MMWR

Morbidity and Mortality Weekly Report

Decline in Breast Cancer Incidence — United States, 1999–2003

PRESS CONTACT: CDC — National Center for Chronic Disease Prevention and Health Promotion
(770) 488-5131

Breast cancer rates decreased significantly among the majority of women across racial and ethnic populations and geographic areas of the United States. However, the reason for the decrease in incidence is not immediately known. It may be attributable to decreases in use of hormone replacement therapy, as well as a recently noted/reported decrease in use of mammography screening. Recent studies have shown decreases in breast cancer incidence rates and some researchers have suggested that decreases in hormone replacement therapy may be associated with these decreases. An analysis using the largest dataset available that CDC maintains to publish the official federal statistics on cancer in the United States, representing 86 percent of the U.S. population and containing over a million breast cancer cases diagnosed from 1999-2003, showed that overall invasive breast cancer rates were decreasing every year from 1999-2003. The largest decrease, of 6 percent, occurred from 2002 to 2003. This decrease was seen in all women over 50 years of age, and women aged 60-69 had the largest decrease. Women of all racial and ethnic populations had a significant decrease in breast cancer incidence rates from 2002 to 2003, with the exception of American Indian/Alaska Native women, for whom breast cancer incidence rates were stable. Significant decreases were seen in 24 of 41 U.S. states from 2002 to 2003, while no state had an increase in breast cancer rates. The decrease in breast cancer incidence is consistent with decreases in use of hormone replacement therapy, as well as a decrease in mammography screening among women. Future studies will continue to monitor this decrease in breast cancer incidence rates and will also examine reasons for this decrease.

Hazardous Substances Released During Rail Transit — 18 States, 2002–2007

PRESS CONTACT: CDC — NCEH/ATSDR Office of Communications
(404) 498-0070

Although rail events constitute only 2% of total hazardous substance releases reported to the Agency for Toxic Substances and Disease Registry’s (ATSDR) Hazardous Substances Emergency Events Surveillance (HSEES) system, releases during rail transit can cause severe public health consequences. Notably, approximately 81% of hazardous-substance releases from rail events occurred in areas with residences within 0.25 mile, and most of the injured were members of the general public. There is a need for all stakeholders in rail safety, including public health, to work together to develop a mechanism to monitor these events and use all available data to identify vulnerabilities and proactively promote safer technologies and practices. Approximately 1.8 million carloads of hazardous substances are shipped annually by rail in the United States, including through densely populated or environmentally sensitive areas. Of these carloads approximately 105,000 contain toxic inhalational hazardous substances such as chlorine, anhydrous ammonia, and hydrochloric acid. This report describes events from 2002 to 2007 that have been reported to the Agency for Toxic Substance and Disease Registry’s Hazardous Substances Emergency Events Surveillance (HSEES) system. The HSEES system is used to collect and analyze data regarding the public health consequences associated with hazardous substance release events, including those that occur during transportation.

West Nile Virus Activity — United States, January 1–December 31, 2006

PRESS CONTACT: CDC — Division of Media Relations
(404) 639-3286

In 2006, 1,491 cases of West Nile neuroinvasive disease were reported, the highest number reported since 2003. West Nile virus activity was detected in all 48 contiguous states for the second consecutive year. This suggests that endemic transmission of West Nile virus in the United States will continue for the foreseeable future. During 2006, West Nile virus (WNV) transmission to humans or animals expanded into 52 counties (primarily in the northwestern region of the United States) that had not previously reported transmission and recurred in 1,350 counties where transmission had been reported in previous years. Additionally, 1,491 cases of WNV neuroinvasive disease (WNND) were reported in the United States in 2006, amounting to a 14% increase from 2005 and the largest number reported since 2003. These findings highlight the need for ongoing surveillance, mosquito control, promotion of personal protection from mosquito bites, and research into additional prevention strategies.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES