What do kidneys do?
Kidneys have many important functions. The most obvious is making urine, but even this is more complicated than you may think. Kidneys filter your blood and flush out waste and excess body salts through your urine. They regulate your fluid status (which is why if you drink more fluids your urine gets lighter) and regulate your body salts (including sodium, potassium, bicarbonate, and phosphorus). They also make a hormone that tells your bone marrow to make red blood cells, they help activate vitamin D so it can do its job, and your kidneys even help control blood pressure. That’s a big role for two organs about the size of your fist!
When I tell people what I do for work, I often hear: You’re a children’s kidney doctor – do kids even get kidney disease?
Sadly, the answer is yes. In 2011, 1,358 children in the United States developed end stage renal disease (ESRD), which means that they needed to start dialysis or have a kidney transplant (1). There is not good data regarding how many children in the US have chronic kidney disease (CKD), which means that their kidney function is impaired, but they don’t need dialysis or a transplant. Developmental abnormalities of the kidneys and urologic tract are the most common cause of kidney disease in children.
What about adults?
CKD is much more common in adults though – and much of it could be prevented. A large representative study of Americans by the National Health and Nutrition Examination Survey found that at least 10 percent of adults had CKD in 2012 (1). Almost 634,000 adults had ESRD in 2012. Diabetes and high blood pressure are the biggest causes of kidney diseases (1). Kidney disease is the ninth leading cause of death in the US (2).
What does it mean to have kidney disease? How do I know if I have it?
It is important to know that while we can’t regenerate kidneys, we can treat CKD so people can live with it. Children still go to school, hang out with friends, and play sports. Early detection is helpful because people can be treated before they feel poorly. The American Academy of Pediatrics recommends that children have their blood pressure taken at their check-ups starting at age 3. This is one way we detect kidney disease. Other times, children are tested because they aren’t growing well, have urinary problems, or are overly tired. Watch for these symptoms and talk to your doctor if you are concerned.
Because CKD is relatively rare in children, we do not routinely screen for it. However, the case is different for adults: the National Kidney Foundation recommends that patients with high blood pressure, diabetes, who are over 60 or who have a family history of kidney disease get blood and urine tests to check for kidney disease.
What can we do to prevent kidney disease?
We hear a lot about heart healthy diets, but not much about kidney wellness. Luckily, many of the recommendations are similar.
- Keep your blood pressure normal (For older adults, the blood pressure target is 140/90 mm Hg, but children and adolescent have age based goals, all of which are below 120/80).
- Choose heart healthy foods (fruits and vegetables and whole grains).
- Maintain a healthy weight.
Being overweight can injure kidneys directly. It also increases risk for diabetes and high blood pressure, both of which cause kidney disease. It is important to get your blood pressure checked periodically and to take medicine if your doctor prescribes it for high blood pressure. Good blood sugar control and following your doctor’s recommendations minimizes the risk of kidney disease in diabetics.
As a pediatrician, I think about keeping kids healthy for the rest of their lives. So, use National Kidney Month to make a commitment to you or your child’s kidneys (and whole body).
- Try to be more active! Even a small increase in your activity level can be helpful.
- Make sure to drink plenty of fluids and limit your alcohol intake.
- Pay attention to food labels and try to limit the amount of salt you eat to less than 2,000 mg per day. High sodium diets may increase the risk for high blood pressure.
- Limit sugar intake and increase fruits and vegetables in your diet.
- If you smoke, take steps to quit. Smoking can worsen kidney damage.
Every small step you take moves you further along the path to wellness. Your kidneys will thank you.
Elizabeth Hunt, MD, is a pediatric nephrologist at The University of Vermont Children’s Hospital.
- USRDS data United States Renal Data System, 2014 Annual Data Report: Epidemiology of Kidney Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2014.
- CDC: http://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm