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University of Turku Department of Biochemistry Jukka-Pekka Suomela. 3rd April 2014 Research planning Functional foods and their ingredients. The challenges.
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University of TurkuDepartment of BiochemistryJukka-Pekka Suomela 3rd April 2014 Research planning Functional foods and their ingredients
The challenges • Key research challenges for functional foods are the need to identify new functional food ingredients, develop products and to gain consumer acceptance of such products • Important topics • stability of functional food ingredients during manufacturing and passage through the GI tract to reach the target organ intact • bioavailability of functional food ingredients • appropriate biomarkers for a wider range of functional endpoints • individual biological responses to functional foods • personalized nutrition and the potential role of functional foods
Research and healthclaims • “Th evidence” should show, to what extent… • …the claimed effect of the food/constituent is relevant for human health • …a cause and effect relationship is established between the consumption of the food/constituent and the claimed effect in humans • …the quantity of the food/constituent and pattern of consumption required to obtain the claimed effect could reasonably be achieved as part of a balanced diet • …the specific study group(s) in which the evidence was obtained is representative of the target population for which the claim is intended
Research and healthclaims • Needed in healthclaimapplications (articles 14(1) and 13(5)): • Allavailablescientific data • Emphasis in humanstudies otherresearch as supporting data • Review of the data: specific relationship between the food/constituent and the claimed effect
Terms • http://medical-dictionary.thefreedictionary.com • Subject= An individual who participates in a clinical trial, either as recipient of the investigational product(s) or as a control. • Cohort= In epidemiology, a group of individuals sharing a common characteristic and observed over time in the group. • Outcome variable • Effects of the exposure are studied • Primary, secondary
Terms • reliability= Repeatability; ability of a test to be repeated by several testers and produce the same result. • validity = The extent to which a measurement correctly measures what it is supposed to measure or to which extent the findings of an investigation reflect the truth. In health sciences, validity is commonly assessed by determining the sensitivity and specificity factors. • incidence= The extent or rate of occurrence, especially the number of new cases of a disease in a population over a period of time. • prevalence = the number of cases of a specific disease present in a given population at a certain time.
Terms • Sensitivity = the probability that a person having a disease will be correctly identified by a clinical test.The proportion of individuals in a population that will be correctly identified when administered a test designed to detect a particular disease, calculated as the number of true positive results divided by the number of true positive and false negative results. • Specificity= The statistical probability that an individual who does not have the particular disease being tested for will be correctly identified as negative, expressed as the proportion of true negative results to the total of true negative and false positive results.The probability that a person who does not have a disease will be correctly identified by a clinical test.
Types of humanstudies • OBSERVATIONAL STUDIES • cross-sectionalstudy • case-controlstudy • typicallyretrospective • follow-upstudy • typically a prospectivecohortstudy
Types of humanstudies From: Bruemmer et al. (2009) Publishing nutrition research: a review of epidemiological methods. J Am Diet Assoc 2009
Types of humanstudies • EXPERIMENTAL STUDIES • clinical trial • alsoknown as intervention study • often a randomizedcontrolled trial (RCT) • parallelorcrossover design • oftendouble-blindorsingle-blind design
Meta-analysis • “meta-analysis refers to methods focused on contrasting and combining results from different studies, in the hope of identifying patterns among study results, sources of disagreement among those results, or other interesting relationships that may come to light in the context of multiple studies” From: Greenland S, O' Rourke K: Meta-Analysis. Page 652 in Modern Epidemiology, 3rd ed. Edited by Rothman KJ, Greenland S, Lash T. Lippincott Williams and Wilkins; 2008
Factors to considerwhenplanning clinicaltrials
