Molloy DW, Standish TI, Nieboer E, Turnbull JD, Smith SD, Dubois S.
Effects of acute exposure to aluminum on cognition in humans.
J Toxicol Environ Health A. 2007 Dec;70(23):2011-9.
PubMed.
While there are a number of scientific flaws in both the experimental design and the interpretation of the results of this paper, these pale into insignificance when placed in the context of the ethical issues raised by dosing individuals with high levels of aluminum. [Abbreviated, 18 January 2008]
Having just discovered this paper, I am astonished that the trial was allowed to take place. If it had been conducted in appropriate animal models, with long-term cognitive studies and postmortem examination of the tissues, then this might have provided us with some insight into the potential impacts of Al dosing. In practice, the trial was performed on humans, with the stated hypothesis “individuals without or with preexisting cognitive decline would exhibit a deterioration in cognition following acute exposure to aluminium....”—where the individuals were Alzheimer's patients and their carers. The authors note that “in some cases the serum levels of aluminium reached after a single dose far exceeded levels at which aluminium has been associated with cognitive effects in dialysis dementia.” They also note their surprise that cognitive effects were not observed—having studied the groups for only 3 days. Whilst long-term monitoring of the individuals is self-evidently required to establish the impact of this study, I am most disturbed (given what is already known, and what was evidently available to the authors) that this research was performed at all, let alone on such a vulnerable sector in our society.
Reply by William Molloy
The authors stand by the experimental design, the ethics approval process, and the conclusions of our study. The experimental work was conducted about 10 years ago. Caution was taken at every step by carefully titrating the doses upwards, using an over-the-counter antacid and carefully monitoring for adverse effects, in the three pilot studies, through to the randomized controlled section of the trial. We did pilots with normal young controls before moving to patients with dementia. Because of the huge variability in absorption rates among subjects, we adjusted individual doses according to the absorption profile of each subject. The data (Table 3) clearly show that the serum aluminum levels dropped significantly overnight after the doses were administered. We observed no adverse cognitive effects in any subjects. The putative role of aluminum in the causation of Alzheimer disease has provoked polarized debate over the years, and will likely continue to do so for some years to come. We refrain from entering that debate.
Comments
While there are a number of scientific flaws in both the experimental design and the interpretation of the results of this paper, these pale into insignificance when placed in the context of the ethical issues raised by dosing individuals with high levels of aluminum. [Abbreviated, 18 January 2008]
University of Warwick
Having just discovered this paper, I am astonished that the trial was allowed to take place. If it had been conducted in appropriate animal models, with long-term cognitive studies and postmortem examination of the tissues, then this might have provided us with some insight into the potential impacts of Al dosing. In practice, the trial was performed on humans, with the stated hypothesis “individuals without or with preexisting cognitive decline would exhibit a deterioration in cognition following acute exposure to aluminium....”—where the individuals were Alzheimer's patients and their carers. The authors note that “in some cases the serum levels of aluminium reached after a single dose far exceeded levels at which aluminium has been associated with cognitive effects in dialysis dementia.” They also note their surprise that cognitive effects were not observed—having studied the groups for only 3 days. Whilst long-term monitoring of the individuals is self-evidently required to establish the impact of this study, I am most disturbed (given what is already known, and what was evidently available to the authors) that this research was performed at all, let alone on such a vulnerable sector in our society.
St. Peter's McMaster
Reply by William Molloy
The authors stand by the experimental design, the ethics approval process, and the conclusions of our study. The experimental work was conducted about 10 years ago. Caution was taken at every step by carefully titrating the doses upwards, using an over-the-counter antacid and carefully monitoring for adverse effects, in the three pilot studies, through to the randomized controlled section of the trial. We did pilots with normal young controls before moving to patients with dementia. Because of the huge variability in absorption rates among subjects, we adjusted individual doses according to the absorption profile of each subject. The data (Table 3) clearly show that the serum aluminum levels dropped significantly overnight after the doses were administered. We observed no adverse cognitive effects in any subjects. The putative role of aluminum in the causation of Alzheimer disease has provoked polarized debate over the years, and will likely continue to do so for some years to come. We refrain from entering that debate.
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