Vitamin D and Calcium are to Maintain Strong Bones, not Every Health Eventuality
Because of an effective PR effort by the Kaiser Permante Center for Health Research, you are likely to see media that vitamin D and calcium supplementation does not improve menopausal symptoms. If you are a woman over 50y of age, what does this mean? Here are some things to know.
The Women’s Health Initiative (WHI) is composed of 3 trials. One trial had a stated objective: to determine if calcium and vitamin D supplements reduced the risk of hip and other factures, and colorectal cancer, in postmenopausal women (50-79y). Women participating in hormone replacement therapy (HRT) and dietary modification trials of the WHI were encouraged to participate. Measuring the effect of calcium and vitamin D supplementation on menopausal outcomes was never a stated objective.
LeBlanc and colleagues report that calcium and vitamin D supplements do not influence menopause-related symptoms. Is there much evidence that vitamin D and calcium supplementation would affect hot flashes and other menopause-related symptoms? Not according to the citations provided in the introduction of the paper. In 2011, the Institute of Medicine updated vitamin D and calcium recommendations. Menopause-related symptoms are not mentioned (other than menopause-related bone losses).
Is this more “creative health news”? Possibly but for different reasons than the ‘chocolate sting’. As explained by the perpetrator, John Bohannon, “If you measure a large number of things about a small number of people, you are almost guaranteed to get a ‘statistically significant’ result. Our study measured 18 different measurements.” In a similar manner, by adding a new measurement (menopause-related symptoms), researchers increase the probability of finding a statistically significant result.
Was Maturitas seduced by a statistically significant finding? Apparently, too much reliance upon statistical measures has resulted in lower-quality research being published for some journals. Not the case today as LeBlanc and colleagues report a p-value of 0.7. Obviously, this study was not rejected by the editor because of a null finding.
Unlike the chocolate publication (retracted from International Archives of Medicine), LeBlanc and colleagues have the advantage of reporting on 17,101 women participating in an exceptionally well-publicized study, the WHI. Presumably, journal editors are keen to publish WHI data. Certainly WHI-related papers are often published in prestigious journals.
The topic, menopause and supplementation with calcium and vitamin D, is also interesting. Should easily lead to a headline guaranteed to attract readers. What should it matter that experts, such as the NIH Office of Dietary Supplements, do not associate menopause-related symptoms with vitamin D or calcium?
As the WHI intervention came to an end over 10 years ago, Jackson and colleagues reported calcium and vitamin D supplementation significantly increased bone mineral density and did not reduce hip fracture. When women who ceased taking their calcium and vitamin D supplements during the study were excluded from the statistical analysis, the hazard ratio for a hip fracture was reduced 29% (vs placebo). Once again providing evidence it is difficult to obtain a nutritional benefit when one doesn’t ingest the nutrient!
Vitamin D and calcium are essential for strong bones and especially in postmenopausal women. Don’t be discouraged from supplementing just because these nutrients aren’t reported to be magic bullets for every health concern people can think of.
LeBlanc ES, Hedlin H, Qin F, Desai M, Wactawaski-Wende J, Perrin N, Manson JE, Johnson KC, Masaki K, Tylavsky FA, Stefanick ML. Calcium and vitamin D supplementation do not influence menopause-related symptoms: Results of the Women’s Health Initiative Trial. 2015 Maturitas doi: 10.1016/j.maturitas.2015.04.007
Jackson RD1, LaCroix AZ, Gass M, Wallace RB, Robbins J, Lewis CE, Bassford T, Beresford SA, Black HR, Blanchette P, Bonds DE, Brunner RL, Brzyski RG, Caan B, Cauley JA, Chlebowski RT, Cummings SR, Granek I, Hays J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Johnson KC, Judd H, Kotchen JM, Kuller LH, Langer RD, Lasser NL, Limacher MC, Ludlam S, Manson JE, Margolis KL, McGowan J, Ockene JK, O'Sullivan MJ, Phillips L, Prentice RL, Sarto GE, Stefanick ML, Van Horn L, Wactawski-Wende J, Whitlock E, Anderson GL, Assaf AR, Barad D; Women's Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of fractures. 2006 NEJM doi: 10.1056/NEJMoa055218
Ross AC, Manson JE, Abrams AA, Alooia JF, Brannon PM, Clinton SK, Durazo-Arvizu RA, Gallagher JC, Gallo RL, Jones G, Kovacs CS, Mayne ST, Rosen CJ, Shapses SA. The 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D from the Institute of Medicine: What clinicians need to know. 2011 J Clin Endocrinol Metab doi: 10.1210/jc.2010-2704