by Heather Simmons
Some Centre County residents may want to think twice before downing that cold, refreshing glass of tap water: It may cause kidney stones in individuals prone to them.
A Voices investigation found that the ratio of magnesium to calcium is extremely low in State College Borough Water Authority water, which may be at least partly responsible for the unusually high prevalence of kidney stones in Centre County.
Kidney stones tend to occur more frequently in the Southeast than in the Northeast, but Centre County appears to be an exception.
“The ‘stone belt’ is normally in the South,” said urologist Jeff Sekula, of State College Urological Associates, “but our area is like a swath of the South up North in that we have a lot of stones.”
According to the Center for Disease Control, in 2004, there were 171,000 kidney stone–related inpatient stays nationwide. Given the national average, Centre County would expect to see between 80 and 110 kidney stone–related inpatient stays.
But Mount Nittany Medical Center, which did not release the number of kidney stone–related inpatient stays, reported 190 kidney stone–related surgeries in the 2006/2007 fiscal year, and Geisinger Health System reported 261 kidney stone–related visits in Centre County between January 2007 and May 2008.
It’s safe to say that the prevalence of kidney stones in Centre County is significantly higher than the national average. And some county residents are feeling it.
“On a scale of one to 10, it’s not even on the page,” said Patton Township resident Daryl Sinn when describing the pain of kidney stones. “‘Pain’ should be spelled in capital letters, with a hyphen between each letter.”
Sinn, who lived in Patton Township from 1973 to 1982 and returned for good in 1990, had an episode involving three separate kidney stones about four years ago. His daughter has also had a kidney stone.
Normally, the kidneys remove excess water and waste from the blood, which produces urine that the body then excretes. Urine contains inhibitors that prevent crystals from forming, but in some individuals, the inhibitors don’t work well, allowing crystals to separate from the urine and form a hard mass.
Kidney stones are often extremely painful. They can be as small as a grain of sand or as large as a golf ball. Some unlucky people end up with stones too large to be passed through the urinary tract.
The causes of kidney stones are varied and hinge on environmental, dietary, genetic, socioeconomic, metabolic and other factors. The most common type of kidney stone is composed of calcium in combination with oxalate or phosphate.
“My doctor’s ideas about how to prevent stones were as nebulous as his ideas as to what causes stones,” Sinn said.
Despite the uncertainties, there is one concrete recommendation for the prevention of kidney stones: Drink plenty of water. But what if the water is part of the problem?
Scientists have debated for years the contribution of hard water to kidney stone formation. The study results have been mixed, with some indicating that hard water does cause kidney stones and others suggesting that it doesn’t.
Water is considered to be hard if the combined calcium and magnesium content exceeds 100 parts per million. The State College Borough Water Authority―which serves State College Borough and Patton, Ferguson, College, Harris and Benner townships―reported that its water contains between 180 and 240 parts of calcium and magnesium per million.
The controversy surrounding hard water’s effect on kidney stones may be due to the fact that although excess calcium may increase kidney stone formation in people predisposed to kidney stones, magnesium actually inhibits kidney stone formation.
That suggests that the ratio of magnesium to calcium determines the water’s kidney stone–causing potential. So water with low magnesium and high calcium concentrations may increase the likelihood of stones in people who are predisposed to them.
That’s the case in State College and the five townships served by the State College Borough Water Authority. The water authority reported that the magnesium concentration in its water ranges from 14 to 20 parts per million, while the calcium concentration ranges from 180 to 220 parts per million. The low ratio of magnesium to calcium in the water consumed by Sinn and the more than 82,000 other water authority customers is likely at least partially responsible for the high number of kidney stone–related cases at Mount Nittany Medical Center and county Geisinger clinics.
Centre Countians looking for softer water should head over to the Philipsburg area. The Pennsylvanian-American Water Company, which serves the Philipsburg area, reported a combined calcium and magnesium level of between 10 and 48 parts per million, which is significantly less than the 100 parts per million needed to be classified as hard water.
The 2007 Bellefonte Borough water quality report did not include the calcium and magnesium levels in the spring that serves the Bellefonte area, and the borough did not respond to a request for the information.
The high level of calcium in the State College Borough Water Authority water may be due in part to the geology of the area. According to the water authority, the local bedrock consists primarily of carbonate limestone and dolomite. Limestone (calcium carbonate) is widely used as a calcium supplement.
It has been shown that taking calcium supplements can cause kidney stones in people predisposed to forming stones. But people need calcium and magnesium in their diets to maintain basic bodily functions, and individuals who are not prone to kidney stones will probably not experience any problems associated with excess calcium in the water.
“Whether or not I would personally recommend avoiding drinking tap water would depend on the underlying metabolic cause of the stone,” Sekula said.
So anyone who has had a kidney stone should consult a physician to determine the cause and type of the stone before doling out $6 for a case of bottled water.