Is autophagy rather than apoptosis the regression driver in imatinib-treated gastrointestinal stromal tumors?
Authors: Tiziana Negri
Elena Conca
Marco A Pierotti
Marco Fiore
Alessandro Gronchi
Elena Fumagalli
Paolo G Casali
Francesca Miselli
Silvia Brich
Elena Tamborini
Silvana Pilotti
Marco Losa
Journal: Translational Oncology (2008)
Discipline: CLINICAL MEDICINE
Keywords: apoptosis; autophagy; imatinib-treated; gastrointestinal stromal tumor (GIST); beclin1
Affiliations: Experimental Molecular Pathology Unit, Department of Pathology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Abstract:  Although apoptosis (programmed cell death type I) is more frequently reported in the literature in imatinib-treated gastrointestinal stromal tumor (GIST) cell lines,morphological features consistent with autophagic changes aremore often encountered in surgical specimens of treated patients. Autophagy (programmed cell death type II) is highly regulated by a tumor-suppressor mechanism that mainly involves the genes beclin1, PI3KIII, and bcl2. Being our material not suitable for electron microscopy analysis (not paraformaldehyde-glutaraldehyde-fixed), we evaluated the morphological, biochemical, and immunophenotypical profiles expected to be related to autophagy and apoptosis in a series of surgically resected samples taken from 11 imatinib-treated patients with molecularly characterized GISTs. The samples were examined for imatinib-induced morphological changes, the presence/interactions of the autophagic-related proteins (beclin1, PI3KIII, bcl2, and LC3-II) and the presence of apoptosis-related proteins (caspase 3, caspase 7, and lamin A/C) by means ofWestern blot analysis and coimmunoprecipitation, complemented by immunohistochemistry. We also studied samples of two untreated GISTs used as controls. Sampling areas with different residual cellularity scores fromboth the imatinib-treated and untreated patients showed biochemical and immunohistochemical evidence of high levels of proautophagy beclin1/PI3KIII and low levels of antiautophagy beclin1/bcl2 complexes, together with the presence of LC3-II detected by Western blot analysis, thus supporting the presence of autophagy. There was no expression of cleaved/activated caspase 3 or 7 or cleaved lamin A/C. Our descriptive results support the idea that GISTs activate autophagy rather than apoptosis in response to imatinib treatment and that their molecular makeup includes fingerprints of autophagy. 

Retracted: No

PubPeer comments:
 This appears to be a very limited study focussing on some aspects of women s use of time but not on others, written by people with conflicts of interest that might not be obvious to most readers. The paper concludes that from 1965-2010 women gradually spent less time and burned fewer calories doing  household management tasks (e.g., cooking, doing dishes, vacuuming, laundry), while at the same time spent gradually spent more time looking at a screen (TV, computer), with a small increase in leisure-time physical activity (LTPA). Here are the graphs that show their results.  Here are my concerns about this paper (prompted by a Twitter thread by Cecile Janssens here: https: twitter.com cecilejanssens status 1217232909914058753 * This paper portrays women as either doing household work or watching television. There is nothing about how much time women spent at work, which presumably increased from 1960s-2010. This is a very sexist view of what women might be doing all day. * The paper only focuses on household work as if this was the only way a woman moves. The authors did not look into e.g. biking as a way to commute to work, physical activity as part of her job, or the calories she might burn while doing house maintenance, gardening, or sweating on her Peloton bike while watching a screen. All of these factors are likely to have changed from the 1960 to 2010. * There were much fewer screens back in the 1960s (no computers, phones, much fewer TVs and much fewer programs), so it is not unexpected that  screen time went up from 1960-2010. Why did the authors not include other activities that also included quiet sitting, such as reading, knitting, or doing a crossword? That might have given a very different graph. This data was available, but focusing on screens only might have given a very skewed view. * The authors goal of the paper (as per introduction) is to investigate risk factors of obesity. So while we can agree that physical activity doing household chores might be one contributing factor to the increase in average weight in the past decades, other physical activities (mentioned in the previous bullet pointz) and, most importantly, dietary intake, have not been part of this investigation. Diet is an obvious player in obesity, so this is a huge confounding factor that appears to be very much ignored, and that is related to the conflicts of interest mentioned in the next bullet point. The omission of dietary changes from 1960-2010 is regrettable, and should have been mentioned in the limitations for this study. * Several authors have conflicts of interests that (although disclosed) make it more likely that they will earn money using the results of this paper. In particular, several have received money ( unrestricted research funding  ) from Coca-Cola, who could use the results of the study to dismiss that the consumption of sugary drinks has anything to do with obesity. I d love to hear the authors reaction to my thoughts. , 
