Readers might easily come away from this story with the impression that dietary supplements intended to shore up aging bones have a pleasant, unintended side effect—weight control. But if the story had included more information about the trial it reports, a little more analysis, and comments from an independent source, readers might instead have come away with the realization that these supplements may be all but useless for weight control. Instead of “Add Bone, Drop Pounds, “ an accurate headline might read, “Bone Supplements No Panacea for Midlife Bulge” or something of the sort. In addition to lacking information about the cost of supplements, their potential harms, and alternative methods of weight control, the story fails to adequately back up its suggestion that women who took supplements were less likely to gain weight than those who did not. Just exactly what was the benefit? Not much. The trial showed that women who took calcium and vitamin D for seven years were about a third of pound lighter (0.13 kg or 0.29 pounds) than women who did not. They did not “drop pounds,” as the news story headline suggests, but simply had smaller weight increases or were less likely to gain weight. The study’s authors themselves characterize the magnitude of the effect as “small” and speculate that it may be an artifact of their very large sample. Large trials are capable of capturing tiny, statistically significant differences between groups that may not be meaningful if the two groups being compared are slightly different in ways (e.g. behaviors or risk factors) that the trial can not detect. (This is known as “randomization error.”) This 187-word news brief fails to capture the tiny “benefit” of these supplements or doubts in the research community about their clinical significance.
Although the brief does not mention costs, calcium supplements are available without a prescription and consumers can easily determine their costs.
The story does not cite the absolute benefit of vitamin supplements on weight control. The trial showed that women who took calcium and vitamin D were on average less than a third of a pound lighter (0.13 kg or 0.29 lbs) seven years later than women who did not. Despite the headline “Add bone, drop pounds,” the story also fails to mention whether the dietary supplements influenced bone health or the incidence of fragility fractures. A closer reading of the trial could easily lead a postmenopausal woman to question both the accuracy of the article’s headline and the clinical relevance of the study it reported.
There was no mention of harms of treatment in the news story or in the published study. Other research suggests that main harm of taking the supplements is kidney stones.
The news brief says some women “were given” vitamin supplements and other women placebo, hinting that the study was a randomized controlled trial. Given the extraordinary size of the population enrolled—more than 36,000 women—readers would be better able to evaluate the quality of the study if the story clarified this. The story also failed to mention that the new study is an analysis of data from a trial initially designed to find out whether calcium and vitamin D reduce the risk of hip fractures or colorectal cancer in postmenopausal women.
No obvious elements of disease-mongering.
The story cited one of the study’s authors, but no independent source who might have expressed greater uncertainty about the significance of the study findings.
The news story neglected to mention other safe methods of controlling weight in postmenopausal women. These include calorie-watching and exercise.
The news brief does not mention availability, but most readers will know where to find calcium and vitamin D supplements.
The news brief begins by saying that women already know they “need calcium to protect against osteoporosis,” suggesting that the treatment has a longstanding history.
We can’t be sure if the story relied solely or largely on a news release. We do know that it only quoted one source – a study author.