Posted by Quintal on August 4, 2007, at 17:19:06
In reply to Re: Proton-pump Inhibitors and Bone Damage » Quintal, posted by Phillipa on August 4, 2007, at 12:27:36
That's about right Phillipa. They're saying that low stomach acid may impair the absorption of calcium. They also say that proton pump inhibitors (PPIs) might interfere with bone resorbtion by inhibiting the proton pump of cells caled osteoclasts that break down bone. Osteoclats secrete hydrogen ions (basically hydrocholric acid) to dissolve bone minerals, and if their proton pump is inhibited this process cannot take place. This would seem to imply that bone mineral denisty actually increases during PPI treatment. I'm not sure why this would lead to brittle bones, although I have read reports from some bone specialists that say it's the collogen content of bone that's more important in preventing brittle bones, since collogen is flexible and acts as a shock absorber. Therefore a high mineral denisty combined with a low collogen denisty makes the bone hard and brittle, and PPIs may be tipping the mineral/collogen blanace in that direction.
There has been some correspondence between the authors of that study and a member of the Cedars-Sinai Medical Centre in Los Angeles in which Jordan L. Geller seems to imply that the results of this study may be due to 'the pandemic of vitamin D deficiency in adults'.
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To the Editor: While secondary causes of osteoporosis frequently contribute to hip fractures,1-2 studies of these associations may be hampered by a lack of control for relevant confounding variables. In assessing the association of gastric acid suppression with hip fractures, Dr Yang and colleagues3 did not address vitamin D status as a potential confounder.
The authors hypothesize that gastric acid suppression may impair the release of ionized calcium from calcium salts, leading to calcium malabsorption and impaired skeletal mineralization. However, despite the pandemic of vitamin D insufficiency in adults,4 this vital component of bone health was not considered. There is an inverse relationship between serum 25-hydroxyvitamin D status and parathyroid hormone levels in patients with hip fractures.5 However, Yang et al3 did not provide data regarding the participants' vitamin D status, parathyroid hormone levels, or urinary calcium concentration.
Without these data, it is not clear whether the observed difference in . . . [Full Text of this Article]
Jordan L. Geller, MD
jordan.geller@cshs.org
John S. Adams, MD
Division of Endocrinology
Cedars-Sinai Medical Center
Los Angeles, Calif
__________________________________________________The authors disagree and reply:
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In Reply: We disagree with the suggestion of Drs Geller and Adams that our observed association between PPI use and hip fracture may be confounded by the pandemic of vitamin D deficiency. By definition, a confounder must not only be associated with the disease of interest, it must also be associated with the exposure under study, and it must not be affected by the exposure or the disease.1 Geller and Adams support their concern about confounding of the association between gastric acid suppression and hip fractures by citing evidence of vitamin D status as a risk factor for hip fractures. However, by not considering how PPI therapy might relate to vitamin D status, they ignored 2 of the 3 essential elements that characterize a confounder.
We are not aware of any data that suggest that PPI use may cause or exacerbate vitamin D deficiency. Our search of the literature did . . . [Full Text of this Article]
http://jama.ama-assn.org/cgi/content/abstract/296/24/2947
__________________________________________________So as yet the mechanism behind the increased risk of hip fracture is unknown. This is worrying because if calcium absorption is affected it's likely that other minerals are too, and possibly many other nutrients. I think vitamin B12 deficiency has also been linked to low stomach acid, so PPI patients may be at risk of that as well. Clearly people receiving PPI therapy long-term are at risk of serious injury so why is more not being done to alert patients and doctors? My dad has noticed strong ridges on his fingernails of late, a sign of mineral deficiency, but we don't know the best course of action to take. Nor does his doctor.
Q
poster:Quintal
thread:773849
URL: http://www.dr-bob.org/babble/20070730/msgs/773980.html