The prevalence of leisure-time physical activity among diabetics in South Carolina.

Background: Diabetes is the seventh leading cause of death among South Carolinians. The benefit of physical activity on the control and prevention of diabetes has been established. This study determined the prevalence of leisure-time physical activity among South Carolinians with and without diabetes and compared the physical activity of those with diabetes between 1990 and 2000.

Methods: Data from the South Carolina Behavioral Risk Factor Surveillance System were used to classify adults with and without diabetes into categories of physical activity.

Results: Physical inactivity was higher among South Carolinians with diabetes (42%) than in those without (27%). A comparison of physical activity in diabetics between 1990 and 2000 demonstrated a slight decrease (2%) in physical inactivity.

Conclusion: The decrease in physical inactivity among diabetics is encouraging; however, further promotion of physical activity is recommended to encourage diabetics to engage in physical activity on a regular basis.

Key Words: diabetes, physical activity, South Carolina

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The prevalence of obesity and Type 2 diabetes among Americans has reached epidemic proportions. Nearly 8% of all Americans report the presence of diabetes mellitus Type 2. (1) Diabetes represents the seventh leading cause of death among South Carolinians and has been estimated to contribute nearly $800 million in health care costs. (2) The health-related benefits associated with regular participation in leisure-time physical activity have been established. (3) Longitudinal studies have consistently revealed that participation in moderate-intensity physical activity, such as brisk walking, is protective against the development of Type 2 diabetes mellitus. (4), (5) In contrast, sedentary behaviors such as prolonged television watching and long periods of occupational in physical inactivity have been associated with reductions energy expenditure, increases in weight gain, and the development of Type 2 diabetes mellitus. (4) Physical activity has also been associated with a reduced risk of cardiovascular disease (CVD), CVD mortality, and all-cause mortality among those with Type 2 diabetes mellitus. (6), (7) It has been estimated that for every 1,000 kcal/wk of energy expenditure, overall mortality decreases by 20 to 30%. (8)

Due to the nationwide burden of diabetes and its associated negative health consequences, the Department of Health and Human Services released a set of goals for the nation in the Healthy People 2010 report. These goals include reducing diabetes-related mortality rates and reducing deaths from CVD in patients with diabetes mellitus. (9) Increasing the amount of physical activity for those with diabetes can help to reduce mortality rates by nonpharmacologically controlling blood glucose levels, reducing hypertension, lowering the incidence of obesity, and managing circulating cholesterol and lipoprotein profiles. Physical activity has also been associated with psychological benefits such as a decrease in anxiety and depression and providing a coping mechanism during prolonged periods of emotional stress. Regular physical activity can also lead to a reduction in health care costs for diabetics by lowering treatment expenses and minimizing diabetes-related complications later in life. (10)

Little is known about the physical activity habits of diabetics in South Carolina and how they compare with adults who do not have diabetes. The purpose of this article was to determine the prevalence of physical activity among adults with and without diabetes in South Carolina and to compare physical activity levels among diabetics between the years 1990 and 2000 using data from the Behavioral Risk Factor Surveillance System (BRFSS). This article also compares prevalence estimates of diabetes in the United States to estimates for those living in South Carolina. Practical recommendations are made for physicians and other health professionals to promote physical activity among the diabetic population.

Methods

Overview of Participants and the BRFSS

Participants for the current study were respondents of the BRFSS conducted between the years 1990 and 2000. The purpose of the BRFSS was to collect state-specific information regarding preventive health practices and risk behaviors among Americans and to examine relationships between these factors and many chronic diseases. The BRFSS is currently administered in all 50 states, the District of Columbia, and U.S. territories; however, this study was limited to residents of South Carolina. The BRFSS uses a standard random-digit dial telephone interview to noninstitutionalized, state residents aged 18 years and older.

Presence of Diabetes and Physical Activity Assessment

In the BRFSS, the presence of diabetes was determined with a single question, which asked participants to report whether a physician had ever diagnosed them with diabetes. To assess physical activity, participants were asked whether they had performed any leisure-time physical activities or exercises during the past month. If participants reported they had performed physical activities or exercises during the past month, they were asked to describe the type(s), frequency (times per week or month), and usual duration of this activity. The intensity of the activity was determined using the Compendium of Physical Activities, (11) which describes the energy costs of specific physical activities ranging from household chores to calisthenics. Leisure-time physical activity was grouped into three distinct categories: 1) recommended amounts of leisure-time physical activity that meet current Centers for Disease Control and Prevention (CDC) and American College of Sports Medicine (ACSM) recommendations for physical activity; 2) amounts of leisure-time physical activity insufficient to meet the current CDC/ACSM recommendations; and 3) physically inactive, self-reported as no leisure-time physical activity during the past month. The current CDC/ACSM physical activity recommendation reflects the minimum amount of moderate-intensity physical activity needed to improve or maintain adequate health and is defined as moderate-intensity physical activities for [greater than or equal to]5 d/wk and [greater than or equal to]30 min/d and/or vigorous physical activities [greater than or equal to]3 d/wk and [greater than or equal to]20 min/d. (12)

Statistical Analysis

To account for the complex sampling design used by the BRFSS, SUDAAN statistical software (version 8.0, Research Triangle Park, Cary, NC) was used to perform all analyses. Prevalence estimates of leisure-time physical activity were calculated as weighted percentages and used to compare those with diabetes to those without diabetes and to compare estimates from 1990 to 2000.

