Palumbo, Pasquale J

Among the 1135 Rochester residents discovered to have diabetes in the period 1945–69, the prevalence of retinopathy was 2.6% at the time of initial diagnosis. Among those free of retinopathy at diagnosis of diabetes, the subsequent incidence of any retinopathy was 17.4 per 1000 person-years and for proliferative retinopathy alone was 1.6 per 1000 person-years, based on 12,000 person-years of follow-up. The incidence rate of retinopathy was almost three times greater among residents with insulin-dependent (IDDM) than with non-insulin-dependent diabetes (NIDDM); however, the actual number of retinopathy cases was over four times greater among the more numerous residents with NIDDM. By 20 yr after diagnosis of diabetes, the cumulative incidence of retinopathy approached 70% among IDDM subjects and was 30% and 36%, respectively, among the obese and nonobese NIDDM residents. The epidemiologic patterns for proliferative retinopathy were qualitatively similar to those for nonproliferative retinopathy. The risk of blindness was greater among those with proliferative than with nonproliferative retinopathy but was substantial even for those without retinopathy. Most blindness was caused by factors other than isolated diabetic retinopathy.

In a population-based investigation among the residents of Rochester, Minnesota, the diabetes mortality rate was 8.5 per 100,000 person-years with diabetes as the underlying cause of death, 31.5 per 100,000 person-years with diabetes as an underlying or contributory cause, and 82.7 per 100,000 person-years if all deaths among diabetic individuals were counted. Diabetes was not mentioned on the certificate in 62% of the 428 diabetic deaths during 1965–1974. When the clinical characteristics of the subgroup of mortality cases in 1969 were compared with those of the prevalence cases on 1 January 1970, it was found that mortality cases tended to be older, were more often on insulin therapy, and were more likely to have macro- and microvascular complications. Because mortality data are sometimes used to infer trends and characteristics for the diabetic population at large, it is important to recognize these biases.

Of all the known diabetic individuals residing in the community of Rochester, Minnesota, only about one-half would have been recognized through a review of the medical records of 1 yr. Only one-fifth of the diabetic residents were hospitalized during the index year and a similarly small proportion were attended in a diabetes clinic. This selective process produced distortion in the apparent clinical spectrum of diabetes observed at different levels in the medical care system. Notable was overestimation of the relative importance of insulin-dependent diabetes and of the vascular complications of diabetes among hospital and diabetes clinic patients. Referral bias should be taken into account when differences are noted in the epidemiologic features of diabetes as reported from different types of medical care settings.

In a population-based study in Rochester, Minnesota, the clinical characteristics of 1135 patients newly diagnosed with diabetes (1945–69) were compared with those of 810 residents with diabetes mellitus on prevalence day (1 January 1970). The prevalence patients were older and the male:female ratio was reduced from that seen among incidence cases. The prevalence patients were more likely to be on oral agents, had lower fasting blood glucose levels, were less likely to be symptomatic, but were more likely to have macrovascular and microvascular complications. These differences seemed to come about as a result of variation in survival rates among patients with specific characteristics, differential migration of certain groups of patients, and changes in the status of individuals.

The incidence of diabetes mellitus by clinical type was determined for the community of Rochester, Minnesota, 1945–69. Overall adjusted incidence rates per 100,000 person-years were 8.4 for IDDM, 80.1 for obese NIDDM, 45.6 for nonobese NIDDM, and 3.6 for secondary diabetes, using our definitions. Strict use of National Diabetes Data Group criteria would have reduced the apparent incidence of all diabetes by about 20% through the deletion of NIDDM cases. The National Diabetes Data Group classification improved the clinical homogeneity of IDDM patients compared with “juvenile-onset” diabetes but had little effect on NIDDM relative to “maturity-onset” diabetes, since essentially the same patients were included in both groups. Separation of NIDDM into obese and nonobese subcategories accomplished little in the way of defining two more homogeneous subgroups.

Clinical peripheral vascular disease (PVD) was studied in an incidence cohort of 1073 residents of Rochester, Minnesota, who were found to have diabetes mellitus in the period 1945–69. About 8%; of patients already had clinical evidence of PVD at the time of diagnosis of diabetes. The proportion increased with the age at which diabetes was discovered. Among those unaffected initially, the incidence of subsequent PVD was slightly greater for men, 21.3 per 1000 person-years, than for women, 17.6 per 1000, and it increased both with age and duration of diabetes. The cumulative incidence of subsequent PVD was estimated to be 15%; at 10 yr and 45% at 20 yr after the diagnosis of diabetes. The age-adjusted prevalence of residents with diabetes and a history of PVD was 3.3 per 1000 population 30 yr of age or over on 1 January 1970.

