The Effects of Macronutrient Intake on the Risk of Developing Type 2 Diabetes: A Systematic Review

Transcription

1 Review Title The Effects of Macronutrient Intake on the Risk of Developing Type 2 Diabetes: A Systematic Review Centre Conducting Review The University of Newcastle Evidence Based Health Care Group: Joanna Briggs Institute Evidence Synthesis Group Reviewers Primary reviewer Name: Amani Alhazmi PhD Candidate, School of Health Science, Faculty of Health, The University of Newcastle Telephone: (02) AmaniHamad.Alhazmi@uon.edu.au Secondary reviewer Name: Mr Mark McEvoy Lecturer in Epidemiology, University of Newcastle Telephone: (02) Mark.McEvoy@newcastle.edu.au Commencement date: November

2 Review Objective To synthesise the best available evidence on the association between macronutrients intake and the development of Type 2 diabetes mellitus. Background The prevalence of Type 2 diabetes mellitus (T2DM) is dramatically increasing worldwide. T2DM is the most prevalent form of diabetes among adults, representing greater than 85% of all cases 1. The total estimated number of adults with T2DM in the world in 2010 was 285 million 2. This is projected to increase to 439 million by The complications arising from T2DM include macrovascular disease (such as atherosclerosis, myocardial infarction, stroke) and microvascular disease (such as nephropathy, retinopathy, neuropathy) 3. In Australia, T2DM has reached epidemic proportions and is known to cause substantial morbidity and mortality 4. Recently, T2DM was nominated as one of the ten most important leading causes of death 5. Moreover, it is recognised as Australia s fastest growing chronic disease and is a costly condition 6. The cost of T2DM in Australia is three billion dollars a year 7. Although the genetic factors involved in the increased risk of developing T2DM are not modifiable, the rapid increases in incidence rates suggests that lifestyle factors, including diet, may play a key role as a modifiable risk factor. Unlike micronutrients, macronutrients (such as protein, fats and carbohydrates) in addition to supplying nutrients to the body for specific physiological functions, also provide energy for the body 8. However, an imbalance in the relative proportions of macronutrients and thus an excess of one macronutrient may be linked to an increase risk of developing a chronic disease, among them type 2 diabetes 8. Previous studies have made great strides in identifying the effect of dietary factors and the increased risk of developing type 2 diabetes. However, the majority of the published reviews addressed the relationship between whole foods (such as meat, and process meats, whole grains, fruit and vegetables) and the risk of developing type 2 diabetes An attempt has also been made to evaluate the association between glycemic index and glycemic load and chronic disease 16. However, 2

3 establishing or defining a relationship between macronutrient intake and the risk of type 2 diabetes has been given little attention. Many of the primary prevention studies which provide the most conclusive evidence are often aimed at preventing diabetes from occurring in high risk individuals or in the general population (for example obese subjects with impaired glucose tolerance and subjects with a family history of type 2 diabetes) This is usually done by modification of one or more lifestyle factors including dietary habits, physical activity and weight reduction Although most of the controlled trials did not assess the incidence of type 2 diabetes because of the long intervention duration needed, some studies, such as the study by Lindstrom et al., 19, extended the follow-up period for 7 years and reported the incidence cases of type 2 diabetes. However, the benefits or adverse effects seen in the trial were not immediately clear as to what intervention factors were responsible for the observed outcome. Several cohort studies reported the relationship between macronutrient intake and the risk of developing type 2 diabetes in healthy population. Therefore, the prospective cohort studies offer the most appropriate study design to assess the effects of macronutrients consumption in relation to the risk of developing type 2 diabetes. The present systematic review, The Effects of Macronutrients on the Development T2DM, will seek to clarify the relationship (if any) between macronutrients in relation to the risk of developing T2DM and will evaluate the evidence for this association. The review will discuss macronutrients including subtypes of macronutrients: fat (saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), trans fatty acids (TFA) and long chain omega-3 (n-3) fatty acids) carbohydrates and protein (animal and vegetable protein). This systematic review aims to synthesise the best available evidence on the association between macronutrients and the development of type 2 diabetes T2DM. Prior to commencement of the review, The Cochrane Library, Medline, Cinahl and the JBI Library of Systematic Reviews were searched to ensure that no other systematic review on the same topic has been published or is underway. Inclusion Criteria 3

4 Type of Participants The population of increase in this review will be adults aged 18 or over without history of type2 diabetes mellitus in the baseline of the study. Phenomenon of Interest The review will aim to determine the relationship (if any) between macronutrients including subtypes of macronutrients: fat (saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), trans fatty acids (TFA) and long chain omega- 3 (n-3) fatty acids) carbohydrates and protein (animal and vegetable protein), and the risk of developing type 2 diabetes. Type of outcome The outcome of interest in this review is the strength and direction of the association (if any) between dietary macronutrients and the risk (incidence) of developing type 2 diabetes. The relationships will be measured by measurement of association, such as the relative risk (RR) or odds ratio (OR). Type of Studies The study types to be considered in the review will be cohort studies that addressed the relationship between macronutrients intake and the risk of developing T2DM. Search strategy A three stage search strategy will be undertaken to find both published and unpublished studies. An initial limited search will be undertaken in MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINHL) databases to identify the key words contained in the title or abstract and index terms used to describe the relevant terms in the article. The second search will search the following electronic data bases MEDLINE, EMBASE, CINAHL, COCHRANE LIBRARY, PROQUEST and MEDNAR to identify published and unpublished studies. The search will be restricted to human participants only, but will not be restricted by date or by language. If any systematic reviews are identified, they will be retrieved for purposes of identifying relevant studies. The third stage will be the 4

