Stroke Belt

Stroke belt is a name given to a region in the southeastern United States that has been recognized by public health authorities for having an unusually high incidence of stroke and other forms of cardiovascular disease. It is typically defined as an 11-state region consisting of Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia.

Although many possible causes for the high stroke incidence have been investigated, the reasons for the phenomenon have not been determined.

Geographic scope

The stroke belt is typically defined to include the states of Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia. [Elizabeth Querna, [http://health.usnews.com/usnews/health/briefs/childrenshealth/hb041008a.htm The Stroke Belt: Why do more people from the Southeast die of stroke?] , "U.S. News & World Report", October 8, 2004] In 1980 these eleven states had age-adjusted stroke mortality rates more than 10% above the national average. [http://www.nhlbi.nih.gov/health/prof/heart/other/sb_spec.pdf Stroke Belt Initiative: Project Accomplishments and Lessons Learned] , National Heart, Lung, and Blood Institute, National Institutes of Health; reports on a conference that occurred in 1996] Some investigators also consider northern Florida to be a part of the stroke belt, based on a stroke mortality rate higher than several states included in the region. [P Z Siegel, L E Wolfe, D Wilcox, and L C Deeb, 1992, [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1403695 North Florida is part of the stroke belt] , Public Health Reports 107(5): 540–543]

History of observations

The stroke belt was first identified in 1962 by Centers for Disease Control (CDC) researchers who noted a concentration of high stroke death rates in the Atlantic coastal plain counties of North Carolina, South Carolina and Georgia. [http://www.cbsnews.com/stories/2005/02/14/health/main673897.shtml Combating Southern Fried Fat] , CBS News, February 14, 2005] Similar high stroke rates were later observed in the Mississippi Delta region as well.Michele L. Casper, Steve Wing, Robert F. Anda, Marilyn Knowles, and Robert A. Pollard, 1995, [http://stroke.ahajournals.org/cgi/content/abstract/26/5/755 The Shifting Stroke Belt: Changes in the Geographic Pattern of Stroke Mortality in the United States, 1962 to 1988] , Stroke 26:755–760]

Analysis by the CDC of U.S. mortality statistics from the period 1991 to 1998 found that for both blacks and whites the counties with the highest stroke death rates were in the southeastern states and the Mississippi Delta region. Stroke death rates for states ranged from a high of 169 per 100,000 in South Carolina to a low of 89 per 100,000 in New York. [ [http://www.cdc.gov/od/oc/media/pressrel/r030220.htm CDC Releases Atlas of Stroke Mortality] , Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention & Health Promotion, February 20, 2003] While most observational studies have focused primarily on stroke incidence in adults, in 2004 researchers reported that children in the eleven stroke belt states also have an increased risk of death from ischemic and hemorrhagic stroke compared with children in other states.Heather J. Fullerton, Jacob S. Elkins, and S. Claiborne Johnston, 2004, [http://stroke.ahajournals.org/cgi/content/abstract/35/7/1570?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=hemorrhagic&searchid=1&FIRSTINDEX=50&resourcetype=HWFIG Geographic Variation in Stroke Mortality in US Children] , "Stroke" 35:1570] Glymour et al. (2007) reported that adults who had resided in the stroke belt during childhood and had moved outside the region had higher stroke risk at ages 50 and older than adults who grew up in areas with lower stroke incidence. Other researchers have made similar observations. [Aiman El-Saed, Lewis H. Kuller, 2007, [http://stroke.ahajournals.org/cgi/content/full/strokeaha;38/9/2403 Is the Stroke Belt Worn From Childhood? Current Knowledge and Future Directions] (editorial), "Stroke" 38:2403–2404]

Hypotheses on causation

The causes of the elevated incidence of stroke in the stroke belt region have not been determined.M. Maria Glymour, Mauricio Avendaño, and Lisa F. Berkman, 2007, [http://stroke.ahajournals.org/cgi/content/full/38/9/2415 Is the ‘Stroke Belt’ Worn From Childhood? Risk of First Stroke and State of Residence in Childhood and Adulthood] , "Stroke" 38:2415] [http://www.newsweek.com/id/117733 Stroke Mystery] , "Newsweek", November 8, 2005] Numerous possible contributing factors have been identified, including hypertension, low socioeconomic status, diet, quality of healthcare facilities, smoking, and infections. Among the specific factors that have been proposed or studied are the following:

