According to the article, the prevalence of hypertension among youth is rising, and African American adolescents have higher systolic blood pressures (the top blood pressure number) than white adolescents. "Caffeine is considered a preventable risk factor for hypertension and cardiovascular disease," the authors write. "It is estimated that 68 percent of boys and 62 percent of girls aged 12 to 17 years drink one or more soft drinks daily and 21 percent of boys and 22 percent of girls consume coffee or tea on a daily basis."
Margaret R. Savoca, Ph.D., of the Medical College of Georgia, Augusta, and colleagues investigated the association between the consumption of caffeinated beverages and blood pressure in 81 African American (32 boys, 49 girls) and 78 white (56 boys, 22 girls) adolescents (average age, 16.4 years). Participants were placed on a sodium-controlled diet for three days, and then asked to select food and drinks from a menu that they would consume for a three-day period. The menu included a variety of breakfast, lunch, dinner, snack, and beverage choices. Of the 15 beverage choices, six contained caffeine. There were also ten chocolate items with small amounts of caffeine. Based on their caffeine intake, participants were categorized into three groups: 0-50 milligrams per day of caffeine, 50-100 milligrams of caffeine per day, and more than 100 milligrams of caffeine per day.
The researchers found that the association between systolic blood pressure and caffeine category varied by race. African Americans consuming more than 100 milligrams per day of caffeine (n=11) had higher systolic blood pressure readings than the other two groups. The effect on diastolic blood pressure (the bottom number) of the participants consuming more than 100 milligrams per day was 3.7 millimeters of mercury higher than the group consuming more than 50 to 100 milligrams per day, and was not significantly different from the group consuming 0 to 50 milligrams per day.
"In this observational study, we identified a group of adolescents who chose and subsequently consumed large amounts of caffeinated beverages during a three-day sodium-controlled diet," the authors write. "The African Americans in the highest caffeine-intake category had higher systolic blood pressure readings than all other adolescents in the study, including white participants in the highest caffeine-intake category."
"For adolescents, especially African American adolescents, caffeine intake may increase blood pressure and thereby increase the risk of hypertension," write the researchers. "Alternatively, caffeinated drink consumption may be a marker for dietary and lifestyle practices that together influence blood pressure. Additional research is needed owing to rising rates of adolescent hypertension and soft drink consumption."
(Arch Pediatr Adolesc Med. 2004;158:473-477. Available post-embargo at archpediatrics.com)
Editor's Note: This study was supported by grants from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md.
Editorial: Diet and Blood Pressure Elevation in Children and Adolescents
In an accompanying editorial, Sarah C. Couch, Ph.D., R.D. of Cincinnati and Stephen R. Daniels, M.D., Ph.D., of Cincinnati Children's Hospital Medical Center, Ohio, comment on the study by Savoca et al. "Of interest, there was no dose-response relationship between blood pressure and caffeine among white teens or in African American adolescents consuming caffeine intakes less than 100 milligrams per day, suggesting individual variations in caffeine metabolism and/or adaptation to habitual use, both of which could influence the effects of caffeine on blood pressure. Alternatively, greater genetic susceptibility to hypertension and/or coexisting 'unhealthful' dietary and lifestyle habits (low fruit, vegetable, and dairy consumption and lack of exercise) among the African American high caffeine users could potentially explain the higher systolic blood pressure in this group of adolescents," the editorialists write.
They conclude, "... the study provides evidence that high caffeine intakes, particularly from soda, should be included among the dietary components to evaluate in adolescents with hypertension or with a family history of high blood pressure. This finding is important, given recent statistics that soft drink consumption has more than tripled among adolescents in the past three decades."
(Arch Pediatr Adolesc Med. 2004;158:418-419)
For more information, contact JAMA/Archives Media Relations at 312/464-JAMA (5262) or e-mail email@example.com .
To contact Margaret R. Savoca, Ph.D., call Toni Baker at 706/721-4421. To contact editorialist Stephen R. Daniels, M.D., call Jim Feuer at 513/636-4656.