5 reference list of all identified studies will be searched for additional studies and checked for eligibility. Initial keywords to be used will be: Type 2 diabetes, diabetes mellitus, non insulin dependent diabetes mellitus, glucose intolerance, hyperglycemia, glucose tolerance, impaired fasting glucose, pre-diabetes, Diet, food preference, dietary fats, dietary proteins, dietary carbohydrates, macronutrient, diet survey, nutrition, diet records, food frequency questionnaire, systematic review, meta analysis, cohort studies, follow up. Studies identified in the search will be assessed for relevance to the review based on the information contained in title, abstract and description/mesh headings by two independent reviewers. A third independent reviewer will review the study in case of disagreement between the two reviewers. For all studies that meet the inclusion criteria the full articles will be retrieved. If eligibility is unclear, based on title, abstract and description/mesh headings, the study will be retrieved for further clarification. Systematic reviews and meta-analysis review studies will use as a resource for identifying primary studies. Assessment of Methodological Quality The methodological quality of the studies that meet the inclusion criteria will be assessed by two independent reviewers using the standardized critical appraisal instrument from the Joanna Briggs Institute (JBI-MASTARI) (Appendix I). In case of disagreement a third independent reviewer will resolve the disagreement. Data Extraction The data will extract from all studies included in the review using the data extraction tool from JBI-MASTARI (Appendix II). This includes information about population, study methods and outcomes of significance to the aim of the review. Data Synthesis Data from papers will, where possible be pooled in statistical meta-analysis using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review 5

6 Instrument (JBI-MASTARI). All results will be subject to double data entry. Odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-square. If statistical pooling is not possible the findings will be presented in narrative form. Conflicts of interests None identified. Acknowledgement Primary reviewer would like to acknowledge the King Abdullah for offering me the scholarship which allowed me to undertake this systemic review. References 1 Barr ELM, Magliano DJ, Zimmet PZ, et al. AusDiab The Australian Diabetes,Obesity and Lifestyle Study Melbourne: International Diabetes Institute, Shaw JE, Sicree RA, Zimmet PZ. Global estimates of the prevalence of diabetes for 2010 and Diabetes Res Clin Pract. 2010; 87: Ginter E, Simko V. Diabetes type 2 pandemic in 21st century. Bratisl Lek Listy. 2010; 111: Australian Institute of Health and Welfare. Diabetes Prevalence in Australia: an assessment ofnational data sources. Canberra: Australian Institute of Health and Welfare Australian Institute of Health and Welfare. Australia's health Canberra: Australian Institute of health and Welfare Graco MG, Jan Jasper, Andrea E. Participation in Physical Activity: Perceptions of Women with a Previous History of Gestational Diabetes Mellitus Colagiuri S., Colagiuri R., Conway B., Grainger D., Davey P. DiabCost Australia Canberra: Assessing the burden of Type 2 Diabetes in Australia, Diabetes Australia Macronutrient balance. NHMRC The Nutrient Reference Values For Australia and New zealand (available from: accessed 13th Dec 2010). 9 Murakami K, Okubo H, Sasaki S, Murakami K, Okubo H, Sasaki S. Effect of dietary factors on incidence of type 2 diabetes: a systematic review of cohort studies. Journal of Nutritional Science & Vitaminology. 2005; 51:

7 10 Hamer M, Chida Y. Intake of fruit, vegetables, and antioxidants and risk of type 2 diabetes: systematic review and meta-analysis. Journal of Hypertension. 2007; 25: Carter P, Gray LJ, Troughton J, et al. Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis. BMJ. 2010; 341: c Aune D, Ursin G, Veierød M. Meat consumption and the risk of type 2 diabetes: a systematic review and meta-analysis of cohort studies. Diabetologia. 2009; 52: de Munter JS, Hu FB, Spiegelman D, et al. Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review. PLoS Medicine / Public Library of Science. 2007; 4: e Priebe M, van Binsbergen J, de Vos R, Vonk Roel J. Whole grain foods for the prevention of type 2 diabetes mellitus. Cochrane Database of Systematic Reviews. Chichester, UK: John Wiley & Sons, Ltd, Van Dam RM, Hu FB. Coffee consumption and risk of type 2 diabetes: A systematic review. Journal of the American Medical Association. 2005; 294 (1): Barclay AW, Petocz P, McMillan-Price J, et al. Glycemic index, glycemic load, and chronic disease risk - A metaanalysis of observational studies. American Journal of Clinical Nutrition. 2008; 87 (3): Tuomilehto J, LindstrÃm J, Eriksson JG, et al. Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with Impaired Glucose Tolerance. New England Journal of Medicine. 2001; 344: Lindstrom J, Eriksson JG, Valle TT, et al. Prevention of diabetes mellitus in subjects with impaired glucose tolerance in the Finnish Diabetes Prevention Study: results from a randomized clinical trial. Journal of the American Society of Nephrology. 2003; 14: S Lindstrom J, Ilanne-Parikka P, Peltonen M, et al. Sustained reduction in the incidence of type 2 diabetes by lifestyle intervention: follow-up of the Finnish Diabetes Prevention Study.[see comment]. Lancet. 2006; 368: Appendix I JBI Critical appraisal tool for cohort studies 7

8 Appendix II JBI Data extraction for cohort studies 8

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