Epidemiology of diabetes and its macrovascular manifestations in Pacific populations: the medical effects of social progress

Worldwide diabetes epidemiology studies have shown quite marked differences in diabetes prevalence rates between ethnic groups. This pattern holds true in the Pacific region and provides unique opportunities for comparative studies. Diabetes is rare in Melanesians, and also in Polynesians, Micronesians, and Australian Aboriginals who retain their traditional life-style. High prevalence rates of insulin-independent diabetes have been demonstrated in Polynesians, Micronesians, and Australian aboriginals who have adopted a Western life-style. Along with the Pima Indians, the Micronesian population of Nauru have the highest diabetes prevalence yet reported--40% of people aged 20 yr and over. As diabetes is rare in traditional living Polynesians and Micronesians, yet high in westernized populations of these ethnic groups, it appears these people may have a "diabetic genotype" that is unmasked by the change in life-style. Obesity, a high caloric Western diet, and reduced physical activity may be the major precipitating factors. Bimodality of glucose tolerance distributions has been demonstrated in both westernized Polynesians and Micronesians. The frequency distributions of both fasting and 2-h postload glucose levels allow separation of these populations into normal and hyperglycemic groups. The optimal cut-off levels between the two groups were a fasting plasma glucose congruent to 140 mg/dl and a 2-h level of congruent 20 mg/dl. These findings provide a valid basis for the diagnosis of diabetes mellitus to be based on the above levels. Only sparse information exists on the prevalence of microvascular and macrovascular complications of diabetes in these populations. However, there is clear evidence that they are occurring and they are similar in nature to the complications seen in Caucasian diabetic patients. Coronary artery disease is not yet a major problem in Pacific Islanders although most of the major risk factors are not present in urbanized communities. However, with increasing westernization, and given more time for the pathologic process of atheroma to develop, it can be expected that coronary artery disease will become a major cause of morbidity and mortality in Polynesians, Micronesians, and the Australian aboriginal.     

Type 2 diabetes and diabetes risk factors in children and adolescents

Long considered a disease of older adults, type 2 diabetes mellitus (DM) is now affecting children. While the prevalence and incidence of type 2 DM are not yet established in children, the number of affected individuals continues to climb. At the same time, obesity, the primary risk factor for type 2 DM, has become epidemic, affecting all ethnic and demographic groups across the United States. The lifestyle trends contributing to both of these phenomena include changes in dietary patterns and habits, declining levels of physical activity, and increasing sedentary behaviors. In response to these problems, the medical profession must become proactive with its patients and in the community.     

The burden and treatment of diabetes in elderly individuals in the u.s

OBJECTIVE: To assess the prevalence of diabetes, distinguishing between elderly individuals with diabetes diagnosed in middle age ("middle age-onset diabetes") from elderly individuals with recently diagnosed diabetes ("elderly onset diabetes") and to assess the burden of complications and control of cardiovascular risk factors in these groups. RESEARCH DESIGN AND METHODS: We analyzed data from 2,809 elderly individuals from the 1999-2002 National Health and Nutrition Examination Survey, a cross-sectional nationally representative survey of the civilian noninstitutionalized population of the U.S. RESULTS: Among adults aged >/=65 years, the prevalence of diagnosed diabetes was 15.3%, representing 5.4 million individuals in the U.S. The prevalence of undiagnosed diabetes was 6.9% or 2.4 million individuals. Elderly individuals with middle age-onset diabetes had a much greater burden of microvascular disease but have a similar burden of macrovascular disease compared with individuals with elderly onset diabetes. Elderly individuals with middle age-onset diabetes had substantially worse glycemic control (proportion of individuals with HbA(1c) >7% = 59.9%) compared with either elderly onset (41.6%) or nonelderly individuals with diabetes (55.3%). Individuals with elderly onset diabetes were also less likely to be taking glucose-lowering medications. CONCLUSIONS: In this study, we documented a high prevalence of diabetes among elderly individuals and high rate of poor glycemic control in this population. Individuals with middle age-and elderly onset diabetes appear to represent distinct groups with differing burdens of disease and possibly differing treatment goals. Future studies of diabetes in elderly individuals may need to consider stratification based on age of diagnosis.     

