Stomach Cancer in Costa Rica: What are the Odds?
|Paul is a hydrogeologist and environmental engineer and the owner/operator of Osa Water Works. You may reach him at firstname.lastname@example.org|
The incidence of gastric cancer varies widely, from 28.3 cases / 100,000 people in Mongolia to 0.78 / 100,000 in Mozambique. That is a ginormous planetary variance of nearly two orders of magnitude! At 17.3/100K Costa Rica ranked 10 th for women and 12 th for men in 2014 according to the World Cancer Research Fund International. In 1998 Costa Rica was 4 th after North and South Korea and Japan in the incidence of this 5 th most common type of cancer. Stomach cancer is documented in the written record since 3000 BC. Until the last decade of the 19 th Century when lung cancer overtook its crown, stomach cancer was the most widespread form of human cancer and had been throughout all of human history.
We were meeting to discuss non-medical business when I sprang the question on Dr. Randall Umaña Villalobos, Resident Doctor at the Clínica de Puerto Jiménez, so he wasn’t expecting it: “So why, Doctor Umaña, is the incidence of gastric cancer so high in Costa Rica?”
“There are many risk factors,” he said, “that make it hard to isolate causes. Getting cancer is like winning the lottery,” he said, “only in reverse. In Costa Rica it is thought that our high incidence is likely related to sanitation and hygiene; it is more prevalent, after all, in the developing world.”
Except for Africa. The Dark Continent at last assessment was still in the developing world class of nations. Yet it has the lowest regional rates of stomach cancer on the planet.
Until 1982, white-bread doughboy gastro-oncologists still counted spicy foods as a risk factor for gastric cancer: of course the Koreans and Japanese were susceptible: look at what they ate! But that very year the bacterium Helicobacter pylori was isolated, cultured and classified, and the medical community quickly seized on and confirmed this unrecognized interloper as a risk factor for gastritis, peptic ulcers, and indeed some varieties of stomach cancer. A raft of research and a number of conclusive findings followed. It turned into a sufficiently big deal over the next 33 years that just last year, Australian researchers Barry Marshall and Robin Warren were awarded the Nobel Prize in Physiology or Medicine for its discovery.
It turns out that only 50% of the world’s population is infected by H. pylori. Miranda and others (1998) found in the Poás and Puriscal regions of Costa Rica an 83 and 82% infection rate respectively. The VI International Helicobacter pylori Symposium was held in San Jose, Costa Rica in 2014, where it was revealed that sub-strains of H. pylori correlate with substantially different health effects. The less virulent strain is common to, ironically, Africa, and the more virulent strain is prevalent in Asia and South America. In Costa Rica, La Nación (2015) reports that 5-15% of the infected population can expect to develop medical complications.
Otzi was a Neolithic denizen that died from an arrow wound in the high Alps 5000 years ago and was mummified by the snow. Researchers have since detected the presence of H. pylori in his stomach.
Helicobacter pylori is not a native resident of human flora. It is an opportunistic bacterium that enters the body through ingestion, typically in childhood or adolescence, and persists outside of treatment in the mucus of the upper stomach for the rest of the subject’s life. In most cases its presence does not cause disease and in some studies its presence has been shown to have a prophylactic effect against other maladies, including asthma of all things, and even some types of stomach cancers themselves.
In 2004, Fujimura et al tested environmental samples from a Japanese region with a particularly high H. pylori infection rate and discovered that the bacterium was for all practical purposes ubiquitous in the surface environment. Since the bacterium is present in native waters and in farmed soils and since the bacterium infects through ingestion, they showed that contaminated water and food are an unambiguous vector of infection. There is a chicken and egg quality, however, to the findings: did the environment have high bacteria because of the prevalence of human infection, or was the environment causing the infection? In practical terms it does not matter. The bacterium is in the environment and infects through ingestion. To avoid infection, therefore, we must guarantee as a first line of defense that drinking water supplies exclude this pathogen.
