Despite a countrywide reform aimed at curbing the number of tobacco users, smokeless tobacco still remains the leading preventable cause of death and disease in the United States, according to a new study.

"The prevalence of smokeless tobacco use among U.S. youths did not change between 2000 and 2011 and remained generally low. However, subgroup differences were observed," explained the study's authors.

"The use of modified traditional smokeless tobacco products, such as moist snuff, coupled with lower taxes on smokeless tobacco products (vs. cigarettes) may have contributed to the stable prevalence of smokeless tobacco (vs. the declining trend for cigarettes)."

Researchers from the Harvard School of Public Health stated that regardless of a perceived decline in smoking among young people dating back to the 1990s "limited information exists on trends in smokeless tobacco use among U.S. youths."

For the purpose of this study, smokeless tobacco use was defined as using snuff, or chewing or dipping tobacco one or more days in the past month. The National Cancer Institute identified 28 cancer-causing properties in the finely ground or shredded tobacco product.

A research team led by Dr. Israel T. Agaku, Research Associate at the Harvard School Public Health, gathered their data using the 2000-2011 National Youth Tobacco Survey. Analysis used reports from 35,828 students from 324 schools in 2000 and 18,866 students from 178 schools in 2011.

The group's findings marked the prevalence of smokeless tobacco use at 5.3 percent in 2000 compared to 5.2 percent in 2011. Although a spike in the number of users from age 15 to 17 was noted, there was a reported drop in the number of users age nine to 14.

Dr. Agaku and his associates finished by saying, "These findings emphasize the need for evidence-based interventions to reduce smokeless tobacco use among youths."

This study was featured in the May 15 edition of the online journal JAMA.