Outcome of pregnancy among immigrant women with diabetes

OBJECTIVE: We studied outcome of pregnancy among immigrant women with diabetes. The women came from regions of the world with high incidence of impaired glucose tolerance and type 2 diabetes. Prevalences, secular trends, and sociodemographic risk factors of diabetes were also explored. RESEARCH DESIGN AND METHODS: Data from the Medical Birth Registry of Norway on all births from 1988 to 1998 for mothers born in South Asia and North Africa (11,268) and Norway (601,785) were analyzed. RESULTS: The prevalence of pregestational diabetes among the immigrants was 8.9/1,000 births, which was more than twice the rate among ethnic Norwegians (3.6/1,000). Time trends indicated increasing prevalences in both groups. Among the immigrants, diabetes was closely associated with maternal age. Maternal diabetes was associated with a significantly increased risk of pregnancy complications in both study groups. Increased risks were found for low birth weight, macrosomia, preterm birth, preeclampsia, and cesarean sections. Among ethnic Norwegians, maternal diabetes conferred a significantly increased risk of infant perinatal death (odds ratio 2.00, 95% CI 1,44-2.77). In the sample of immigrant women with predominantly type 2 diabetes, maternal diabetes was not significantly associated with perinatal death or congenital malformations in the offspring. CONCLUSIONS: The high prevalence of diabetes among immigrants from South Asia and North Africa represents a challenge for health care providers. To prevent adverse pregnancy outcomes and later cardiovascular and renal morbidity among these groups, early diagnosis of diabetes, adequate metabolic control, and relevant preventive measures are warranted.     

Impact of maternal nativity on the prevalence of diabetes during pregnancy among U.S. ethnic groups.

OBJECTIVE: This study examines the impact of maternal nativity (birthplace) on the overall prevalence of diabetes during pregnancy and among 15 racial and ethnic groups in the U.S. RESEARCH DESIGN AND METHODS: Birth certificate data for all resident single live births in the U.S. from 1994 to 1996 were used to calculate reported diabetes prevalence during pregnancy and to assess the impact of maternal birthplace outside of the 50 states and Washington, DC, on the risk of diabetes before and after adjustment for differences in maternal age, other sociodemographic characteristics, and late or no initiation of prenatal care overall and for each racial and ethnic group. RESULTS: Mothers born outside of the U.S. are significantly more likely to have diabetes during pregnancy. The impact of maternal nativity on diabetes prevalence is largely explained by the older childbearing age of immigrant mothers. However, adjusted diabetes risk remains elevated for Asian-Indian, non-Hispanic black, Filipino, Puerto Rican, and Central and South American mothers who were born outside the U.S. Conversely, birthplace outside the U.S. significantly reduces diabetes risk for Japanese, Mexican, and Native American women. CONCLUSIONS: Identification, treatment, and follow-up of immigrant mothers with diabetes during pregnancy may require special attention to language and sociocultural barriers to effective care. Systematic surveillance of the prevalence and impact of diabetes during pregnancy for immigrant and nonimmigrant women, particularly in racial and ethnic minority groups, and more detailed studies on the impact of acculturation on diabetes may increase understanding of the epidemiology of diabetes during pregnancy in our increasingly diverse society.     

Prevalence and risk factors for urinary incontinence in women with type 2 diabetes and impaired fasting glucose: findings from the National Health and Nutrition Examination Survey (NHANES) 2001-2002

OBJECTIVE: Diabetes is associated with increased risk of urinary incontinence. It is unknown whether women with pre-diabetes, or impaired fasting glucose (IFG), have increased prevalence of incontinence. We determined the prevalence of, and risk factors for, incontinence among U.S. women with diabetes and IFG. RESEARCH DESIGN AND METHODS: The 2001-2002 National Health and Nutrition Examination Survey measured fasting plasma glucose and obtained information about diabetes and urinary incontinence among 1,461 nonpregnant adult women. Self-reported weekly or more frequent incontinence, both overall and by type (urge and stress), was our outcome. RESULTS: Of the 1,461 women, 17% had diabetes and 11% met criteria for IFG. Prevalence of weekly incontinence was similar among women in these two groups (35.4 and 33.4%, respectively) and significantly higher than among women with normal fasting glucose (16.8%); both urge and stress incontinence were increased. In addition to well-recognized risk factors including age, weight, and oral estrogen use, two microvascular complications caused by diabetes, specifically macroalbuminuria and peripheral neuropathic pain, were associated with incontinence. CONCLUSIONS: Physicians should be alert for incontinence, an often unrecognized and therefore undertreated disorder, among women with diabetes and IFG, in particular those with microvascular complications. The additional prospect of improvements in their incontinence may help motivate some high-risk women to undertake difficult lifestyle changes to reduce their more serious risk of diabetes and its sequelae.     

