusted OR (95% CI) of night shifts for depersonalisation was 1.32 (1.05 to 1.66). In addition, Adjusted ORs (95% Cis) of irregular schedules for emotional exhaustion and depersonalisation were 1.91 (1.44 to 2.54) and 1.39 (1.02 to 1.89), respectively. Furthermore, adjusted ORs (95% Cis) of sleeping <6 hours and excessive sleepiness for motional exhaustion were 1.60 (1.33 to 1.93) and 1.81 (1.50 to 2.18), respectively. I have a comment about their study.
Ogundipe et al. determined factors burnout among 204 medical doctors undergoing residency training. General Health Questionnaire (GHQ-12) and Maslach Burnout Inventory (MBI) were used for the analysis. Adjusted OR (95% CI) of call duty as being not stressful for emotional exhaustion was 0.52 (0.29, 0.97). In contrast, adjusted OR (95% CI) of emotional distress, based on GHQ score of ≥3, for emotional exhaustion was 6.97 (3.28, 14.81). In addition, adjusted OR (95% CI) of absence of doc...
Show MoreHopefully this will become an invaluable study. Can I alert the authors to the role of nearness to death (the nearness to death effect) in both cognitive and functional decline especially in the last year of life.
In the references you cite, the definition of multimorbidity is showed as the co-existence of two or more chronic conditions, where one is not necessarily more central than the others. But you have defined multi-morbidity comorbidity as the presence of two or more chronic health conditions in an individual. Does your definition indicate comorbidity?
To the editor:
In response to the article titled “Incidence and risk factors of retinopathy of prematurity in Korle-Bu Teaching Hospital: a baseline prospective study.” published in your esteemed journal, I would like to raise a few points regarding this study. This is a well thought of and written paper which demonstrated that birth weight less than 1.5 kg, confirmed neonatal sepsis, nasogastric tube feeding and poor pupil dilation were independently associated with increased incidence of ROP. ROP screening should be a part of the routine service for premature infants in Ghana. (1)
Retinopathy of prematurity (ROP) has a prevalence of 6 to 18% as one of the main causes of vision loss in childhood worldwide (2). Early diagnosis is of fundamental importance to avoid sequelae associated with this disease. However, we have a lack of trained professionals for the proper screening and monitoring of this disease. In addition, studies have shown that there may be a discrepancy in the diagnosis of this pathology among the specialists themselves. (3)
Show MoreDue to this difficulty in monitoring, new technologies can be developed to assist in early diagnosis and monitoring, avoiding this important cause of childhood blindness. There are devices such as Retcam that can assist in telemedicine monitoring. This device has a high cost that can be compensated with the development of technologies that allow the registration of newborn images with smartphones, facilitating documen...
We thank Drs Müller and Shukri(1) for their interest in our recent publication in BMJ Open entitled “Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark”(2).
We agree with the authors, that clarity and transparency are crucial when reporting research in order to interpret findings. Below we have responded to each of the two comments given by the authors.
First, while Table 2 and 3 of our publication reflects the actual, observed cost and health utilities, the incremental cost and health utilities presented in table 4 is estimated based on the regression analyses2. As such you cannot go directly from the numbers in Table 2 and 3 to the results in Table 4 without the parameters used for the regression. In order to ensure full transparency, please see the parameters used for the primary regression analyses in the new Table 1 below.
Table 1: https://blogs.bmj.com/bmjopen/files/2020/08/eLetter-Table-1-full-3.jpg
Second, during follow-up, three persons died in TKR plus non-surgical treatment group, while one person in the non-surgical treatment only group died. We decided to exclude the four persons who died from the primary analyses as we had no reason to believe that either of the treatments would be associated with an increased risk of dying and as including deaths...
Show MoreIt is of interest to note that risk of infection is associated with population density in this study. My research indicates that weighted population density is associated with higher SARS-CoV-2 deaths in US states, in UK local authorities and sub-local authority geographies [1,2]. This is an entirely logical association.
