November 25, 2004
An Epidemiological Perspective on Type 2 Diabetes Among Adult Men
I Diabetes prevalence, costs, and complications are growing at alarming rates in the United States. The prevalence of diabetes is increasing at similar rates for men and women. Some complications, such as lower-extremity amputation and end-stage renal disease, are more prevalent among men, particularly among ethnic minority groups. Diabetes is also a significant contributor to erectile dysfunction. Because men are less likely to engage in the health care system, primary and secondary prevention efforts need to be implemented in culturally appropriate, male-oriented venues.
In this article, we will review the epidemiology of diabetes among men, specifically examining the prevalence and incidence of diabetes, including rates among high-risk populations, diabetes complications, and primary and secondary diabetes prevention practices. We will also offer some perspectives on addressing the diabetes epidemic among men.
The most recent estimates of diabetes prevalence (2002) indicate that -18 million Americans ≥ 20 years of age have diabetes. This represents 8.7% of all people in this age group. Prevalence rates of diabetes are essentially identical for men and women, although the absolute number of people with diabetes varies somewhat by sex (8.7 million men, 9.3 million women).10
Trends in diabetes prevalence since 1980 have shown consistent increases in prevalence rates among men and women (Figure 1), with marked increases during the 1990s, consistent with increases in obesity during this time period.5,6,11 Diabetes prevalence increased by 78% for men and 62% for women from 1980 to 2002.10 Similarly, self-reported body weight increased by 3.5 kg for men and 3.7 kg for women from 3990 to 1998.11
According to data collected in the National Health and Nutrition Examination Survey (NHANES) for the period 1999-2000, there was no significant difference in diabetes prevalence rates for men and women. However, impaired fasting glucose (IFG) affected men to a greater degree than women (7.9 vs. 4.5%).2 Combined age-adjusted estimates of diagnosed and undiagnosed diabetes and IFG during the 1999-2000 period indicate the prevalence to be 17.6% in men and 12.5% in women (Figure 2). Similarly, in an analysis of data from the third NHANES (NHANES III),12 the overall prevalence of pre- diabetes (either impaired glucose tolerance [IGT] or IFG) did not differ significantly between overweight men and overweight women aged 45-74 years, but IFG specifically was ~ 30% higher for men than for women (Figure 3).
There is a significantly higher prevalence of diabetes in non- Hispanic blacks (NHB) and Mexican Americans than in non-Hispanic whites (NHW)-21.1 and 18.8 vs. 13.1%, respectively (Figure 2).10 The rate of diabetes increased in NHB from 19.5% (NHANES III data) to 21.1% (NHANES 1999-2000 data) but decreased in Mexican Americans from 23.7 to 18.8%. Studies conducted in American Indians and Alaska Natives have shown a high prevalence of diabetes in this population. Analyses of data provided by the Indian Health Service and the Behavioral Risk Factor Surveillance System indicate the prevalence of diabetes in this population to be more than twice that of the general U.S. population in 2002 (15.3 vs. 7.3%).13
Data from these ethnic minority groups show only slight differences in the diabetes prevalence rates of men and women. The most notable difference occurs for American Indians, which shows an ~ 20% higher prevalence rate for women than for men.11
Figure 1. Trends in Self-Reported Diabetes Prevalence, 1980- 2000, by Sex and Race/Ethnicity
Figure 2. Diabetes Prevalence Trends by Sex and Ethnicity, 1988- 1994 to 1999-2000.
Figure 3. Prevalence of Pre-Diabetes, IGT, and IFG Among Overweight Adults 45-74 Years Old, by Sex12
Evidence from population data indicates that the incidence of diabetes is increasing in most segments of the population, consistent with increases in obesity, increased awareness of diabetes, and recent modifications in the definitions of diabetes. In 2000, diabetes incidence was slightly lower for men than for women in the age groups 18-44 years and 45-64 years, but it was markedly different among the age group 65-79 years (14.5/1,000 for men; 9.4/1,000 for women) (Figure 4).14
Data collected from 1997 to 2000 show that, while the incidence of diabetes has increased in both men and women, there has been a higher rate of increase in men. Incidence of diabetes increased by > 50% in the oldest age group for men (9.7/1,000 in 1997; 14.5/1,000 in 2000), while declining slightly in this age group for women (10.9/ 1,000 in 1997; 9.4/1,000 in 200O).14 Interestingly, diabetes incidence reversed trends for men and women in the age group 65-79 years, with men having slightly lower rates than women in 1997, but much higher rates 4 years later.
Diabetes-related complications that can be prevented or delayed include CVD, stroke, renal disease, retinopathy, peripheral vascular disease resulting in LEA, erectile dysfunction (ED), and associated depression. In this section, we will provide an overview of the prevalence of diabetes complications for men and women.
