February 2014 · Issue 71
In this issue:
- A closer look at NCCMTs video series: Understanding Research Evidence
- Coming soon: another NCCMT learning module
- New from Public Health+
- Spotlight on Methods and Tools webinar - Register now!
- Register now for week-long Evidence-Informed Decision Making Workshop
A closer look at NCCMTs video series: Understanding Research Evidence
This week: Understanding a Confidence Interval
While the overall result of an intervention is important, the range of effect is just as critical. That’s where confidence intervals come in. They describe the range of results found in a research study. Understanding a Confidence Interval describes the 95% confidence interval, which tells us that 95 times out of 100, the effect of an intervention will be within the range specified.
Knowing the confidence interval provides a measure of certainty of the effectiveness of an intervention in the real world. To explain, the video describes the effect of a hypothetical social media campaign to prevent cyber-bullying in schools. While the research shows that the campaign did indeed reduce cyber-bullying, the range of results, as determined by the 95% confidence interval, may not be so clear-cut.
The video also explores what it means if the range crosses the ‘line of no difference’. In that case, we should expect that the cyber-bullying could actually increase. Whenever making a decision on whether the results of an intervention warrant the cost and effort of implementing it, it’s important to take a close look at the confidence interval.
About the series
These short videos to explain some important terms that you may encounter in research evidence. They provide a valuable refresher or useful introduction to terms public health professionals need to make good decisions using research evidence.
Currently, the Understanding Research Evidence series includes four videos, each less than six minutes long, which explain key terms in statistical analysis. The videos look at “odds ratios”, “confidence intervals”, “forest plots” and “clinical significance”, explaining each term in plain language with realistic public health examples and engaging visuals.
We are currently working on more videos for this series. Be sure to watch the Round-up for details!
Watch all the videos in the series!
The videos are available on YouTube and on the NCCMT website (http://www.nccmt.ca/resources/multimedia-eng.html#ure). They are part of a series of products and services on the website and in the Learning Centre (http://www.nccmt.ca/learningcentre) designed to help you make good public health decisions, based on the best research evidence available.
Coming soon: another NCCMT learning module
Critical Appraisal of Qualitative Studies
Critical Appraisal of Qualitative Studies will help you develop and practice critical appraisal skills you need to assess qualitative studies relevant to public health. With this knowledge, you will know whether the findings of the qualitative study can be applied to your public health decisions.
Watch for our announcement in next week's Round-up!
New from Public Health+
Supervised exercise-based intervention to prevent excessive gestational weight gain: a randomized controlled trial.
OBJECTIVE: To study the effect on maternal weight gain of a supervised light- to moderate-intensity exercise-based intervention performed from the ninth week of pregnancy. PARTICIPANTS AND METHODS: A total of 962 healthy pregnant women were randomly assigned to a standard care or exercise intervention group conducted between September 1, 2007, and January 31, 2011. The intervention included light- to moderate-intensity aerobic and resistance exercises performed 3 days a week (50-55 minutes per session). Excessive gestational weight gain was calculated on the basis of the 2009 Institute of Medicine (IOM) recommendations. Gestational body weight gain was calculated on the basis of the weight measured at the first prenatal visit (fifth to sixth weeks of gestation) and weight measured at the last visit to the clinic before delivery. Women were categorized into normal weight or overweight or obese. RESULTS: Women in the intervention group gained less weight (adjusted mean difference, 1.039 kg; 95% CI, 0.534-1.545 kg; P<.001) and were less likely to gain weight above the IOM recommendations (odds ratio, 0.625; 95% CI, 0.461-0.847) compared with those in the standard care group. The main treatment effects according to body mass index category were that normal weight women in the intervention group gained less weight (adjusted mean difference, 1.393 kg; 95% CI, 0.813-1.972 kg; P<.001) and were less likely to gain weight above the IOM recommendations (odds ratio, 0.508; 95% CI, 0.334-0.774) than normal weight women who received standard care. No significant treatment effect was observed in overweight or obese women. CONCLUSION: Supervised exercise of light to moderate intensity can be used to prevent excessive gestational weight gain, especially in normal weight women. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01790347.
The full text may be available from PubMed
Long-term multivitamin supplementation and cognitive function in men: a randomized trial.
