A salty confession
I have never figured out who said "confession is good for the soul," but she was right. And a confession is in order tonight. Four days ago, I succumbed to the very sin I've decried publicly so often in the blogosphere: the sin of bestowing credibility, even endorsing results of a medical study whose conclusions support one's own worldview. It's natural. Understandable. But, sans apology and full repentance, nigh unto unforgivable.
Still, we learn from our experiences. As I humbly recant the ill-considered, cyber-published product of my passion, I hope I can be granted not only absolution, but insight into the difficulty others may likewise be experiencing when jumping quickly to endorse a "politically correct" end result without regard to the quality of the "science" employed to reach that result.
Four days ago I celebrated a new study, declaring with exuberance :
Today's publication in PLoS Medicine of a massive (20,244 persons) 14-year mortality study, showed that four simple interventions -- increasing fruits and vegetables, becoming physically active, not smoking and consuming no more than moderate amounts of alcohol -- increased lifespan by 14 years.
Kay-Tee Khaw et al report that "the trends were strongest for cardiovascular causes." It's time we got serious about promoting the DASH Diet and stopped diverting resources to interventions like salt reduction which have been endorsed by experts but are unsupported by actual scientific evidence.
My enthusiasm and endorsement of the DASH Diet remain intact, but my respect for the Khaw study is gone. Having now read the January 10th post by Sandy Szwarc on her Junkfood Science blog , I am hoist on my own petard. My admonition to "get serious" about the science underlying nutrition recommendations is exposed as pure self-righteous cheerleading. Not to excuse my excesses, but as Ms. Szwarc points out:
Within hours this week, television newscasters, as well as some 500 published articles - for scientists, medical professionals, nursing professionals, business professionals and consumers - were all reporting the same interpretation of this study. The script was provided by the publication's press release: "4 health behaviors can add 14 extra years of life."
Thank you, Sandy, for your very relevant reminder:
Simply making extraordinary statements about a study, however, does not make them true - no matter how much we might want them to be. And who wouldn't want to believe that by doing just four easy things we could add 14 years to our lives?
After reviewing the methodology, Szwarc cuts to the chase:
Their key finding, which has not been reported, was they were unable to find a tenable correlation between any of the health behaviors and mortality: all-cause, cardiovascular disease, cancer or any other cause of death. The relative risks all hugged either side of 1 - null findings. (emphasis in original) …
In other words, reports of higher relative risks associated with not engaging in four healthy behaviors were based on 49 people, 0.2% of the cohort. But the absolute (actual) risk of dying differed only 0.2% between those doing zero and those doing all four healthy behaviors (0.25% and 0.05%, respectively). (emphasis in original)
This is just the kind of book-cooking that we've prided ourselves on exposing here at the Salt Institute. And it stands exposed - at least in this instance - as that proverbial pride that goeth before a fall. Mea culpa. Note to self: pay attention to details. Look at the "p value." Beware author bias. May I learn patience and sympathy for others of you who ascribe authority to a medical study that "sounds right" because it confirms what one is predisposed to believe. May I find the discipline to "walk the talk" and insist to myself as I've admonished others to insist on quality science, eschewing the authors' news releases and the funding agencies' "spin."
Let us sinners go forth together seeking truth.
