Department of Food and Human Nutritional Sciences, Faculty of Agricultural and Food Sciences, University of Manitoba, 407 Human Ecology Building, Winnipeg, MB, R3T 2N2, Canada.
Department of Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.
Nutr J. 2018 Sep 7;17(1):83. doi: 10.1186/s12937-018-0390-6.
Scholars have documented presumptions regarding the relationships between diet, exercise, weight, and type 2 diabetes. However, it is unclear to what extent researchers contribute to these presumptions, and how often these relationships are thoroughly delineated within the context of randomized controlled trials (RCTs). Thus, the aim was to conduct a systematic search and qualitative, thematic analysis of RCTs focusing on lifestyle interventions for diabetes prevention or management, to examine how researchers discuss body weight in 1) the rationale and design of their RCTs; and 2) their presentation and interpretation of their findings.
We completed an electronic search for records published between 2007 and November 2016. Selection criteria included: RCTs with a follow-up period of ≥12 months; adult participants with type 2 diabetes/pre-diabetes; lifestyle interventions classified as dietary, exercise, and/or behavioural; primary outcomes of incident diabetes and complications, mortality, cardiovascular disease, and quality of life; and secondary outcomes of glycemic control and blood pressure. Nineteen articles were identified for inclusion and subject to thematic content analysis.
Obesity and weight loss figured prominently in the rationale and outcomes of the majority of the articles, despite intentional exclusion of "weight loss" and "obesity" as search terms. There was ambiguity over whether weight loss was classified as inclusive to the intervention, an outcome, or a measure of adherence. Results revealed that authors frequently engaged in "spin reporting" by pooling data from intervention and control groups to test the relationship between weight lost and outcomes and in their presentation of results.
Researchers need to be aware of their biases and assumptions regarding body weight in designing, analyzing, and interpreting lifestyle interventions for diabetes prevention and management.
学者们已经记录了饮食、运动、体重和 2 型糖尿病之间关系的假设。然而，目前尚不清楚研究人员在多大程度上促成了这些假设，以及这些关系在随机对照试验（RCT）中是如何被彻底描述的。因此，本研究旨在对以糖尿病预防或管理为目的的生活方式干预 RCT 进行系统检索和定性、主题分析，以考察研究人员在以下两个方面讨论体重的情况：1）RCT 的原理和设计；2）研究结果的呈现和解释。
我们对 2007 年至 2016 年 11 月期间发表的记录进行了电子检索。入选标准包括：随访时间≥12 个月的 RCT；患有 2 型糖尿病/前期糖尿病的成年参与者；分类为饮食、运动和/或行为的生活方式干预；新发糖尿病和并发症、死亡率、心血管疾病和生活质量的主要结局；血糖控制和血压的次要结局。确定了 19 篇文章纳入并进行主题内容分析。
尽管故意将“体重减轻”和“肥胖”作为检索词排除在外，但肥胖和体重减轻在大多数文章的原理和结果中占据了重要地位。对于体重减轻是否被归类为干预措施、结局还是依从性的衡量标准存在歧义。研究结果表明，作者经常通过合并干预组和对照组的数据来检验体重减轻与结局之间的关系，并在结果呈现中进行“歪曲报告”。
研究人员在设计、分析和解释生活方式干预以预防和管理糖尿病时，需要意识到他们对体重的偏见和假设。