Effect of pioglitazone on the drivers of cardiovascular risk in type 2 diabetes

The prevalence of type 2 diabetes and its associated mortality and morbidity are continuing to increase across the world. People with type 2 diabetes typically have a cluster of risk factors for cardiovascular disease, including hyperglycaemia, hypertension and lipid abnormalities, which contribute to the high cardiovascular morbidity and mortality in these patients. Targets for glycosylated haemoglobin, lipids and blood pressure are becoming more stringent, and most patients will require multiple therapies to maximally reduce cardiovascular risk. In a large randomised, controlled, long-term cardiovascular outcomes study pioglitazone showed durable glycaemic control, a powerful insulin-sparing effect and changes in the lipid profile associated with reduced cardiovascular risk. This article reviews these metabolic findings in the context of previous randomised, controlled studies for pioglitazone and discusses whether the integration of this agent into the treatment regimen of appropriate patient groups has the potential to improve cardiovascular outcomes in type 2 diabetes.     

Prevalence of Diabetes in Persons with Disabilities in Primary Care

This research was designed to answer the question: Does the prevalence of diabetes differ between adults with and without disability, in the same family medicine practice? A retrospective cohort design was used, to study diabetes among adults, with sensory, trauma, developmental, and psychiatric disabilities so comparisons can be made between disability groups and to comparison patients without disabilities. There was a 5.3 fold risk for diabetes, given obesity, for patients with sensory disabilities, a 3.6 fold risk for patients with trauma disabilities, a 4.1 fold risk for adults with developmental disabilities, and a 3.1 fold risk for adults with psychiatric disability, compared to those with the same disability without obesity. The general principle that obesity is a major risk factor for the onset of Type 2 diabetes holds true and the actual risk for diabetes given obesity, is not significantly different between patients with and without disability.     

Diabetes and impaired fasting glycemia in the tribes of Khagrachari hill tracts of Bangladesh

OBJECTIVE: To determine the prevalence of type 2 diabetes and impaired fasting glycemia (IFG) in a tribal population of Bangladesh. RESEARCH DESIGN AND METHODS: A cluster sampling of 1,287 tribal subjects of age > or =20 years was investigated. They live in a hilly area of Khagrachari in the far northeast of Bangladesh. Fasting plasma glucose, blood pressure, height, weight, waist girth, and hip girth were measured. Lipid fractions were also estimated. We used the 1997 American Diabetes Association diagnostic criteria. RESULTS: The crude prevalence of type 2 diabetes was 6.6% and IFG was 8.5%. The age-standardized (20-70 years) prevalence of type 2 diabetes (95% CI) was 6.4% (4.96-7.87) and of IFG was 8.4% (6.48-10.37). Both tribesmen and women had equal risk for diabetes and IFG. Compared with the lower-income group, the participants with higher income had a significantly higher prevalence of type 2 diabetes (18.8 vs. 3.1%, P < 0.001) and IFG (17.2 vs. 4.3%, P < 0.001). Using logistic regression, we found that increased age, high-income group, and increased central obesity were the important risk factors of diabetes. CONCLUSIONS: The prevalence of diabetes in the tribal population was higher than that of the nontribal population of Bangladesh. Older age, higher central obesity, and higher income were proven significant risk factors of diabetes. High prevalence of diabetes among these tribes indicates that the prevalence of diabetes and its complications will continue to increase. Evidently, health professionals and planners should initiate diabetes care in these tribal communities.     

颈动脉硬化患病情况及危险因素分析

目的 探讨颈动脉硬化（CAS）的患病情况及其危险因素。 方法 将该院603例住院患者根据颈动脉彩超检查结果分为非硬化组和硬化组,计算CAS的患病率,分析比较两组临床资料及生化指标,利用多因素Logistic回归分析各危险因素与CAS的相关性。 结果 入选患者CAS的发生率为57.5%。两组年龄、糖化血红蛋白、血尿酸、甘油三酯、低密度脂蛋白胆固醇、高血压、糖尿病、吸烟差异有统计学意义（P<0.05）。Logistic回归分析显示,年龄、吸烟、高血压、糖尿病、低密度脂蛋白胆固醇为CAS的独立危险因素。 结论 年龄、吸烟、高血压、糖尿病、低密度脂蛋白胆固醇与CAS的发生具有明显相关性,合并危险因素的中老年人应尽早行颈动脉彩超检查。血尿酸与CAS的相关性有待进一步研究证实。       

Cardiovascular risk factor modification: is it effective in older adults?

