Friday, October 31, 2014
Study Finds Kidney Stones Linked to Weakened Bones
Researchers led by Dr. Michelle Denburg, of the Children’s Hospital of Philadelphia, analyzed data from nearly 52,000 British kidney stone patients and more than 517,000 people without kidney stones.
During a median follow-up of nearly five years, kidney stone patients were at significantly higher risk for fractures, and this increased risk affected all bones, Denburg’s team found.
Overall, males with kidney stones were 10% more likely to suffer broken bones than those without kidney stones. The risk was highest among male teens – those with kidney stones had a 65% higher risk for fractures than those without kidney stones.
Among women, those with kidney stones had a 17% to 52% increased risk of fractures from their 20s to their 60s, with the highest risk among women age 30 to 39, according to the study published October 23 in the Clinical Journal of the American Society of Nephrology.
The findings only point to an association between kidney stones and fracture risk, and do not prove a cause-and-effect relationship. However, the researchers believe that efforts to boost kidney stone patients bone health might help shield them from fractures.
“Given that the median time from diagnosis of [kidney stones] to fracture was a decade, we might be able to intervene during this interval to reduce the burden of future fracture,” Denburg said in a news release from the American Society of Nephrology.
This study is examining the relationship between pathology (kidney stones) and normal physiology (bone strength). The key is calcium metabolism.
Most kidney stones contain calcium with calcium oxalate crystals being the most common. There are two kinds of abnormal calcification in the body. The first is dystrophic calcification – a calcium deposit secondary to an injury. I developed a kidney stone when my ribs were broken during a soccer game and the underlying kidney was bruised. Calcium deposits in joints following trauma are another example as are calcium deposits in artery walls (atherosclerosis).
The second is metastrophic calcification – calcium deposition secondary to altered chemical metabolism. A vast majority of kidney stones fall into this category. When mineral metabolism goes awry, deposits can occur anyplace in the body.
Calcium metabolism is controlled by the parathyroid and vitamin D, moving this mineral in and out of bone as needed to buffer the pH of the blood stream. If calcium is leached from bone to form kidney stones then bone strength will suffer and fracture is more likely.
THE BOTTOM LINE:
If you have had a kidney stone, it is vital that you learn the composition of the stone to determine whether it was due to dystrophic or metastrophic calcification. If it was the later, then have a qualified nutritionist evaluate and treat the involved metabolic pathways.
Source: National Institutes of Health -October 23, 2014