New York, NY (August 3, 2009) - Parents of newborns who tip the scales at less than 5 ½ pounds should put some heavy thought to a possible future consequence: kidney disease. Low birth weight babies have a 70% greater risk of developing chronic kidney disease (CKD) in later life, according to research published in the August issue of the American Journal of Kidney Diseases, the official journal of the National Kidney Foundation.
Twenty six million American adults have CKD and millions of others are at increased risk, according to the National Kidney Foundation. "High risk groups include those with diabetes, hypertension or a family history of kidney failure," says Dr. Kerry Willis, National Kidney Foundation Senior VP for Scientific Activities.
"Experimental studies suggest that restricted growth of a fetus in the womb can interfere with normal kidney development and result in fewer and smaller filtering units, or nephrons, at birth," says the study's lead author, Sarah L. White, MPH of the George Institute and the University of Sydney in Sydney, Australia. "Those with low birth weight may therefore be vulnerable to accelerated loss of kidney function later on as a result of any additional injuries to the kidney caused, for example, by accidents, infections or the presence of other risk factors such as diabetes."
The investigators completed a systematic review and meta-analysis of 32 observational studies from diverse populations, all of which had collected data on birth weight and kidney function at greater than 12 months of age. The meta-analysis found that low birth weight babies (less than 2,500g or 5 ½ pounds) were 70% more likely to develop CKD in later life compared with individuals with normal birth weight. Significant associations were identified between low birth weight and both of the principal markers of CKD-- albuminuria, or protein in the urine and low estimated glomerular filtration rate, or kidney function measurement of less than 60. Researchers also found a connection between low birth weight and subsequent development of end-stage kidney disease, or kidney failure.
Additionally, in comparing data from two large twin studies, investigators found significant differences in kidney function between members of the same set of twins where one twin was smaller, but not among different sets of twins. This suggests that the association between birth weight and kidney function is more closely connected with fetoplacental factors affecting intrauterine growth than with maternal or genetic factors.
"Despite the association between low birth weight and risk of chronic kidney disease in later life, early detection and management of chronic kidney disease and its risk factors are highly effective in preventing adverse outcomes," says White.
"People who were very small at birth should avoid obesity that could lead to diabetes, maintain regular physical activity, avoid medications that could be toxic for the kidneys and see their doctors for simple assessment of chronic kidney disease including blood pressure measurement, a dipstick test for urinary protein and a blood test of serum creatinine level," continues White.
The National Kidney Foundation, a major voluntary nonprofit health organization, is dedicated to preventing kidney disease, improving the health and well-being of individuals and families affected by kidney disease and increasing the availability of kidneys for transplantation.
To learn more about chronic kidney disease, risk factors or free screenings through the Kidney Early Evaluation Program contact the National Kidney Foundation at www.kidney.org or (800) 622-9010.