Older adults over the age of 65 are the fastest growing segment of the US population. However, the prevalence of cardiovascular disease (CVD) is highest in this population and CVD is the primary cause of death for elders. Cardiovascular disease risk factors are similar for both younger and older age groups and include hypertension, cigarette smoking, hyperlipidemia, and diabetes. Evidence for managing and treating these CVD risk factors in elders is presented.     

Early and more vigorous detection of diabetes

Currently 17 million Americans have diabetes mellitus (DM); 90% of these have type 2 DM. Of these 17 million, 5.9 million remain undiagnosed. The undiagnosed patient with type 2 DM may be asymptomatic for years, while hyperglycemic injury to target organs occurs long before the development of frank diabetes. The prevalence of diabetes among adults is estimated to increase to almost double the present number by 2025. People with diabetes and at risk for diabetes are also at risk for cardiovascular disease. Several investigators have now demonstrated the benefit of controlling blood glucose levels as well as other risk factors in this population to decrease the incidence of microvascular and macrovascular disease. Prevention or delaying the onset of type 2 DM can be accomplished with a program of diet, weight loss, and exercise.     

Ethnic differences in peripheral vascular disease

The wide variation in the way coronary artery disease (CAD) affects different ethnic groups and the associated risk factor profiles of these groups have been extensively studied, but ethnic differences in the clinical manifestations of peripheral vascular disease (PVD) have been relatively neglected. The aim of the present review is to provide an overview of PVD in different ethnic groups and to explore possible pathophysiological factors accounting for these differences. Atherosclerotic PVD is generally less prevalent in Indo-Asians and Afro-Caribbeans than in caucasians, despite the 'classical' risk factors being as prevalent, if not more so, suggesting the possibility of as yet unidentified risk factors in these groups. Angiographic and microscopic evidence suggests that patients of African or Afro-Caribbean origin suffer from a different pattern of PVD, which primarily affects the distal arteries. In contrast, Indo-Asians tend to suffer from thromboangiitis obliterans (Buerger's disease) far more frequently than other ethnic groups; thus, their arterial disease appears to present much earlier and with greater severity. However, if this sub-category of patient is excluded, they seem to suffer much less from 'simple' atherosclerotic disease than their caucasian counterparts. Despite a higher prevalence of diabetes among Indo-Asians, the prevalence of intermittent claudication is considerably less in this ethnic group.     

2014年浙江省湖州市吴兴区农村居民高血压合并糖尿病患病情况及危险因素分析

目的 了解浙江省湖州市吴兴区农村居民高血压合并糖尿病患病情况及其危险因素,为制定防治策略提供科学依据。方法 采用两阶段随机抽样方法对湖州市吴兴区4230名农村居民进行问卷调查、体格检查和实验室检测。选择其中高血压合并糖尿病患者作为病例组,选择单纯高血压患者作为对照组,对高血压合并糖尿病患者患病情况和其危险因素进行分析。结果 调查对象高血压、糖尿病以及高血压合并糖尿病调查患病率和复杂加权患病率分别为23.76%、5.98%、3.17%和14.21%、3.78%、1.81%。高血压患者中患糖尿病和糖尿病患者中患高血压比例分别为13.33%和52.96%。高血压合并糖尿病患病率女性高于男性,与年龄呈正相关,与文化程度呈负相关,且55岁以上人群患病率增幅明显高于高血压和糖尿病。多因素logistic回归分析显示,糖尿病家族史、体质指数、总胆固醇是高血压合并糖尿病的危险因素。结论 应进一步重视农村地区高血压、糖尿病以及高血压合并糖尿病的防控工作,多应用具体事例开展更具针对性的健康教育工作。对高血压患者,应在积极控制血压和肥胖的同时,重视空腹血糖、血脂等指标的监测,并在高血压合并糖尿病药物预防和治疗方面进一步加强医防合作。     

Ethnic differences in mortality, end-stage complications, and quality of care among diabetic patients: a review