 Dear Ms. Bik, It is customary in scholarly discourse to read and attempt to understand an entire paper, and not merely the abstract, prior to commenting. To begin, this paper (Archer et al. 2013) was the second in a series. The first paper (Church et al. 2011) examined trends in occupation-related physical activity and energy expenditure (EE). We explicitly cited our prior work and its conclusions throughout the paper. For example, below is a quote (from Archer et al 2013): u201cIn 2011, Church et al., examined occupational EE via US Bureau of Labor Statisticsu201d surveys that included data on employment and earnings from more than 140,000 businesses, government agencies and 440,000 individual worksites, and found a significant decreasing trend over the past 50 years. They concluded that the reduction in this single domain of PA may account for a considerable portion of the increase in mean body weights for men and womenu201d. Additionally, we used employment status to examine differences in EE between  employed and  non-employed women. Thus, your comment u201cThere is nothing about how much time women spent at worku201d is misguided due to a lack of research due diligence. Second, it is important to note that there is a large and significant difference between the amount of time spent at performing various activities and the amount of energy expended during those activities. In our methods, we explicitly stated that we u201cexamined 90 subcategories of daily activityu201d inclusive of u201cexerciseu201d [and] u201cour final analyses included only those activities that significantly affected total daily EE over the 45-year period.u201d Once again, your comments stating that u201cother physical activitiesu201d were not u201cpart of this investigationu201d is uninformed and false. Third, we explicitly addressed dietary energy intake data in multiple sections. For example, please see u201cthe lack of reliable data on population-level EI [energy intake]u2026u201d, u201cEnergy intake and obesityu201d, and u201cData on population-level trends [on energy intake]; and u201cEnergy Balance, Obesity and Health.u201d Thus, your comment that we u201cignoredu201d or u201comittedu201d dietary intake is simply uninformed and false. More importantly, our recent papers in this series (see references below) demonstrated that your comment that u201cDiet is an obvious player in obesityu201d is emblematic of u201cDiet-Centrismu201d and the fictional discourse on diet-disease relations that has prevented progress in obesity. What is u201cobviousu201d is that eating and drinking do not cause obesity; rather, it is what oneu2019s body does with what was consumed (i.e., nutrient-partitioning). For details, please see: Archer et al. Cell-Specific u201cCompetition for Caloriesu201d Drives Asymmetric Nutrient-Energy Partitioning, Obesity, and Metabolic Diseases in Human and Non-human Animals. Frontiers in Physiology. 2018;9(1053). Link: https: www.frontiersin.org articles 10.3389 fphys.2018.01053 abstract Fourth, your comments about alleged conflicts of interest and sexism are irrelevant to the rigor and validity of our results and conclusions. If I say 2+2= 4, it is correct regardless of my funders. Thus, comments about alleged conflicts and biases are simply unscientific and irrelevant because they do not critique the methods, results, or conclusions. Thus, your Ad hominems (personal attacks) are fallacious and emblematic of the ubiquitous and childish u2018Cancel Cultureu2019 on social media. Since it is always easy to attack the scientists when you cannot offer valid critiques of the research, specious Ad hominems do not belong on PubPeer and merit no further response. Finally, anyone interested in our refutations of u2018diet-centrismu2019 and the etiology of the obesity and cardio-metabolic diseases epidemics should read our entire series of papers (below). I sincerely appreciate (informed) criticism and look forward to a continuation of the (scientific) discourse with those who take the time to perform at least the minimum of research due diligence and read our work. 1)tChurch TS, Thomas DM, Tudor-Locke C, et al. Trends over 5 decades in U.S. occupation-related physical activity and their associations with obesity. PLoS One. 2011;6(5):e19657. 