What's the most common cause of death in your county?

The data included the county of residence for each person who died, at the time of their death, but did not include data on deaths of Americans outside the United States.

After taking a close look at which causes of deaths occurred in which counties, the researchers found trends in how many deaths were due to tumors; cardiovascular disease; diabetes and diseases that affect the urinary tract, genitals, blood, thyroid or pancreas; neurological disorders; suicide and violence; chronic respiratory diseases; transportation-related injuries; mental and substance disorders; chronic liver diseases; and infectious diseases.

The 2014 mortality rates and geographic patterns in the data are a good indicator of current trends, Murray said.

The findings appear to be the most comprehensive yet to describe how a broad set of causes of death differ across counties, said Ellen Meara, a professor at the Dartmouth Institute for Health Policy and Clinical Practice in New Hampshire, who was not involved in the new study.

“It is unique in its ability to track cause-specific death rates in small areas over a long time period, three decades,” Meara said of the study.

Regions with highest cancer, heart-related deaths

The study showed very high mortality rates due to tumors, especially when cancerous, in counties along the southern half of the Mississippi River, eastern Kentucky, western West Virginia and western Alaska.

However, many counties in states stretching from Idaho and Wyoming in the north to western Texas in the south had lower-than-average mortality rates from tumors, according to the results.

For cardiovascular disease, mortality rates decreased by about 50% overall between 1980 and 2014, but the rate of decline varied by county, according to the study. Slow rates of improvement were observed in Southern counties stretching from Oklahoma to Alabama and Kentucky.

The new study also showed that mortality rates due to diabetes and diseases that affect the urinary tract, genitals, blood, thyroid or pancreas were particularly high in counties in Arkansas, Louisiana and Mississippi along the Mississippi River and in counties with Native American reservations in North Dakota and South Dakota.

Large increases in deaths due to neurological disorders were observed in Southern counties stretching from eastern Texas and Oklahoma to Alabama, according to the study. Declines in mortality were found in counties in the West, an area reaching from central Idaho and western Montana to central Colorado.

Do you live in the county with highest drug deaths?

Increased mortality rates due to chronic respiratory diseases were observed in a prominent cluster of counties in eastern Kentucky and West Virginia and in a second cluster in southeastern Colorado, according to the new study.

The lowest mortality rates were found in counties in the District of Columbia area, the upper Midwest, southern Florida, southern Texas and central Colorado.

For deaths due to mental and substance use disorders, the mortality rate increased by 188% overall between 1980 and 2014, according to the new study.

Several clusters of counties in Kentucky, West Virginia, Ohio, Indiana, western Pennsylvania and east-central Missouri saw mortality rates rise by more than 1,000%.

For diarrhea, lower respiratory and other common infectious diseases, mortality rates were highest in counties in Southern states, from Louisiana and Arkansas to Georgia, Tennessee and Kentucky, according to the new study.

Meanwhile, rates were lower than average in counties in southern Florida, New England, the upper Midwest, central Colorado and the Pacific Northwest.

Where self-harm, violence are highest

The highest mortality rates due to self-harm and interpersonal violence were observed in counties in Alaska, in Native American reservations in North Dakota and South Dakota, and in states in the Southwest, according to the new study.

Lower rates were found in counties in the upper Midwest, New England, southwestern Texas and southern California.

Additionally, “about half of US counties saw increases in suicide and violence, while the other half of counties experienced decreases,” Murray said. “Kusilvak Census Area in Alaska topped the list with a 131% mortality rate increase, while the rate in New York County, New York (which encompasses Manhattan), dropped by 72% — the most dramatic decrease in the country.”

The county with highest fatal accident rate

For deaths due to transportation-related injuries, in general, lower mortality rates were found in more urban counties, and higher mortality rates were found in more rural counties.

Todd County, South Dakota, had the highest mortality rate from transportation-related injuries in 2014, and the county with the lowest mortality rate was New York County, Murray said.

“An interesting finding when deaths are mapped by small areas is the way some causes of death follow state boundaries, which suggests that state policies likely play a role in saving lives,” said Meara, the Dartmouth Institute professor.

“Deaths due to transport injuries, for example, look very different north of the Ohio River, in Ohio, Indiana and Michigan, compared with Kentucky,” she said. “You can see some of these state-by-state patterns in the maps of deaths due to self-harm and interpersonal violence, as well.”

Disturbing disparities in rural, urban counties

It revealed that rural counties tended to have higher rates of smoking, obesity, child poverty and teen births, as well as higher numbers of uninsured adults, than their urban counterparts.

Additionally, similar to the new study, the County Health Rankings report showed that the average rate of drug overdose deaths appeared higher in rural counties.

Meara said that such county-specific research remains important.

“This research demonstrates that the tools needed to improve health and survival in places like eastern Kentucky, where mortality from chronic respiratory disease is high and rising, differ from the tools needed to address mortality in New Mexico and western Texas, where deaths due to cirrhosis and other chronic liver disease are high and rising,” Meara said.

“The typical studies of all-cause mortality mask these differences, leading to one-size-fits all policies that may not be effective. With studies like these, everyone, from clinicians to local and state policy-makers, can better address the needs of their communities,” she said.

Although the new study does not offer a definitive conclusion for some big questions, Meara said, “it opens up a new set of important questions about why areas experienced such different trends in particular causes of death. It provides an opportunity to learn from success and failure in different counties.”

Murray said he hopes to further examine trends and details in causes of death across the country to help improve public health in communities nationwide.

“State and county health departments could use county-level data to identify pressing local needs and tailor their policies appropriately. Physicians could use the estimates to better understand the health concerns of the populations they serve,” Murray said.

“Researchers could identify counties that have done especially well or poor with regard to certain causes of death, warranting additional study to identify factors driving trends. Communities can use these estimates to understand the health needs of their community and advocate for change,” he said. “These results could also provide a mechanism for evaluating the effect of certain policies and programs.”