Comparative effects of vitamin K and vitamin D supplementation on prevention of osteopenia in calcium-deficient young rats
Authors: T Takeda
S Ichimura
Y Sato
J Iwamoto
J K Yeh
Journal: Bone (2003)
Discipline: CLINICAL MEDICINE
Keywords: Retracted article; Integrity of data; Authorship; Ethical approval; Co-authors
Affiliations: Department of Sports Medicine, Keio University School of Medicine, Tokyo, Japan. 

Abstract:  This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. The Journal has been made aware of concerns regarding the integrity of the data, authorship and ethical approval for this study. Despite repeated attempts to contact the co-authors we have been unable to confirm the authorship of this paper. 

Retracted: No

PubPeer comments:
 There are many concerns about the integrity of this publication. They were raised with the journal and publisher (which has now retracted several papers by the same authors) in August 2017 and again in March 2020. No response has been forthcoming. This paper is one of 6 published from the same study. None of the papers reports the parent study or acknowledges the multiple other publications. The other 5 papers have been retracted because of various concerns, which overlap with those that apply to this paper. In chronological order of submission for publication, the 6 papers are: A2, [this paper, submitted 13 5 03, revised 19 6 03, accepted 30 6 03] Iwamoto J, Yeh JK, Takeda T, Ichimura S, Sato Y. Comparative effects of vitamin K and vitamin D supplementation on prevention of osteopenia in calcium-deficient young rats. Bone 2003;33:557-66. A6 [submitted 5 8 03, accepted 19 1 04, online 17 3 04] Iwamoto J, Yeh JK, Takeda T, Sato Y. Effects of vitamin D supplementation on calcium balance and bone growth in young rats fed normal or low calcium diet. Horm Res 2004;61:293-9 Retracted May 2019 u2013 as a u201cresult of concerns about data integrity and scientific misconduct, which have been brought to our attentionu201d A4 [submitted 6 8 03, accepted 26 1 04] Iwamoto J, Takeda T, Ichimura S, Sato Y, Yeh JK. Differential effect of vitamin K and vitamin D supplementation on bone mass in young rats fed normal or low calcium diet. Yonsei Med J 2004;45:314-24 Retracted Jan 2019 u2013 u201ca number of issues related to data duplication and scientific misconductu201d A5 [submitted 19 1 04, accepted 30 3 04] Iwamoto J, Takeda T, Sato Y, Yeh JK. Response of cortical and cancellous bones to mild calcium deficiency in young growing female rats: a bone histomorphometry study. Exp Anim 2004;53:347-54. Retracted March 2019 u2013 u201cbecause some parts of (the) contents were published elsewhereu201d A8 [submitted 28 4 04] Iwamoto J, Yeh JK, Takeda T, Sato Y. Comparative effects of vitamin K and vitamin D supplementation on calcium balance in young rats fed normal or low calcium diets. J Nutr Sci Vitaminol (Tokyo) 2005;51:211-5 Retracted Feb 2019 u2013 u201cbecause some parts of (the) contents were published in other journalsu201d A9 [submitted 8 9 04, accepted 8 3 05, online 9 5 05] Iwamoto J, Yeh JK, Takeda T, Sato Y. Effects of vitamin K2 administration on calcium balance and bone mass in young rats fed normal or low calcium diet. Horm Res 2005;63:211-219 Retracted May 2019 u2013 as u201ca result of concerns about data integrity and scientific misconductu201d Concerns about the integrity of this paper (A2): 1. Authorship Drs Iwamoto and Sato engaged in systematic gift authorship between 2002 and late 2013. Statements by both Dr Sato and Dr Iwamoto (seen by multiple editors and publishers, including those at Bone Elsevier). acknowledge that neither was involved in research published by the other. In Dr Satou2019s affidavit, he specifies he was a gift author on this Bone paper. This authorship problem has prompted contributed to retractions of several publications, including those in Bone, eg Bone 2005;36;721-726. Dr Ichimura was a co-author on 2 papers (this one and A4), but not on the other 4 papers u2013 why was that? 2. Study conduct The study was performed at Winthrop-University Hospital in the United States, and published in 2003-4. But Dr Iwamoto returned to Japan from the United States in 1999. When was the study performed? Who did the considerable amount of work required? What contributions did Drs Ichimura and Takeda (based in different areas of Japan) make to the work? 3. Implausible animal data Female 4-week old Sprague Dawley rats were purchased from Hilltop labs for the study, fed a standard chow for 2 weeks, then randomized to study interventions. So at study baseline they were 6 weeks old. The mean baseline body weight of 115g (see Table 1) is implausibly low. Data from Hilltops Laboratories website (http: www.hilltoplabs.com public sdgrowth.html) indicates a mean of 165g, SD 10g for rats of that strain, gender and age. Thus, the mean baseline weight of the rats reported in the Bone paper is about 5 SDs below that expected. This is wholly implausible. 4. Duplicate data reporting and text duplication The amount of duplicate data reported between this paper and each of the other 5 papers ranges from 63% to 79%. The proportion of sentences in the Introduction and Discussion sections of this paper that share at least 50% of the words with a sentence in the same sections of each of the other 5 papers ranges from 21% to 64%. 6. Methodology discrepancies and concerns In this paper, why did only 8 rats in each group undergo calcium balance studies? In A5 u201cpair feeding was appliedu201d. It is not mentioned in this or any of the other papers. In A5, frontal sections of the proximal tibia were cut at 5u00b5m. In this paper (and the other papers) they were cut at 8u00b5m 7. Major data analysis discrepancies In this paper, Table 5, the mean and SD for food intake in g d are identical to the values for calcium intake in mg d in the LC, LCD, LCK and LCKD groups. In this paper, Figure 1, top right panel, the mean values for Tb.N mm are 4.5-6 for NC, LC and LCK. In A9, Figure 1, top right panel, the mean values for Tb.N mm is 175-225 for NC, LC and LCK. In this paper, Figure 1, bottom right panel, the mean values for Tb.Sp are 200-250u00b5M for NC, LC and LCK. In A9, Figure 1, bottom right panel, the mean values for Tb.Sp are 4.5-6u00b5M for NC, LC and LCK. 8. Other data analysis concerns In this paper Table 1, the SD for NC femoral length is much higher than that in the other groups In this paper Table 1, the femoral length for BLC is shown as being significantly different from itself (superscript a) In this paper Table 1, It seems very unlikely that LCKD femoral bone density (1.262 u00b1 0.016) is significantly different from that in LCD (1.245 u00b1 0.015, superscript e). 9. Funding No funding statement is provided for a large and complex study with several interventions and a very large number of endpoints This paper cannot be regarded as reliable. , 
 These integrity concerns remain unresolved, 5 years after the journal was notified. in January 2022 the editor indicated that the matter is now in the hands of the Elsevier Ethics group. Elsevier staff do not respond to requests for an update. On 22 February 2022 the matter was raised with COPE, which did not reply. , 
 Correction: On 20 January 2022 an Elsevier staff member indicated that she was awaiting the advice of the ethics team . ,