By Carmen Castaneda, MD, PhD and Odilia I Bermudez, PhD, MPH
Type 2 diabetes (formerly known as non-insulin dependent diabetes mellitus - NIDDM) poses a major health threat worldwide. Based on 1994 extrapolations from prevalence studies, there are now about 28 million persons with diabetes in the Americas (15 million in the United States and Canada and 13 million in Latin America and the Caribbean). This accounts for 25% of the world's total population suffering from diabetes (Table 1). This 28 million estimate for persons with diabetes in the Americas is projected to increase by about 45% by the year 2010, with Latin America and the Caribbean surpassing the US and Canada. According to projections, however, the most dramatic increase will be seen in Central America with an increase close to 100%. In the Caribbean Islands prevalence is expected to increase by 74%, compared to a 40% and 25% for South America and the US and Canada, respectively.1 Although these figures represent diabetes of all types, the majority of persons (90-95%) 20 years of age and older have type 2 diabetes. Metabolic, genetic, and environmental factors may play a role in the development of diabetes and its complications. It has been documented that the risk of developing type 2 diabetes increases with age, obesity, sedentary lifestyle, family history of diabetes, and low high-density lipoprotein (HDL) or high triglyceride concentrations.
Table 1. Estimates and projections of prevalence of type 2 diabetes In the Americas (1994 to 2010).
|
Subregion |
1994 |
2000 |
2010 |
|
Mesoamerica (including Mexico) |
3.7 |
5.4 |
7.1 |
|
Caribbean region |
0.9 |
1.3 |
1.6 |
|
South America |
6.7 |
8.1 |
18.2 |
|
Subtotal |
11.3 |
14.8 |
18.2 |
|
Canada & United States |
13.4 |
15.1 |
16.8 |
|
Total |
24.7 |
29.9 |
34.9 |
Source: PAHO (1998). Health in the Americas. Washington DC. Volume I.People with diabetes are subject to both acute and long-term complications.2 In the US, diabetes is associated with 7.5-20% of cardiovascular disease in people over 45 years of age. People with diabetes are two to four times more likely to report having heart disease, and the age-adjusted death rate from coronary heart disease is about twice that of people without diabetes. Peripheral vascular disease is another serious complication, leading to 50% of all amputations of the lower extremities in adults. Diabetes is the most common cause of end-stage renal disease, and the leading cause of blindness in adults.3 Diabetes ranks sixth as a primary cause of death in the US, and when its complications are considered, it ranks third. The estimated economic impact of diabetes is considerable. In 1997, the total medical expenditures incurred by people with diabetes were $77.7 billion, or $10,071 per capita, compared with $2,669 for people without diabetes.2 Proper care of diabetes is essential because no known cure exists and good management reduces the frequency of long-term complications. Diabetes management requires early diagnosis, intensive treatment, and education and communication; patient knowledge is vital because diabetes health care is primarily self-care.3
Hispanics in the US
International migration is one of the least documented demographic phenomena worldwide. An estimate of international migration is usually determined by the change in the number of foreign-born individuals based on national census data. The US is the largest recipient of immigrants in the world, surpassing the rate of entry into any other country on earth. Based on the 1990 census data, the US had 10.2 million residents who were born elsewhere in the Americas. The largest proportion of immigrants to the US comes from Mexico, the Latin Caribbean, and Central American. As for older Hispanics in the US, 60% are Mexican Americans, followed by Puerto Ricans and Central and South Americans. The proportion of Hispanic elders in the general elderly population is projected to increase from 4% in 1994 to 16% by 2050.1
Diabetes mortality among Hispanics is higher compared to non-Hispanic whites, possibly reflecting limited access to health care, and lack of adequate monitoring.4 In Latin America mortality rates from diabetes mellitus have increased dramatically, especially among the population over 25 years old (see Box 1). Recent changes in mortality profiles in the Region of the Americas (between 1980 and 1990) indicate that diabetes mellitus is the seventh leading cause of death and the third most common chronic condition leading to high mortality, only after infectious diseases and malignant neoplasms. Rates of diabetes have been reported to be 25% higher among Hispanic Americans in comparison to African Americans. This is of great concern given that Hispanics are the fastest growing minority group in the US. Data from the Third National Health and Nutrition Examination Survey (NHANES III) showed that minority persons with diabetes in the US, particularly Mexican Americans, were more likely to have poorer glycemic control than African Americans and non-Hispanic whites.4 Poor glycemic control requires more intensive insulin treatment and may be a risk factor for functional limitations and disability in the elders. Functional limitations and disability influence quality of life, likelihood of hospitalization, and survival. The burden of disease on functional limitations has been established for chronic conditions such as diabetes. The Established Populations for Epidemiologic Studies in the Elderly (EPESE) showed that non-institutionalized Mexican Americans over 65 years with diabetes had greater likelihood of impairment in activities of daily living than non-Hispanic white populations.6
|
BOX 1 |
|
|
Americas Region |
+147% |
|
Andean Area |
+126% |
|
Brazil |
+113% |
|
Mexico |
+107% |
|
Southern Cone |
+44% |
|
North America |
+64% |
|
Caribbean |
+63% |
Risk Factors
Type 2 diabetes is associated with risk factors that need to be identified in order to prevent or treat the development or progression of this disease. In addition to environmental factors (particularly dietary patterns, lack of physical activity, and increased body weight), socio-demographic factors are also important and often underestimated. Socioeconomically disadvantaged and less educated minority elders are not as likely to follow health preventive measures such as diet and exercise. Low income and educational attainment increase the risk of health and functional problems. Poorer levels of health and functional status are thought to be common barriers to physical activity among older minority groups. In addition, lower levels of education and income are associated with lower levels of self-confidence in specific behavioural domains, including physical activity and dietary patterns.
