Substandard Studies or Substandard “Standard-of-Care”

To the Editor: We read with concern the recent paper by Sato et al.,1 which studied the effect of sunlight deprivation versus sunlight exposure on the biochemical and densitometry status and fracture outcomes of elderly institutionalized patients with Alzheimer's Disease (AD). We question the ethical justification of conducting this study on a group of highly vulnerable individuals whose baseline 25(OH)D levels were already low, at a mean level of 24 nM (by the authors own reference range of 47-61 nM and by international standards). Given the reported benefits of vitamin D supplementation in the prevention of fractures2, 3 and the authors earlier work reporting the high risk of hip fracture in AD patients with low BMD and vitamin D deficiency,4 we consider that the first requirement should have been to return all patients to a replete state with vitamin D supplementation and examine the additional benefits of daily controlled sunlight exposure. Alternatively, all those with a low vitamin D level could have been excluded from randomization, albeit offering them hip protectors. With mean Mini Mental State Examination (MMSE) values of 16/30, the majority of these subjects would have had limited capacity to give informed consent regarding participation in this study. We doubt whether consenting relatives would have appreciated the potential risks they unwittingly exposed their families to, as evidenced by the almost 4-fold increase in hip fracture rate in the “sunlight-deprived” group. No mortality data were provided for the hip fracture patients despite widely available evidence of increased mortality after this fracture,5, 6 especially in AD patients.7 In summary, this study on a vulnerable population had the potential for doing harm, and the results could have been largely predictable.