References
1. Jones R. Would the United States have had too few beds for universal emergency care in the event of a more widespread Covid-19 epidemic? IJERPH 2020; 17: 5210. https://doi.org/doi:10.3390/ijerph17145210
2. Jones R. How many extra deaths have really occurred in the UK due to the Covid-19 outbreak? XIII. Population density and risk of Covid-19 death. DOI: 10.13140/RG.2.2.23027.35365
Dear Dr Aldcroft,
We read with interest the paper entitled “Efficacy and safety of the pulsed electromagnetic field in osteoarthritis: a meta-analysis”.1 This paper concluded that “PEMF could alleviate pain and improve physical function for patients with knee and hand [osteoarthritis] OA, but not for patients with cervical [osteoarthritis] OA.” We have a few concerns with their conclusion.
The first concern is that the review reports very large effect sizes for some trials,2-5 but does not alert the reader to how atypical these results are. For example, Figure 3 of the manuscript1 contains three examples of effect sizes of ~3 and 4 standardised mean difference (SMD). Effect sizes this large are usually a red flag that something is amiss, either with the results of the review or the original trial. Unfortunately, both problems are present.
The review reported a SMD for the Nelson trial5 of -3.72; but this a mistake. The authors have confused the standard deviation (SD) with the standard error (SE) and when their error is corrected the true effect size is -0.74 [95% confidence interval (CI) -1.44 to -0.04] compared with -3.72 [95% CI -4.88 to -2.56] reported in the review. The correction also changes the pooled effect to -0.33 [-0.70 to 0.04] and would support the conclusion that the treatment is not effective for knee OA.
The other two large effect sizes are driven by outcomes in the treatment group and no change in the control group.2,3 For...
Show MoreAltschul et al. conducted a prospective study to investigate the association between blood pressure (BP) and cognitive functions across the eighth decade (1). Women with higher early-life cognitive function had lower BP during the eighth decade. In addition, prescribed antihypertensive medication was closely associated with lower BP, but antihypertensive medication had no effect on better cognitive function. Regarding no relationship between BP and cognitive decline, I have some concerns.
First, Ou et al. conducted a meta-analysis regarding the association between BP and cognitive impairment/dementia in prospective studies (2). The significant relationship of BP with cognitive impairment/dementia was observed in different BP variables, which were classified into midlife and late-life periods. In addition, prescribed antihypertensive medications exhibited a 21% reduction in dementia risk, which was different from data by Altschul et al. I suspect that long-term follow-up might change the relationship between BP and cognitive functions. Long survivors’ effect on BP and cognitive functions should be specified by further study.
Second, visit-to-visit variability in blood pressure was a significant predictor of subsequent cognitive decline in old subjects (3,4). But the association between BP variability and cognitive impairment was not mediated by BP lowering medication (5). As BP variables such as high systolic BP, low diastolic BP, excessive BP variability, and...
Show MoreWe would like to thank RJ Aitken for presenting his basic scientist view on our clinical trial.
His first comment addresses the fact that we include “idiopathic infertility patients irrespective of their redox status “. He suggests that we should only include patients with proven oxidative stress. We would like to respond that, of course, we would prefer to follow his advice, on the condition that validated test are available to differentiate between men that do suffer (constantly) from oxidative stress and those that do not, or that are even at risk for reductive stress. If we could all agree on the reliability of such tests, then it would certainly be worthwhile to try and get additional funding for pre- and post-therapy testing in (a subset of) our patients, then analyze them separately according to their redox status. Such an addition might provide a more solid basis for the antioxidant therapy. However, sperm DNA fragmentation tests are very costly and there is as yet no international consensus on which sperm DNA fragmentation test should be used as becomes obviously clear when reading the extensive review of the literature composed by Agarwal et al and the extensive discussion it awakened with more than 50 commentary letters published.(1,2) As to the danger of causing reductive stress, we think this is limited, as Impryl does not contain direct and strong scavenging antioxidants such as vitamin C and E, but rather focuses on the homocysteine pathway and the 1...
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