The estimated population prevalence of childhood hypertension (elevated blood pressure) is 1-2% in the developed countries. Small surveys in school children from various parts of our country suggest a prevalence ranging from 2-5%, although population prevalence data comparable to the developed countries is lacking. The prevalence of hypertension is significantly higher in groups of children with obesity.
Hypertension in children is defined as blood pressure above the 95th percentile for age, sex and height of the child. Normative values for blood pressure in children are defined in percentile in relation to the age, sex & height of the child. Blood pressure readings between the 90th and 95th percentile in childhood are termed pre-hypertensive and are an indication for lifestyle modifications. BP readings between 95th & 99th percentile are classified as stage 1 hypertension while those greater than the 99th percentile are classified as stage 2 hypertension.
Elevated blood pressure at any age in either sex is a contributor for all forms of cardiovascular disease. Target organ abnormalities are commonly associated with hypertension in children and adolescents. The risk factors for hypertension are multifactorial and are influenced by genetic, racial, geographic, cultural and dietary patterns. Obesity, family history of diabetes mellitus, hypertension and ischemic heart disease have been found to have a significant association with childhood hypertension. The awareness that essential hypertension has its origin in childhood has resulted in increased emphasis on screening. The Indian Pediatric Nephrology Group recommends annual measurement of blood pressure in all children older than three years of age, who are seen in clinics or hospital setting. Earlier screening is recommended for children with risk factors.
What To Do
It is generally accepted that hypertensive individuals can benefit from dietary increase in fresh vegetables, fresh fruits, fibre, non-fat dairy as well as restriction of sodium. Physical activity leads to a small but not statistically significant decrease in BP. Weight reduction is the primary therapy for obesity-related hypertension. Prevention of excess or abnormal weight gain will limit future increases in BP. Regular aerobic physical activity (30-60 minutes of moderate physical activity on most days) and limitation of sedentary activities to less than two hours per day are recommended for prevention of obesity, hypertension and other cardiovascular risk factors. Dietary modifications should be strongly encouraged in children and adolescents who have BP levels in the pre-hypertensive range.
Treatment
Recent clinical trials have expanded the number of drugs that have paediatric dosing information. Dosing recommendations for many of the newer drugs have been provided in the medical literature. The goal for anti-hypertensive treatment in children should be the reduction of BP to < 95th percentile unless concurrent conditions are present. In that case, BP should be lowered to < 90th percentile. Important adjunctive aspects to drug therapy of childhood hypertension include ongoing monitoring of target organ damage as well as BP monitoring, surveillance for drug side effects, counselling regarding other cardiovascular risk factors and continued emphasis on non-pharmacologic measures.
(The writer is Consultant Pediatric & Adolescent Endocrinologist, Jaslok Hospital & Research Centre)