Most people know that diabetes and extra weight affect the heart, eyes and kidneys, but fewer know they also raise the chance of kidney stones. The link is not simply about diet. It comes from how these conditions change the acidity of urine. This article explains that mechanism, what research shows, how doctors investigate it and what helps reduce the risk.
What metabolic syndrome means
Metabolic syndrome is the name for a group of problems that often occur together: extra fat around the waist, raised blood sugar or diabetes, raised blood fats (triglycerides), low “good” HDL cholesterol and high blood pressure. The same pattern also changes the chemistry of urine, and that is where the link with kidney stones begins. The EAU 2026 urolithiasis guidelines list metabolic syndrome among the diseases associated with stone formation.
How these conditions change urine
The key change is urine that is too acidic. A review by Bernhard Hess in the Arab Journal of Urology explains that insulin resistance, which is common with abdominal obesity and type 2 diabetes, reduces the kidney’s ability to release ammonium. Ammonium normally helps buffer acid, so when less is made, urine pH falls.
Uric acid dissolves poorly in acidic urine. According to the same review, uric acid stones are mainly caused by low urine pH rather than by very high uric acid levels. The National Kidney Foundation also states that uric acid stones form when urine is too acidic, and lists diabetes, obesity, gout and metabolic syndrome among the risk factors. So a person can have a normal blood uric acid level and still form uric acid stones if the urine is persistently acidic.
What the research shows
The Hess review summarises several studies that tie metabolic health to stone risk:
| Finding | Reported in the Hess review |
|---|---|
| Stones and metabolic syndrome traits (NHANES III survey) | Kidney stones were reported by 3% of people with no traits, 7.5% with three traits and 9.8% with five traits |
| Diabetes in uric acid stone formers | In one study, a third of people with pure uric acid stones had diabetes |
| Body weight | Uric acid stones became progressively more common as body mass index rose |
| Urine acidity | Lower urine pH was linked to larger waist size, higher fasting glucose and HbA1c, higher triglycerides and lower HDL cholesterol |
The National Kidney Foundation notes that uric acid stones make up only about 7% of kidney stones overall, yet the findings above show they are much more frequent with diabetes and excess weight. Calcium stones still occur, and stone type matters for prevention. The page on stone types and stone analysis explains how the type is found.
Weight-loss surgery and stones
Losing weight is helpful, but the method matters. The Hess review notes that gastric bypass surgery can predispose to calcium oxalate stones linked to high urine oxalate. The National Kidney Foundation also lists past weight-loss surgery, especially gastric bypass, as a risk factor. Anyone who has had this surgery and develops stone symptoms should mention it to their doctor.
When to see a doctor urgently
Stones cause the same symptoms whatever the cause: severe pain in the side, back or groin, blood in the urine, frequent or painful urination, nausea or vomiting. The National Kidney Foundation advises that fever and chills can be signs of infection and need urgent medical care. Seek emergency help the same day if you have:
- stone pain with fever, chills or shivering
- pain that does not settle, or vomiting that stops you keeping fluids down
- very little or no urine
- blood sugar that becomes hard to control while you are unwell, if you have diabetes
The main guide to kidney and ureteric stones describes the general symptoms in more detail.
How the link is investigated
Diagnosing the stone itself uses imaging such as ultrasound, X-ray or CT, which the National Kidney Foundation lists among the tests used. The extra step in people with diabetes, obesity or metabolic syndrome is finding out why the stone formed:
- Stone analysis of any passed or removed stone, to confirm whether it is uric acid, calcium or mixed
- 24-hour urine collection, which the National Kidney Foundation says measures urine pH, uric acid and total volume
- Blood tests, including kidney function, blood sugar and uric acid; MedlinePlus notes that high urine uric acid can be linked to obesity and kidney stones
- Urine pH checks over time, since a single reading can vary
If a person with uric acid stones has never been tested for diabetes, the doctor may also check for it. A urologist can assess the stone and plan follow-up with the doctor who manages your diabetes or weight.
