Women are six times more likely to die from brest cancer in different counties within the same state due to a ZIP code lottery, a first-of-its-kind study shows.
The county-to-county variations reflect the varying degrees of influence of major risk factors for dying from breast cancer, including obesity and a history of smoking.
Virginia researchers used federal data to look at breast cancer deaths in more than 2,000 counties to plot differences in death rates.
Death rates can vary dramatically from one county to its neighbor, such as Lamar County, Alabama, where about one in every 33 women overall dies from breast cancer compared to nearby Cullman, where that rate is as high as one. every nine.
The researchers said: “These results suggest that breast cancer mortality in the US may be affected by where people live, and that more comprehensive, geographically specific interventions may lead to healthier communities.”
The counties are colored in shades of purple. The researchers’ work showed not only which states have higher breast cancer death rates, but also those rates in individual counties. Alabama, for example, is an example of significant variation from county to county. The northern part of the state showed more variation in death rates than the southern region
Breast cancer is the leading cause of cancer-related deaths among women in the US, but death rates have plummeted 43 percent between 1989 and 2020.
The authors added: ‘Alabama is a clear example of the diverse outcomes breast cancer patients experience depending on their geographic location, even under unified state programs.
“While the northern part of the state showed significant variation in age-adjusted mortality rates between counties, the southern part of the state showed more homogeneous rates.”
Alabama wasn’t the only state to show a collection of counties with very different death rates. For example, the death rate ranged from nine to 17 per 100,000 women in Person County, North Carolina. But in Caswell County, right next door, that rate fell within the range of 25 to 33 per 100,000 women.
In Garfield County, Utah, between one in 33 and one in 57 die from breast cancer, compared to one in nine to 17 in neighboring Iron County.
In Putnam County, Ohio, between one in 25 and one in 33 die from breast cancer compared to Paulding County, right next door, where an estimated one in 17 to 21 die from the same cause .
And in Okanogan County, the death rate ranges from 33 to 57 deaths per 100,000 people, compared to nine to 17 per 100,000 in Douglas County, directly to the south.
The different variables contributing to fatal breast cancer cases had different levels of impact.
Obesity influenced 100 percent of counties, but those in the southeastern U.S. had slightly higher coefficient rates, meaning obesity rates had a slightly larger impact in those counties.
Counties in red have lower coefficient ranges than counties shaded in yellow, meaning that while access to preventive breast x-rays was universally influential, the relationship between access to mammograms and breast cancer deaths was strongest in the eastern states.
In the South and East, whose counties are colored in shades of yellow and orange, the association between access to nutritious foods and breast cancer mortality rates is represented by a coefficient range of -1.55 to -2, 85, while the west’s coefficient fell between -1.07. to -0.36. However, the map shows areas in Ohio, Pennsylvania, Tennessee and Kentucky where the relationship between the two is stronger than the region as a whole.
They found that obesity rates in certain areas, particularly a long string of counties in the Bible Belt states, had a stronger link to breast cancer deaths than those in the Pacific Northwest. In the eastern states, access to mammograms influenced mortality.
Obesity contributed to deaths in all the counties the researchers analyzed, but cigarette smoking was estimated to play a role in increasing death rates in less than 17 percent of the counties.
And whether people in a county had access to nutritious, healthy food influenced death rates in more than 80 percent of counties.
Access to health services, including preventive measures such as mammograms, had a universal impact on breast cancer deaths. As more women underwent x-rays to detect cancer, fewer died.
And while breast cancer is the most common type among women, with more than 264,000 diagnosed each year in the United States, mammograms and other screening tools, as well as innovations in cancer treatments, have helped reduce mortality rates.
Breast cancer deaths have plummeted 43 percent between 1989 and 2020 after successful public health awareness campaigns, better screening and new medications.
To help researchers drill down into county-level data, researchers relied on two statistical analysis methods: ordinary least squares (OLS) and multiscale geographically weighted regression (MGWR).
The relationship between breast cancer deaths and the different variables that influence them, including access to healthy foods and mammograms, is shown by a coefficient or a number that shows the strength of a relationship between two variables.
A higher coefficient number indicates a stronger relationship.
Both models showed that the effects of mammography and obesity had a uniform impact, allowing the researchers to see that those relationships were strongest in most counties spanning North Carolina and Florida to eastern Oklahoma and Texas. .
They also determined that access to mammograms had an even greater influence in keeping breast cancer death rates low in most counties on the East Coast stretching from Maine to North Carolina.
The food environment influenced most counties, but was even greater in counties in southern and eastern states compared to the western United States.
Obesity had an even greater impact in counties in southern states compared to those in the west.
The findings were published in the journal. Open JAMA Network.