October 24 (HealthDay News) -- Elevated sodium levels in the blood aren't related to the future risk of high blood pressure, say U.S. researchers who looked at almost 2,200 people.

At the start of the four-year study, the participants' blood pressure levels were defined as optimal, normal or high-normal. None of them had high blood pressure. Sodium levels increased with age, and those with higher sodium levels had a higher rate of diabetes and higher creatine levels, which suggests decreased kidney function.

However, study leader Dr. Rodrigo M. Lago and colleagues found no association between blood sodium levels and blood pressure, and no link between sodium and gender or body weight.

During the study, blood pressure increased by at least one stage (for example, from normal to high-normal) in 37 percent of the participants, including 15 percent who developed high blood pressure. But the risk of increasing blood pressure was unrelated to blood sodium levels. In fact, the study found that those with the highest sodium levels had a lower risk of developing high blood pressure.

The findings, which were published in the November issue of the Journal of Hypertension, suggest that many different factors contribute to differences in blood pressure between individuals, the study authors said.

But they added that people still need to watch the amount of salt in their diet.

SOURCE: Lippincott, Williams & Wilkins, news release, Oct. 18, 2008