Essential Guide to Hypertension: Hypertension in Special Groups
Doctors have long recognized that hypertension is particularly common in certain groups of people, such as African Americans and older adults. These and other groups, such as children, require special consideration when evaluating hypertension and planning treatment. Information that applies to these groups has been provided throughout this book. This chapter summarizes some important characteristics of high blood pressure as it relates to African Americans, older adults and children.
High blood pressure is twice as common in African Americans as it is in whites. The disease tends to develop earlier in life in African Americans and usually is more severe. Secondary (and thus curable) hypertension is less common in African Americans than in whites. Both African Americans and whites from the southeastern United States have a greater risk of and higher death rates from stroke than other regions of the country. Studies showed that 11 states have stroke death rates that are 10 percent or more above the national average. These states, including Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee and Virginia, are sometimes referred to as the “stroke belt.” Although the degree to which heredity versus environment plays a role has not yet been determined, hypertension does tend to run in African American families and is most common in African American women.
In a study of older African Americans with hypertension and chronic kidney problems, those who said they were less satisfied with their medical care also were less likely to follow medication instructions and were more likely to report symptoms related to antihypertensive drug use. It is important for people with hypertension to take an active role in their treatment planning and blood pressure management to ensure satisfaction with treatment and outcome.
As a group, African Americans have hypertension characterized by low renin activity and increased peripheral resistance (the degree to which blood vessels resist blood flow). African Americans are more likely to have organ damage related to their hypertension, such as stroke, left ventricular hypertrophy and kidney disease. Hypertension combined with diabetes or insulin resistance syndrome accounts for much of the end-stage kidney disease seen in African Americans.
African Americans are likely to be salt sensitive and their hypertension is likely to respond both to weight loss and salt restriction. Their hypertension responds well to diuretics also, but they are likely to require a second medication (both at low dose), such as an angiotensin converting enzyme (ACE) inhibitor. Calcium channel blockers, beta blockers, alpha blockers, and alpha-beta blockers are all equally effective in blacks and whites.
Although blood pressure tends to increase with age, this change is not inevitable, particularly among people who live low-stress, active lives. Doctors must be especially careful in monitoring blood pressure in their older patients. In one study of repeated blood pressure measurements (one reading after another over a 20-minute period), blood pressure in older people dropped with each successive reading. The researchers suggested that allowing older people to relax for 15 minutes before a blood pressure check may result in a more accurate reading.
In many older adults, only systolic blood pressure goes up. Throughout the body, arteries become stiffer and lose their elasticity over the years. The main artery in the body, the aorta, experiences the same changes and cannot expand as much when the heart pumps blood through it. Because the aorta is stiff, the heart has to pump harder, and systolic blood pressure is elevated. This is called isolated systolic hypertension.
Recent clinical studies have shown that treating hypertension is quite beneficial for older adults, perhaps even more so than for younger adults. A study in Europe found that treatment to lower blood pressure resulted in fewer strokes and heart attacks in older adults with isolated systolic hypertension. An analysis of all studies of hypertension treatment in older adults ??? even those with mild to moderate hypertension ??? noted that treatment lowered the risk of death, stroke, heart attack, congestive heart failure and other related health problems. However, in patients above age 85, most doctors do not recommend starting new treatment for mildly elevated blood pressure; stopping existing treatment is not recommended either.
Because older people are particularly sensitive to medication, antihypertensive drugs should be prescribed with caution at a dose lower than the normally recommended starting level. Dose adjustments should be made slowly at six- to eight-week intervals. Older adults are more prone to postural hypotension (abnormally low blood pressure that occurs when a person suddenly stands or sits up), so blood pressure should be checked in standing, sitting and lying positions. This will indicate whether the medication is causing excessively low blood pressure following changes in position. Drugs likely to cause postural hypotension should be avoided.
Hypertension is rare among children. However, the lifestyle habits a child learns while growing up can affect his or her blood pressure and can increase the chances of developing hypertension in adulthood. Poor diet, little activity, weight gain and smoking in childhood all increase the likelihood of adult hypertension. In addition, children whose parents have hypertension are 20 percent to 30 percent more likely to develop high blood pressure than children whose parents have normal blood pressure levels.
