Diabetes Mellitus among African Americans

Final Research Paper

Peggy Hollie

Epidemiology Disease

Dr. Peters

May 9, 2012

Diabetes Mellitus is characterized by abnormal metabolism of carbohydrate, protein, and fat, resulting in increased levels of blood sugar. The adjective mellitus (for sweet) is used with diabetes insipidus (tasteless), which is so rare that the word diabetes by itself generally refers to diabetes mellitus. The only thing that diabetes mellitus and diabetes insipidus have in common is polyuria, or frequent urination. There are two forms of diabetes mellitus: Type I, or insulin-dependent diabetes mellitus IDDM), and Type II, or non-insulin-dependent diabetes (NIDDM). Diabetes is one of the ten leading causes of death from disease in the United States. It is the result of an insufficient supply of insulin or an inadequate use of insulin that is supplied from the islets of Langerhans in the pancreas. According to Centers for Disease Control and Prevention CDC (2010), diabetes affects 25.8 million people 8.3% of the U.S. population, diagnosed 18.8 million people and undiagnosed 7.0 million people. African Americans who have diabetes are 4.9 million or 18.7% aged 20 years or older. African Americans are twice as likely to be diagnosed with diabetes as non-Hispanic whites. In addition, they are more likely to suffer complications from diabetes, such as end-stage renal disease and lower extremity amputations. Although African Americans have the same or lower rate of high cholesterol as their non-Hispanic white counterparts, they are more likely to have high blood pressure (Table 1). African American adults are twice as likely as non-Hispanic white adults to have been diagnosed with diabetes by a physician. African American men were 2.2 times as likely to start treatment for end-stage renal disease related to diabetes, as compared to non-Hispanic white men. Diabetic African Americans were 1.5 times as likely as diabetic Whites to be hospitalized. African Americans were 2.3 times as likely as non-Hispanic Whites to die from diabetes (Table 1).
|Table 1. Diagnosed and undiagnosed diabetes among people aged 20 years or older, United States, 2010 |
|Group |Number or percentage who have Diabetes |
|Age ≥20 years |25.6 million or 11.3% of all people in this age group |
|Age ≥65 years |10.9 million or 26.9% of all people in this age |
|Men |13.0 million or 11.8% of all men aged 20 years or older |
|Women |12.6 million or 10.8% of all women aged 20 years or older |
|Whites |15.7 million or 10.2% of all non-Hispanic whites aged 20 years or |
| |older |
|Blacks |4.9 million or 18.7% of all non-Hispanic Blacks aged 20 years or older|
| |(CDC, 2010) |

The purpose of this paper is to compare diabetes between African Americans, Whites and other ethnic groups. The objective is to examine whether racial disparities in the prevalence of type II diabetes exist beyond what may be attributable to differences in socioeconomic status and other modifiable risk factors. Members of racial and ethnic minority groups in the United States, including African Americans, suffer disproportionately from many chronic diseases, including type II diabetes (Wong, 2002; Carter, 1996). Prevailing statistics suggest that African American adults are 50% to 100% more likely to have diabetes than are Whites, (Carter, 1996; Harris, 1990) with evidence that diabetes precursors may even be more common in African American than in White children (Gower, 2003 ; Lindquist, 2000). Reasons for racial disparities in diabetes prevalence are not clear, but behavioral, environmental, socioeconomic, physiological, and genetic contributors have all been postulated (Carter, 1996; Harris, 1990; Abate, 2003). Because of the high prevalence of diabetes in the African American community, it has been suggested that African Americans may be more susceptible to the disease compared with Whites through direct genetic propensity or unfavorable gene environment interactions (Abate, 2003). The fact that diabetes prevalence rates among Whites exceeded those among African Americans through at least the first half of the 20th century (Roseman, 1985) has led to the hypothesis that modern lifestyle factors (especially those that promote obesity) may have a greater effect on African Americans than on Whites (Abate, 2003; Brancati, 1996). Diabetes, the nation’s seventh leading cause of death by disease, disproportionately affects African Americans, who are nearly 1.8 times more likely to have diabetes than whites of the same age. Medical expenses for people with diabetes are more than two higher than for people without diabetes. According to CDC (2007) estimated diabetes costs in the Unites States, total (direct and indirect) is 174 billion, direct medical costs 116 billion after adjusting the population age and sex differences, average medical expenditures among people with diagnosed diabetes were 2.3 times higher than what expenditures would be in the absence of diabetes. Indirect costs are 58 billion for people with a disability, work loss, and premature mortality. CDC (2010), African Americans have higher age adjusted hospital discharge rate per 1,000 diabetic populations compare to Whites, 264.3 African Americans and Whites are 174.2, total ratio is 1.5. Diabetes is having a devastating effect on the African American community. Genes definitely play a role, so does the environment in which people live, socioeconomic status and racism (O’Brien et al., 1990). All humans have the same physiology, are vulnerable to the same illnesses, and respond to the same medicines. Naturally, diseases and responses to treatment do vary from person to person. But, he says, there are unique issues that affect black Americans. We must recognize there are some arbitrary issues that are present in the way we practice medicine and dole out health care (O’Brien, 1990; Brancati, 1996).

