Relationship of change in body mass to blood pressure among children in Korea and black and white children in the United States

Body mass is a major factor in determining blood pressure levels in children. We compared associations of body mass with blood pressure in 121 white and 91 black children in Bogalusa, Louisiana with that of 370 children in Kangwha, Korea. All children were seven years old at entry into the study and were followed for three years. Korean children were shorter (p< 0.001) thinner (p<0.0001), and had a lower body mass index (p< 0.01) than white or black children. At age seven, systolic blood pressure levels were 2 approximately 5 mm Hg lower, but at age 10, they were 2 approximately 5 mm Hg higher in Korean than white or black children. The increases in blood pressure levels from age seven to ten years were much greater in Korean than black or white children, while changes in height, weight, and body mass index were generally less. Change in blood pressure level was positively associated with change in body mass index for systolic (but not diastolic) levels; however, the association was no stronger for Korean than for U.S. children, except for Korean males vs Bogalusa black males. Cross-cultural studies of other factors, such as diet and physical activity, may explain these differences.