Screening for Vitamin D Status: What Do Experts Think?
Last month, we had posted an article about the release of the US Preventive Services Task Force (USPSTF) recommendation on screening for vitamin D deficiency, which effectively said that they were neither for or against screening, and that more evidence was needed before making a decision. However, we were of the opinion that given the widespread prevalence of low vitamin D intake and the increasing prevalence of vitamin D deficiency, screening was a good idea. What do the experts think?
An accompanying editorial was published by noted vitamin D expert Dr. Robert Heaney of Creighton University, which brings up a number of very interesting counterpoints to the USPSTF report. (Ok full disclosure, it was published online some time ago, but only published in print this week).
Dr. Heaney explains that the explicit focus of the USPSTF is disease prevention – or as he interprets it that their approach “effectively equates health with the absence of disease”. He rejects this viewpoint, stating that when supplies of a micronutrient, such as vitamin D, are inadequate, cellular response is blunted. A state Dr. Heaney characterizes as “dysfunction, but not clinically manifest[ed] disease”. In essence, that nutrients help to maintain the normal structure and function of the body.
Much like we did in our analysis of the USPSTF report (which we cited Dr. Heaney’s thoughts on, in fact), he also discussed the importance of considering vitamin D status when designing and interpreting clinical trials. He believes that the USPSTF report does not consider the impact of the vitamin D status of the trial participants, which has skewed their interpretation towards a null conclusion.
Finally, he believes that even though vitamin D treatment is safe and inexpensive, the fact that supplementing with vitamin D requires a compelling motivator, such as knowing their vitamin D status. In other words, screening will be a call to action for those with insufficient status, which could help to reduce the prevalence of inadequacy and deficiency.
At the end of the day, the facts remain the same. Dietary intakes of certain nutrients, like vitamin D, are well below the recommendation for the overwhelming majority of the population. Better understanding nutrient status is a way to help design and interpret clinical trials and most importantly, a potential call to action for people to affect positive behavior change.
Heaney RP, Armas LA. Screening for vitamin D deficiency: is the goal disease prevention or full nutrient repletion? Ann Intern Med 2015; 162(2): 144-5.
Fulgoni VL III, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: Where do Americans get their nutrients? J Nutr 2011; 141(10): 1847-1854.
Heaney RP. Guidelines for optimizing design and analysis of clinical studies of nutrient effects. Nutr Rev 2014; 72(1): 48-54.
LeBlanc ES, Zakher B, Daeges M, et al. Screening for vitamin D deficiency: a systematic review for the US Preventive Services Task Force. Ann Intern Med 2015; 162(2): 109-122.