Cross-sectional, retrospective review.
Data was collected on 201 patients 10 to 18 years of age, referred to the pediatric hypertension clinic at the University of Rochester Medical Center over a 3-year period. Subjects were assessed as either having or not having primary hypertension. Patients were considered hypertensive if either systolic or diastolic measurements were above the 95th percentile at the initial visit with subsequent confirmation by 24-hour ambulatory blood pressure monitoring, assessment by a school nurse, or home monitoring. Provider-confirmed learning disabilities (LDs) and/or formal treatment for attention deficit/hyperactivity disorder (ADHD) were assessed per parent report. Patients with secondary hypertension, known developmental delay or those receiving anti-hypertensive medication were excluded from the study.
Of the children evaluated, 18% (n=37) had LDs, which is significantly higher than the estimated 5% of the general population. Compared to the normotensive group, the hypertensive group was significantly more likely to have LDs, (28% vs 9%, P < 0.001), regardless of comorbid ADHD. The rate of LDs among the hypertensive group remained elevated when adjusted for age, gender, low socio-economic status and obesity.
According to the International Pediatric Hypertension Association up to 5% of children have primary hypertension.1 The epidemic of pediatric obesity further highlights this concern as obese children have a 3-fold risk for developing hypertension.2 Studies indicate that lifetime prevalence of LDs in US children is nearly 10%.3 The CDC reports that the prevalence of parent-reported ADHD among children has increased by more than 20% from 2003 to 2007.4 It is clear that hypertension, LDs and ADHD are major challenges faced by this generation of children and their healthcare providers.
Treatment strategies for hypertension outlined by the American Academy of Pediatrics focus first on lifestyle modifications, reserving pharmacologic intervention for cases with insufficient response to lifestyle changes and for secondary hypertension.5 While recent clinical trials have expanded the number of anti-hypertensive drugs with pediatric dosing information, these trials also showed a number of commonly used anti-hypertensive medications to be ineffective in the pediatric population.6,7 It should also be noted that there is no data available on the long-term effects of these drugs on growth and development, yet they are still routinely prescribed to children.8,9
There is no data available on the long-term effects of these drugs on growth and development, yet they are still routinely prescribed to children.
Current treatment strategies for ADHD focus on stimulant medication and/or behavior therapy.10 The authors recognize that the inclusion of children taking stimulant medication for ADHD is a limitation of the study because of the potential side effect of elevated blood pressure. Interestingly, guanfacine (Tenex), an alpha-2-adrenoceptor agonist prescribed as an anti-hypertensive medication in adults, has been used in the management of ADHD in recent years either alone or in conjunction with stimulant medications. While the mechanism of action of guanfacine in ADHD is thought to be due to the binding of adrenoceptors in the pre-frontal cortex, perhaps its effectiveness may be attributed to its hypotensive properties as well.11
From a naturopathic perspective this study encourages practitioners to find and treat the cause. The mechanism linking primary hypertension to LDs in children has not yet been investigated. However, inflammation, toxic and heavy metal burden, nutrient deficiencies and an exaggerated stress response should be evaluated. When reviewing successful treatments widely used by naturopathic physicians for both hypertension and supporting cognitive function, an overlap is immediately apparent. Dietary changes, weight reduction and exercise would be the initial recommendations given by most, if not all naturopathic physicians. Following this, anti-oxidant and essential fatty acid status, as well as B vitamins, calcium and magnesium would all be important considerations for both of these conditions; as would the use of botanical medicines with cardiotonic, adaptogen and nervine qualities.
By linking neurocognitive function in the pediatric population with hypertension, this study may help to direct the diagnosis, treatment and ultimately the prevention of these conditions. A causative relationship has not yet been established, and further research is warranted. However, investigating the occurrence of one when presented with the other in a clinical setting seems justified and easily implemented.