Myriad biological and societal factors can impact the occurrence and accelerate progression of chronic kidney disease (CKD) for children of African descent – including preterm birth, exposure to toxins during gestation and lower socioeconomic status – and can complicate these children’s access to effective treatments, according to an invited commentary published in the November 2018 edition of American Journal of Kidney Diseases.
Clinicians caring for “these vulnerable children should be mindful of these multiple competing and compounding issues as treatment options are being considered along the continuum from CKD to kidney failure to transplantation,” writes Marva Moxey-Mims, M.D., chief of the Division of Nephrology at Children’s National Health System.
The supplemental article was informed by lessons learned from The Chronic Kidney Disease in Children (CKiD) longitudinal study and conversations that occurred during the Frank M. Norfleet Forum for Advancement of Health, “African Americans and Kidney Disease in the 21st Century.”
African American children represent 23 percent of the overall population of kids with CKD in the CKiD study. While acquired kidney diseases can get their start during childhood when the diseases betray few symptoms, the full impact of illness may not be felt until adulthood. A number of factors can uniquely affect children of African descent, heightening risk for some kids who already are predisposed to suffering more severe symptoms. These include:
- Preterm birth. African American children make up 36 percent of patients in CKiD with glomerular disease, which tends to have faster progression to end-stage renal disease. These diseases impair kidney function by weakening glomeruli, which impairs the kidneys’ ability to clean blood. Patients with a high-risk apolipoprotein L1 (APOL1) genotype already are at higher risk for focal segmental glomerulosclerosis (FSGS) and CKD. Researchers hypothesize that preterm birth may represent “a second hit that facilitates the development of glomerular damage resulting from the high-risk genotype.” According to the Centers for Disease Control and Prevention, 1 in 10 U.S. infants in 2016 was born preterm, e.g., prior to 37 weeks gestation.
- APOL1 genotype. Compared with children who had a low-risk genotype and FSGS, children with a high-risk genotype had higher rates of uncontrolled hypertension, left ventricular hypertrophy, elevated C-reactive protein levels and obesity.
- Human immunodeficiency viral (HIV) status. About 65 percent of U.S. children with HIV-1/AIDS are African American. In a recent nested case-control study of children infected with HIV in the womb, infants with high-risk APOL1 genotypes were 3.5 times more likely to develop CKD with viral infection serving as “a likely second hit.”
- Access to kidney transplant. African American adults experience a faster transition to end-stage renal disease and are less likely to receive kidney transplants. African American children with CKD from nonglomerular diseases begin renal replacement therapy 1.6 years earlier than children of other races, after adjusting for socioeconomic status. Their wait for dialysis therapy was 37.5 percent shorter. However, these African American children waited 53.7 percent longer for transplants. Although donor blood types, genetic characteristics and other biological factors each play contributing roles, “these findings may reflect sociocultural and institutional differences not captured by socioeconomic status,” Dr. Moxey-Mims writes.
To alleviate future health care disparities, she suggests that additional research explore the impact of expanding services to pregnant women to lower their chances of giving birth prematurely; early childhood interventions to help boost children’s educational outcomes, future job prospects and income levels; expanded studies about the impact of environmental toxicities on prenatal and postnatal development; and heightened surveillance of preterm infants as they grow older to spot signs of kidney disease earlier to slow or prevent disease progression.
“Clinicians can now begin to take into account genetics, socioeconomic status and the impact of the built environment, rather than blaming people and assuming that their behavior alone brought on kidney disease,” Dr. Moxey-Mims adds. “Smoking, not eating properly and not exercising can certainly make people vulnerable to disease. However, there are so many factors that go into developing a disease that patients cannot control: You don’t control to whom you’re born, where you live or available resources where you live. These research projects will be useful to help us really get to the bottom of which factors we can impact and which things can’t we prevent but can strive to mitigate.”
The article covered in this post is part of a supplement that arose from the Frank M. Norfleet Forum for Advancement of Health: African Americans and Kidney Disease in the 21st Century, held March 24, 2017, in Memphis, Tennessee. The Forum and the publication of this supplement were funded by the Frank M. Norfleet Forum for Advancement of Health, the Community Foundation of Greater Memphis and the University of Tennessee Health Science Center.
For more than a decade and a half, researchers and clinicians have used the term “metabolic syndrome” (MetS) to describe a set of symptoms that can raise the risk of cardiovascular disease. Although this constellation of factors has proven to be a good predictor of cardiometabolic risk in adults, it has not been as useful for children. That’s why the American Academy of Pediatrics (AAP) now recommends that pediatricians instead focus on clusters of cardiometabolic risk factors that are associated with obesity, a condition that currently affects one in six U.S. children and adolescents.
In a new collaborative report, a study team from Children’s National Health System’s Division of Endocrinology and Diabetes, Harvard Medical School and Duke Children’s Hospital and Health Center describes the current state of play and offers evidence-based recommendations to guide clinicians on how to approach MetS in children and adolescents.
Adults with MetS have at least three of the following five individual risk factors:
- High blood sugar (hyperglycemia)
- Increased waist circumference (central adiposity)
- Elevated triglycerides
- Decreased high-density lipoprotein cholesterol (HDL-C), so-called “good” cholesterol and
- Elevated blood pressure (hypertension).
This toxic combination ups adults’ odds of developing diabetes or heart disease. The process is set in motion by insulin resistance. Think Mousetrap, with each new development facilitating the next worrisome step. As fat expands, the cells become enlarged and become more resistant to insulin – a hormone that normally helps cells absorb glucose, an energy source. However, insulin retains the ability to stimulate fatty acids, which promotes even more fat cell expansion. Ectopic fat ends up stored in unexpected places, such as the liver. To top it off, the increased fat deposits end up causing increased inflammation in the system.
At least five health entities, including the World Health Organization, introduced clinical criteria to define MetS among adults, the study authors write. Although more than 40 varying definitions have been used for kids, there is no clear consensus whether to use a MetS definition for children at all, especially as adolescents mature into adulthood. Depending on the study, at least 50 percent of kids no longer meet the diagnostic criteria weeks or years after diagnosis.
“Given the absence of a consensus on the definition of MetS, the unstable nature of MetS and the lack of clarity about the predictive value of MetS for future health in pediatric populations, pediatricians are rightly confused about MetS,” the study authors write.
As a first step to lowering their patients’ cardiometabolic risks, pediatricians should prevent and treat obesity among children and adolescents, the study authors write. Each year, clinicians should perform annual obesity screening using body mass index (BMI) as a measure, and also should screen children once a year for elevated blood pressure. Nonfasting non-HDL-C or fasting lipid screening should be done for children aged 9 to 11 to identify kids whose cholesterol levels are out of line. The team also recommends screening for abnormal glucose tolerance and Type 2 diabetes in youth with BMI greater than or equal to the 85th percentile, 10 years or older (or pubertal), with two additional risk factors, such as family history, high-risk race/ethnicity, hypertension or a mother with gestational diabetes.
Pediatricians do not need to use cut points based on MetS definitions since, for many risk factors, the growing child’s risk lies along a continuum.
Treatments can include lifestyle modifications – such as adopting a negative energy balance diet, drinking water instead of sugar-sweetened beverages, participating in a moderate- to high-intensity weight-loss program, increasing physical activity and behavioral counseling.
“Identifying children with multiple cardiometabolic risk factors will enable pediatricians to target the most intensive interventions to patients who have the greatest need for risk reduction and who have the greatest potential to experience benefits from such personalized medicine,” the study authors conclude.
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