It forces us to think very carefully about the very volatile issue of race and what race means. At the end of the day, all of us acknowledge that race is a very poor physiological construct. Race is a placeholder for something else. That something is less likely to be genetic. It is more likely to have to do with socioeconomics and political issues of bias as well as physiologic and genetic issues that go into that same bucket. Some racial differences are more nuances. But there are issues of disparity and there are issues relative to racism that operate in a very broad context (O’Brien, 1990; Brancati, 1996; Pavlik, 1996).

The cause of diabetes is a mystery, but (Flegal & Evans, 2000) believe that both genetics and environmental factors play roles in who will develop the disease. These researchers believe that African Americans and African Immigrants are predisposed to developing diabetes. Research suggests that African Americans and recent African immigrants have inherited a "thrifty gene" from their African ancestors. This gene may have enabled Africans to use food energy more efficiently during cycles of feast and famine (Gibbons, 2004; Paradies, 2007). With fewer cycles of feast and famine, this gene may make weight control more difficult for African Americans and African Immigrants. This genetic predisposition, coupled with impaired glucose tolerance, is often associated with the genetic tendency toward high blood pressure. People with impaired glucose tolerance have higher than normal blood glucose levels and are at a higher risk for developing diabetes (Cowie, 1993; Pavlik, 1996).

However, treating race as an etiological factor has been the subject of debate, (Karter, 2003; Lin, 2000; Kaufman, 1997) and it has been argued that despite some genotypic delineation, race largely represents a complex mixture of behavioral, environmental, and social exposures (Shields, 2005; Williams, 1997). In comparison with Whites, African Americans often are poorer, have less education, are more likely to live in distressed households and communities, are less able to access quality health care, and have a less favorable risk factor profile for many diseases (Williams, 1997; Krieger, 1993; Jones, 2000). Because socioeconomic and associated environmental differences between racial groups are so pervasive, attempts to isolate an effect of race will typically involve substantial confounding (Kaufman, 1997), resulting in difficulty estimating the relative contributions of genetic and environmental factors. According to a study by researchers, (Cowie, 1993; Robbins, 2000; Bonham, 1985), which pose a challenge in that the average African American is of substantially lower socioeconomic status (SES) than the average White American. Because racial disparities persisted in these studies after adjustment for known diabetes risk factors, including some measures of SES, a possible genetic explanation has been invoked for the residual association, although the precise biological mechanisms remain speculative. Many of the studies conducted to evaluate the underlying reasons for racial disparities in diabetes prevalence have included fewer than 1000 each of African American men and women (Mokdad, 2001; O’Brien, 1989). According to (Signorello et al., 2005) in this study shows that diabetes prevalence rates in relation to age, educational level, income and BMI have significant associations with the disease as reported in (Table 2). As expected, the prevalence of diabetes increased with increasing age and BMI, and with decreasing education and income. Diabetes prevalence rose 8-fold from a low of 5% among participants whose highest BMI was less than 25 kg/m2 to 40% among those whose highest BMI was 40 kg/m2 or greater. Among participants who had ever been obese, the prevalence of diabetes varied little according to race or gender, 30% among African American women, 29% among White women, 28% among African American men, and 30% among White men Kumari, 2004; Lonetti, 1992). Studies show that at the time of the baseline interview, 73% of participants were overweight, 44% were obese, and 11% were extremely obese. The prevalence of obesity was significantly (P< .001) higher among women than among men and significantly (P< .001) higher among African American than among White women. The prevalence of diabetes was inversely related to educational level, particularly among women, and overall it was 1.6 times higher among participants with less than 9 years of education than among those who had graduated from college (Table 2). Similarly, among participants in the lowest income category (less than $15000 per year), the prevalence of diabetes was 1.4 times higher than among participants with a household income of $50 000 per year or more; however, (Brancati, 2000) there were variations in the relationship between income and diabetes in each gender–race stratum, and the general trend of prevalence rising with decreasing income did not hold for African American men (Table 2).

