Significant Geographic Disparities Among Causes of Death in the United States

Death rates attributed to alcohol, drugs, and mental disorders nearly tripled since 1980 in the United States, according to a new study that revealed substantial geographic differences among many causes of death.

The investigators examined deaths in 21 cause groups, which ranged from chronic illnesses and infectious diseases to accidents. They researched mortality rates, and how they have changed in every US county between 1980 and 2014.

The study, published in JAMA, was conducted by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington in Seattle, and is the most comprehensive view to date of how Americans die.

The investigators examined mortality in more than 3100 US counties. Overall, cardiovascular disease was the leading cause of death in 2014, but cancers accounted for more years of life lost to early death than any other cause.

The results of the study showed that the rate at which Americans die from cancer and other diseases or injuries significantly differed among communities, highlighting the health disparities across the country.

The counties with the highest and the lowest mortality rates from cirrhosis and other liver diseases were both in South Dakota, with 193 deaths per 100,000 individuals in Oglala Lakota County, to 7 deaths per 100,000 individuals in Lincoln County.

“While the leading causes of death are similar across counties, we found massive disparities in the rates at which people are dying among causes and communities,” said lead author Laura Dwyer-Lindgren. “For causes of death with effective treatments, inequalities in mortality rates spotlight areas where access to essential health services and quality of care needs to be improved.”

Other causes vary by changes in mortality rates since 1980, according to the study. About one-half of US counties saw increases in violence and suicide, while the other half experienced a decrease.

In Alaska, Kusilvak Census Area topped the list with a 131% mortality rate increase, while the rate in New York County, NY, dropped by 72%, which was the most dramatic decrease in the country.

The mortality rates from substance abuse, including drug and alcohol abuse, and mental health disorders also greatly vary. The largest increases were seen in Clermont County, Ohio (2206%), and Boone County, West Virginia (2030%). The largest decreases were in Aleutians East Borough, Aleutians West Census Area, Alaska, and Miami-Dade County, Florida, which dropped by 51% and 45%, respectively.

“The mortality trends in mental and substance use disorders, as well as with other causes of death covered in the study, point to the need for a well-considered response from local and state governments, as well as care providers, to help reduce the disparities we are seeing across the country,” said Dr Christopher Murray, director of IHME.

To account for some of the recorded causes of deaths that are vague or even implausible, the investigators reassigned deaths with nonspecific causes to their likely underlying causes, to improve the accuracy of their estimates.

Additional county-level trends included:

• Chronic respiratory disease saw the most dramatic increases in counties that spanned from northern Texas to the Carolinas, while a small number of counties along the Mexico border, in northwestern New Mexico, and in central Colorado saw decreases.
• The national mortality rate from traffic accidents decreased by 45% between 1980 and 2014. In general, lower death rates were seen in urban areas, while higher rates were found in rural counties.
• Select counties in Montana, North and South Dakota, and Florida have the highest morality rates from cirrhosis and liver disease. Since 1980, sharp increases were seen in southwestern Oregon and northwestern Texas.
• Deaths caused by neurological disorders, such as Alzheimer’s disease, increased in a majority of the counties during the study’s time period. In particular, large increases were seen in counties that stretched from eastern Texas and Oklahoma to Alabama.

“We know that unequal medical access and quality of care create health disparities in the US for many cause of death, while other causes are linked to risk factors or policies,” said study co-author Dr Ali Mokdad. “Indeed, this study will inform the debate on how to improve the health of our nation.”

From 1980 to 2014, the counties with the largest increases in mortality rates from cancer included:

• Owsley County, Kentucky (+46%)
• Lee County, Kentucky (+40%)
• Estill County, Kentucky (+38%)
• Breathitt County, Kentucky (+38%)
• Madison County, Mississippi (+36%)
• Anderson County, Texas (+35%)
• Union County, Florida (+33%)
• Marlboro County, South Carolina (+32%)
• Powell County, Kentucky (+30%)
• Johnson County, Kentucky (+29%)

The 10 counties with the largest decreases in mortality rates from cancer from 1980 to 2014 included:

• Aleutians East Borough, Aleutians West Census Area, Alaska (-58%)
• Alexandria City, Virginia (-46%)
• Loudoun County, Virginia (-46%)
• Summit County, Colorado (-46%)
• Howard County, Maryland (-46%)
• Eagle County, Colorado (-45%)
• Pitkin County, Colorado (-44%)
• Presidio County, Texas (-44%)
• Rockland County, New York (-43%)
• Falls Church City, Virginia (-43%)