Kidney Stone Risks After Menopause

Kidney stone risk was reduced by light exercise

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Eating healthily and exercising regularly have many health benefits for your heart and metabolism. New research suggests these healthy habits may also protect against kidney stones.

Researchers looked at data from postmenopausal women to see if body mass index (BMI), exercise and calorie intake were linked to kidney stones.

These researchers found that women who exercised, even lightly, were significantly less likely to develop a kidney stone.

Additionally, women who ate more calories than they needed were at an increased risk for kidney stones.

"Exercise regularly and watch your calorie intake."

Mathew Sorenson, MD, MS, of the Division of Urology in the Department of Veteran Affairs Medical Center, led this study on the link between kidney stones, exercise and calorie intake in postmenopausal women.

Kidney stones are small formations of minerals that form in the kidney. They pass through the body through the urine.

Although small kidney stones may pass without pain or noticeable symptoms, some stones become large enough to partially block the flow of urine, resulting in pain and sometimes nausea.

According to the authors of this study, obesity and weight gain are associated with an increase in kidney stones, but the dietary and exercise factors in this relationship are not fully understood.

To better understand how physical activity and calorie intake affects kidney stones, Dr. Sorensen and colleagues used data from the Women's Health Initiative Observational Study.

From 1993 to 1998, they evaluated 84,225 postmenopausal women who had no history of kidney stones.

During the follow-up period, 2,392 women reported developing a kidney stone. The average age of the participants who developed kidney stones was 64 years old.

After analyzing the data, the researchers found that a higher than normal BMI (a measure of height and weight) was associated with a 1.30- to 1.81-fold increased risk of developing kidney stones.

Women who reported low weekly physical activity were 16 percent less likely to develop a kidney stone than women who did not exercise at all.

As women exercised more, their risk of developing a kidney stone fell further, up to a 31 percent reduction in risk.

The researchers also found that the intensity of the exercise did not significantly affect the participants' kidney stone risk.

Additionally, the women who ate more calories had up to a 42 percent increased risk of kidney stones compared with women who ate an average number of calories.

Low dietary intake (less than 1,800 calories per day) did not reduce the risk of developing a kidney stone.

The researchers suggested that women who exercise may be less at risk for kidney stones because they take in more water, which helps the body to excrete kidney stone causing minerals.

The authors of this study acknowledged that their research had limitations, primarily because the participants were exclusively postmenopausal women.

dailyRx News spoke with Deborah Gordon, MD, nutrition and preventive medicine expert and integrative physician at Madrona Homeopathy in Ashland, Oregon, about this study.

Dr. Gordon said, "There are some encouraging findings amidst this study of largely observational associations, which do not always help us understand and direct therapeutic steps. What is helpful is the study's observations that actions protective against kidney stone formation are healthful actions in other regards: regular physical activity and maintaining an optimal weight."

Dr. Gordon continued, "I shy away from BMI which doesn't distinguish well between muscle weight and fat weight, so I would like to see a study that distinguishes the effects of the two kinds of tissue. In my own practice I like to see women consuming 2000 low-carbohydrate calories, pursuing regular physical activity, and maintaining optimal vitamin and mineral balance, which includes adequate fat-soluble vitamins D and K2, with adequate — not excessive — calcium from food sources and magnesium supplements when necessary."

This study was published in the Journal of the American Society of Nephrology on December 12.

The researchers did not disclose any conflicts of interest. The research was funded by the Women's Health Initiative, the National Center for Advancing Translational Sciences and the National Institutes of Health.

Review Date: 
December 11, 2013
Last Updated:
January 2, 2014