ETHICS APPROVAL • Volunteers • Sometimes animal studies • Permission from an ethical committee a must • Persons can withdraw their participation from the study at any given time
WHAT IS BEING COMPARED? DIFFERENT FOODS? DIFFERENT GROUPS OF PERSONS? PLACEBO? • Allways have a hypothesis – what is being compared? • Do you have a placebo or not? • Placebo should look, taste and smell the same as the real thing • At the end ask your volunteers in which group they think they were / started with
CROSS-OVER vs. TWO PARALLEL GROUPS • Less deviation when the subjects act as their own controls • All subjects receive all interventions in randomized order -> the influence of confounding covariates is reduced • If different persons are compared (parallel groups), more deviation in the results Wash-out
TWO GROUPS RATHER THAN CROSS-OVER? • If the volunteers have certain predetermined criteria which are either filled or not filled • If there is limited time available
RANDOMIZATION • Volunteers randomly assigned to different groups • In cross-over studies, the order of the intervention is different for different volunteers • This minimizes the effects of possible carry-over and effects of the time of the year (e.g. summer barbeque or christmasparties)
“WASH-OUT” IN CROSS-OVER STUDIES • The break between the interventions is called a wash-out period • During the wash-out period the volunteers live their normal life without interventions • This minimizes the carry-over effect in cross-over studies, i.e. the first intervention does not interfere with the following interventions • Carry-over can be measured by analyzing the zero time point samples before each intervention
DOUBLE-BLIND • Volunteers do not know in which group they are • Until all data is collected and analyzed, researchers do not know who was when in which group • The person who does the grouping is not involved in the interpretation of the results
SINGLE-BLIND • Sometimes it is difficult / impossible to blind the volunteers • => single blind
SOURCES OF ERROR • Biasrelated to sampling and follow-up • Biasrelated to measuremnents • randomerror (precision) • systematicerror (accuracy) • How to enhance the trustworthinessof a measurement? • externalorinternalstandard • duplicate/triplicatesamplesand/ormeasurements • parallelmethods
CONFOUNDERS • A factorthat is related to bothexposure and outcome, ”confounder” • e.g. age, gender, smoking/nonsmoking • example: • itseemsthat the risk of cardiacinfarction is higher in coffee-drinkerscompared with non-drinkers • smoking seems to be a confoundersinceit is related to bothincrasedcoffee-drinking and to higherrisk of cardiacinfarction • sothere is necessarily no realconnectionbetweencoffee-drinking and the risk of cardiacinfarction • Theseneed to betaken into accountwhenplanning the study
Planning of research • Whathasbeendoneearlier, whatnot? • Phrasing of questions, goals • Possiblecollaborators • Outcomevariables • Hypotheses • Study design • Studysubjects (e.g. samplesize, inclusion/exclusioncriteria, recruitingplan, consentforms…) • RCT: randomization and blinding • Methodsused • Pilotstudy?
Planning of research “A badly designed study can never be retrieved, whereas a poorly analyzed one can usually be reanalyzed.” Campbell & Machin Attention to detail about the research objective or hypothesis, in addition to the study design, will contribute positively to a reader’s ability to comprehend the scope of the study. Boushey et al.
Planning of research • Need to be planned • The essential resources (human, premises, instrumental) • The methods for data collection (planning of the questionnaries etc.) • The budget, financial planning • The forthcomingpublications • Aresearch plan and appendixes • for possible sources of funding • for ethical consideration
Planning of research • Research contracts (with the collaborators) • Timetables (for follow-up, taking the samples etc.) • How the data will be stored, coded, and classified • Uniformpractices, whodoes and where?, statisticalanalyses
Guides • www. turkucrc.fi (Turku ClinicalResearch Centre) • http://www.vsshp.fi/fi/tutkijoille/Sivut/default.aspx (Ethical Committee of the Hospital District of Southwest Finland) • English web site to be opened later this year
Trial registration(clinicaltrials) • Guidelines: ICMJE Clinical Trial Registration 2004 • databases: • www.clinicaltrials.gov (US National Institute of Health) • www.controlled-trials.com • www.isrctn.org
References • Boushey C et al(2006). Publishing Nutrition Research: A Review of Study Design, Statistical Analyses, and Other Key Elements of Manuscript Preparation, Part 1. Journal of the American Dietetic Association 106: 89–96.