BMJ Open: first published as 10.1136/bmjopen-2017-018768 on 22 June 2018. Downloaded from PEER REVIEW HISTORY BMJ Open publishes all reviews undertaken for accepted manuscripts. Reviewers are asked to complete a checklist review form (http://bmjopen.bmj.com/site/about/resources/checklist.pdf) and are provided with free text boxes to elaborate on their assessment. These free text comments are reproduced below. ARTICLE DETAILS TITLE (PROVISIONAL) Association between Acculturation and Body Weight Status among Migrant Children in Guangzhou, China: A Cross-Sectional Study AUTHORS Huang, Xiaoling; Chen, Wen; Lin, Yanwei; Zhang, Qi; Ling, Li VERSION 1 – REVIEW REVIEWER Zhihong Sa Beijing Normal University REVIEW RETURNED 11-Sep-2017 GENERAL COMMENTS General comments: A study of the association between socio-cultural integration and migrant children’s body weight status has important implications for health intervention of this disadvantaged group in China. In my point of view, the manuscript needs drastic revision before it can be accepted for publication. Its potential contribution is weakened by the vague problematization of the issue under study and some methodological flaws. Specific comments: Background – http://bmjopen.bmj.com/ 1) The focus of the paper is the association between acculturation and body weight status among migrant children in China. However, the authors did not provide enough background information to help readers better understand the rationale behind the study. For example, what’s the prevalence of childhood overweight/obesity in urban and rural China, respectively? What’s the prevalence of overweight/obesity among local children in Guangzhou (if data is available)? What aspect of Cantonese or urban culture and related on October 1, 2021 by guest. Protected copyright. behavioral pathways that might lead to change in weight status among migrant children in Guangzhou? 2) A related issue is whether the concept and definition of acculturation is appropriate for the present study. While it’s possible that healthy Cantonese food is a protective factor for overweight/obesity, to what extent other aspects of urban culture (i.e. language, social interaction, custom) may be related to weight status among migrant children? What’s the difference between urban-to-urban migrant children and local children in Guangzhou in terms of their culture and exposure to risk factors for obesity? The clarification of these issues can provide a better justification for their conceptualization of acculturation. 3) It’d be helpful for us to understand the empirical analysis if more relevant literature on childhood obesity in China is included in the background secion. For example, a brief review of empirical evidence on major risk factors for overweight/obesity among migrant 1 BMJ Open: first published as 10.1136/bmjopen-2017-018768 on 22 June 2018. Downloaded from children in China would be useful. Methodology – 1) The authors provided literature support for the definition of childhood overweight/obesity in China (p. 7, 2nd paragraph). It’d be helpful if further explanation is provided on method used to construct childhood overweight/obsity in this study, for example, whether age- and gender-specific BMI measures were used to define overweight and obesity. 2) More careful validation of acculturation is needed if the paper focuses on it. 3) Is children’s survey self-administered or based on face-to-face interviews? 4) Level of physical exercise and place of origin are important confounding factors, but they are not included in the analysis. Results 1) In bivariate analyses, neither acculturation index nor individual factors of acculturation is significantly associated with overweight/obesity (Tables 3 and 4). Acculturation is found to be significantly related to overweight/obesity in model 2 of Table 4. I wonder whether the significant association exists if important correlates of overweight/obesity such as physical exercise is included. 2) Is there interaction effect between acculturation and primary caregiver’s type of migration in their relationship to overweight/obesity? 3) It seems that gender plays an important and interesting role, but the effect of gender is not thoroughly explored. http://bmjopen.bmj.com/ REVIEWER Myoungock Jang USA REVIEW RETURNED 04-Oct-2017 GENERAL COMMENTS This study discussed very interesting topic regarding domestic migration as related to overweight and obesity in China. Since this journal target international audience, please include more specific on October 1, 2021 by guest. Protected copyright. cultural and environmental characteristics for promoting the understanding of the study outcomes. Here are several specific comments. Background More specific economic situation in china would be helpful for audience who is not familiar with China. The authors touched based on the migration phenomena, but readers may want to know what is caused, how actively it is occurred, and what resulted in. Need more information about obesity in China. If there were more 2 BMJ Open: first published as 10.1136/bmjopen-2017-018768 on 22 June 2018. Downloaded from statistical information regarding rate of obesity by different geographical areas (i.e., rural vs. urban) etc., it would be much helpful and specific characteristics about Guangzhou may need in the background section. Without any information, the readers may be surprised with the study results. Authors developed an instrument. Need more information. Is this paper for testing the instrument? Or has it been already developed and tested? Methods Comparison of demographic difference between public school and private school children would be helpful. The reason for using social anxiety and child diet intake as a confounding factors is needed. For food intake variable, food intake and food preference are different. You may be consistent with terminology by saying food intake. What is the point of collecting animal food vs. milk, beans and http://bmjopen.bmj.com/ products? One is supposed to be high fat and another is high protein? Overall, you may consider including food intake for your data analysis to see relationship with acculturation and weight status. on October 1, 2021 by guest. Protected copyright. Results The sample size difference is too small to compare group difference by weight status. Questionable to see the difference with this much small variation within sample. There is no information about range of BMI. Rather you may consider linear regression modeling to see the association between the score of acculturation and BMI. You may calculate BMI Z-score. Be consistent with presentation of numbers and percentage Need to describe why the age group by younger than 14 vs. older 3 BMJ Open: first published as 10.1136/bmjopen-2017-018768 on 22 June 2018. Downloaded from than 14 I would recommend not controlling food intake for the model. Readers may want to see difference of food intake between groups. Discussion Need a definition of international migrant. Is it meaning by country to country? Need to discuss cultural perspectives of acculturation in china. When you discuss the diet as a factor for the negative relationship of acculturation and overweight/obesity, readers may want to know their diet behaviors. How did you know they are engaged in healthy diet behaviors? You need to include diet intake variables in your model to explain the relationship. If the environment in Guangzhou is healthier, it should be mentioned in the background to allow readers have a sense of the environmental effect on weight status. The first paragraph on page 13 has two main points. If you want to http://bmjopen.bmj.com/ focus on parental influence, please focus on that. The age difference is a different point so that you may have a separate paragraph to discuss this. VERSION 1 – AUTHOR RESPONSE on October 1, 2021 by guest. Protected copyright. Reviewer #1s' Comments Background 1) The focus of the paper is the association between acculturation and body weight status among migrant children in China. However, the authors did not provide enough background information to help readers better understand the rationale behind the study. For example, what’s the prevalence of childhood overweight/obesity in urban and rural China, respectively? What’s the prevalence of overweight/obesity among local children in Guangzhou (if data is available)? What aspect of Cantonese or urban culture and related behavioral pathways that might lead to change in weight status among migrant children in Guangzhou? Author’s reply: We thank the reviewer for pointing out the need for more background information. We have provided the information about the prevalence of childhood overweight/obesity based on available data in China, including Guangzhou, and other countries. In general, the body weight status 4 BMJ Open: first published as 10.1136/bmjopen-2017-018768 on 22 June 2018. Downloaded from among children varies across regions in China. Urban areas have higher prevalence of childhood overweight/obesity than rural areas, and southern China has lower prevalence than northern China. (p. 4, 3rd paragraph) In terms of the association between Cantonese culture and weight status among migrant children in Guangzhou, it can be summarized as follows. First, Guangzhou is the capital city and a metropolitan in Guangdong Province. Influenced by its time-honor history and migration features, Guangzhou has very unique and diverse culture, including diet, language, and custom. For instance, comparing with cities in other