* It has been suggested that the higher stroke death rates in the stroke belt are due to the region's high African American population, because African Americans' stroke death rates are higher than the national average. [African American males age 45 to 54 have a threefold greater risk of ischemic stroke than white males in the same age range. [http://www.strokecenter.org/patients/stats.htm] ] However, because white people also have higher rates of stroke death in the stroke belt than in other parts of the country, the higher death rates in the stroke belt cannot be attributed solely to the region's higher proportion of African Americans.
* In the early 1990s it was hypothesized that selenium deficiency in the soils of the coastal plain might be a causative factor. [Felicity Barringer, [http://query.nytimes.com/gst/fullpage.html?res=9E0CE0DD1431F93AA15754C0A964958260 Toward Solving the Mystery Of the American 'Stroke Belt' ] , "The New York Times", July 29, 1992] The subsequent recognition of high stroke incidence in areas with different soil characteristics led researchers to reject this hypothesis. [ [http://www.cdc.gov/DHDSP/library/maps/strokeatlas/02-introduction.htm Introduction] , "Atlas of Stroke Mortality: Racial, Ethnic, and Geographic Disparities in the United States" (Casper ML, Barnett E, Williams GI Jr., Halverson JA, Braham VE, Greenlund KJ). Atlanta, GA: Department of Health and Human Services, Centers for Disease Control and Prevention, 2003]
*Some observers have assumed that more stroke belt residents suffer from untreated hypertension. However, researchers have found that residents of the southern United States are as likely to be aware of hypertension and receiving treatment as residents of other U.S. regions.Lisa Nainggolan, [http://www.medscape.com/viewarticle/538637 Hypertension may not be the whole story in the Stroke Belt] , Medscape Medical News, February 9, 2005] Additionally, researchers who documented the region's elevated incidence of pediatric stroke noted that "If the stroke belt is solely caused by regional differences in atherosclerotic stroke risk factors, it should not apply to children."
*Glymour et al. (2007) suggested that the higher stroke incidence in the stroke belt is related to experiences or exposures in childhood.
*Diets high in fried and high-fat foods, which are prevalent in the region, are thought to contribute to higher risk.
*It has been proposed that poverty and malnutrition in previous generations, which resulted in poor maternal prenatal nutrition and low birth weights, led to a predisposition to cardiovascular disease in adult life. [ [http://www.obgyn.net/newsheadlines/womens_health-Stroke-20030714-32.asp Risk may be associated with mother's health] , Health & Medicine Week, July 14, 2003]
*It has been suggested that one cause of higher mortality may be the predominantly rural character of the region, which increases the distances that patients must travel to obtain emergency medical treatment. Regional differences in standards of medical care also have been suggested as a contributing factor. In one study, researchers found that patients discharged from hospitals in the stroke belt after suffering acute myocardial infarction were less likely to be treated with warfarin than patients in most other U.S. regions. [ [http://findarticles.com/p/articles/mi_m0BJI/is_/ai_63690758 Stroke Belt — A Standard of Care Phenomenon?] , Family Practice News, June 1, 2000]

Public health initiatives to reduce stroke incidence in the region

The U.S. federal government has conducted public health programs specifically aimed at reducing stroke incidence and mortality in the stroke belt. In the 1990s the Stroke Belt Initiative operated in eleven stroke belt states, providing nutrition education, blood pressure screening, smoking cessation programs, weight loss programs, and other health promotion and public education initiatives targeted at stroke risk factors. In 2004, the Stroke Belt Elimination Initiative of the U.S. Department of Health and Human Services awarded grants aimed at reducing the high incidence of stroke and high rates of stroke death and disability in the seven states with the highest rates of stroke (Alabama, Arkansas, Georgia, Mississippi, North Carolina, South Carolina, and Tennessee). [http://www.hhs.gov/news/press/2004pres/20040805.html HHS Announces Initiative to Reduce the Incidence of Stroke in Stroke Belt States] , press release, Department of Health and Human Services, August 5, 2004]

Terminology

The term "stroke belt" is modeled on similar terms for U.S. regions such as "snow belt" and "sun belt." [ [http://www.wordspy.com/words/strokebelt.asp WordSpy website] , posted on March 25, 2003] Extending the analogy to the belt as an article of clothing, the coastal plain counties of the Carolinas and Georgia, where the stroke belt phenomenon was first described and where stroke incidence is highest, are sometimes called the "buckle of the stroke belt." [Howard G, Anderson R, Johnson NJ, Sorlie P, Russell G, Howard VJ, 1997, [http://www.ncbi.nlm.nih.gov/pubmed/9158628?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedarticles&logdbfrom=pubmed Evaluation of social status as a contributing factor to the stroke belt region of the United States] , Stroke 28(5):936–40]

ee also

* French paradox

References

External links

* [http://www.cdc.gov/dhdsp/library/maps/strokeatlas/ Atlas of Stroke Mortality: Racial, Ethnic and Geographic Disparities in the United States] , Centers for Disease Control and Prevention
* [http://www.strokecenter.org/patients/stats.htm Stroke Statistics] , Internet Stroke Center at Washington University