Sir,
Newer data have emerged attempting to address the possible inverse relationship between Helicobacter pylori (H. pylori) infection and the risk of asthma in children or young adults1.
Two pathophysiologic mechanisms have been speculated:
Because a) a percentage of asthma might be associated with gastro-esophageal reflux disease (GERD); and b) according to a few initial studies, H. pylori eradication might also deteriorate GERD, it is deduced that H. pylori may protect against asthma by protecting against GERD.
The potential protective role of H. pylori is consistent with the hygiene hypothesis that microbial infections during early childhood may prevent or diminish asthma.
Rebutting the first argument, we believe that it is confusing because if H. pylori "protects" against GERD by inducing corpus gastritis associated with reduced acidity, then corpus gastritis also protects against duodenal ulcer disease. Therefore, using the same argument one could state that H. pylori protects against duodenal ulcer disease, statement that is irrational2. The studies that investigated the association between H. pylori and asthma relied on serology for detection of H. pylori infection and have not evaluated corpus gastritis or atrophy. Thus, this pathophysiologic mechanism remains clearly a speculation.
Although the second pathophysiological mechanism proposed might be reasonable and merits future elucidation, not recommending eradication of H. pylori even in symptomatic children or young adults is not justified. However, in older ages, H. pylori has been associated with various upper gastrointestinal diseases and extradigestive conditions including functional vascular disorders caused by vascular dysregulation (e.g., Raynaud phenomenon and migraine), ischemic heart disease, ischemic cerebrovascular disorders, glaucoma, Alzheimer disease, mild cognitive impairment, multiple sclerosis, and some autoimmune conditions such as Sjögren syndrome3– 5, possibly necessitating its eradication.
We have recently acknowledged a number of specific factors, such as increased contact with other children, pets or farm animals, and cross-infections between siblings in early life that may decrease the severity or protect against the progression of asthma in children. In rural areas, children are often exposed to these natural allergens and, according to our data collected from children living in an agricultural area6,7, this might be the reason why asthma did not dramatically deteriorate in any of our patients, and was managed entirely in the primary care center with very few hospital referrals or admissions.
Summarizing, the role of H. pylori infection in protecting against childhood asthma remains unclear, although persistence of this infection is likely to cause more problems later in life, rather than potentially protect against asthma and its complications.
Footnotes
Competing interests: None
References
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