What reduces the risk
Prevention combines stone advice with better metabolic health. The EAU 2026 guidelines recommend keeping a normal body mass index, adequate physical activity, a diet rich in vegetables and fibre, and limiting salt and animal protein.
- Drink enough: the NHS advises adults to drink 2.5 to 3 litres of water a day to prevent stones.
- Cut sugary drinks: the National Kidney Foundation advises limiting added sugar, especially drinks with high-fructose corn syrup, and alcohol.
- Lose weight steadily with diet and activity, with your doctor’s guidance.
- Keep diabetes well controlled, working with your doctor.
- Treat acidic urine if advised: for uric acid stones, the National Kidney Foundation explains that making urine less acidic can help dissolve them. Whether this is needed, and which medicine is used, is a decision for your doctor.
Read more about the uric acid side in gout, uric acid and kidney stones, and about food in the stone prevention diet. If a stone needs removing, see stone treatment.
Frequently asked questions
Does diabetes cause kidney stones?
Diabetes does not cause stones directly, but it is linked to them. According to a review in the Arab Journal of Urology, insulin resistance lowers urine pH, and acidic urine allows uric acid stones to form. In one study it cited, a third of people with pure uric acid stones had diabetes.
Why do overweight people get more kidney stones?
Extra weight, especially around the waist, is linked to insulin resistance, which makes urine more acidic. The Hess review reports that uric acid stones became progressively more common as body mass index rose. Diet patterns, such as more salt, animal protein and sugary drinks, may also play a part.
Can losing weight reduce kidney stone risk?
The EAU 2026 guidelines recommend keeping a normal body mass index and adequate physical activity as part of stone prevention. Weight-loss surgery is different: the Hess review notes gastric bypass can predispose to calcium oxalate stones.
What urine pH causes uric acid stones?
Uric acid stones form in persistently acidic urine. The Hess review describes low urine pH as the main cause, rather than high uric acid. Your doctor can measure urine pH with a 24-hour collection or repeated checks, and decide whether treatment to make urine less acidic is needed.
Are all kidney stones in diabetes uric acid stones?
No. Calcium stones are the most common type overall, and people with diabetes can form them too. Uric acid stones are, however, more frequent in people with diabetes and metabolic syndrome. Analysing a passed or removed stone is the only reliable way to know which type you have.
References
- Metabolic syndrome, obesity and kidney stones (Arab Journal of Urology, 2012)
- Uric Acid Kidney Stones: Symptoms, Treatment, & Prevention | National Kidney Foundation
- EAU Pocket Guidelines on Urolithiasis 2026
- Kidney stones – Prevention – NHS
- Uric Acid Test: MedlinePlus Medical Test
Book a consultation
Prof. Samir Al-Samarrai and Dr. Amer Mousa assess urological conditions at Prof. Al-Samarrai Medical Center, Dubai Healthcare City, and discuss the options that suit your case. Medical consultations are confidential.
Read more: Urologist in Dubai: doctors, services, insurance and booking
This information is for health education and does not replace a medical examination. See our medical content policy.
Medically reviewed by: Prof. Dr. Samir Ahmed Al-Samarrai, consultant urologist. Review date: .
About the doctor
Prof. Dr. Samir Ahmed Al-Samarrai, consultant urologist. He studied medicine at the universities of Heidelberg and Johannes Gutenberg in Germany and graduated with distinction, earned his doctorate (PhD) with a research thesis in 1980, and on 23 August 1978 received his specialist certificate in the treatment and surgery of male urological diseases from the Free University of Berlin, at its medical school hospital, under the specialist regulations of the Berlin Chamber of Physicians.
Clinic: Prof. Al-Samarrai Medical Center, Al Razi Medical Complex 64, Building D, 2nd floor, No. 2018, Dubai Healthcare City, Dubai. MOHAP licence: ZGU3I12X-291225.
This article is for health education and does not replace a consultation with a doctor. Last updated: 6 November 2026.
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