Results

In 1990, the self-reported prevalence of diabetes among South Carolinians who participated in the BRFSS was 6.9%. In 2000, the prevalence of diabetes was 6.8%. Figure 1 displays the levels of leisure-time physical activity among diabetics (n = 221) and nondiabetics (n = 3,037) in 2000. Forty-two percent of adults with diabetes were classified as physically inactive as compared with 27% of adults without diabetes. Nearly half (48%) of all nondiabetics were insufficiently active compared with 39% of diabetics. The prevalence of meeting recommendations for leisure-time physical activity was higher among nondiabetics (25%) than among diabetics (19%).

[FIGURE 1 OMITTED]

Figure 2 shows the prevalence of leisure-time physical activity among diabetics participating in the 1990 BRFSS (n = 150) and diabetics participating in the 2000 BRFSS (n = 221). The prevalence of physical inactivity for diabetics declined by 2% between 1990 and 2000. Diabetics classified as insufficiently active increased from 36% in 1990 to 39% in 2000. There was a slight (1%) decrease in the proportion of diabetics meeting current health recommendations for physical activity between 1990 and 2000.

[FIGURE 2 OMITTED]

Discussion

The primary purposes of the present study were to determine the prevalence of physical activity among diabetics and nondiabetics in South Carolina and to compare the prevalence of physical activity in diabetics in 1990 and 2000. The results of this study indicated those with self-reported diabetes in South Carolina were less physically active than their counterparts who reported no diabetes. Nearly half (42%) of all diabetics in 2000 were classified as physically inactive compared with just over a quarter (27%) of nondiabetics. Of the diabetics in 2000 who were physically active, less than one-fifth (19%) met recommended guidelines for moderate-and/or vigorous-intensity leisure-time physical activity. Nationwide, the median percentage of adults who reported no leisure-time physical activity (physically inactive) was similar (26.9%) to that reported for nondiabetic adults living in South Carolina. Reducing the relatively high prevalence rate of physically inactive diabetic adults living in South Carolina should be a statewide priority, given the numerous health benefits of a physically active lifestyle. Physicians and other health professionals are encouraged to recommend a program of regular physical activity for their diabetic patients.

Self-reported diabetes rates among South Carolinians were nearly unchanged between 1990 and 2000 (from 6.9%-7.1%), whereas the median proportion of adults with diabetes increased nationally from 4.9% to 6.1%. In 2000, the estimated prevalence of diabetes in the southern United States was approximately 6.8%. As seen in Figure 2, the percentage of diabetics reporting no leisure-time physical activity decreased by 2% and the proportion who reported physical activity but not at levels sufficient to meet the CDC/ACSM recommendations increased by 3%. These small increases in leisure-time physical activity among diabetics are important because physical activity has multiple benefits for reducing the complications of diabetes.

The ACSM and the American Diabetes Association encourage diabetics to participate in most physical activities at a moderate intensity for at least 30 min/d on most days of the week, provided that they take the proper precautions. (12-15) A detailed medical evaluation with appropriate diagnostic studies is advised before prescribing an individualized physical activity program. Once a preliminary examination is completed and there are no signs or symptoms leading the physician to believe CVD or other complications are present, a comprehensive and individualized program of physical activity can be implemented. If CVD is suspected, a graded exercise test is advised to determine cardiovascular responses to exercise. When prescribing the physical activity program, proper warm-up and cool-down periods consisting of 5 to 10 minutes of low-intensity aerobic activity should be included. Those with diabetes-related complications should be advised to avoid strenuous activities that substantially increase blood pressure and that may involve jarring or pounding motions. Diabetics with peripheral neuropathies should be encouraged to participate in nonimpact and non-weight-bearing activities such as swimming, rowing, cycling, and water aerobics. For all diabetics, the use of comfortable, well-fitting footwear to prevent possible injuries to the feet is suggested. Among diabetics with retinopathies, visual disorders may impair the field of vision. Therefore, a stationary bicycle may be more appropriate, to minimize the risk of possible injuries. In all cases, a common-sense approach that incorporates the patient's physical condition and seeks to avoid possible injuries is advised.

Possible limitations to this study should be noted. The BRFSS, administered separately through state health agencies under the supervision of the CDC, is widely regarded as one of the best available tools for tracking the incidence of disease, preventive health practices, and nationwide disease trends. However, like many surveys, the BRFSS relies on participants' self-reported health status and does not determine the duration of any possible health conditions. The cross-sectional nature of the BRFSS limits the ability to determine a causal influence between factors associated with disease risk factors and health outcomes. In addition, the BRFSS does not provide data about the type of diabetes (Type 1 or Type 2), the presence of gestational diabetes, or the length of time a respondent has been diagnosed as diabetic.

