ATLANTA—Higher dietary acid load is independently associated with an increased risk of kidney stones, researchers reported at the American Society of Nephrology’s Kidney Week 2013 meeting.
Ernest I. Mandel, MD, of Brigham and Women’s Hospital in Boston, and colleagues examined the association between dietary acid load and kidney stones in 44,581 men in the Health Professionals Follow-up Study, 73,154 older women and 91,509 younger women in the Nurses’ Health Study I and II, respectively. Subjects had 24 years, 26 years, and 16 years of follow-up, respectively.
The investigators identified a total of 6,361 incident cases of kidney stones during about 4.4 million person-years of follow-up. After adjusting for potential confounders, the men, older women, and younger women in the highest quintile of diet-estimated net endogenous acid production had a significant 59%, 48%, and 53% increased risk of kidney stones, respectively, compared with those in the lowest quintile.
The men and younger women in the highest quintile of diet-estimated potential renal acid load had a significant 54% and 30% increased risk of kidney stones compared with those in the lowest quintile. The older women had a non-significant 8% increased risk.
The researchers noted that higher dietary acid load may reduce urinary citrate excretion, which is associated with an increased risk of kidney stone formation.