2)tArcher E, Shook RP, Thomas DM, et al. 45-Year Trends in Women s Use of Time and Household Management Energy Expenditure. PLoS One. 2013;8(2):e56620. 3)tArcher E, Lavie CJ, McDonald SM, et al. [Maternal Inactivity: 45-Year Trends in Mothersu2019 Use of Time. Mayo Clinic Proceedings. 2013;88(12):1368-1377. Link: https: www.mayoclinicproceedings.org article S0025-6196(13)00828-8 fulltext 4)tArcher E. The Childhood Obesity Epidemic as a Result of Nongenetic Evolution: The Maternal Resources Hypothesis. Mayo Clinic Proceedings. 2015;90(1):77-92. Video: https: www.youtube.com watch?v=jO3vIJpzZV8 Paper: http: www.mayoclinicproceedings.org article S0025-6196(14)00740-X fulltext 5)tShook RP, Hand GA, Drenowatz C, et al. Low levels of physical activity are associated with dysregulation of energy intake and fat mass gain over 1 year. The American Journal of Clinical Nutrition. 2015. 6)tArcher E. In Defense of Sugar: A Critique of Diet-Centrism. Progress in Cardiovascular Diseases. 2018;61(1):10-19. Link: https: www.sciencedirect.com science article abs pii S0033062018300847?via%3Dihub 7)tArcher, E., Lavie, C. J. Hill, J. O. The Failure to Measure Dietary Intake Engendered a Fictional Discourse on Diet-Disease Relations. Frontiers in Nutrition 5, doi:10.3389 fnut.2018.00105 (2018). Link: https: www.frontiersin.org articles 10.3389 fnut.2018.00105 full 8)tArcher, E., Marlow, M. L. Lavie, C. J. Controversy and Debate: Memory-Based Methods Paper 1: The Fatal Flaws of Food Frequency Questionnaires and other Memory-Based Dietary Assessment Methods. Journal of Clinical Epidemiology 104, 113-124, doi:https: doi.org 10.1016 j.jclinepi.2018.08.003 (2018). Link: https: linkinghub.elsevier.com retrieve pii S0895-4356(17)31375-6 9)tArcher E, Lavie CJ, Hill JO. The Contributions of u2018Dietu2019, u2018Genesu2019, and Physical Activity to the Etiology of Obesity: Contrary Evidence and Consilience. Progress in Cardiovascular Diseases. 2018;60(July August). Link: https: www.sciencedirect.com science article abs pii S0033062018301087?via%3Dihub 10)tArcher E, Pavela G, McDonald S, Lavie CJ, Hill JO. Cell-Specific u201cCompetition for Caloriesu201d Drives Asymmetric Nutrient-Energy Partitioning, Obesity, and Metabolic Diseases in Human and Non-human Animals. Frontiers in Physiology. 2018;9(1053). Link: https: www.frontiersin.org articles 10.3389 fphys.2018.01053 full Sincerely, Edward Archer PhD., MS , 
 Thank you for your views, Dr. Archer, and the long list of self-citations, which suggest that your hypothesis might not take into account other scientists views or works. Some reactions: You wrote:  your comments about alleged conflicts of interest and sexism are irrelevant to the rigor and validity of our results and conclusions. If I say 2+2= 4, it is correct regardless of my funders. Thus, comments about alleged conflicts and biases are simply unscientific and irrelevant because they do not critique the methods, results, or conclusions. Conflicts of interest are very much relevant to hypotheses and conclusions. Instead of stating a simple fact like  2+2= 4 , the paper analyzes data and describes a hypothesis that could fit the interests of the sponsors. You also wrote in #2 that  your Ad hominems (personal attacks) are fallacious and emblematic of the ubiquitous and childish u2018Cancel Cultureu2019 on social media. Since it is always easy to attack the scientists when you cannot offer valid critiques of the research, specious Ad hominems do not belong on PubPeer and merit no further response . My concerns are about the paper and conflict of interest, not about persons. Your reply and salutation might be interpreted as more personal and denigrating than my concerns about the paper in #1. Sincerely, Elisabeth Bik, PhD , 
 Some comments on the rigour of the methods and the validity of the conclusions. 1) No data has been presented in this study to relate weight of the respective groups back to the presented data. It is therefore not possible to draw conclusions as to the effect of the suggested decrease in EE to weight gain. This also means that there was no statistical analysis done to establish if an actual measurable correlation exists between the two variables. As a result, the statement  This growing body of research suggests that the rise in bodyweight and obesity may be due to decreases in PA alone. is unfounded as no analysis on this was actually presented in this study or, as far as I can see, in the cited studies. 