Costa Rica is a nation with a prolific abundance of water, and Ticos have for most of recorded history and all of prehistory gotten water from springs and highland streams and shallow wells and only in recent decades bumped up against such novelties as municipal water systems. In all fairness, Costa Rica stepped up to that plate many years ago and is one of the few Latin American nations that has fully potable water supply as national policy. As a water engineer, I warn off-grid folks that due to the ubiquity of the protozoan Giardia lamblia, all surface water in this nation and for all practical purposes anywhere on the planet with wild or domesticated animals should be considered contaminated by this particularly widespread sponsor of a rough patch for first timers: amoebic dysentery, or beaver fever if you prefer. I have found from testing across 16 years that hard-rock and saprolite springs in Costa Rica are in my experience universally free of fecal coliform and are of superlative water quality from a physicchemical perspective as well. But contact with the surface environment quickly contaminates these pristine sources with zillions of biospheric pathogens, and proper intake designs that protect against this contamination are in practice seldom used and irregularly maintained, a quirk unseen in most parts of the world, where water is less abundant. In Costa Rica, the predominant malefactor is Giardia, and most of us have developed a physiologic tolerance from a lifetime of exposure. Like H. pylori, Giardia also resides opportunistically in infected subjects unless and until intervened with a proper antibiotic regimen.
The indicator organism fecal coliform, enshrined by the World Health Organization as the planet’s standard-bearer for water potability, provides for a low-cost test to confirm the absence of intestinaltract waterborne parasites. However, unlike microbes that transmit cholera, hepatitis-A, typhus, typhoid fever, amoebic and bacterial dysentery, and all kinds of other bad nasties, Helicobacter pylori does not live in either of the intestines but in the upper stomach. It is an aerobe that requires oxygen to live. Oxygen is poison to the anaerobic pathogens that dwell in the intestinal tracts of mammals and birds. The WHO guidelines for water potability is non-detection of fecal coliform. Any detection whatsoever classifies the water as non-potable without treatment. Costa Rica uses this standard for its own national water-quality policy. So does the US. All countries do.
But fecal coliform is not an indicator of H. pylori and says nothing at all about its possible presence or absence in surface waters.
So I called up the head of the microbiology division at Laboratorios Agrotec, the lab I rely on for minor and trace ion hydrochemistry and biological analysis.
“I’d have to prepare or order a culture medium probably,” Fabricio demurred. “It’s not something we routinely do, but it’s not rocket science.”
After a telephone survey no private labs that we contacted offered H. pylori analyses on even human fluids or biopsy tissue, far less water or soil samples. “They do it in public institutions,” we were told, “when requested by doctors at clinics from biopsies.”
Dr. Umaña says it would be unusual inside national institutional medicine to call for H. pylori tests, or to treat patients to rid them of the infection. With 80% of the population already infected, a positive detection would appear to simply be a confirmation of the obvious.
“And if I had an H. pylori infection,” I said, “and wanted to get rid of it,” I asked him, “what would I have to do?”
“No single medication will treat it,” he said. “But the treatment regimen is two antibiotics, one a single dose, the other across seven days, assisted with a medication that reduces stomach acidity.”
So . . .
* H. pylori infection has been incontrovertibly linked with stomach cancer.
*Costa Rica has a high incidence of stomach cancer.
* Seven out of ten Ticos have the H. pylori infection, which results from oral ingestion, usually as children or teenagers.
*The strain of H. pylori present in Costa Rica is the most likely to cause gastric maladies.
* Costa Rica has a disproportionate rural dependence on haphazard home water supply systems from natural sources (springs, streams, shallow wells) where H. pylori is known to exist.
Could it be possible there is a relation here? Might we correct in future epidemiological research for the effects of: 1) genetics; 2) age; 3) alcohol and tobacco consumption; 4) salt intake; and 5) exercise and lifestyle and dial down on the role that environmental H. pylori actually plays in our heightened national vulnerability to stomach cancer?
I think this dialing down is in this nation’s and indeed humanity’s near future. In the meantime, it seems reasonable to assume that our water supply is the first line of defense against infection at any age but particularly for the more vulnerable young.
Both ultraviolet and chlorine kill all microbes, aerobic and anaerobic, pathogens and innocuous alike. Ultraviolet light is a form of energy located on the electromagnetic spectrum just below the visible range of light that is toxic to microbes upon exposure. Chlorine is an element that remains in the water after contact, a chemical if you prefer, and is toxic to all life and is a known human carcinogen. Both UV and chlorine make the water indisputably safe from microbial contamination, but chlorine carries a latent risk factor. In town, the water is chlorinated. But for everyone off-grid, ultraviolet disinfection is an inexpensive water purification solution that is non-chemical, has no known adverse side effects, and guarantees your family against all microbial and viral pathogens, including the one we have not yet properly recognized and indoctrinated into the hallowed hall of gastro-enteric bad boys: Helicobacter pylori.