OBJECTIVE: To determine the influence of ethnic differences in diabetes care on inequalities in mortality and prevalence of end-stage complications among diabetic patients. The following questions were examined: 1) Are there ethnic differences among diabetic patients in mortality and end-stage complications and 2) are there ethnic differences among diabetic patients in quality of care? RESEARCH DESIGN AND METHODS: A review of the literature on ethnic differences in the prevalence of complications and mortality among diabetic patients and in the quality of diabetes care was performed by systematically searching articles on Medline published from 1987 through October 2004. RESULTS: A total of 51 studies were included, mainly conducted in the U.S. and the U.K. In general, after adjusting for confounders, diabetic patients from ethnic minorities had higher mortality rates and higher risk of diabetes complications. After additional adjustment for risk factors such as smoking, socioeconomic status, income, years of education, and BMI, in most instances ethnic differences disappear. Nevertheless, blacks and Hispanics in the U.S. and Asians in the U.K. have an increased risk of end-stage renal disease, and blacks and Hispanics in the U.S. have an increased risk of retinopathy. Intermediate outcomes of care were worse in blacks, and they were inclined to be worse in Hispanics. Likewise, ethnic differences in quality of care in the U.S. exist: process of care was worse in blacks. CONCLUSIONS: Given the fact that there are ethnic differences in diabetes care and that ethnic differences in some diabetes complications persist after adjustment for risk factors other than diabetes care, it seems the case that ethnic differences in diabetes care contribute to the more adverse disease outcomes of diabetic patients from some ethnic minority groups. Although no generalizations can be made for all ethnic groups in all regions for all kinds of complications, the results do implicate the importance of quality of care in striving for equal health outcomes among ethnic minorities.     

Effects of traditional and western environments on prevalence of type 2 diabetes in Pima Indians in Mexico and the U.S

OBJECTIVE: Type 2 diabetes and obesity have genetic and environmental determinants. We studied the effects of different environments on these diseases in Pima Indians in Mexico and the U.S. RESEARCH DESIGN AND METHODS: Adult Pima-Indian and non-Pima populations in the Sierra Madre mountains of Mexico were examined using oral glucose tolerance tests and assessments for obesity, physical activity, and other risk factors. Results were compared with those from Pima Indians in Arizona. Both Pima populations were typed for DNA polymorphisms to establish their genetic similarity. RESULTS: The age- and sex-adjusted prevalence of type 2 diabetes in the Mexican Pima Indians (6.9%) was less than one-fifth that in the U.S. Pima Indians (38%) and similar to that of non-Pima Mexicans (2.6%). The prevalence of obesity was similar in the Mexican Pima Indians (7% in men and 20% in women) and non-Pima Mexicans (9% in men and 27% in women) but was much lower than in the U.S. Pima Indians. Levels of physical activity were much higher in both Mexican groups than in the U.S. Pima Indians. The two Pima groups share considerable genetic similarity relative to other Native Americans. CONCLUSIONS: The much lower prevalence of type 2 diabetes and obesity in the Pima Indians in Mexico than in the U.S. indicates that even in populations genetically prone to these conditions, their development is determined mostly by environmental circumstances, thereby suggesting that type 2 diabetes is largely preventable. This study provides compelling evidence that changes in lifestyle associated with Westernization play a major role in the global epidemic of type 2 diabetes.     

Diabetes and associated cardiovascular risk factors in the State of Kuwait: the first national survey

Background: Cardiovascular diseases (CVD) are the leading cause of mortality worldwide as well as in Kuwait. People with diabetes have two to five times greater risk of developing CVD as compared with non‐diabetic individuals. To date, little information exists on the prevalence and characteristics of cardiovascular risk factors in Kuwait. The objective of this survey was to address the growing burden of diabetes and related cardiovascular risk factors, and to estimate, for the first time, the prevalence of cardiovascular risk factors in the State of Kuwait. Methods: The study was carried out using the World Health Organization (WHO) STEPwise approach for surveillance of non‐communicable disease risk factors. This study represents a national survey for Kuwaiti nationals aged between 20 and 65 years. All participants were involved in an interview for gathering sociodemographic information, underwent focused physical examination and donated a blood sample for the study‐specific laboratory investigations. Results: A total of 1970 subjects, with a mean age of 48.9 ± 10.5, were screened. The prevalence of cardiovascular risk factors was as follows: diabetes 17.9%, dyslipidaemia 70.3%, hypertension 25.3% and obesity 48.2%. Over 62% had a sedentary lifestyle, and 17.8% were smokers. The prevalence of diabetes and dyslipidaemia increased with age and body mass index. Diabetes was also significantly associated with age above 40 years (OR = 10.5), family history of diabetes (OR = 2.79), hypertension (OR = 2.22), obesity (OR = 2.87) and lower literacy (OR = 4.23). Conclusions: This study found that advancing age (≥ 40 years), diabetes mellitus, obesity, positive family history of diabetes, hypertension and dyslipidaemia are significant risk factors for developing CVD in Kuwait as in other parts of the world. Understanding these factors allows for preventive measures to be taken for Kuwaiti population.     