2) The authors do not present an estimate for EE during working hours. Considering part of the conclusion of the article is that increase in full-time work amongst women has led to a decrease in overall EE, the absence of data on EE during work hours is highly conspicuous. The only mention of this appears in the discussion wherein the authors state  This shift from more active (i.e., energetically costly) activities such as HM to more sedentary occupational activities has an obvious impact of energy expenditure and health. . In addition to this, the cited article (reference #30) relating to Occupation Related Daily EE (ORDEE) indicates a current average ORDEE for full-time employed women of ~1200 calories day. Over a five day work week this would amount to 6,000 calories. The estimated EE week during HME in this study for an unemployed woman in the 1960s was 6,004 calories week. If you correct to the same amount of time, then in the 33.1 hrs an unemployed woman in the 1960s doing HM would burn 6,004 kcal, a full-time employed woman in the present day would burn 2,182 kcal in 10.4 hrs of HM and a further 3,891 kcal in 22.7 hrs of full-time work for a total of 6,074 kcal 33.1 hrs. Correcting for weight as well results in a deficit for a present day woman of ~714kcal wk (3,246 kcal work, 1,892 kcal HM). However, this doesn t take into account the additional 2,108 kcal (at 75kg, 1758 kcal at 65kg) of EE during the remaining minimum 12.3 hrs per week of time spent at work. Assuming an unemployed woman in the 1960s spent the remainder of this time in low intensity METs (1.9 [1]) activity the expected EE would be 1,519 kcal. This brings the difference down to ~475 kcal wk assuming both women weigh 65kg. The authors estimated increase in LPTAEE was 460 kcal wk at 75kg which corresponds to 351 kcal wk if both women are 65kg. This gives us a final discrepancy of ~124 kcal wk for a woman weighing 65kg which would correspond to less than 1kg weight gain over the course of a year assuming a woman of average height (160cm). Based on the data presented in both this study and the cited study (#30), it therefore would be expected that a woman in full-time employ today would have an EE week slightly lower than if they were unemployed in the 1960s. Even assuming the author s numbers are all valid the difference in weekly EE would only amount to 1kg weight gain in a year for an average woman at 160cm and 65kg, and this weight gain would not continue unless further caloric surplus came about. This is also only true when comparing the 2010 data to the 1960s data, which is where the highest discrepancy in EE is evident. The assertion that a trend towards more women in full-time employ means a decrease in EE and therefore weight gain for those women that enter the work force is not supported by the data presented. 3) The measurements of LTPA assume a constant METs of LTPA over the decades, which does not seem likely. I understand this data is likely not available but this represents a significant limitation of the analyses which wasn t mentioned. The cited articles for the assertion that  Walking (2u20134 METs) accounted for the vast majority of LTPA in the AHTUS and US population do not contain estimates of time spent walking vs total time spent exercising as far as I can see. The closest statements I found to support this were  We estimated that nearly 4 in 10 U.S. adults walked for exercise in 1998, and that for most walkers (57.6%), this was their only LTPA. in reference #42 and  over 54.5% of adults in the U.S. who are active in their leisure-time reporting that they walk in reference in #41. Reporting a METS of 4.5 for LTPA as being liberal seems a stretch as even assuming 75% of LTPA is walking (3.2 METs at 5km h [1]), if 25% of that time is a higher intensity exercise such as jogging (9km hr METs 8.8 [1]) then the estimated METs would be 4.6. I don t believe an estimated METs of 4.5 can really be considered liberal in this case. In addition to the arguably conservative METs for LTPA, the METs for HMEE is, in my opinion, not as conservative as claimed by the authors. Housework generally has a much lower METs that 2.8, with light housework ~2, moderate 2.5, and heavy 3 [1]. For reference, cooking and dishwashing, which the authors decry the downfall of in their discussion, respectively have METs of 2.5 and 2.1 [1]. As a result it is likely that the HMEE estimates the authors have arrived at are overestimates, just as their LTPA estimates are likely underestimates. 4) The authors suggest a relationship between reduced HMEE and increased obesity rates. However, based on the author s presented data, average HMEE has been static at approximately 2,800 calories wk since the 1990s. According the the US NIH statistics on obesity, rates of obesity have increased significantly since the 1980s and  More recently, between 2005- 2014, the prevalence of overall obesity and extreme obesity increased significantly among women, however, there were no significant increases for men. [2]. Given that the author s presented HMEE estimates and LTPA estimates have been constant over this time period the assertion of the author s that the decrease in HMEE is associated with an increase in obesity is called further into question, particularly given the absence of any statistical analysis to determine a correlation