Conclusion

Physical activity is an essential element of a healthy lifestyle, especially for those with diabetes. Despite no change in the prevalence of self-reported diabetes in South Carolina from 1990 to 2000 BRFSS surveys, the proportion of diabetics reporting no leisure-time physical activity decreased from 44% to 42%. People with diabetes should be encouraged to perform at least 30 minutes of moderate-intensity physical activity on most days of the week to gain the optimal health-related benefits of regular physical activity. These benefits include reductions in the complications associated with diabetes and CVD. To meet national goals for reducing diabetes-related mortality, physicians and other health care professionals are encouraged to promote physical activity among their diabetic patients.

Of course there is no formula for success except, perhaps, an unconditional acceptance of life and what it brings.

--Arthur Rubinstein

Key Points

* Diabetes is the seventh leading cause of death among South Carolinians; however, regular physical activity may reduce the number of diabetes-related deaths.

* South Carolinians with self-reported diabetes are less physically active than those without diabetes.

* Self-reported diabetes rates among South Carolinians were unchanged between 1990 and 2000, whereas diabetes rates increased nationally.

* The percentage of South Carolinians with diabetes reported decreases in physical inactivity from 1990 to 2000.

Fig. 1 Prevalence of leisure-time physical activity among diabetics (n =
221) and nondiabetics (n = 3,037): SC BRFSS, 2002.

Physical Activity Level *      Prevalence (%)

                           Diabetic  Non-diabetic

        Inactive             42%         27%
      Insufficient           39%         48%
       Recommended           19%         25%

Note: Table made from bar graph.

Fig. 2 Comparison of leisure-time physical activity among diabetics in
1990 (n = 150) and 2000 (n = 221): SC BRFSS, 1990 and 2000.

Physical Activity Level *  Prevalence (%)

                           1990  2000

        Inactive           44%   42%
      Insufficient         36%   39%
       Recommended         20%   19%

Note: Table made from bar graph.

Accepted July 14, 2003.

Copyright [c] 2004 by The Southern Medical Association

0038-4348/04/9702-0141

References

(1.) Knowler WC, Barrett-Connor E, Fowler SE, et al; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393-403.

(2.) South Carolina Department of Health and Environmental Control. The Health of South Carolinians 2000. Columbia, SC, Department of Health and Environmental Control. Available at: http://www.scdhec.net/co/media_relations/releases/pdf_files/HOSC2000.pdf. Accessed July 31, 2003.

(3.) U.S. Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta GA, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1996.

(4.) Hu FB, Li TY, Colditz GA, et al. Television watching and other sedentary behaviors in relation to risk of obesity and type 2 diabetes mellitus in women. JAMA 2003;289:1785-1791.

(5.) Manson JE, Nathan DM, Krolewski AS, et al. A prospective study of exercise and incidence of diabetes among US male physicians. JAMA 1992;268:63-67.

(6.) Ford ES, DeStefano F. Risk factors for mortality from all causes and from coronary heart disease among persons with diabetes: Findings from the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study. Am J Epidemiol 1991;133:1220-1230.

(7.) Wei M, Gibbons LW, Kampert JB, et al. Low cardiorespiratory fitness and physical inactivity as predictors of mortality in men with type 2 diabetes. Ann Intern Med 2000;132:605-611.

(8.) Lee IM, Skerrett PJ. Physical activity and all-cause mortality: What is the dose-response relation? Med Sci Sports Exerc 2001;33(6 Suppl): S459-S471, S494.

(9.) U.S. Department of Health and Human Services. Healthy People 2010: Understanding and Improving Health Objectives. Washington, DC, U.S. Government Printing Office, 2000, ed 2, pp 5-34.

(10.) Kohl HW, Gordon NF, Villegas JA, et al. Cardiorespiratory fitness, glycemic status, and mortality risk in men. Diabetes Care 1992;15:184-192.

(11.) Ainsworth BE, Haskell WL, Leon AS, et al. Compendium of physical activities: Classification of energy costs of human physical activities. Med Sci Sports Exerc 1993;25:71-80.

(12.) Pate RR, Pratt M, Blair SN, et al. Physical activity and public health: A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402-407.

(13.) Albright A, Franz M, Hornsby G, et al. American College of Sports Medicine position stand: Exercise and type 2 diabetes. Med Sci Sports Exerc 2000;32:1345-1360.

(14.) American Diabetes Association. Diabetes mellitus and exercise. Diabetes Care 1997;20:1908-1912.

(15.) Zinman B, Ruderman N, Campaigne BN, et al; American Diabetes Association. Physical activity/exercise and diabetes mellitus. Diabetes Care 2003;26(Suppl 1):S73-S77.

Connie Van Vrancken, MA, Christopher M. Bopp, MS, Jared P. Reis, MS, Katrina D. DuBose, MS, Karen A. Kirtland, PHD, and Barbara E. Ainsworth, PHD

From the Department of Exercise Science, the Prevention Research Center, and the Department of Epidemiology & Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC.

There was no financial support for this study. The University of South Carolina, where the study was conducted, provided all supplies used to complete this study.

Reprint requests to Karen A. Kirtland, PhD, Prevention Research Center, Arnold School of Public Health, University of South Carolina, 730 Devine Street, Columbia, SC 29208. Email: [e-mail]