Figure 1. Prevalence of Type 2 Diabetes among elders in the US. The Massachusetts Hispanic Elders Study.
Of all Hispanic American families, 25% live below the US poverty level compared with 10% of families that are not Hispanics. The economic impact of illness on Hispanic workers is exacerbated by their over-representation in low-paying jobs and jobs that do not provide health insurance, sick leave, parental leave, disability benefits, or retirement benefits. Among individuals aged 65 and older, 38% of Mexican Americans, 16% of Puerto Ricans, and 24% of Cuban Americans do not have health insurance. Furthermore, Hispanics are less likely to have graduated from high school than any other US population. English literacy is also low in the Hispanic population in general, a problem compounded by the fact that some groups have low Spanish literacy also.1 Studies comparing migrant populations with native nonimmigrant populations have established a consistent theme of elevated prevalence of type 2 diabetes with acculturation. The common elements of acculturation include a diet higher in total calories and fat and lower in fiber, and less need to expend energy because of labour saving devices. Data from other parts of the world also show increased prevalence of diabetes in urban compared with rural areas and in minority persons who have moved to other more developed nations. Further, as Hispanic Americans have changed their diet and physical activity patterns over time, diabetes prevalence has also increased. Acculturation exerts an effect, primarily with its association to language skills, employment, and education.1
Lifestyle Modification Interventions
Physical activity is one of the environmental factors important in the management of diabetes that can be modified. Several studies on endurance exercise training support its efficacy for diabetes prevention and management. Another type of exercise known as resistance exercise training (or weight lifting) has also been shown to have the same beneficial effects as aerobic exercise. In addition, weight lifting exercises increase muscle mass and strength, and improve functional capacity. The fact that the prevalence of diabetes increases with age and related body composition changes may support the usefulness of resistance exercise training in people with diabetes.
We are currently conducting a randomized controlled trial of resistance training in community-dwelling Hispanic men and women over 60 year of age. All subjects are followed for 16 weeks. Exercises are performed under supervision 3 times per week. Both groups continue standard medical care. Preliminary results from the first 19 subjects showed that persons in the exercise group improved muscle strength, physical performance, physical self-confidence, and increased leisure-time physical activity, and less depression. Compared to the control group, exercise resulted in decreased glycosylated haemoglobin and plasma insulin levels, and body fat (Table 2). The improvement in glycemic control with resistance exercise was higher than that reported with 200 mg of troglitazone (rezulin) treatment. The advantage is that resistance exercise is not only safer but also it is a non-pharmacological intervention that has other important benefits on body composition, muscle strength, functional capacity, and quality of life in this patient population. More studies are needed to better understand the effectiveness of physical activity programs in people with diabetes; however, these results are promising.
Recommendations
A rise in the prevalence of overweight, obesity, and sedentary lifestyles, coupled with the ageing of the population in all countries, has contributed to move diabetes to the forefront of public health concerns worldwide. Most persons with the disease have type 2 diabetes, the form most intimately associated with lifestyle and, therefore, theoretically preventable through health promotion and lifestyle modification. Given the increasing prevalence of diabetes in many populations, increased awareness of the disease, surveillance of high-risk populations, early diagnosis and treatment are all important in reducing the morbidity associated with this disease. There are simple tools to determine risk of becoming a diabetic that can be easily adapted to different regions of the world. Examples of these are available on the World Wide Web: http://spin.com.mx/~jledesma/nhweb/nhweb.html in Spanish, and http://www.diabetes.org/ada/risktest.asp in English.
