Using published data to determine the temperature-dependence of stone disease, researchers applied predictions of temperature increase to determine the impact of global warming on the incidence and cost of stone disease in the United States. The Intergovernmental Panel on Climate Change indicates a 1-20 C increase in temperature by 2050 for much of the United States. These findings place a greater significance on the harmful effects of global warming, an ongoing economic and political issue.
The southern United States is considered “the stone belt” because these states have higher incidences of kidney stones. Rising global temperatures could expand this region; the fraction of the U.S. population living in high-risk stone zones is predicted to grow from 40 percent in 2000 to 50 percent by 2050. This could lead to an increase of one to two million lifetime cases of stone disease. The impact of climate-related changes in stone disease will be non-uniformly distributed and likely concentrated in the southern half of the country (linear model) or upper Midwest (non-linear model). The cost associated with treating stone disease could climb as high as one $1 billion annually by 2050, representing a 10-20 percent increase over present-day estimates.
Reference; Pearle MS, Lotan Y, Brikowski T: Predicted climate-related increase in the prevalence and cost of nephrolithiasis in the U.S. J Urol, suppl., 2008; 179: 481, abstract 1407.
About Kidney Stones
Kidney stones, also called renal calculi, are solid concretions (crystal aggregations) of dissolved minerals in urine; calculi typically form inside the kidneys or bladder.
Renal calculi can vary in size from as small as grains of sand to as large as a golf ball. Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms. If stones grow to sufficient size before passage — on the order of at least 2-3 millimeters — they can cause obstruction of the ureter. The resulting obstruction with dilation or stretching of the upper ureter and renal pelvis as well as spasm of muscle, trying to move the stone, can cause severe episodic pain, most commonly felt in the flank, lower abdomen and groin (a condition called renal colic). Renal colic can be associated with nausea and vomiting due to the embryological association of the kidneys with the intestinal tract. Hematuria (bloody urine) is commonly present due to damage to the lining of the urinary tract.
Kidney Stones Statistics
Within the United States, about 10–15% of adults will be diagnosed with a kidney stone.
For unknown reasons, the number of people in the United States with kidney stones has been increasing over the past 30 years. In the late 1970s, less than 4 percent of the population had stone-forming disease. By the early 1990s, the portion of the population with the disease had increased to more than 5 percent.
The incidence rate increases to 20–25% in the Middle East.
Caucasians are more prone to develop kidney stones than African Americans. Stones occur more frequently in men. The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s. For women, the prevalence of kidney stones peaks in their 50s.
Once a person gets more than one stone, other stones are likely to develop. Recurrence rates are estimated at about 10% per year, totaling 50% over a 5–10 year period and 75% over 20 years.
Kidney Stones Causes
Kidney stones can be due to underlying metabolic conditions, such as renal tubular acidosis,]Dent's disease and medullary sponge kidney.[Many health facilities will screen for such disorders in patients with recurrent kidney stones. This is typically done with a 24 hour urine collection that is chemically analyzed for deficiencies and excesses that promote stone formation.