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zoom RSS 胃潰瘍の治療薬はビタミンB12欠乏症の潜在的な原因

<<   作成日時 : 2013/12/16 21:12   >>

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胃潰瘍の治療薬はビタミンB12欠乏症の潜在的な原因
20万人にたいする米国での研究によれば、
胸焼けや消化不良といった胃潰瘍の治療に使われるプロトンポンプ阻害薬(PPI)やヒスタミン拮抗薬(H2RAs)を服用した人々は、健康のための十分なビタミンB12が不足している可能性が高かった。B12欠乏症が放置されると、認知症や神経学的疾患になる可能性がある。
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11 December 2013 Last updated at 03:04 GMT
Ulcer drugs linked to vitamin B12 deficiency
http://www.bbc.co.uk/news/health-25314643

Medication used to treat stomach ulcers may cause potentially harmful vitamin B12 deficiency, say experts.

A US study of 200,000 people in the Journal of the American Medical Association found the link.
People who took tablets known as proton pump inhibitors (PPIs) or histamine antagonists (H2RAs) were more likely to lack enough vitamin B12 for good health.
Left untreated, B12 deficiency can lead to dementia and neurological problems.
The study authors say doctors should still prescribe these medicines, but that they should weigh possible harms against any benefits in patients who need the drugs for prolonged periods of time.
More investigations are needed to fully evaluate the risk which appears to be in people who take these medications for two or more years, they say.

Link not proof
The Kaiser Permanente researchers found that the link with B12 deficiency increased with dose and was stronger in women and younger age groups.
But the overall risk was still low.
PPIs and H2RAs are commonly prescribed for patients with symptoms of stomach ulcers such as heartburn and indigestion.
The tablets are also widely available to buy without a prescription, 'over-the-counter' at pharmacies.
They work by reducing the amount of acid made by your stomach.
Stomach acid is needed for us to absorb vitamin B12 from our food, such as meat, fish and dairy.
If identified, most cases of B12 deficiency can be easily treated by giving supplements or an injection of vitamin B12.
But symptoms, such as lethargy, can be vague and overlooked.
Prof Mark Pritchard of the British Society of Gastroenterology said people should not be concerned by the findings.
"Only patients who had taken these tablets for more than two years were at risk and only a minority of patients on long-term proton pump inhibitors showed evidence of vitamin B12 deficiency."
He said people taking ulcer medications could ask their GP for a simple blood test to measure vitamin B12 levels if they are worried.


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Proton Pump Inhibitor and Histamine 2 Receptor Antagonist Use and Vitamin B12 Deficiency
Jameson R. Lam, MPH1; Jennifer L. Schneider, MPH1; Wei Zhao, MPH1; Douglas A. Corley, MD, PhD1

JAMA. 2013;310(22):2435-2442. doi:10.1001/jama.2013.280490.

Importance Proton pump inhibitors (PPIs) and histamine 2 receptor antagonists (H2RAs) suppress the production of gastric acid and thus may lead to malabsorption of vitamin B12. However, few data exist regarding the associations between long-term exposure to these medications and vitamin B12 deficiency in large population-based studies.

Objective To study the association between use of PPIs and H2RAs and vitamin B12 deficiency in a community-based setting in the United States.

Design, Setting, and Patients We evaluated the association between vitamin B12 deficiency and prior use of acid-suppressing medication using a case-control study within the Kaiser Permanente Northern California population. We compared 25?956 patients having incident diagnoses of vitamin B12 deficiency between January 1997 and June 2011 with 184?199 patients without B12 deficiency. Exposures and outcomes were ascertained via electronic pharmacy, laboratory, and diagnostic databases.

Main Outcomes and Measures Risk of vitamin B12 deficiency was estimated using odds ratios (ORs) from conditional logistic regression.

Results Among patients with incident diagnoses of vitamin B12 deficiency, 3120 (12.0%) were dispensed a 2 or more years’ supply of PPIs, 1087 (4.2%) were dispensed a 2 or more years’ supply of H2RAs (without any PPI use), and 21?749 (83.8%) had not received prescriptions for either PPIs or H2RAs. Among patients without vitamin B12 deficiency, 13?210 (7.2%) were dispensed a 2 or more years’ supply of PPIs, 5897 (3.2%) were dispensed a 2 or more years’ supply of H2RAs (without any PPI use), and 165?092 (89.6%) had not received prescriptions for either PPIs or H2RAs. Both a 2 or more years’ supply of PPIs (OR, 1.65 [95% CI, 1.58-1.73]) and a 2 or more years’ supply of H2RAs (OR, 1.25 [95% CI, 1.17-1.34]) were associated with an increased risk for vitamin B12 deficiency. Doses more than 1.5 PPI pills/d were more strongly associated with vitamin B12 deficiency (OR, 1.95 [95% CI, 1.77-2.15]) than were doses less than 0.75 pills/d (OR, 1.63 [95% CI, 1.48-1.78]; P?=?.007 for interaction).

Conclusions and Relevance Previous and current gastric acid inhibitor use was significantly associated with the presence of vitamin B12 deficiency. These findings should be considered when balancing the risks and benefits of using these medications.

Vitamin B12 deficiency is relatively common, especially among older adults; it has potentially serious medical complications if undiagnosed. Left untreated, vitamin B12 deficiency can lead to dementia, neurologic damage, anemia, and other complications, which may be irreversible. According to data from the National Health and Nutrition Examination Survey, 3.2% of adults older than 50 years are estimated to have low serum vitamin B12 levels.1 Other studies have reported prevalence rates of 5% to 15%, although these may be underestimates of the true prevalence in some population subgroups.2,3 Thus, identifying modifiable risk factors for vitamin B12 deficiency is of significant public health importance.

Acid inhibitors are among the most commonly used pharmaceuticals in the United States. In 2012, 14.9 million patients received 157 million prescriptions for proton pump inhibitors (PPIs); thus, use of PPIs could theoretically increase the population’s risk of vitamin B12 deficiency.4 Gastric acid is required to cleave vitamin B12 from ingested dietary proteins for the essential vitamins to be absorbed, and it is produced by the same cells that produce intrinsic factor, a compound required for vitamin B12 absorption.5 Thus, PPIs and histamine 2 receptor antagonists (H2RAs), which suppress the production of gastric acid, may lead to malabsorption of vitamin B12.

Studies examining the relationship of PPI use and vitamin B12 deficiency have focused primarily on small groups of elderly individuals and yielded inconsistent results. Although some studies suggested that acid suppressive medications are associated with lower vitamin B12 levels in older populations,6- 9 others found no association.10- 15 To our knowledge, no large population-based studies exist. Therefore, we performed a case-control study to evaluate the relationship between the use of acid-suppressing prescription medications and the risk of vitamin B12 deficiency within a large, community-based population.

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胃潰瘍の治療薬はビタミンB12欠乏症の潜在的な原因 医師の一分/BIGLOBEウェブリブログ
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