Kidney Stones May Increase Patients’ Bone Fracture Risk Over Multiple Years
People who develop kidney stones may be at an increased risk for bone fractures later in life, a new study reports. Experts say the findings should motivate physicians to take greater preventive efforts among those who develop stones.
The formation of kidney stones in the kidneys and urinary tract is a condition called urolithiasis. Since the stones are composed of clusters of dietary minerals found in the urine, researchers have speculated whether the same decreased bone density that produces stones could also lead to outright fracture. These risks don’t appear immediately, however, making them more threatening if the patient fails to take precautions.
It also may be liberating to have a long timeline, says Dr. Michelle Denburg, of the Children's Hospital of Philadelphia and lead author of the new study. “Given that the median time from diagnosis of urolithiasis to fracture was a decade, we might be able to intervene during this interval to reduce the burden of future fracture,” she said in a statement.
Denburg and her colleagues analyzed information on 51,785 people from the UK who were diagnosed with urolithiasis and 517,267 people without the condition. Over a median period of 4.7 years, people who had been diagnosed with urolithiasis showed a significantly greater risk for bone fracture, regardless of where that fracture occurred. Risks jumped about 10 percent for men, though the greatest risks were in adolescence, where they peaked at a 55-percent increase. In women, risks fell between 17 and 52 percent over seven decades of life, peaking between 30 and 39 years.
Kidney stones affect men more than women, though they’re still rare overall. Lifetime incidence, for example, is nearly 13 percent for men and seven percent in women, according to the National Kidney and Urologic Diseases Information Clearinghouse, a division of the National Institutes of Health. People who face them once also have a far greater risk of recurrence, with a five-year risk of 50 percent and a 10-year risk of 80 percent.
Generally, kidney stones won’t form because of a specific diet. More often than not, substances in a person’s urine, like calcium oxalate, and phosphorous, tend to clump together because of some underlying disorder or coexisting condition, like hypercalciuria — a surplus of calcium in the urine. Families that have a history of gastrointestinal tract surgery, gout, or chronic inflammation of the bowel also face an increased risk.
The new research, according to Denburg, could help physicians make more accurate predictions when they design long-term patient plans, ultimately reducing the overall burden of kidney stones on the country. “The significantly higher risk at certain ages in males and females has profound public health implications,” she said.
Source: Denburg M, Leonard M, Haynes K, et al. Risk of Fracture in Urolithiasis: A Population-Based Cohort Study Using the Health Improvement Network. Clinical Journal of the American Society of Nephrology. 2014.