TUESDAY, Feb. 3 (HealthDay News) -- Mammography use has declined this decade in nearly two-thirds of the states, according to a new study from the U.S. Centers for Disease Control and Prevention.

The CDC's data analysis showed that mammography use increased slightly from 2000 to 2006 in 17 states -- including Minnesota, Tennessee, Georgia and Alabama. But it fell by 0.3 to 5.3 percent in the 34 states and the District of Columbia, including Utah, South Carolina, New Mexico and Delaware.

The study also found that breast cancer incidence rates fell in all but one state (Tennessee) between 2000 and 2004. However, the researchers did not identify a clear pattern among the states in terms of region, average age, average income or population density.

The study was published in the February issue of the American Journal of Roentgenology.

Dr. Jacqueline Miller, the study's lead author, expressed concern in a CDC news release that the rate might actually be higher among women who live in "low resource areas."

"Women in these areas may not have a convenient place to go," Miller said. "Also, reports have shown that insurance co-pays were related to women not getting their mammogram, and we know that some insurance companies have increased their co-pay requirements. When there are more out-of-pocket costs, women start weighing the costs of screening against other competing factors."

Miller said that monitoring state-level trends in breast cancer screening practices and breast cancer incidence should help researchers identify changes at an early stage.

"If we do start to see that screening rates are going down, we can work to identify where and who interventions need to be targeted," she said. "In doing so, we can decrease invasive breast cancer incidences and breast cancer mortalities."

"We need to do more to get the word out to women and health-care providers about the importance of mammography," Miller said.