One of the longest-running debates among nephrologists is whether late-life kidney disease is a natural part of aging, or if it is attributable to specific, modifiable lifestyle factors.
A study in the National Kidney Foundation's American Journal of Kidney Diseases suggests that moderate elevations of blood pressure in midlife could contribute to late-life kidney disease and kidney failure.
"We think kidney disease could be caused by subclinical issues with the kidneys that would not register as problematic in midlife," said Lesley Inker, MD, an Associate Professor at Tufts University School of Medicine. "Even if an individual doesn't have blood pressure that is so out of control that requires treatment, this study indicates that there could be lifestyle modifications that can prevent the onset of late-life kidney disease."
In the study, kidney function was measured in 805 participants with mean age in midlife of 51.0. These same patients were checked again in late life when their mean age was 80.8.
Tying blood pressure readings to Albumin/Creatinine Ratio (ACR) measurements (ACR is a simple urine test for kidney damage), researchers found that for every 5mm Hg higher systolic pressure at midlife, ACR was 5.6% greater in later life. For every 5mm Hg higher diastolic pressure was at midlife, ACR was 9.2% greater in later life.
Also, among patients in the sample population, those classified as having midlife hypertension were more likely to have a lower measured glomerular filtration rate (mGFR) in later life, than were people without midlife hypertension.
"If you have elevated blood pressure (defined as greater than 140/90) in midlife then you are at greater risk for kidney disease later in life," said Thomas Manley, Director of Scientific Activities at the National Kidney Foundation, "Most notably, these measured declines in kidney function were independent of the decline seen with aging, suggesting that efforts to improve health status in midlife could help maintain your kidney function as you age."
In the United States, aging is associated with a decline in glomerular filtration rate (GFR) and an increase in albuminuria. This means that 47% for those age 70 and older have clinically defined chronic kidney disease.
However, the associations of higher midlife systolic and diastolic blood pressure with lower late-life GFR and higher ACR suggest there are underlying health causes contributing to these higher rates of late-life kidney disease.
"Identifying those underlying causes, and researching how to properly manage them to delay or stop the onset of kidney disease, will have to be teased our in further studies." Dr. Inker said.
- 1 in 3 American adults is at high risk for developing kidney disease today.
- High blood pressure, diabetes, a family history of kidney failure and being over 60 are major risk factors for developing kidney disease.
- 1 in 9 American adults has kidney disease - and most don't know it.
- Early detection and treatment can slow or prevent the progression of kidney disease.
- Kidney disease risk can be reduced by controlling blood pressure and blood sugar, quitting smoking, regular exercise, maintaining a healthy weight, and avoiding excessive use of pain medications.