Open Season on Salt: What the Science on Hypertension Really Shows

News Brief by Evan Balmuth


   On September 26th, Melinda Wenner Moyer of Scientific American published this important article questioning interpretations of a recent study in Pediatrics. The study in question, conducted by CDC researchers, has resulted in claims by newspapers including the Associated Press and USA Today that the 25 percent of American children who ingest the most sodium are two to three times likelier to develop hypertension than the 25 percent who take in the least sodium. However, the Scientific American article reveals that, as the lead author of this study and results from several other studies suggest, there is not enough statistically significant data to make this bold and causal claim. The primary reasons for this are that: this was a cross-sectional study, which cannot guarantee total control of confounding variables; and that two past studies found no significant correlation between urinary sodium levels and hypertension. In fact, Scientific American juxtaposes with a 2011 study in The Journal of the American Medical Association which found that – most likely due to adverse effects of a low-sodium diet – consumers of the most sodium had a 3.3 percent higher death rate over time than consumers of the least sodium.
Ultimately, this Scientific American article has shed some light on the dangerous phenomenon of media falsely interpreting study results. Instead of focusing on the less sensational yet true finding that high salt intake may correlate with high blood pressure in obese children, media outlets have skewed the results into a striking yet unjustifiable causality. This can sell papers, but it can also disseminate the misconception that salt is deadly, when in fact it has been shown that a low-sodium diet has deadly correlates as well. The end of this article is an example of how to properly interpret statistically significant findings, as it suggests the superiority of cutting weight over cutting salt due to much proven causality. Hopefully, for the sake of public health, Scientific American and other media publications will continue to blow the whistle on unjustified interpretations of scientific findings.

Reference:
Moyer, Melinda. "Open Season on Salt: What the Science on Hypertension Really Shows." Scientific American. 26 Sep 2012: n. page. Web. 3 Oct. 2012.