The pediatrician should measure your child’s blood pressure during routine health examinations starting as early as when the child is 3 years old. A child with a slight elevation may need monitoring and another blood pressure check within three to six months, while a child with significantly elevated blood pressure should be checked again within a few days to a week. Children with early signs of essential hypertension usually have only mildly elevated blood pressure.
Hypertension in children is diagnosed according to the results of three or more separate blood pressure readings. Appropriate cuff size is very important in measuring blood pressure in children, and special blood pressure monitors are required for infants. Blood pressure readings in the upper ranges usually indicate secondary hypertension. Children who have blood pressure that is high-normal or significantly elevated on occasion should be monitored regularly for hypertension and other risk factors for heart disease, such as high blood cholesterol levels. Children who have been diagnosed with type I diabetes are likely to develop hypertension also, often as a result of kidney damage.
The probable causes of hypertension in children change with age. Among infants and young children, kidney disease, coarctation of the aorta (a defect present from birth), and blockage of the renal artery (the artery that supplies blood to the kidney) are most likely to raise blood pressure. In school-age children, both secondary (due mainly to kidney disorders) and essential hypertension occur. In adolescents, essential hypertension is most common, followed by secondary hypertension caused by kidney disease. Use of alcohol, cigarettes, cocaine or other addictive substances also may cause increased blood pressure in children and adolescents, as can steroid use. Neurofibromatosis, Turner’s syndrome, heart failure and other disorders also can cause secondary hypertension in children.
As in adults, body weight and weight gain are directly related to blood pressure in children. Efforts to prevent childhood obesity may be useful in preventing adult hypertension and adult obesity. Low physical fitness and activity levels are generally linked with higher levels of body fat. Not surprisingly, then, in elementary school children, systolic blood pressure has been found to be highest in children with poor physical fitness. Children with uncomplicated hypertension should be encouraged to exercise regularly.
Although stroke, heart attack, kidney failure, and other complications of high blood pressure seem a long way off, you must realize that hypertension in an otherwise healthy, active child is not a harmless condition. Treatment planning must be individualized. Because the long-term effects of antihypertensive drugs on children who are growing and developing are largely unknown, and because it is likely that treatment for hypertension will be lifelong, the issue about whether to give blood pressure medication to children is a matter of serious debate. Except in cases of curable secondary hypertension, treatment usually focuses on supporting lifestyle changes and heart-healthy habits.
This is particularly true regarding diet. Researchers now believe that what people eat during adolescence and young adulthood greatly affects future health. Children establish their food preferences early and learn from example. Therefore, eating a healthy, balanced diet must be a family activity. If your child has or is at risk for high blood pressure, gradually reduce the amount of fat and salt in his or her diet. Children over the age of 2 years who are at risk for hypertension or heart disease can safely drink nonfat milk and should be encouraged to eat low-fat dairy products. Fresh fruits and vegetables and whole-grain products should also be standard fare in the household. If your child needs to lose weight, avoid emphasizing favorite but forbidden foods to help prevent development of a possible eating disorder. Instead, make meaningful, permanent changes in eating patterns that will last a lifetime and promote a healthy body weight.
Exercise and general physical activity are important both to help maintain a healthy body weight and to strengthen your child’s cardiovascular system. Daily walking, bicycling, and other outdoor play should be encouraged. If safety is a concern, find a supervised, age-appropriate sport or group activity for your child to join. Be sure to tell your school and parents’ groups that you support regular and after-school physical education programs. At home, you may need to limit the total amount of time spent watching television, using a computer, or playing video games to ensure that your child remains physically active.
Excerpted from: Essential Guide to Hypertension, American Medical Association, 1998.
This article was reviewed by Alfred Bove, M.D., Ph.D., Department of Cardiology, Temple University Hospital and School of Medicine, Philadelphia, in December 2007.