Table 2. Effects of Progressive Resistance Training on Glycemic Control in Hispanic Elders with Type 2 Diabetes. A Pilot Study. (Castaneda, C. unpublished).
|
Outcome Measure |
Exercise Group |
% D |
Control Group |
% D |
||
|
INITIAL1 |
FINAL |
INITIAL1 |
FINAL |
|||
|
Body mass index (kg/m2) |
30.4 ± 4.3 |
30.3 ± 4.6 |
none |
29.7 ± 3.9 |
30.1 ± 3.3 |
+ 1 |
|
Glycosylated haemoglobin (%) |
8.9 ± 1.4 |
7.9 ± 1.0 |
- 11 |
8.8 ± 1.8 |
8.4 ± 1.9 |
- 4 |
|
Fasting plasma glucose (mg/dl) |
175 ± 58 |
154 ± 32 |
- 12 |
188 ± 72 |
151 ± 36 |
- 20 |
|
Fasting insulin level (m/mL) |
24 ± 18 |
15 ± 7 |
- 38 |
23 ± 14 |
32 ± 29 |
+ 39 |
|
Body fat by DXA2 (kg) |
34.5 ± 8.1 |
33.5 ± 8.6 |
- 3 |
29.7 ± 8.9 |
29.9 ± 8.3 |
none |
|
Lean tissue mass by DXA2 (kg) |
42.8 ± 8.5 |
43.9 ± 9.7 |
+ 3 |
43.8 ± 11.5 |
44.1 ± 11.2 |
none |
|
Waist circumference (cm) |
98 ± 12 |
97 ± 11 |
- 1 |
97 ± 11 |
98 ± 11 |
+ 1 |
|
Leisure time physical activity |
10 ± 10 |
27 ± 11 |
+ 170 |
23 ± 21 |
11 ± 25 |
- 52 |
|
Physical performance score |
28 ± 6 |
32 ± 2 |
+ 14 |
25 ± 6 |
25 ± 6 |
none |
|
Self-efficacy for walking (%) |
77 ± 35 |
95 ± 7 |
+ 27 |
80 ± 17 |
71 ± 20 |
- 11 |
|
Geriatric depression scale |
12 ± 7 |
5 ± 6 |
- 58 |
9 ± 8 |
11 ± 9 |
+ 22 |
|
Muscle strength (1 -RM lbs.) 3 |
323 ± 113 |
451 ± 168 |
+ 40 |
233 ± 96 |
203 ± 94 |
- 13 |
1 Initial subject characteristics not statistically different when adjusted for age and genderDiabetes prevalence, complications, and mortality are by far higher in minority populations, particularly among those physically inactive, less educated, and with lower income. Interventions that improve people's awareness and understanding of diabetes disease are needed. Lifestyle modification interventions are important in increasing one's self-efficacy and self-esteem. Self-confidence is positively associated with levels of education and income, thus increasing the individuals' assurance necessary to adopt and adhere to a behavioural modification, such as that required for a healthier diet and a more physically active lifestyle. Hispanics living in the US or in their own countries are caught in a reinforcing cycle of environmental factors that exacerbate diabetes. Public health interventions that increase exercise and physical activity would improve several aspects of this cycle (self-efficacy, glucose control, functional capacity, etc.). The goal of diabetes treatment should be to empower those individuals with diabetes to take better control of their disease while working together with the health care team. Health services delivery should be based on accessibility and quality in a framework of equality and social justice. It should be expected to eliminate many of the barriers that hinder access at various levels of the health care system (social, economic, etc.). Health care should emphasise the need to design and implement educational programs, and lifestyle behaviour modification practices, while maintaining an adequate standard of health care. It is important to determine the effectiveness of such programs, and to work closely with existing community resources, community leaders, and organisations working directly in health promotion, health education, and disease prevention.
2 DXA: dual X-ray absorptiometry
3 1 -RM: one repetition maximum strength
References
|
1. |
Pan American Health Organization (1998). Health in the
Americas. Washington, DC, PAHO. |
|
|
|
|
2. |
Centers for Disease Control and Prevention (1998). National
Diabetes Fact Sheet. Washington, DC, US Department of Health and Human
Services and the Centers for Disease Control and Prevention. |
|
|
|
|
3. |
American Diabetes Association (1996). Vital Statistics.
Alexandria, Virginia. |
|
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|
4. |
Stem M P and Mitchell BD (1995). Diabetes in Hispanic
Americans. Diabetes in America. NIH. Washington, DC, National Institutes of
Health. 2nd ed p631-659. |
|
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|
5. |
Tucker KL, Bermudez OL et al. (1999). NIDDM is prevalent and
poorly controlled among Caribbean origin Hispanic elders. Am J Public Health:
in press. |
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6. |
Markides KS, Stroup-Benham CA et al. (1996). The effects of
medical conditions on the functional limitations of Mexican-American elderly.
Ann Epidemiol 6:386-391. |
Odilia I Bermudez, PhD, MPH is a Scientist at the above institution and an Associate at the Frances Stem Nutrition Center, New England Medical Hospital, Boston, Massachusetts 02111 USA; tel 617 556 3183; email
