Obesity is an increasingly alarming health condition worldwide and a new study adds to the alarm: by 2015, 75 percent of American adults will be overweight, 41 percent obese, it says.

Researchers at the Johns Hopkins Bloomberg School of Public Health's Center for Human Nutrition have done a study that shows obesity is becoming more and more prevalent in the US.

The paper, published online Tuesday in advance of the 2007 issue of the journal Epidemiologic Reviews, says the percentage of American adults who were obese more than doubled in 40 years, from 13 percent in the ‘60s to 32 percent in 2004.

The researchers say the percentage of overweight and obese Americans has increased average rate of 0.3 to 0.8 percentage points a year.

Particularly at risk are women ages 20 to 34, regardless of race and ethnicity, who seem to be becoming obese and overweight at a significantly faster rate than men and children. The study also found that 80 percent of black women age 40 and above are overweight, while 50 percent are obese.

“Obesity is a public health crisis. If the rate of obesity and overweight continues at this pace, by 2015, 75 percent of adults and nearly 24 percent of U.S. children and adolescents will be overweight or obese,” Dr. Youfa Wang, lead author of the study and an assistant professor at the Bloomberg School of Public Health’s Department of International Health, said in a statement.

The researchers involved in the study analyzed 20 journal papers, reports and online data, as well as information from four national surveys.