Reduced coronary artery and abdominal aortic calcification in Hispanics with type 2 diabetes

OBJECTIVE: To compare lifestyle factors, cardiovascular risk factors, and coronary artery calcium (CAC) and abdominal aortic calcium (AAC) levels in Hispanic and non-Hispanic white (NHW) individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: We recently demonstrated in a small group of nonreferred, healthy, nondiabetic subjects that CAC was reduced in Hispanics compared with NHWs, despite a worse cardiovascular risk factor profile. In this study, we evaluated whether this ethnic disparity in vascular calcification was present in individuals with type 2 diabetes and in several different arterial beds. Hispanic and NHW subjects (n = 245) with type 2 diabetes were evaluated for cardiovascular risk factors using questionnaires and assays of plasma biomarkers. CAC and AAC were measured by electron-beam computer-assisted tomography. RESULTS: Although Hispanics were slightly younger than NHWs, other standard risk factors and novel cardiovascular risk factors, including plasminogen activator-1 and fibrinogen levels, were similar between the groups. Despite the similar risk factor profile, the prevalence of cardiovascular disease (CVD) and mean and median levels of CAC and AAC were lower in Hispanics. Furthermore, the distribution of these calcium scores differed from that of NHWs (P < 0.05), with significantly fewer Hispanic subjects having high CAC or AAC scores. These differences were not explained by differences in CVD prevalence or any measured lifestyle or risk factor. CONCLUSIONS: Hispanics with type 2 diabetes have reduced CAC and AAC levels compared with NHW subjects, suggesting a reduction in the overall burden of vascular calcification and atherosclerosis. These data are consistent with the notion that Hispanics are protected against the development of CVD.     

血脂异常对糖尿病发病及相关危险因素的影响

目的探讨血脂异常对糖尿病发病及相关危险因素的影响。方法在糖尿病流行病学调查基础上,根据血脂是否异常将人群分为两组,正常对照组A,实验组B,分别对两组糖尿病患病率进行统计学分析,并采用logistic回归分析筛选糖尿病的危险因素,根据危险因素的回归值β不同,判断各危险因素的影响性。结果 A组糖尿病患病率6.25%,B组糖尿病患病率28.08%,两组糖尿病的患病率χ2检验有统计学意义（P〈0.001）。结论血脂异常人群糖尿病患病率明显高于正常人群,对其进行早期干预可以预防或延缓糖尿病的发生发展,减少并发症的出现。     

Onset of NIDDM occurs at least 4-7 yr before clinical diagnosis.

OBJECTIVE--To investigate duration of the period between diabetes onset and its clinical diagnosis. RESEARCH DESIGN AND METHODS--Two population-based groups of white patients with non-insulin-dependent diabetes (NIDDM) in the United States and Australia were studied. Prevalence of retinopathy and duration of diabetes subsequent to clinical diagnosis were determined for all subjects. Weighted linear regression was used to examine the relationship between diabetes duration and prevalence of retinopathy. RESULTS--Prevalence of retinopathy at clinical diagnosis of diabetes was estimated to be 20.8% in the U.S. and 9.9% in Australia and increased linearly with longer duration of diabetes. By extrapolating this linear relationship to the time when retinopathy prevalence was estimated to be zero, onset of detectable retinopathy was calculated to have occurred approximately 4-7 yr before diagnosis of NIDDM. Because other data indicate that diabetes may be present for 5 yr before retinopathy becomes evident, onset of NIDDM may occur 9-12 yr before its clinical diagnosis. CONCLUSIONS--These findings suggest that undiagnosed NIDDM is not a benign condition. Clinically significant morbidity is present at diagnosis and for years before diagnosis. During this preclinical period, treatment is not being offered for diabetes or its specific complications, despite the fact that reduction in hyperglycemia, hypertension, and cardiovascular risk factors is believed to benefit patients. Imprecise dating of diabetes onset also obscures investigations of the etiology of NIDDM and studies of the nature and importance of risk factors for diabetes complications.