between the two. It is clear that modern society has trended towards a more sedentary lifestyle, which has no doubt contributed to the rise in obesity. However for the authors to claim  This growing body of research suggests that the rise in bodyweight and obesity may be due to decreases in PA alone. when the caloric discrepancy from their own set of data relating to HMEE is only ~124 kcal wk even when corrected for body weight is simply not supported by the evidence provided. Regarding the comments on conflict of interest. The author s conflict of interest is relevant, despite what Dr. Archer asserted in his response to Dr. Bik. From the data presented in this study it cannot be concluded that a woman in the present day working full-time would experience a significant weight gain due to reduced time spent doing HM compared to an unemployed woman in the 1960s as my calculations demonstrate. This is despite the authors using arguably liberal estimates for HM METs and conservative for LTPA METs (regardless of their claims to the contrary) as I outlined above. The statement  If I say 2+2= 4, it is correct regardless of my funders. is a strawman. In reality the authors have said  If I assume 2 is 3 and 3 is basically 4 then obesity is caused by women doing less housework . This is a conclusion that clearly suits the company funding the study (Coca-Cola) and which is not supported even by the author s own presented data. Regards, J Hamm 1. M. JETTE. K. SIDNEY. G. BLUMCHEN Metabolic Equivalents (METS) in Exercise Testing, Exercise Prescription, and Evaluation of Functional Capacity, *Clin. Cardiol.* 13, 555-565 (1990) 2. Overweight Obesity Statistics, NIH-NIDDKD, https: www.niddk.nih.gov health-information health-statistics overweight-obesity, August 2017, Accessed 22 01 2020 , 
 A further comment on why Dr Bik flagging the COI is not an ad hominem attack. Dr Archer and colleagues have submitted several PubPeer comments and BMJ Rapid Responses over the years on nutritional epidemiology papers. These comments have usually been welcome exposures of low standards of rigour and uncertainty of data collection in research that needed to be held to a higher standard. These authors have thus demonstrated that they have the ability to recognise and maintain a high standard of data collection and statistical interpretation in  energy in research. The concern around COI is thus that Dr Archer and colleagues appear to have applied different standards to  energy out , EE calculations [using grants from] Coca Cola, a company that has - independently of the work of Dr Archer and colleagues - used EE arguments to mute and distract from public health concerns about the results of research into the metabolic effects and nutritional value of their products and the ingredients they use. Coca Cola does not sell exercise, and it is always possible that a bad diet - as well as weight gain, if a bad diet can cause weight gain - tends to stop people from exercising, so that causality around EE is a complex problem and can only be determined by the results of experiments. Dr Archer and colleagues, in stating  Given the homeostatic nature of human behavior and energy physiology, and the fact that physical activity and body composition determine nutrient partitioning (i.e., the metabolic fate of the food we consume), we postulate that it is highly unlikely that the obesity epidemic is the result of superficial food economics. have failed to mention or cite a large body of experimental evidence into the differential effects of macronutrients, including sugar, on both nutrient partitioning and appetite control mechanisms. , 
 #4 Mr. Hamm, The science of obesity has progressed exponentially since we published the first paper in this series back in 2011. Thus, while your re-analysis of our data on womenu2019s EE might have been fodder for a short debate in 2011, it is now wholly irrelevant to scientific discussions of obesity and cardio-metabolic diseases. To be precise, over the past few years we demonstrated that the u2018energy-balanceu2019 paradigm was fatally flawed. We stated u201cthe restricted focus over the past five decades on energy expenditure rather than PA s [physical activityu2019s] effects on energy intake, metabolic control, and nutrient-energy partitioning was extremely misleading.u201d Please see: Archer E, Lavie CJ, Hill JO. The Contributions of u2018Dietu2019, u2018Genesu2019, and Physical Activity to the Etiology of Obesity: Contrary Evidence and Consilience. Progress in Cardiovascular Diseases. 