NEW YORK, Oct. 29 /CNW/ - Widespread misinterpretation of health-related
research, especially reports that conflate association with causation, leads
to confusion and mistrust of health advice, according to physicians and
scientists associated with the American Council on Science and Health (ACSH).
A new ACSH publication, "Distinguishing Association from Causation: A
Backgrounder for Journalists," explains some of the basic issues and pitfalls
involved in interpreting scientific studies. The paper offers tips to assist
journalists and consumers in making sense of scientific reports.
"The news media are awash with headlines about the supposed risks or
benefits of various foods, drugs, environmental chemicals or dietary
supplements," said ACSH president Dr. Elizabeth Whelan. "But the supposed
causal connections between exposures and health effects are often conflicting
or change over time," she continued.
The ACSH report describes the different types of studies scientists use
to explore links between exposures and health. In addition, it presents
important criteria for distinguishing if a link between an exposure and a
health effect is truly causal (e.g., smoking and lung cancer) or if the
connection is merely an association (e.g., carrying matches and lung cancer).
The most useful criteria include:
- Temporality. For an association to be causal, the cause must precede
- Strength. Scientists can be more confident in the causality of strong
associations than weak ones.
- Dose-response. Responses that increase in frequency as exposure
increases are more convincingly supportive of causality than those
that do not show this pattern.
- Consistency. Relationships that are repeatedly observed by different
investigators, in different places, circumstances and times, are more
likely to be causal.
- Biological plausibility. Associations that fit the known biology of
the disease or health effect under investigation are more likely to
"Imprudent optimism about the significance of results or the importance
of a discovery can lead consumers to mistrust scientific evidence or to ignore
it entirely. Unfortunately, over-interpretation or emphasis can lead consumers
to believe that a harmless exposure is dangerous, or conversely that some
useless or dangerous product might be beneficial," stated Dr. John W. Morgan,
cancer epidemiologist at Loma Linda University.
Download the full ACSH report, "Distinguishing Association from
Causation: A Backgrounder for Journalists," at ACSH.org.
The American Council on Science and Health is an independent, non-profit
consumer education organization concerned with issues related to food,
nutrition, chemicals, pharmaceuticals, lifestyle, the environment and health.
This information was found online at:
For further information:
For further information: Dr. Ruth Kava, Kava@acsh.org, (212) 362-7044
x234; Dr. Elizabeth Whelan, Whelan@acsh.org, (212) 362-7044 x228