Diabetes is the sixth leading cause of death in the United States, accounting for 3.0% of deaths each year. An estimated 400,000 adults with diabetes die each year. Over 69,000 death certificates in 2000 had diabetes listed as the underlying cause of death.14 Because diabetes is often not listed on death certificates, these numbers are believed to be underestimates.
Diabetes mortality rates vary dramatically by race/ethnic group. Diabetes is the seventh leading cause of death for whites, fifth for blacks, Asian/Pacific Islanders, and Hispanics, and fourth for American Indians. Overall, diabetes is the sixth leading cause of death for men and the fifth leading cause for women.ls Despite significant overall ethnic differences, diabetes mortality rates are fairly comparable for blacks and whites by sex, with the notable exception of a 35% greater death rate for those with diabetes from any mentioned cause for white men compared to white women (Figure 5).10
Figure 4. Diabetes Incidence by Age and Sex, 2000
CVD remains the number one cause of death in the United States and is responsible for nearly 1 million deaths annually. CVD affected an estimated 22.6% of the total U.S. population in 2001. It is more prevalent in women (22.4%) than in men (21.5%), and mortality rates associated with this disease for women have exceeded those for men since the mid-1980s.16
CVD is the leading cause of death for people with diabetes, accounting for > 65% of all deaths in this population. Diabetes is recognized as a major risk factor for CVD, increasing risk by two to four times. Recent initiatives have been launched by the American Heart Association and the American Diabetes Association to increase awareness of CVD risk factors (hyperglycemia, high blood pressure, and dyslipidemia) among people with diabetes. Unfortunately,
Figure 5. Diabetes Mortality Rates by Sex and Race, 1996
Impaired glucose metabolism is one of a cluster of CVD risk factors comprising the metabolic syndrome, which affects ~ 25% of adults.18 Rates of the metabolic syndrome are roughly similar between white men and white women, but it was 30-50% higher for African-American and Mexican-American women than for men of the same race/ethnic groups.19
While diabetes increases the risk of CVD, the impact of diabetes differs by sex. Data from the Atherosclerosis Risk in Communities Study showed that, compared to their respective sex group without diabetes, incidence of coronary heart disease was 2.52 times higher for men with diabetes and 3.45 times higher for women with diabetes. However, the incidence rate for men with diabetes was more than two times higher than for women with diabetes.20 Data from the NHANES Epidemiologie Follow-up Survey recently showed a reduction in heart disease mortality of 13.1% (P = 0.51) in men with diabetes versus a 36.4% reduction in men without diabetes (P
CVD rates among people with diabetes differ considerably across race/ethnic groups. Prevalence of diabetes-related CVD is higher for white men compared to white women, but it was higher for black women compared to black men. Rates for white men are higher \than for black men, although the reverse is true for women. Rates for Hispanics, which are lower overall than for whites and blacks, are only marginally different for men and women (Table 1).14
Diabetes is the leading cause of non-traumatic LEA, accounting for more than half of all cases. Foot infections and ulcers account for nearly 20% of diabetes-related hospitalizations. Approximately 15% of all people with diabetes will have a foot ulcer, a significant precursor to LEA, at some point in their lives.22 Hospitalizations for diabetes-related LEAs increased gradually from the early 1980s to the mid-1990s, with a reduction from that time period until 2000 (Table I).14
At every time period, men had significantly higher rates of discharge than women. In the most recent time period (2000), discharge rates were 1.8 times greater for men than for women. It is suspected that at least some of the sex difference in diabetes- related LEA can be attributed to the extremely high rates of this condition among ethnic minority men. In the Wisconsin Epidemiologie Study of Diabetic Retinopathy, LEA rates were four times higher for men than for women with younger-onset diabetes and two times higher for men than for women with older-onset diabetes.23
Table 1. Prevalence* of Diabetes-Related Complications by Year, Sex, and Race/Ethnicity
In 2000, 96,200 new cases of ESRD were diagnosed, and 378,862 patients were being treated for ESRD. Diabetes is the leading cause of ESRD, with > 40% of ESRD patients having diabetes.14 Rates of ESRD among people with diabetes are generally four to six times higher for African Americans, Hispanics, and American Indians than for whites. Across most ethnic groups, rates of overall and diabetes- related ESRD are higher for men than for women, more markedly so in the African-American population (40% higher for men than for women) (Table I).14
Diabetes is the leading cause of adult blindness in the United States. Visual impairments affect ~ 25% of all adults with diabetes, or nearly 1.6 million Americans.24 Diabetic retinopathy affects nearly 70% of people with type I diabetes10 and > 60% of those with type 2 diabetes.25 There are an estimated 12,000-24,000 new cases of blindness in the United States each year.10 Currently, diabetic retinopathy affects > 700,000 people in the United States. Prevalence of diabetic retinopathy varies greatly across ethnic groups, with Mexican Americans and African Americans at greater risk compared to whites.26 Data on sex differences for diabetic retinopathy are sparse, but a study from the Massachusetts Commission for the Blind registry indicated that incidence and prevalence rates of diabetes-related blindness in 1994 were ~ 40% higher for men than for women.27
An estimated 15-30 million American men have ED. This condition affects 50-60% of men with diabetes-nearly twice as many as men without diabetes.28 ED may be caused by vascular disease, endothelial dysfunction, failed neural transmission, or reduced arterial blood flow.28 It may also affect depression in men, which in turn may have a negative effect on how diabetic men care for their diabetes. Rates of office visits for ED have tripled since the mid-1980s as a result of increased availability and effectiveness of treatment regimens.28
PRIMARY AND secONDARY PREVENTION
The causes of type 2 diabetes are multifactorial. Causal components of this disease are intertwined and occasionally interdependent. One main component of causality is obesity, which is affected by dietary intake and physical activity.
