PEN eNews 9(5) December 2019

Cranberry and UTIs - Tis the Season?

Weight Stigma – Are You Aware?

The latest background in the PEN^® System is the Weight Stigma Background. The overall aim of this background is to provide information, challenge assumptions and create bridges for greater collaboration among dietitians and other health professionals across different perspectives in the field of weight stigma. This background summarizes evidence on weight stigma from both critical and dominant perspectives, with the primary goal of minimizing harm while promoting health and well-being for people of all weights and sizes.

This timely background challenges dietitians to question the way they think and talk about body weight and how weight stigma and bias, which is often unintentional, can have a negative impact on their patients, clients and communities.

PEN TIP

The PEN System allows you to access evidence-based answers to practice-based questions. These questions reflect everyday situations that dietitians face.

They are organized in to Knowledge Pathways, a bit like chapters in a book.

Watch this short video tutorial where we show you how to find knowledge pathways in PEN and how to locate key features within them.

What’s New for PEN^® Client Handouts  

PEN Handouts for Your Clients

There are hundreds of PEN-developed handouts in the PEN System; many of which have been culturally adapted and are available in a variety of languages.

New and Updated Handouts

Some of our latest new and updated handouts include:
Constipation in Babies (0-12 months)   English   French
Food Sources of Sodium (French to be available soon)
Quick Check for Protein  Chinese   English   French   Punjabi   Spanish   Vietnamese
Managing Constipation in Children Over 1 Year of Age   English   French

Handout Collections

There are eight PEN Handout Collections:

1. Breastfeeding Friendly
2. Food Service
3. Food Sources and Nutrients (Canada)
4. Food Sources and Nutrients (U.K.)
5. Health Conditions
6. Healthy Living
7. Nutrition Over the Lifespan
8. Pediatrics

Read more about the Handout Collections in this PEN eNews article.

CVD and Fibre - GRADEing the Evidence

The PEN System has a new GRADE Practice Question on fibre and primary and secondary cardiovascular disease prevention: Are diets higher in total dietary fibre (including whole grains, cereals, vegetable, fruit and legume fibre) recommended to decrease the risk of cardiovascular disease (CVD)?

A search in the PEN System for “cardiovascular disease” returns 399 results, including:

• 5 Knowledge Pathways
• More than 100 Practice Questions
• >More than 80 Client Handouts
• And much more!

Mary Anne Smith's Surprised Finding - The Obesity Paradox

I may be late to the game but I recently learned about the ‘obesity paradox’; that is, the idea that in people with some chronic diseases, those with a BMI classified as “overweight” or “obese” are more likely to outlive their “normal” BMI counterparts (1).

The term was first introduced in 2002 by Gruberg et al., who reported that having a BMI ≥25 was associated with decreased mortality after percutaneous coronary intervention compared to having a BMI between 18.5 and 24.9 (2). Since then, similar observational studies have reported increased longevity in other populations with a BMI ≥25 , including those with heart failure (3,4), anticoagulated atrial fibrillation (5), stroke (6), COPD (7) and type 2 diabetes mellitus (8) and in those undergoing heart surgery (9-11), lung cancer surgery (12) and peritoneal dialysis (13). However, we cannot conclude that ‘the fatter, the better’; in every review that separated a BMI >30 into smaller categories, there was evidence of a nonlinear relationship between BMI and mortality (3,4,6,8-10). The nadir was different in different populations, but most often, a BMI of 25 to 34.9 was associated with the lowest risk of mortality (3,4,8-10).

Several explanations for the paradox have been proposed and debated within the literature, many of which have been summarized by Charnigo and Guglin (1).

• Age: several studies have suggested that individuals with a BMI ≥25 are significantly younger than individuals with the same chronic illness and a BMI <25, which may account for the increased longevity.
• Other residual confounding: important baseline differences between BMI groups may explain mortality differences, causing the paradox to disappear when these variables have been controlled for statistically. Examples include sex, co-morbidities, medications and smoking status. Furthermore, BMI can be a poor indicator of adiposity and does not account for fat distribution, both of which are more closely linked to measures of health.
• Unintentional weight loss (i.e. reverse causality): rather than an increased BMI causing decreased mortality, it may be that an increased risk of mortality is representative of a more serious illness and results in unintentional weight loss that causes a change in BMI status.
• Statistical artifact:  epidemiologists have contested that the obesity paradox is no more than a statistical artifact; that is, a result that does not accurately portray the real world due to bias in the way the data is collected or analyzed (14). The obesity paradox may be subject to collider stratification bias, whereby there is a distorted interaction between unmeasured variables that are improperly controlled for and the result is similar to selection bias (1). For example, there may be an association between two diseases in hospitalized populations that disappears in outpatient populations because of unmeasured variables associated with needing to be hospitalized (15). Using a hypothetical dataset, Charnigo and Guglin described how obesity could be subject to collider stratification bias and appear to decrease mortality in statistical analyses (i.e. a negative association) even if the true relationship between the two variables was actually positive or unrelated.

