Relationship between High Blood Pressure and Microalbuminuria in Children Aged 6–9 Years in a South African Population

Abstract

Though the association between high blood pressure and microalbuminuria is well established in adults, there is a paucity of information on microalbuminuria in children. This study investigated the relationship between high blood pressure and microalbuminuria in 6–9-year-old children. A cross-sectional study, which included 306 primary school children of age 6–9 years old from urban areas (n = 154) and rural areas (n = 152) of the Eastern Cape Province of South Africa, was conducted. Participants’ anthropometric data were determined and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and converted to BP percentiles for age, sex and height. Creatinine and albumin concentrations were assayed in early morning midstream urine and the albumin to creatinine ratio (ACR) was calculated. There was a 42.8% prevalence of elevated blood pressure/high blood pressure (E-BP/H-BP) and a 10.1% prevalence of microalbuminuria. Among the 131 children with E-BP/H-BP, 17 had elevated ACR with a prevalence of 13.95%. SBP and HR increased with increasing range of ACR and, furthermore, SBP was significantly (p < 0.05) higher in children with moderately and severely increased ACR. SBP was associated with ACR and increased SBP predicted microalbuminuria (R2 = 0.42, adj R2 = 0.039, B: 0.120, p = < 0.05). In conclusion, microalbuminuria was present in 6–9-year-old South African children of African Ancestry and a weak association was observed with SBP in children.

Dehydration Status Aggravates Early Renal Impairment in Children: A Longitudinal Study

“…Urine β 2 -MG helps assess the damage or dysfunction on the tubules [12] and MA reflects the early renal injury of glomerular [13]. Studies on urine β 2 -MG and MA in children have focused on kidney-related diseases [14], diabetes [15], urinary tract infections [16], blood pressure [17], and the prevalence of early renal impairment among children and adolescents [18][19][20]. To our knowledge, there are no longitudinal studies investigating the effect of hydration status on early renal impairment in school children relating to weekly activity patterns.…”

Assessment of the Cardiovascular Risk Profile of Infants Exposed to Pre-eclampsia in-utero: A Prospective Case-Control Study in South African Children of African Ancestry

“…To our knowledge there is yet to be such a study in an African population. Conversely, it remains unclear whether the high prevalence of cardiovascular risk factors (obesity, hypertension etc) observed in South African children of African ancestry ( 47 , 48 ) may have originated from pre-eclamptic mothers. The assessment of cardiovascular risk in pre-eclamptic pregnant women and the follow-up of their offspring after birth for possible cardiovascular risk may address this concern.…”

What Level of Blood Pressure Is Concerning in Childhood?

“…43 Finally, a more recent study conducted in 6-to 9-year-old South African children demonstrated low-grade microalbuminuria (defined as 3 to <30 mg/ mmol creatinine) even at BP levels below the hypertensive range, as well as a linear correlation (R 2 =0.003) between systolic BP level and urinary albumin to creatinine ratio. 44 A relationship between elevated BP and altered cognition in children and adolescents was first seen in a study conducted by Lande et al using data from the National Health and Nutrition Examination Survey III. 45 In this nationally representative sample of 5100 youth aged 6 to 16 years, 217 who had systolic BP ≥90th percentile (about half were between the 90th and 95th percentiles) had poorer performance than those with normal BP on several cognitive assessments, including digit span, block design, and mathematics.…”