Behavioral modifications such as changes to dietary intake and physical activity can retard diabetes and its sequelae in people with IGT.29-31 The Diabetes Prevention Program (DPP) showed that lifestyle intervention can reduce complications of diabetes better than the administration of metformin, an oral antiglycemic agent. The DPP showed a 58% reduction in the incidence of diabetes in the group assigned to lifestyle intervention and a 31% reduction in the incidence of diabetes in the metformin group versus placebo. The effectiveness of lifestyle change was noted across ethnic groups.32
Studies indicate a consistent rise in the prevalence of overweight and obesity in the United States. Approx-imately 67% of adult men and 61.9% of adult women are overweight or obese. Rates of overweight/obesity are higher for white, Hispanic, and Asian/ Pacific Islander men than for women of those race/ethnic groups, whereas the reverse is true among African Americans and American Indians.16 During the period 1971- 2000, energy intake in men increased significantly from 2,450 to 2,618 kcal/day, or 6%.33 The proportion of men considered physically active decreased between 1988 and 2000 from 29 to 22%-nearly 1% per year.34 Energy intake for women increased from 1,542 to 1,877 kcal/day, or nearly 18%,33 while the proportion of women considered physically active dropped from 32 to 28%.34
secondary prevention for people with diabetes includes regular interaction with primary and specialty health care providers and self-care practices such as blood glucose monitoring, foot self- care, and adherence to dietary and physical activity regimens. Table 2 shows the prevalence of self-reported diabetes medical care and self-management among adults with diabetes in 2002.14 Generally, men and women do not differ in their diabetes care. Notable exceptions include lower rates for men than for women for annual eye exams (61.3 vs. 66.6%), self-monitoring of blood glucose (50.7 vs. 61.5%), and foot self-exams (64.0 vs. 70.1%).14
Diabetes is a growing public health problem in the United States and around the world. Recent research has. shown promise for primary and secondary prevention of diabetes and its complications. Although rates for diabetes are similar for men and women, men are disproportionately burdened by many of the complications of diabetes. Some indicators of diabetes self-management that are relatively low among men are more than likely the consequences of this gap in diabetes sequelae.
Table 2. Diabetes Self-Care Practices by Sex, Behavioral Risk Factor Surveillance System, 2002
Increasing awareness is being generated towards men's health issues. Preventive measures aimed at reducing the risk of CVD have shown a reduction in heart disease in men with diabetes. However, other complications of diabetes, especially ESRD, LEA, and ED, require more aggressive preventive measures to reduce the upward trends.
Primary prevention efforts targeting men offer more challenges. Prevention should be multifocal, accessing as many settings as possible that treat men, including physician offices, clinics, and hospital programs. Special segments of the adult male population may be particularly difficult to reach. Recent efforts to reach men with health messages include having the message delivered by people men can identify with (e.g., sports figures), or in venues frequented by men (e.g., barber shops for African-American men or pow-wows for American-Indian men).
Diabetes, especially type 2 diabetes, is a controllable condition. Preventing diabetes can reduce morbidity and mortality and improve the quality of life for those in whom the disease would have developed.
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Lynda R. Hardy, PhD, RN, and Ronny A. Bell, PhD, MS
Lynda R. Hardy, PhD, RN, is an assistant professor in the Department of General Surgery, and Ronny A. Bell, PhD, MS, is an associate professor in the Department of Public Health Sciences at Wake Forest University School of Medicine in Winston-Salem, N.C.
Copyright American Diabetes Association Fall 2004