All this debate got me thinking about how the BMI categories were initially created back in 1998, a mere four years before the term ‘obesity paradox’ was coined. The cut-offs we use today were primarily based on evidence linking BMI to mortality (16), but even at that time, there was an awareness of many of the issues later noted by Charnigo and Guglin. So, are the cut-offs wrong? And, at the end of the day, does it even matter? For one thing, health care is currently in the process of switching from an obesity-centric paradigm toward a health-centric approach. For another, the definition of obesity is evolving such that it is no longer based entirely on a BMI cut-off. According to the Canadian Obesity Advocacy Network, “Obesity is a chronic disease that is defined by having adipose tissue (body fat) that impairs health. It is not solely based on weight, BMI or body size but rather the degree of physiological, functional and psychosocial barriers that affect one’s holistic health” (17). If research has shown that BMI, in isolation, is not an indicator of health (18), why turn to it, in isolation, as an indicator of survival? Moving forward, using a more comprehensive measure to diagnose obesity in research populations will likely shed new light on the obesity paradox to support better treatment options.

References

1. Charnigo R, Guglin M. Obesity paradox in heart failure: a statistical artifact, or impetus to rethink clinical practice? Heart Fail Rev. 2017 Jan;22(1):13-23. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/27567626
2. Gruberg L, Weissman NJ, Waskman R, Fuchs S, Deible R, Pinnow EE, et al. The impact of obesity on the short-term and long-term outcomes after percutaneous coronary intervention: the obesity paradox? J Am Coll Cardiol. 2002 Feb 20;39(4):578-84. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/11849854
3. Mahajan R, Stokes M, Elliott A, Munawar DA, Khokhar KB, Thiyagarajah A, et al. Complex interaction of obesity, intentional weight loss and heart failure: a systematic review and meta-analysis. Heart. 2019 Sep 17 [epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31530572
4. Wawrzeńczyk A, Anaszewicz M, Wawrzeńczyk A, Budzyński J. Clinical significance of nutritional status in patients with chronic heart failure-a systematic review. Heart Fail Rev. 2019 Sep;24(5):671-700. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31016426
5. Zhou Y, Ma J, Zhu W. Efficacy and safety of direct oral anticoagulants versus warfarin in patients with atrial fibrillation across BMI categories: a systematic review and meta-analysis. Am J Cardiovasc Drugs. 2019 Jul 24 [epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/31342343
6. Oesch L, Tatlisumak T, Arnold M, Sarikaya H. Obesity paradox in stroke – myth or reality? A systematic review. PLoS One. 2017 Mar 14;12(3):e0171334. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28291782
7. Spelta F, Fratta Pasini AM, Cazzoletti L, Ferrari M. Body weight and mortality in COPD: focus on the obesity paradox. Eat Weight Disord. 2018 Feb;23(1):15-22. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29110280
8. Kwon Y, Kim HJ, Park S, Park YG, Cho KH. Body mass index-related mortality in patients with type 2 diabetes and heterogeneity in obesity paradox studies: a dose-response meta-analysis. PLoS One. 2017 Jan 3;12(1):e0168247. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28046128
9. Ma WQ, Sun XJ, Wang Y, Han XQ, Zhu Y, Liu NF. Does body mass index truly affect mortality and cardiovascular outcomes in patients after coronary revascularization with percutaneous coronary intervention or coronary artery bypass graft? A systematic review and network meta-analysis. Obes Rev. 2018;19(9):1236-47. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30035367
10. Marsicalo G, Wozniak MJ, Dawson AG, Serraino GF, Porter R, Nath M, et al. Body mass index and mortality among adults undergoing cardiac surgery: a nationwide study with a systematic review and meta-analysis. Circulation. 2017 Feb 28;135(9):850-63. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28034901
11. Lv W, Li S, Liao Y, Zhao Z, Che G, Chen M, Feng Y. The ‘obesity paradox’ does exist in patients undergoing transcather aortic valve implantation for aortic stenosis: a systematic review and meta-analysis. Interact Cardiovasc Thorac Surg. 2017 Oct 1;25(4):633-42. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28962502
12. Li S, Wang Z, Huang J, Fan J, Du H, Liu L, et al. Systematic review of prognostic roles of body mass index for patients undergoing lung cancer surgery: Does the ‘obesity paradox’ really exist? Eur J Cardiothorac Surg. 2017 May 1;51(5):817-28. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/28040677
13. Ahmadi SF, Zahmatkesh G, Streja E, Mehrotra R, Rhee CM, Kovesdy CP, et al. Association of body mass index with mortality in peritoneal dialysis patients: a systematic review and meta-analysis. Perit Dial Int. 2016 May-Jun;36(3):315-25. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/26475847
14. Oxford Index. Artefacts, statistical and methodological. 2019 [cited 2019 Dec 5]. Available from: https://oxfordindex.oup.com/view/10.1093/oi/authority.20110803095426317
15. Lee H, Aronson JK, Nunan D. Collider bias. Catalogue of Bias [cited 2019 Dec 5]. Available from:  https://catalogofbias.org/biases/collider-bias/
16. World Health Organization. Obesity: preventing and managing the global epidemic. WHO Technical Report Series 894. Geneva: World Health Organization; 2000. Available from: https://www.who.int/nutrition/publications/obesity/WHO_TRS_894/en/
17. Sharma A. Canadian Obesity Advocacy Network. 2019 May 20. Available from: http://www.drsharma.ca/canadian-obesity-advocacy-network
18. Dietitians of Canada. Weight stigma background. In: Practice-based Evidence in Nutrition [PEN]. 2019 Dec 3 [cited 2019 Dec 5]. Available from: https://www.pennutrition.com/KnowledgePathway.aspx?kpid=803&trid=28010&trcatid=38. Access only by subscription.
    
