LOS ANGELES, July 20 (Xinhua) -- With the obesity level in the United States continuing to climb, 75 percent of American adults will be overweight and 41 percent of them will be obese by the year 2015, a new study predicts.

    In the study, researchers at the Johns Hopkins Bloomberg School of Public Health found that the prevalence of obesity and overweight in the U.S. has increased at a median rate of 0.3 to 0.8 percentage points per year during the past 30 years across a wide variety of socioeconomic groups.

    As a whole, the U.S obesity prevalence escalated from 13 percent in the 1960s to 32 percent in 2004, according to the study.

    The research team noted that there was a disproportionate increase in obesity levels amongst minorities and low socioeconomic groups, including non-Hispanic black women and children, Mexican-American women and children, white women and black men of low socioeconomic status, Pacific Islanders, and Native Americans.

    "The obesity rate in the United States has increased at an alarming rate over the past three decades," said Youfa Wang, assistant professor in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health.

    "We set out to estimate the average annual increase in prevalence as well as the variation between population groups to predict the future situation regarding obesity and overweight among U.S. adults and children," he said.

    Wang also cautioned "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."

    They also found that in 2003 and 2004, two-thirds (66 percent) of the U.S. adults were overweight or obese. Women between the ages of 20 to 34, have the fastest rate of increase to be overweight or obese. Eighty percent of black women aged 40 years or over are overweight with 50 percent being classified as obese. Although Asians have the lowest obesity prevalence when compared to other ethnic groups; U.S.-born Asians are four times more likely to be obese than Asian nationals.

    The study was published in the latest issue of the journal Epidemiologic Reviews.