Paper title: Thyroid Nodules in Centenarians: Prevalence and Relationship to Lifestyle Characteristics and Dietary Habits

Aim(s): To determine the prevalence of TNs in Chinese centenarians using high-resolution ultrasound equipment and investigate its relationship to lifestyles and dietary habits.

DOI: 10.20944/preprints201801.0138.v1

Review of Abstract, Title and references:

● The aim is clear ● They found a high prevalence of nodules in the Chinese centenarians and certain health conditions, gender and diet were a factor. They performed ultra sounds on all participants and did a detailed questionnaire for diet and health issues. ● The title if informative and relevant. ● References were relevant, most were from the last 10 years, and they were appropriate and associated with the study. References were well documented in the body of the study.

● The topic is clearly defined as the detection of Thyroid nodules in Chinese Centenarians in relation to dietary and lifestyle habits. ● The research question was not as clearly defined as it could have been in the introduction section. ● The background on thyroid nodule studies in the past showed several recent studies assessing the rate of TN by US and palpation indicating an increased risk in certain populations and with age, toxic exposure and poor lifestyle choices. They indicated a gap in literature with studies that focused on diet alone in the centenarian population of China. The study aimed to correlate certain dietary habits and to assess risk based on diet in this population. ● While the supporting studies showed a gap in literature, researchers studying this population alone may not be able to generalize to the entire population due to vast differences in diet and lifestyle choices. The amount of recent studies to support this theory were adequately shown.

● The sample selection was clearly defined. They began with 1002 study subjects from a previous study called the China Hainan Centenarian Cohort study. Subjects were chosen based on age alone in the Hainan province. 128 were excluded due to lack of relevant data and/or refusal of US procedure. ● The variables tested were US of thyroid, blood labs, BMI and V/S to assess health of these individuals. The measurements were clearly defined. ● The methods were reliable and valid and high quality and consistent equipment was used with experienced technicians and doctors reading the reports. They trained the US techs and radiologists giving them specific guidelines for the study.
● There was a detailed report of the population selection without any bias seen. ● All subjects had consistent testing and evaluations with interviews. ● There is some question of the ability to generalize but this study is easily reproducible in many other populations.

● Results were separated into sections that were clearly defined by general characteristics, Thyroid nodules and lifestyle and dietary habits. The tables were easily read and results with P values for each marker were visible. ● The charts from the survey were marked and rounded into percentages that were clear and relevant with calculations of P values given. ● The text provided with the chart explained the chart relatively well but did have some grammar mistakes likely from translation into English. They discussed the significance of many but not all of the chart findings.
● The text added to the results and clearly stated significant and non-significant findings in each category for statistical purposes. ● The lifestyle section could have been clearer in the findings. More details in this section would be useful to the reader. The general characteristics and thyroid nodule sections were more clearly defined. The results did not seem repetitive.

● The results section was detailed but some of the wording was confusing and did not properly translate into English. The way the writer discussed the percentages was unclear and took a few minutes to read to understand the meaning. ● One example was: “The prevalence of chronic conditions was 67.3%, 10.2%, and 23.7% for hypertension, diabetes, and dyslipidemia, respectively”. There were several sentences like this that could be reworded to avoid confusion to the reader.
● The conclusion section was confusing regarding the prevalence of TN in those who are underweight. A few sentences noted a higher prevalence in underweight patients while the main results stated the opposite. That needs to be clearly stated by the researcher. ● The results did answer the aim of the study and was not over interpreted. ● There were significant references that supported the research and they stated the need to assess other segments of populations in the future. ● One other note was the detail about the consumption of betel quid in this population that seems to increase the prevalence of TN and cancer. This factor would need to be modified in future studies with different populations of people due to the lack of consumption in other areas of the world. ● The 2 limitations of the study were clearly stated. One was the cross-sectional design so the results could not be noted as causal. The second was the inability to check thyroid blood levels in this population ongoing.

Final Thoughts:

The research article “Thyroid Nodules in Centenarians: Prevalence and Relationship to Lifestyle Characteristics and Dietary Habits” reviewed the prevalence of TN in centenarians in relation to dietary habits and lifestyle. The results found many key factors that increase the risk for thyroid nodules including being female or overweight, a diagnosis of diabetes, hypertension, and eating certain foods such as betel quid or red meat. Patients who were underweight and ate nuts were less likely to develop thyroid nodules. This population lives in an iodine sufficient area and did not commonly use iodine supplementation. The study was clearly described and could be easily reproduced.

The strengths of the study were the following: 1. Clearly designed and easily reproducible in different populations 2. Lack of selection bias 3. Easy to track results of measurements 4. Consistency and experience of ultrasound technicians and radiologists involved in the study 5. The format was easy to follow, and the tables were professionally done 6. The conclusion section was clear and stated limitations and areas of opportunity for future research.

This study provides a framework for future research connecting lifestyle and the development of thyroid nodules and possibly thyroid disease. It can be used as a guide in other areas of the world to assess what lifestyle modifications might be useful in the prevention of thyroid nodules.

Major points in the article which needs clarification, refinement, reanalysis, rewrites and/or additional information and suggestions for what could be done to improve the article.

1. There were several statements similar to this one: “The prevalence of chronic conditions was 67.3%, 10.2%, and 23.7% for hypertension, diabetes, and dyslipidemia, respectively. It needs to be restated to be clearer to the reader as to which numbers correspond to which diagnosis.
2. The paper needs to be read and refined by someone who is very proficient in English. There were many statements that were not properly written due to translation into English. This is one example, “When examining the health-related factors, the prevalence of TNs was significantly more common among those who were hypertension and diabetes.”
3. The vast amount of information on betel quid and past studies correlating the consumption to cancer in the discussion section of the paper seemed out of place since this was not at all mentioned prior. If this part is left in the paper, I would recommend having it stated at the beginning with research articles linking it. In my opinion, most could be omitted.

Minor points like figures/tables not being mentioned in the text, a missing reference, typos, and other inconsistencies.

1. This statement and a few others like it were inconsistent with the final results “Proportions of Underweight and dyslipidemia were higher in participants who had TNs than those who had no TN. Further down in the article, it was clearly stated that patients who were underweight had a reduction in TN. This needs to be clarified and consistent.
2. The main inconsistency found was the statement in the results section that would lead the reader to believe being under weight was a risk factor and then in the conclusion it was clearly defined as a protective measure.
3. More information on the type of nuts eaten and the type and quality of red meat would be helpful to readers and for researchers who intend to reproduce this study in different populations.