    

Written by:
Mary Anne Smith, PhD, RD
PEN^® Evidence Analyst

Reviewed by:
Dawna Royall, MSc, RD
PEN^® Senior Evidence Analyst

Jayne Thirsk RD, PhD, FDC
Director of PEN^® System

Dietitians of Canada is Cultivating Possibilities in Saskatoon, June 10 to 13, 2020

Join us in Saskatoon for the latest scientific and practice updates on cannabis, vitamin D, the management of food allergies, workshops on dietetics and food as pathways to reconciliation and much more. Registration opens on Monday December 16, 2020. Super early bird registration fees will be in effect until January 10 and members save $130 when registering by this deadline.

Visit the Conference website (www.dcconference.ca) to find the complete program, links to travel and accommodation information, and details and deadlines for submitting professional and student research abstracts.

CFDR Research Showcase

Understanding and using the results of high quality evidence is what sets dietitians apart from other food and nutrition practitioners. It is the foundation of dietetic practice and an essential part of critical thinking and practice application skills. Conference is the ideal time to share what you have been working on that could make a difference in someone else’s work. The 2020 Research Showcase will share peer-reviewed, oral presentations and electronic posters. The deadline to submit your research abstract is January 31, 2020.

New this Year

1. The highly successful three-day Dysphagia Workshop will be offered as a pre-conference event. The program includes classroom and food lab learning as well as  observational and hands-on assessment with those who experience dysphagia. This program has limited seats, so register early.

2. The program will have five major sessions that look at food and dietetics and the implications of the recommendations of TRC including three in-depth workshops, our opening plenary session and a tour to Wanuskewin Heritage Park, recently awarded the 2019 National Indigenous Tourism Award.  

3. Being in Saskatchewan provides an excellent opportunity to look at food and agriculture, and the possibilities for dietitians in that space. Learn about current agricultural practices, food innovation and value-add product development, and finish your visit to Saskatoon with a tour of local farms and producers.

4. Practicing in many parts of Canada as a sole dietitian has great benefits and many challenges. This year we will have a special session for those who work in remote and rural settings that aims to foster collaboration and identify opportunities for growth and career enhancement in these sometimes challenging work settings.

5. Canada’s Food Guide and Dietary Guidelines were released last year to much fanfare. How are practitioners using these tools, and what are the difficulties experienced when trying to use population-directed tools for applications, like institutional menu planning? Our panel of esteemed academics and experienced practitioners present perspectives on using the CFG for older adults in community and institutional settings.

Peer-to-peer Learning Opportunities

Meeting great people and learning new things is one of the main reasons members attend the Conference. But how do you spark those meaningful conversations? It all starts with a Braindate - one-on-one or small group meetings that you book with other participants based on shared interests. Everyone has valuable knowledge and experience to share. In 2019, DC launched Braindate for attendees to tap into the collective genius at the Conference and meaningfully connect with one another. It was a huge success and we are happy to announce it’s back for 2020! Learn more about it on the Conference website.

The Conference program will be available December 16.  Be sure to register early and take advantage of great prices and limited availability session.