A new study shows that gun-related homicides among young men in the U.S. spiked dramatically between 1999 and 2005. The report, published in the online edition of the Journal of Urban Health came on the heels of a Supreme Court decision that a ban on handguns in Washington, D.C., is unconstitutional. According to the study by Johns Hopkins Bloomberg School of Public health, murders involving firearms increased by 31 percent among black men ages 25 to 44 and by 12 percent among white men of the same age during the same years the study covers. The researchers analyzed data from the U.S. Department of Health and Human Services's Web-based Injury Statistics Query and Reporting System, which includes information on injury-related deaths and mortality rates per 100,000 population from 1981 to 2005. Researchers found that the overall homicide rate remained between 6.0 and 6.1 deaths per 100,000 (other than an increase in 2001 attributed to the terrorist attacks of September 11). The most significant increases in gun deaths occurred in Alabama, California, Michigan, Minnesota, Nebraska, Nevada, New Jersey, Ohio, Pennsylvania, Texas and Washington State—mostly in and around large metropolitan areas. Factors that may influence urban homicide trends, the study says, include early exposure to lead and unusually high rates of gun homicides surrounding the victims during their adolescence.