Letters to the Editors: Authors’ Response

• Pınar ^[1] ; Nejat ^[2] ; Özgün ^[3] ; Nurcan ^[4] ; Ayşe ^[5]
  1. [1] Gümüş
  2. [2] Nizam
  3. [3] Özçaka
  4. [4] Buduneli
  5. [5] Nalbantsoy

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• Localización: Journal of periodontology, ISSN 0022-3492, Vol. 86, Nº. 4, 2015, págs. 486-488
• Idioma: inglés
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  • We appreciate the opportunity to respond to the letter by Drs. Agilli, Aydin, Cayci, and Kurt. The authors raise some methodologic points to be clarified regarding our study.1 We thank the authors for their critical reading, and we believe this letter, written by four MDs from departments of biochemistry, clearly emphasizes the importance of collaboration between clinical and laboratory branches since laboratory findings may not provide the whole clinical picture and vice versa. A more holistic approach is expected to combine the clinical and laboratory data as much as possible.

    The authors suggest selecting participants for our study after simple laboratory tests such as C-reactive protein (CRP) and erythrocyte sedimentation rate. We strongly disagree with them on this point because such a methodology would create bias and lead readers to biased data. Moreover, CRP is a component of the pentraxin superfamily,2 and it is already stated in our manuscript that circulating CRP levels have been reported to be associated with periodontal disease3,4 and that significantly higher CRP levels were found in a group of patients with aggressive periodontitis (AgP) compared to a group with chronic periodontitis,4,5 possibly arising from the rapid rate of disease progression in AgP.6 Therefore, we believe a meticulous patient history is more reliable for unbiased study outcomes.

    The authors refer to a study that suggests dietary supplements such as omega-3 fatty acid, vitamin D, vitamin A, and vitamin E could affect pentraxin-3 (PTX3) levels.7 However, the study by Røsjø et al.7 was accepted for publication on March 17, 2014, whereas the date of acceptance for our study was July 17, 2013, and it was published in March 2014. Therefore, the data published by Røsjø et al. can be of use for studies planned or at least conducted/continued after March 2014. Furthermore, the authors of the letter refer to a study by Bailey et al.8 reporting the frequency of dietary supplement use as 49% in the United States population. Every population/race has its own dynamics and characteristics, including dietary habits. Therefore, each study deserves to be judged within the realities of the particular ethnic population involved in the study. Although we could not find a study reporting the prevalence of dietary supplement usage in the Turkish population, it is estimated to be much lower than that in the United States.

    In their letter, Agilli et al. report that obesity is another confounding factor for PTX3 measurement and suggest defining body mass indexes of the participants. However, they refer to a study that was published in May 2014,9 which is 2 months later than our study was published. To the best of our knowledge, there was no published study such as this one when our manuscript was written or even accepted for publication. Therefore, even though these studies provide evidence against published studies or blur published data, they can only enlighten the pathway for future studies rather than being used as a background to discuss previously published studies.

    It is also stated that matching sex between the study groups is of utmost importance because Yamasaki et al.10 reported significant differences between the sexes in PTX3 levels. Contrary to that study, Kume et al.11 found similar circulating PTX3 levels in males and females, and we believe that at present there are not enough studies to draw conclusions about such a relationship since the published data are conflicting. As already stated in our paper, the individuals in the healthy control group were free of any periodontal disease, and few of them volunteered for blood sampling. Therefore, serum analysis could not be performed in this group.

    Science is an ever-evolving field, and facts can significantly change in time. Furthermore, a biomarker requires truly strong evidence coming from numerous studies and preferentially should be verified in hundreds of patients/individuals before being termed a biomarker.12 Chronic conditions such as cardiovascular diseases have similar complexity as periodontal diseases, and despite the application of even greater expenditure and manpower, recent reports reveal that previously lauded vascular risk factors such as CRP and N-terminal proB-type natriuretic peptide are, in fact, not useful.13 In the case of PTX3, it is still too early to conclude not only whether it is affected by parameters like sex, dietary supplements, or various systemic diseases but also the nature of the possible effects. At present, the published data are conflicting, and we look forward to further studies to better clarify functions of PTX3 as well as its complex interactions with various demographic parameters.

    The authors report no conflicts of interest related to this letter.