BACKGROUND: Despite widespread use of multivitamin supplements, their effect on cognitive health-a critical issue with aging-remains inconclusive. To date, no long-term clinical trials have studied multivitamin use and cognitive decline in older persons. OBJECTIVE: To evaluate whether long-term multivitamin supplementation affects cognitive health in later life. DESIGN: Randomized, double-blind, placebo-controlled trial of a multivitamin from 1997 to 1 June 2011. The cognitive function substudy began in 1998. Up to 4 repeated cognitive assessments by telephone interview were completed over 12 years. (ClinicalTrials.gov: NCT00270647) SETTING: The Physicians` Health Study II. PATIENTS: 5947 male physicians aged 65 years or older. INTERVENTION: Daily multivitamin or placebo. MEASUREMENTS: A global composite score averaging 5 tests of global cognition, verbal memory, and category fluency. The secondary end point was a verbal memory score combining 4 tests of verbal memory, which is a strong predictor of Alzheimer disease. RESULTS: No difference was found in mean cognitive change over time between the multivitamin and placebo groups or in the mean level of cognition at any of the 4 assessments. Specifically, for the global composite score, the mean difference in cognitive change over follow-up was -0.01 SU (95% CI, -0.04 to 0.02 SU) when treatment was compared with placebo. Similarly, cognitive performance did not differ between the multivitamin and placebo groups on the secondary outcome, verbal memory (mean difference in cognitive change over follow-up, -0.005 SU [CI, -0.04 to 0.03 SU]). LIMITATION: Doses of vitamins may be too low or the population may be too well-nourished to benefit from a multivitamin. CONCLUSION: In male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits. PRIMARY FUNDING SOURCE: National Institutes of Health, BASF, Pfizer, and DSM Nutritional Products.
The full text may be available from PubMed
School-based obesity prevention programs: a meta-analysis of randomized controlled trials.
OBJECTIVE: Attempts have been made to reduce childhood obesity through school-based programs. Systematic reviews of studies until 2006 reported a lack of consistency about effectiveness of such programs. Presented is an updated systematic review and meta-analysis. DESIGN AND METHODS: Replication of methodology used in previous comprehensive systematic review and meta-analysis of randomized controlled trials of school-based obesity prevention programs covering studies until 2006 to review studies thru January 2012. RESULTS: Based on 32 studies (n = 52,109), programs were mildly effective in reducing BMI relative to controls not receiving intervention. Studies of children had significant intervention effects, those of teenagers did not, though the difference between the two groups was not statistically significant. Meta-regression showed a significant linear hierarchy of studies with the largest effects for comprehensive programs more than 1 year long that aimed to provide information on nutrition and physical activity, change attitudes, monitor behavior, modify environment, involve parents, increase physical activity and improve diet, particularly among children. CONCLUSIONS: Unlike earlier studies, more recent studies showed convincing evidence that school-based prevention interventions are at least mildly effective in reducing BMI in children, possibly because these newer studies tended to be longer, more comprehensive and included parental support.
The full text may be available from PubMed
Community-based interventions to promote management for older people: an integrative review.
AIMS AND OBJECTIVES: To review community programmes promoting self-care or self-management for older people with chronic disease in Thailand. BACKGROUND: Identifying successful elements of culturally appropriate and effective community-based interventions to promote self-care with chronic illness is increasingly important. DESIGN: Integrative review. DATA SOURCES: CINAHL, Medline, Health Source Nursing Academic databases. METHODS: Integrative review of peer-reviewed articles written between 1946-2012. Articles were included if they described self-care, self-management, chronic disease and community care interventions targeting older people in Thailand. RESULTS: Of the 58 articles retrieved, only 13 articles met the eligibility criteria. Elements of effective interventions included: (1) providing culturally sensitive information, (2) including approaches of shared decision-making and mutual goal setting and (3) flexibility within the intervention to adapt to participant needs. CONCLUSIONS: Shared decision-making and mutual goal setting between interventionists and patients improved health behaviours and outcomes. Moreover, the flexibility to adopt the intervention to local characteristics demonstrated positive results. RELEVANCE TO CLINICAL PRACTICE: Promoting effective self-care and self-management behaviours is critical to improving outcomes for chronic conditions. The tailoring and targeting of interventions appropriate to individuals and communities are likely to be most effective in leveraging behaviour change. This review has identified that mutual goal setting improved health behaviours. The flexibility to adopt self-care interventions to community-based settings showed improved patient outcomes.
The full text may be available from PubMed
Screening and subsequent management for gestational diabetes for improving maternal and infant health.