2018;60(July August). Link: https: www.sciencedirect.com science article abs pii S0033062018301087?via%3Dihub Stated most simply, our thesis is thus: the demonstrated decline in womenu2019s PA over time (as per our studies) led to decrements in maternal metabolic control (e.g., sub-clinical insulin resistance). This pathological insulin resistance in concert with the naturally occurring insulin resistance of pregnancy altered the partitioning of nutrient-energy between mother and fetus; this resulted in irreversible metabolic alterations and life-long adipogenic nutrient-partitioning in children. The nongenetic evolutionary process by which a motheru2019s behavioral and metabolic characteristics alter her offspringu2019s phenotype is known as a maternal effect. And accumulated maternal effects caused (yes, u201ccausedu201d) the twin epidemic of obesity and T2DM. For details, please see: Archer E. The Childhood Obesity Epidemic as a Result of Nongenetic Evolution: The Maternal Resources Hypothesis. Mayo Clinic Proceedings. 2015;90(1):77-92. Video: https: www.youtube.com watch?v=jO3vIJpzZV8 Paper: http: www.mayoclinicproceedings.org article S0025-6196(14)00740-X fulltext And Archer E, Pavela G, McDonald S, Lavie CJ, Hill JO. Cell-Specific u201cCompetition for Caloriesu201d Drives Asymmetric Nutrient-Energy Partitioning, Obesity, and Metabolic Diseases in Human and Non-human Animals. Frontiers in Physiology. 2018;9(1053). Link: https: www.frontiersin.org articles 10.3389 fphys.2018.01053 full And for a very brief summary: Archer, E. The u2018fundamental questions of obesityu2019: asked and answered. (Atlas of Science 2019) Link: https: atlasofscience.org the-fundamental-questions-of-obesity-asked-and-answered Comments about conflicts of interest are merely uninformed personal attacks. Dr. Steven N. Blair, the senior author of our series of papers, first published his work demonstrating that physical inactivity was causal to (and not merely associated with) obesity and cardio-metabolic diseases back in the 1960s 70s. Thus, our hypothesis and initial conclusions were published 50 years before we acquired the industry funding that caused our alleged conflicts of interest. It is simply ignorant to state that funding that was obtained for replication studies in 2009-10 was causal to hypotheses and conclusions published five decades earlier. , 
 Dear scientists, this is an interesting topic. In addition to the comments already posted by others, I would like to raise a few issues that readers should consider, starting with a minor one: I. Logical fallacy The paper states:  The objective of this analysis was to examine 45-year trends in time-use, household management (HM) and energy expenditure in women. . Without commenting on how well or not the paper examines this hypothesis, in no way does this support the statement  that it is highly unlikely that the obesity epidemic is the result of superficial food economics. . As long as there is no further evidence, it should be assumed that both postulates are unrelated. II. Inaccuracy With respect to the estimate of energy expenditure, there are four sources of inaccuracy. 1. sample error. The paper states that it uses a complex sample and takes weighting into account. However, it is not explained whether this sample design has been considered, e.g. using specific software like SUDAAN or SPSS complex samples. 2. MET estimates. The paper takes very rough plug-in estimates for energy expenditure for certain activities into account, without any kind of analysis (e.g., what would be the result for different plug-ins). 3. Age distribution in the underlying population changed a lot between first and last epoch. Even though the authors used three age groups in an attempt to harmonize these changes, it is still likely that the data are biased. 4. The paper is based on diaries, and hence suffers from all bias associated with such self-reported data. For example, it is possible that the quality of the diaries changed between the first and the last epoch, in particular since there have been differences in diary technology and education level of participants. I also wonder how the participants considered competing activities, e.g. when vacuuming in a room where there was a screen running. This is much more likely these days than in 1960. The paper does not take these sources of inaccuracy into account. Instead, it always gives precise point estimates. It would be more valuable to have estimates that take these points into account. (PS: Mr. Hamm has analysed this point is much further detail. ) III. What is a  trend The paper states that it analsed trends. I did not find a definition of  trend in the paper, and no analysis that is typically used for trends. Instead, it only uses decade-to-decade changes. This is not a trend analysis. Even more, the visualization of the point estimates indicate that there was considerable change before 1990, and almost no change later. This hints at factors that the authors were not able to or reluctant to disclose. One such factor could be a change in coding. The authors state  Full time employment was 21 hr of paid work per week for 1965u20131990 and 35 hr week for 1990u20132010.  . Firstly, it is not explained why the authors changed the categories, and secondly, it is an inefficient and potentially biased use of data to categorize a metric variable. IV. Cause-effect The authors postulate that change in time spend on household management has an effect of obesity. However, they do not examine the question whether it could be the other way around: That weight gain has a negative effect on time spend for household activities. V. Confounding There is a large set of socio-economic factors that have an effect on weight. None of these are considered in this paper, except for a (very coarse) consideration of age and employment status. It is possible that these non-included socio-economic factors have changed over time. This would counfound the results. In conclusion, the results need to be validated using better data sources. IV. Lack of validation The authors did not validate their data. For example, it would have been possible to at least look into the data on men to check if the results (i.e., correlation between time spend on household management and obesity) are consistent. Another option would have been to cross-validate the estimates for the effect of time spend on household management using the cross-sectional samples. Another option would have been to compare against data from other countries. And the, in my opinion, best option would have been to look for longitudinal data sources (e.g., BHPS, SOEP, or a similar US data source). In conclusion, I thank the authors for conducting this interesting study and hope that my humble comments may be helpful to the occasional reader. Sincerely, Dr. Jens Hanisch , 
 Dr. Hanisch, While I am pleased that people continue to find our early work worthy of comment, I find it disquieting that many individuals neglect to familiarize themselves with the literature of the field. This lack of research due diligence may be a major driver of the publicu2019s lack of faith in u2018scienceu2019 to inform their daily lives. As such, I recently wrote a popular media article that anyone interested in research and science will find of interest: u2018The Intellectual and Moral Decline in Academic Researchu2019 Link: https: www.jamesgmartin.center 2020 01 the-intellectual-and-moral-decline-in-academic-research More to the point, scientific progress builds upon and extends (or refutes) prior work. As such, authors cite previously published research to alert readers to information that, while relevant and important, is beyond the scope (or space constraints) of the study or paper in question. Additionally, when talented investigators publish a paper, it is usually a stepping-stone to future (and hopefully improved) work. Thus, if one wishes to comment intelligently on the validity (or lack thereof) of a published study, it is essential to familiarize oneself with the prior and subsequent work of the authors and the references cited within. In other words, because science progresses by building upon or refuting past research, a comprehensive and competent literature review is an absolute requirement for an informed critique. Given this fact, it is apparent that you are not familiar with the literature on physical activity and obesity and cardio-metabolic diseases. If you were, you would know that your comments are either obvious, uninformed, misinformed, or irrelevant because they were addressed in detail in our text (e.g., our u201cLimitationsu201d section) or the papers we cited. For example, we stated that u201cit is highly unlikely that the obesity epidemic is the result of superficial food economics and provided over 20 in-text citations for support. We subsequently published nearly 40 papers providing u201cfurther evidenceu201d that u2018diet-centrismu2019 is an exemplar of nau00efve reductionism and physiologic illiteracy. Thus, your comment, u201cAs long as there is no further evidenceu2026u201d, is wholly nonsensical. If you had taken the time to perform a competent literature review before commenting, you would have known that we cited a voluminous amount of u201cfurther evidenceu201d both in our original paper and our subsequent body of work. As such, it is both presumptuous and illiterate to think that your lack of familiarity with the evidence is the equivalent of a lack of evidence. For those interested, u2018Diet-centrismu2019 is the conflation of u2018dietu2019 with nutrition and health. It is usually expressed via the nau00efve and unscientific ideas that u2018we are what we eatu2019 and that eating and drinking are causally related to obesity and cardio-metabolic diseases (as opposed to being merely necessary). Please see: Archer E, Lavie CJ, Hill JO. The Contributions of u2018Dietu2019, u2018Genesu2019, and Physical Activity to the Etiology of Obesity: Contrary Evidence and Consilience. Progress in Cardiovascular Diseases. 2018;60(July August). Link: https: www.sciencedirect.com science