Mortality due to substance abuse has increased in Appalachia by more than 1,000 percent since 1980. Deaths from diabetes, blood and endocrine diseases also increased in most counties in the United States during that time.

That’s according to a new study, published Tuesday in the Journal of the American Medical Association, examining the mortality rates for 21 leading causes of death. The study also found that the death rate from cardiovascular disease, the leading cause of mortality in the U.S., is down in most parts of the country. And the research highlights numerous disparities between counties. For example, a newborn is nearly 10 times more likely to die from a neonatal disorder if she is born in Humphreys County, Mississippi, which has the highest neonatal mortality rate in the country, than if she is born in Marin County, a wealthy area north of San Francisco, which has the lowest rate.

The study also looked at how mortality from the 21 causes of death has changed over time, from 1980 through 2014. For example, neurological disorders such as Alzheimer’s were the third leading cause of death in 2014 and were prevalent across the country. But they have become more common in much of the South, while decreasing in the West.

The study diverges from previous work on mortality by accounting for “garbage codes” — vague causes of death that can be listed when doctors have no reason or resources to find a more specific cause. For example, death certificates frequently list generic causes of death like “unspecified heart disease” or “unspecified stroke.” It’s also difficult to estimate mortality for relatively rare causes of death in counties with small populations. Using death records from the National Vital Statistics System, the authors found that of the 80.4 million deaths that occurred from 1980 through 2014 in the United States, a full quarter, 19.4 million, were assigned garbage codes. After applying a combination of statistical methods that took into account previously published literature, demographics, and estimates of diseases’ prevalence and severity, the authors assigned more specific causes of death to records with garbage codes. What results is a geographical look at mortality rates for leading causes of death and how those rates have changed over time.

Lead author Laura Dwyer-Lindgren, a researcher at the Institute for Health Metrics and Evaluation at the University of Washington, says she hopes the data can be useful to local health workers and the public. “If you go to any state health coordinator, they probably know what was recorded on the death certificates. But it can be really difficult to interpret them,” she said. She hopes that collapsing the various causes of death down to 21, rather than looking at everything that can kill a person, will make it easier to target regional problems.

The institute makes the data available to the public, along with its previous work on life expectancy and other health outcomes. There’s a lot of information worth exploring, but here are a few trends that emerged from Tuesday’s report:

Cancer and cardiovascular disease hit Appalachia and the lower Mississippi River region hard

The rate of death from cardiovascular disease has gone down all over the country in the last 35 years. It has decreased less, however, in the areas that already had the highest death rates for cardiovascular disease — counties surrounding the lower Mississippi River and the heart of Appalachia. Meanwhile, cancer is responsible for the largest number of “years of life lost,” a measure of the number of years a person likely would have lived if she hadn’t died of a given cause. While deaths from cancer have decreased in southern Florida, the California coast and parts of New England by as much as 58 percent since 1980, they have increased in Kentucky and the western side of West Virginia. Both diseases contribute to a growing disparity in mortality that separates Appalachia and the lower Mississippi from the rest of the country.

These two areas glow red on many of the mortality maps, and both regions have for decades had a lower life expectancy than much of the country. There are some differences, however. Deaths from substance abuse have skyrocketed in rural, white Appalachia, but they remain relatively rare in the predominantly African-American counties of the Deep South, adding to evidence that an epidemic of opioid use has led to an increase in death rates among middle-aged whites.

Infrastructure and access can be an issue in rural areas

While transportation-related deaths went down 50 percent or more in most of New England and California, much of the central United States saw much more modest declines. Troublingly, vehicle-related deaths increased by as much as 45 percent in rural areas of Appalachia and the South. Those increases have previously been shown to be linked to the infrastructure of rural areas. Country roads are less likely to be divided, making head-on collisions more common. A trend of rural hospital closings may also make it harder for crash victims to get treatment in time to save their lives.

Meanwhile, many of those same areas have seen an increase in deaths from diarrhea, pneumonia and other infectious diseases. More than a quarter of counties, 28.3 percent, saw increased mortality from infectious disease from 1980 through 2014, diseases that are largely preventable and may reflect a lack of access to medical care.

Self-harm is a growing problem in Western states

Although several of the maps for leading causes of death, such as heart disease, parallel maps of life expectancy, a handful show very different trends. Among them is the map showing deaths from suicide and interpersonal violence, which highlights the epidemic of suicide in the West that we wrote about earlier this year. While that trend is well-documented in other research, the county-based analysis used in this paper can mask the effect of violence in places like Cook County, Illinois, home to Chicago, where the population is large and violence is concentrated in specific neighborhoods.