OBJECTIVE—Birth weight is a risk factor for both diabetes and mortality. Diabetes is a risk factor for mortality. Whether the excess mortality observed for diabetes varies with birth weight is unclear. RESEARCH DESIGN AND METHODS—Among all 2,508 Rochester, Minnesota, residents who first met research criteria for adult-onset diabetes in 1960–1995, 171 were born locally in-hospital after 1922 (i.e., birth weights available) as singleton, term infants. Each case subject and two age- and sex-matched nondiabetic control subjects (born locally, residing locally when the case subject met the criteria for diabetes) were followed through 31 December 2000 for vital status. RESULTS—Of the diabetic case subjects, 16% (27 of 171) died vs. 7% (25 of 342) of control subjects (P = 0.004). The difference was less for normal-birth-weight (NBW) (2,948–<3,856 g) individuals (12% [12 of 102] vs. 8% [20 of 246], P = 0.31) than for abnormal-birth-weight individuals (low birth weight [LBW] 20% [8 of 39] vs. 2% [1 of 46], P = 0.01; high birth weight [HBW] 23% [7 of 30] vs. 8% [4 of 50], P = 0.16), as confirmed with age- and sex-adjusted Cox proportional hazards (diabetes-associated hazard ratio 1.4 [95% CI 0.69–2.90] for NBW vs. 4.8 [1.7–13.3] for abnormal birth weight, test for interaction P = 0.056). The observed diabetes deaths were greater than expected, based on mortality for the general population (27 vs. 13.3, P < 0.001), with 70% of excess deaths occurring among LBW (8 vs. 2.2, P < 0.001) and HBW (7 vs. 3.1, P = 0.03) individuals. CONCLUSIONS—The excess mortality observed for diabetes appears disproportionately concentrated among abnormal-birth-weight individuals, thus identifying a subset of at-risk diabetic individuals and reinforcing the importance of NBW deliveries.

OBJECTIVE—The aims of this study were to provide estimates of 1) the risk of mortality for individuals with both diabetes and peripheral arterial disease (PAD) relative to that for individuals with either condition alone and 2) the association between PAD progression and mortality for individuals with diabetes, PAD, and both conditions. RESEARCH DESIGN AND METHODS—This longitudinal cohort study was conducted in Rochester, Minnesota. Local residents age 50–70 years with a prior diagnosis of PAD and/or diabetes were identified from the Mayo Clinic diagnostic registry and invited to a baseline examination (1977–1978). Those who met inclusion criteria were assessed for PAD progression at 2 and 4 years and followed for vital status through 31 December 1999. RESULTS—The numbers who met criteria for PAD, diabetes, and both conditions at baseline were 149, 238, and 186, respectively. Within each group, observed survival was less than expected (P < 0.001). The adjusted risk of death for both conditions was 2.2 times that for PAD alone. Among the 449 who returned at 4 years, the risk of subsequent death was greater for those whose PAD had progressed; among individuals with diabetes alone at baseline, 100% (17 of 17) who met criteria for PAD progression were dead by 31 December 1999 compared with 62% (111 of 178) of those who had not met criteria (adjusted relative hazard 2.29 [95% CI 1.30–4.02], P = 0.004). The increased mortality associated with PAD progression was significant only for individuals with diabetes (alone or with PAD). CONCLUSIONS—Diabetes is a risk factor for both PAD and PAD-associated mortality, emphasizing the critical need to detect and monitor PAD in diabetic patients.

OBJECTIVE—Increasing obesity within the general population has been accompanied by rising rates of diabetes. The extent to which obesity has increased among people with diabetes is unknown, as are the potential consequences for diabetes outcomes. RESEARCH DESIGN AND METHODS—Community medical records (hospital and ambulatory) of all Rochester, Minnesota, residents aged ≥30 years who first met standardized research criteria for diabetes from 1970 to 1989 (n = 1,306) were reviewed to obtain data on BMI and related characteristics as of the diabetes identification date (±3 months). Vital status as of 31 December 1999 and date of death for those who died were obtained from medical records, State of Minnesota death tapes, and active follow-up. RESULTS—As of the identification date, data on BMI were available for 1,290 cases. Of the 272 who first met diabetes criteria in 1970–1974, 33% were obese (BMI ≥30), including 5% who were extremely obese (BMI ≥40). These proportions increased to 49% (P < 0.001) and 9% (P = 0.012), respectively, for the 426 residents who first met diabetes criteria in 1985–1989. BMI increased significantly with increasing calendar year of diabetes identification in multivariable regression analysis. Analysis of survival revealed an increased hazard of mortality for BMI ≥41, relative to BMI of 23–25 (hazard ratio 1.60, 95% CI 1.09–2.34, P = 0.016). CONCLUSIONS—The prevalence of obesity and extreme obesity among individuals at the time they first met criteria for diabetes has increased over time. This is disturbing in light of the finding that diabetic individuals who are extremely obese are at increased risk of mortality compared with their nonobese diabetic counterparts.