According to a new study published in the December 19 issue of Circulation (the journal of the American Heart Association), some black children already have high nighttime blood pressure which greatly increases as they grow up.

A high nighttime blood pressure is an early signal of an impending cardiovascular disease.

A genetic explanation is more likely because of the fact that black people retain more sodium (than white people) thereby increasing the fluid volume in their bodies and blood pressure.

Apparently, blood pressure should drop at night because the body is resting.

According to Dr. Xiaoling Wang, genetic epidemiologist and the study's lead author:

"Most previous studies have looked at a cross section of people and this 15-year study allows us to look at one population over an extended period of time. This helps us identify the age that these problems begin to occur - as early as age 10.

That most likely means that the problem is not purely genetic and also is likely caused by environmental factors like salt intake and stress. It has already been proven that stress causes sodium retention, but there could be also other factors. This study further supports existing research and warrants further study of the causes for racial differences in blood pressure at an early age."

Though the genetic factor is at play here, the environmental factors cannot be ignored.

Source: Medical College of Georgia