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Summary: A new meta-analysis focuses on what we know and don’t know about what’s good and bad for our health.
Source: IHME
A new set of meta-analyses sheds light on the often complex and conflicting health guidelines that link specific diets, behaviors and conditions to disease.
The analysis, conducted by researchers at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington School of Medicine, was published today in naturopathy.
IHME analyzed the strength of evidence for 180 pairs of risk factors and health outcomes – such as smoking and lung cancer, a diet low in vegetables and type 2 diabetes, as well as high systolic blood pressure and ischemic heart disease.
The results are presented in an easy-to-understand star rating system that shows the strength of the evidence for each link.
The new star rating system is designed to help people make personal health decisions, inform health policy, and guide future research.
“Extensive research has been conducted into the associations between different risks and health outcomes, but the results often vary widely across studies,” explained Dr. Christopher Murray, director of the Institute for Health Metrics and Evaluation and lead author of the study.
“One of the goals of this new star rating system is to eliminate confusion and help consumers make informed decisions about diet, exercise and other activities that can impact their long-term health.”
In many areas, IHME found that the association between a risk factor and a health outcome was weaker than some believe. Almost two-thirds of the risk-reward pairs studied — 112 out of 180 — received only a one- or two-star rating.
These include common combinations such as a diet high in unprocessed red meat and ischemic stroke (one star). In other cases, the IHME’s analysis confirmed a widespread consensus.
Eight risk-outcome pairs received a five-star rating, including smoking and lung cancer, and high systolic blood pressure and ischemic heart disease. A list of star ratings, including a data visualization tool, can be found on IHME’s website.
More star ratings will be added in the near future.
The analysis takes into account both the level of risk that previous studies have shown and the consistency of results between these studies.
Star rating is based on the most conservative interpretation of the available evidence to limit the impact of error or bias in the underlying data. A one-star rating indicates that there may not be a true association between the behavior or condition and health outcome.
Two stars indicate the behavior or condition is associated with at least a 0-15 percent change in the likelihood of a health outcome, while three stars indicate at least a 15-50 percent change and four stars indicate at least a 50-85 percent change , and five stars indicate more than 85% change.
For example, the five-star rating for smoking and lung cancer means that smoking increases the likelihood of developing or dying from lung cancer by more than 85%. At the other end of the scale, the one-star rating for red meat and ischemic stroke means there may not be a link—in this case, because studies on the link have found conflicting results.
See also
Notable reviews from the study include:
“Our analysis not only helps consumers, but can also guide decision-makers in developing health and wellness education programs to focus on the risk factors with the greatest impact on health,” said Dr. Emmanuela Gakidou, Professor of Health Metrics Sciences at the Institute for Health Metrics and Evaluation and lead author of the study.
“Health researchers can also use this analysis to identify areas where the current evidence is weak and more definitive studies are needed.” The IHME researchers also note that while the meta-analytical approach used by this study does not replace expert advice should, but can provide useful input to expert committees and advisory groups making formal health policy recommendations.
IHME’s analysis, based on the landmark Global Burden of Disease study, which celebrates its 30th anniversary this year, is regularly updated.
Due to constantly evolving research, star ratings may change as more data becomes available. This is especially true for low star rating pairings due to limited or conflicting research.
On the other hand, high star ratings are unlikely to change significantly as the evidence is already strong.
About these news from health and nutrition research
Author: Connie Kim
Source: IHME
Contact: Connie Kim-IHME
Picture: The image is in the public domain
Original research: The results appear in naturopathy
