What is Helicobacter pylori, the bacteria that can cause stomach cancer in more than 15 million children?

The Helicobacter pylori bacterium , responsible for major digestive disorders, could become a serious public health problem if effective preventive measures are not implemented. A new study published in the journal Nature Medicine estimates that more than 15 million children born between 2008 and 2017 will develop stomach cancer during their lifetime, and that 76% of these cases will be related to this infection.

The study's authors emphasize that the distribution of cases will not be homogeneous. The majority of the future burden of this disease will fall in Asia , where 68% of expected diagnoses are concentrated. The Americas and Africa will also experience worrying developments, with 13% and 11% of total cases, respectively. Projections also indicate that China and India alone will account for nearly 42% of all diagnoses globally. Sub-Saharan Africa, meanwhile, could see its current number of cases increase sixfold in just a few decades due to population growth.

What is Helicobacter pylori?

This bacteria of global impact is once again attracting the attention of the medical community. Helicobacter pylori, a microorganism that can lodge in the stomach from childhood and, in some cases, trigger serious digestive tract diseases. As explained by the World Gastroenterology Organization, Helicobacter pylori infection tends to be persistent. Without treatment, it can persist for the patient's entire life. It is only eliminated naturally in exceptional cases, such as when a prolonged chronic infection causes atrophy and extensive metaplasia of the gastric mucosa, leading to the loss of gastric acid (achlorhydria).

In infants, however, transient infections may occur, which clear up without treatment. In adults who have received appropriate antibiotics, reinfection is rare , even in areas with a high prevalence of the bacteria. However, in some cases, a recrudescence may occur, when therapy does not completely eliminate the infection and it reappears after temporary suppression.

Furthermore, the different strains of H. pylori present in different regions of the world have varying levels of virulence. These differences, along with the interaction between environmental factors and the host's genetic characteristics , directly influence how the disease manifests and the clinical course of each patient.

H. pylori infection causes chronically active gastritis . Although many people remain asymptomatic throughout their lives, a significant proportion of cases develop gastroduodenal diseases of varying severity. Among the most common complications is peptic ulcer , which can affect the stomach or duodenum. This condition carries a risk of gastrointestinal bleeding and, occasionally, gastric wall perforation.

The bacterium is also implicated in the development of non-cardiac gastric cancer and MALT lymphoma , a type of tumor associated with the lymphoid tissue of the gastric mucosa. It may also be responsible for symptoms in certain patients with functional dyspepsia, a difficult-to-treat digestive disorder.

As the Mayo Clinic explains, the infection usually occurs at an early age and is primarily transmitted through direct contact with saliva, vomit, or feces , although it can also be spread through the consumption of contaminated food or water . Factors such as overcrowding, lack of access to clean water, and living in developing countries significantly increase the risk of infection.

In many cases, carriers don't develop any obvious symptoms. However, when they do appear, they may manifest as abdominal pain , nausea , bloating , frequent belching , or unintentional weight loss . Furthermore, in some individuals, the infection progressively progresses to more severe illness.

Experts point out that in addition to the infectious component, there are modifiable risk factors such as alcohol consumption, tobacco use, physical inactivity, and excess weight. Genetic variables also play a role, determining the progression to more serious diseases.

The authors of the aforementioned study quantify, for the first time, the future burden of gastric cancer in individuals born between 2008 and 2017, assuming no substantial changes are made to current prevention policies. They warn that the 11.8 million cases attributable to H. pylori are potentially preventable through systematic screening and treatment.

However, despite this opportunity, few countries have implemented large-scale early detection programs. Research suggests that addressing this threat with effective preventive strategies could reduce expected cases by up to 75% .