|TABLE 2—Diabetes Prevalence Rates in Relation to Age, Education, Income, and Body Mass Index |
| |Men, % |Women, % | |
|Characteristic |African American |White |African American |White |Total, % |
|Age, years |
| 40–44 |9.7 |10.8 |13.3 |13.1 |11.8 |
| 45–49 |14.2 |17.4 |19.1 |17.8 |17.1 |
| 55–59 |24.4 |20.8 |34.9 |25.9 |29.2 |
| ≥65 |
| Less than 9th grade |24.3 |22.1 |36.5 |26.8 |29.4 |
| High school/vocational school |15.4 |19.0 |23.3 |20.8 |20.0 |
| College or higher |
| < 15 000 |16.2 |21.1 |26.9 |23.4 |22.4 |
| 25 000–49 999 |18.5 |18.1 |18.2 |14.6 |17.7 |
|Highest body mass index,a kg/m2 |
| < 25 |4.6 |4.6 |6.7 |3.5 |5.1 |
| 25–29.99 |10.4 |8.2 |13.9 |9.9 |11.4 |
| 35–39.99 |33.5 |34.1 |30.4 |26.6 |30.8 |
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| |Men, No. (%) |Women, No. (%) |
|Characteristic |African American |White |African American |White |
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| None |7 065 (49.6) |1 513 (47.8) |7 703 (38.3) |2 654 (42.5) |
| Any private insurance |2 503 (17.6) |449 (14.2) |4 653 (23.2) |1 475 (23.3) |
| Medicaid only |1 756 (12.3) |341 (10.8) |3 618 (18.0) |789 (12.5) |
| Medicare only |1 205 (8.5) |426 (13.5) |1 942 (9.7) |679 (10.7) |
| Military only |483 (3.4) |89 (2.8) |95 (0.5) |35 (0.6) |
| Other combinations |1 162 (8.2) |340 (10.7) |1 963 (9.8) |655 (10.4) |
| Unknown |62 (0.4) |7 (0.2) |121 (0.6) |39 (0.6) |
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|Hypertension |
| No |7 346 (51.6) |1 602 (50.6) |7 431 (37.0) |3 077 (48.6) |
| Yes |6 879 (48.3) |1 562 (49.4) |12 658 (63.0) |3 246 (51.3) |
| Unknown |11 (0.1) |1 (0.0) |6 (0.0) |3 (0.1) |
|Moderate sports activity in 30s, h/wk |
| 0 |4 917 (34.5) |1 354 (42.8) |8 098 (40.3) |2 932 (46.4) |
| 0.01–2.00 |2 739 (19.2) |597 (18.9) |4 255 (21.2) |1 204 (19.0) |
| 2.01–4.99 |2 724 (19.1) |480 (15.2) |3 596 (17.9) |958 (15.1) |
| ≥5 |3 748 (26.3) |716 (22.6) |3 897 (19.4) |1 182 (18.7) |
| Unknown |108 (0.8) |18 (0.6) |249 (1.2) |50 (0.8) |
|Vigorous sports activity in 30s, h/wk |
| 0 |4 520 (31.8) |1 499 (47.4) |11 038 (54.9) |3 486 (55.1) |
| 0.01–2.00 |3 096 (21.8) |611 (19.3) |3 977 (19.8) |1 151 (18.2) |
| 2.01–4.00 |2 397 (16.8) |357 (11.3) |2 131 (10.6) |620 (9.8) |
| > 4 |4 120 (28.9) |683 (21.6) |2 728 (13.6) |1 029 (16.3) |
| Unknown |103 (0.7) |15 (0.5) |221 (1.1) |40 (0.6) |
|Diabetes |
| No |11 858 (83.3) |2 546 (80.4) |15 178 (75.5) |5 017 (79.3) |
| Yes |2 378 (16.7) |619 (19.6) |4 917 (24.5) |1 309 (20.7) |
|Currently taking diabetes medication |
| No |12 217 (85.8) |2 642 (83.5) |15 736 (78.3) |5 276 (83.4) |
| Yes |2 018 (14.2) |523 (16.5) |4 356 (21.7) |1 050 (16.6) |
| Unknown |1 (0.0) |. . . |3 (0.0) |. . . |
| | | | |(Signorello et al. 2005 |

According to Walker et al (1997), points out that compared with the majority population there is significantly more retinopathy in African Americans, as well as in Mexican Americans, and a higher potential for diabetes-related blindness. There is also a much higher prevalence of end-stage renal disease. African Americans are approximately 12% of the population, but are over one third of the occupants in dialysis centers. Consequently, this has a disproportionately high impact in the African American community.
(Harris & Flegal, 1998) reports particularly distressing are the data on amputations; African Americans, perhaps for reasons to do with underlying biological differences, we see enormous increases in amputations, up to 4 times more in African Americans compared with the majority population. (Brancati et al., 2000) looked at the risk factors in the insulin-resistance syndrome there is a high preponderance of clusters of these risk factors in both men and in women. In his study, diabetes incidence per 1000 person-years was about 2.4-fold greater in African American women 25.1 and about 1.5-fold greater in men 23.4 than in their white counterparts (P