Guest Columnists

Access-to-Data Is the Key to Strong Science and Solid Public Policy

Richard L. Hanneman, President, Salt Institute and Andrew Briscoe, Director, Public Policy, Salt Institute

March 28, 2000

On July 30, 1988, the British Medical Journal published the massive Intersalt Study. The study was conceived as the definitive population study examining the question: Is dietary salt intake related to blood pressure? -- a question that had produced conflicting answers in previous studies. The study found scant evidence of a relationship, and even that disappeared when the four primitive populations were excluded and the remaining 48 acculturated societies were analyzed. The authors also reported confirmation of a post-hoc hypothesis that blood pressures would "rise with age," although the snapshot study design required them to consider age cohorts as a longitudinal sample.

The study was carried out by zealous advocates of the "sodium restriction hypothesis" which postulated that hypertension was caused by "high" intakes of dietary salt. It was funded with $1.3 million from the U.S. Department of Health and Human Services. It was intended to guide public health nutrition policy and, in fact, was cited as support for having the U.S. encourage universal sodium reduction.

But the numbers didn't make sense to the Salt Institute, representing the salt industry. Salt is the primary source of dietary sodium. Knowing that "the devil is in the details, the Institute asked how could there be a dramatic "rise with age" if, overall, population blood pressures were not associated with dietary sodium intakes? So the Institute asked the authors if they could have an independent expert statistical analysis done of the Intersalt data. The authors refused.

The Intersalt researchers claimed proprietary ownership stating that the Intersalt data "has publicly disclosed enormous amounts of information relating to the data it has generated." They claimed Intersalt investigators had only published the first in a series of papers (which was true). And, they alleged, the requested data "include confidential information about participants in the Intersalt study, which under Intersalt's policies and under applicable federal regulations, Intersalt is obligated to protect from disclosure." They summarized that in their judgment, "the Salt Institute's request - apparently for all the raw data generated by Intersalt -- is unreasonable and unjustified."

The Salt Institute asked that the National Heart, Lung and Blood Institute, the HHS unit that funded the study, to obtain the data from the Intersalt researchers. They claimed that they had structured their financial arrangement so that they were unable to obtain the raw data themselves. The Institute then requested that the HHS Office of Research Integrity examine the situation to determine if the authors had fairly reported their findings. ORI said they could only proceed if the Salt Institute alleged fraud on the part of the authors. With no evidence to determine if fraud may have occurred, since the raw data bearing on the question were unreported, the Institute averred. The Institute tried the Intersalt authors one more time and received a response from their attorneys rejecting the request. So the Institute engaged its attorneys who spent three years and finally were able to have the authors provide a data run on one very narrowly-crafted (and heavily-negotiated) question.

Those data, alone, however, were enough to expose the house of cards crafted by the Intersalt statisticians who had access to the full data tapes. The Institute's letter explaining the manipulation was published by the British Medical Journal in 1996 and received expert endorsement (as well as bitter castigation by the Intersalt authors). Today, 12 years after publication, the original Intersalt data tapes are still unavailable for independent confirmation.

Yet the study has been referenced repeatedly by NHLBI, the Food and Drug Administration, the Department of Health and Human Services, and by the U.S. Department of Agriculture as supportive of sodium reduction in such initiatives as the Dietary Guidelines for Americans, the HHS Healthy People 2000 program and the FDA food labeling program. The former two declared: "the study found the rate of increase in blood pressure with age to be significantly related to sodium intake as measured by sodium excretion." FDA authorized a "sodium and hypertension" food labeling health claim with the justification that: "The INTERSALT study reported a statistically significant relationship between sodium intake and the slope of SBP and diastolic blood pressure (DSP) with age."

In 1998, when Congress, led by Senator Richard Shelby, mandated that federal agencies make available to the public all data produced under a grant or agreement with an "Institution of Higher Education, Hospital, or Other Non-Profit Organization" broadening the Freedom of Information Act (FOIA), the Salt Institute was elated. Finally, with Congress's help, we had some relief on examining raw data to determine if the science was accurate and the interpretations did indeed reflect what the data reveals. With the inclusion of the "Uniform Administrative Requirements for Grants and Agreements", the Office of Management and Budget (OMB) is now charged with requiring federal agencies to adhere to this new access-to-data standard.

We may never know the truth about the shenanigans that played out on the Intersalt Study; the expanded FOIA rules are not retroactive. Thousands of federal policies and positions continue to be used to justify policy without recourse to scientific scrutiny. Congress should mandate retroactive application of the newly created Access-to-Data provision.

But the Shelby Amendment puts conniving bureaucrats and their scientific lackeys on notice for the future: You will be watched. Your science, if used for policy purposes, will be examined by peers who take time to ask the necessary detailed questions.

Scientific data are our best understanding of truth. They are the best hope for solid public policy. The new expansion of FOIA does exactly that for any data produced under a federal grant after Nov. 7, 1999. If science is federally-funded and used to support public policy involving millions of Americans, then it should be made publicly available after being published so that the interpretations can be reviewed, verified, and/or replicated. The public has a right to the data which their taxpayer dollars helped produce. Your help and support for implementing this important OMB reg and refining it to include retroactive application will lead to stronger science and solid public policy.