CHICAGO, Feb. 16 (Xinhua) -- Analyzing the genetics and smoking habits of more than half a million people has shed new light on the complexities of controlling blood pressure, according to a study led by researchers at Washington University School of Medicine in St. Louis.

The study included more than 600,000 participants from multiple studies that recorded data on smoking status, systolic and diastolic blood pressure, and genetic markers across the genome. It included participants of European, African, Asian, Hispanic and Brazilian ancestries. The analysis uncovered some surprisingly novel results.

In the study, the researchers found genes governing the length of telomeres, the protective caps on the ends of chromosomes. And another thing they found is that some of the identified genes are involved with the structure and function of cilia, tiny hairlike extensions on cells that beat rhythmically to clear microbes from the lungs, nose and ears.

They found many genes associated with blood pressure are also implicated in metabolic problems, including diabetes, obesity and kidney disease. Another interesting thing is the study linked blood pressure to genes associated with addiction, including alcohol and nicotine dependence. In short, the picture emerging in blood pressure control involves central and peripheral systems of the body that span the brain, kidneys, adrenal glands and vasculature, according to the researchers.

"Blood pressure involves everything from how well your heart squeezes, to how well your blood vessels relax, to how well your brain signals your adrenal glands telling your kidneys to hold on to saltwater," said co-first author and cardiologist Lisa de las Fuentes, an associate professor of medicine and of biostatistics at Washington University.

"It's a sophisticated and elegant system, and we're still working to understand it so we can better treat our patients."

In the study, the researchers also pinpoint 35 locations in the genome associated with blood pressure that were unique in people of African ancestry.

"We are using data from studies that are already available, and historically, these tend to be concentrated on people of European ancestry," said first author Yun J. Sung, an associate professor of biostatistics at Washington University.

The study has been published Thursday in the American Journal of Human Genetics.