BACKGROUND: Gestational diabetes mellitus (GDM) is a form of diabetes that occurs in pregnancy. Although GDM usually resolves following birth, it is associated with significant morbidities for mother and baby both perinatally and in the long term. There is strong evidence to support treatment for GDM. However, there is little consensus on whether or not screening for GDM will improve maternal and infant health and if so, the most appropriate protocol to follow. OBJECTIVES: To assess the effects of different methods of screening for GDM and maternal and infant outcomes. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group`s Trials Register (1 December 2013). SELECTION CRITERIA: Randomised and quasi-randomised trials evaluating the effects of different methods of screening for GDM. DATA COLLECTION AND ANALYSIS: Two review authors independently conducted data extraction and quality assessment. We resolved disagreements through discussion or through a third author. MAIN RESULTS: We included four trials involving 3972 women in the review. One quasi-randomised trial compared risk factor screening with universal or routine screening by 50 g oral glucose challenge testing. Women in the universal screening group were more likely to be diagnosed with GDM (one trial, 3152 women, risk ratio (RR) 0.44, 95% confidence interval (CI) 0.26 to 0.75). This trial did not report on the other primary outcomes of the review (positive screen for GDM, mode of birth, large-for-gestational age, or macrosomia). Considering secondary outcomes, infants of mothers in the risk factor screening group were born marginally earlier than infants of mothers in the routine screening group (one trial, 3152 women, mean difference (MD) -0.15 weeks, 95% CI -0.27 to -0.03).The remaining three trials evaluated different methods of administering a 50 g glucose load. Two small trials compared glucose monomer with glucose polymer testing, with one of these trials including a candy bar group. One trial compared a glucose solution with food. No differences in diagnosis of GDM were found between each comparison. However, in one trial significantly more women in the glucose monomer group screened positive for GDM than women in the candy bar group (80 women, RR 3.49, 95% CI 1.05 to 11.57). The three trials did not report on the primary review outcomes of mode of birth, large-for-gestational age or macrosomia. Overall, women drinking the glucose monomer experienced fewer side effects from testing than women drinking the glucose polymer (two trials, 151 women, RR 2.80, 95% CI 1.10 to 7.13). However, we observed substantial heterogeneity between the trials for this result (I(2) = 61%). AUTHORS` CONCLUSIONS: There was insufficient evidence to determine if screening for gestational diabetes, or what types of screening, can improve maternal and infant health outcomes.
The full text may be available from PubMed
Spotlight on Methods and Tools webinar - Register now!
Featuring: NCCMT's Search Pyramids
March 7, 2014
1:00pm – 2:30pm (EST)
Need a faster, more efficient way to find high quality research evidence?
Searching online for research evidence can be frustrating. Searching can take a lot of time and may not produce the results you need. Efficient searching is an acquired skill. The National Collaborating Centre for Methods and Tools (NCCMT) has developed Search Pyramids to support efficient searching for research evidence. These pre-populated Search Pyramids, based on the 6S Pyramid (hierarchy of synthesized evidence), save you time and ensure you find the most synthesized evidence available to answer your public health questions. Our topic-specific Search Pyramids focus on issues identified by public health professionals as high priority issues in Canada.
Who are these tools for?
Search Pyramids are designed for public health professionals who need to find research evidence to support their program and policy decisions.
How can you use these tools?
A general public health Search Pyramid is available without login on the NCCMT website. Or login to the Learning Centre with your free NCCMT account to access and customize the topic-specific Search Pyramids. Within each topic, you will find links to relevant sources of evidence at each level in the 6S Pyramid. Clicking on the links will take users directly to the online sources of evidence. Topics include:
- Environmental health
- Injury prevention
- Mental health
- Health communication and social media
- Healthy habits (healthy eating, physical activity) (for children and for adults)
Login to the Learning Centre to access the customizable topic-specific Search Pyramids here http://www.nccmt.ca/learningcentre/index.php
Join us to learn more! http://ow.ly/tPbz7
Register now for week-long Evidence-Informed Decision Making Workshop
Offered by the Canadian Centre for Evidence-Based Nursing
Monday May 5 – Friday May 9, 2014
McMaster University, Hamilton, ON
What is EIDM?
Evidence-informed decision making (EIDM) is the purposeful and systematic use of the best available evidence to inform the assessment of various options and related decision-making in practice, program development, and policy making.
Workshop Outcomes
- Search for, access, and critically appraise the relevance and quality of evidence.
- Interpret and apply the evidence.
- Identify strategies to implement evidence-informed decision making (EIDM).
This workshop is open to participants of all skill levels related to EIDM. Health professionals, administrators, librarians, managers, policy makers, and faculty members are welcome to attend. See the attached brochure for more information.
