Kidney health in Down syndrome emerges as a hidden risk in major nationwide study

A large nationwide study from Denmark has revealed that kidney disease is a significantly under-recognised health risk in people with Down syndrome, adding a critical new dimension to long-term care planning. While heart conditions and learning challenges are widely monitored, the kidneys have largely remained out of focus until now.

The research shows that individuals with Down syndrome face dramatically higher rates of acute kidney injury and chronic kidney disease, often beginning in childhood or early adulthood.

Inside the landmark study

The study, titled “Acute kidney injury and chronic kidney disease in individuals with Down syndrome: A nationwide cohort study”, was conducted by researchers from Aarhus University Hospital and published in the 2025 Clinical Kidney Journal.

The team analysed national health registry data from 2,815 people with genetically confirmed Down syndrome, born between 1961 and 2021. Their kidney function was tracked using blood creatinine measurements from the 1990s through 2024.

For comparison, researchers matched them with 28,150 individuals without Down syndrome, aligned by age and sex, and assessed kidney outcomes using international Kidney Disease: Improving Global Outcomes diagnostic criteria.

The numbers that raise concern

The results show a striking gap.

By age 20, nearly 29 percent of people with Down syndrome had already experienced acute kidney injury, compared with just 1 to 2 percent in the comparison group.

By age 40, the figure rose to about 33 percent, versus around 5 percent in those without Down syndrome. By age 70, half of individuals with Down syndrome had experienced acute kidney injury, compared with less than one quarter of others.

Chronic kidney disease followed a similar pattern. At age 20, about 1 percent of people with Down syndrome had chronic kidney disease, compared with almost none in the general population. By age 40, rates climbed to nearly 4 percent versus less than 0.5 percent, and by age 70, 23 percent were affected compared with 14 percent of others.

Importantly, researchers found that the increased risk remained even after excluding cases linked to congenital heart disease, pointing to underlying biological vulnerability related to chromosome 21.

Why kidneys matter more than we think

Kidneys regulate waste removal, fluid balance and blood pressure, meaning damage can quietly affect energy levels, heart health and overall resilience.

Experts note that people with Down syndrome often have smaller kidneys or urinary tract abnormalities, increasing the risk of infections and long-term damage. The extra copy of chromosome 21 may also make kidney tissue more sensitive to stress, illness or certain medications, causing faster rises in creatinine levels.

Conditions more common in Down syndrome, such as obesity and sleep-related breathing disorders, can further strain kidney function over time.

What doctors and families can do now

The study urges a shift in routine care.

Clinicians are encouraged to introduce regular kidney function testing from early adulthood, including creatinine and blood pressure checks, as part of standard Down syndrome follow-ups.

Families and caregivers should watch for warning signs such as persistent fatigue, swelling around the eyes or ankles, foamy urine and repeated infections. Early treatment of dehydration and urinary infections can significantly reduce long-term damage.

Daily habits also matter. Consistent hydration, balanced low-salt diets, regular physical activity and blood pressure monitoring can all help protect kidney health.

A call for updated care guidelines

With Down syndrome affecting about 1 in 700 newborns worldwide, researchers say the findings should prompt updates to clinical guidelines and long-term care strategies.

Early detection and routine monitoring could delay or prevent severe kidney failure, reducing the need for dialysis and improving quality of life.

The study makes clear that kidney health should no longer be an afterthought in Down syndrome care.