Biomedical subjects

Robert G Nelson

Publications and source records attributed to Robert G Nelson.

21 records · Page 2Linked to original sources

PubMed2003

Incidence of retinopathy and nephropathy in youth-onset compared with adult-onset type 2 diabetes.

OBJECTIVE: To examine the risk of retinopathy and nephropathy in participants in whom type 2 diabetes was diagnosed in youth (before 20 years of age) compared with those in whom type 2 diabetes was diagnosed at older ages. RESEARCH DESIGN AND METHODS: Subjects in whom youth-onset or adult-onset diabetes was diagnosed in the longitudinal study of health in the Pima Indians of Arizona were followed for microvascular complications. Diabetes was diagnosed in 178 subjects before 20 years of age (youth), in 1,359 subjects at 20-39 years of age (younger adults), and in 971 subjects at 40-59 years of age (older adults). Incidence rates of diabetic retinopathy diagnosed by direct ophthalmoscopy through dilated pupils and nephropathy (protein-to-creatinine ratio > or =0.5 g/g) were calculated by age at diagnosis. RESULTS: Over 25 years, nephropathy developed in 35 of the participants with youth-onset type 2 diabetes; this incidence rate was not significantly different from that in patients with adult-onset diabetes (P = 0.77). Incidence rates of retinopathy, however, were significantly lower for the youth-onset group (P = 0.007). Adjusted for sex, glycemia, and blood pressure, risk of retinopathy was lower in patients with youth-onset diabetes than in those with adult-onset diabetes (hazard rate ratio [HRR] 0.42, 95% CI 0.24-0.74, P = 0.003), but risk of nephropathy was not different (HRR 1.2, 95% CI 0.77-1.3, P = 0.38). CONCLUSIONS: In Pima Indians, the risk of nephropathy as a function of duration of diabetes is similar in all age groups. By contrast, the risk of retinopathy is lower in patients with youth-onset type 2 diabetes.

Adult↗

PubMed2000

Glomerular permselectivity at the onset of nephropathy in type 2 diabetes mellitus.

The development of microalbuminuria in individuals with type 2 diabetes mellitus is associated with a 10-fold increase in the risk of progression to overt nephropathy and eventual end-stage renal failure. The present study reports long-term (up to 8 yr) follow-up of 43 Pima Indians with type 2 diabetes detected on screening to have microalbuminuria. The natural history of albuminuria in these individuals included progression to overt proteinuria (urinary albumin excretion > or = 300 mg/d) in half of the participants by 7 yr of follow-up. The size selectivity of the glomerular barrier was also investigated using dextran sieving and pore theory. Whereas a comparison group of macroalbuminuric Pima Indians had an excess of large pores that served as a macromolecular "shunt," individuals with microalbuminuria had a shunt size no different from long-term diabetic, normoalbuminuric control subjects. An abrupt transition from little or no relationship to a highly significant and positive relationship between increasing albuminuria and shunt size occurred at an albumin-to-creatinine ratio of approximately 3000 mg/g. Shunt size in macroalbuminuric individuals correlated with the extent of foot process broadening. Podocyte foot processes in microalbuminuric participants were not different from those in control subjects. In conclusion, although microalbuminuria in type 2 diabetic Pima Indians often heralds progressive glomerular injury, it is not the result of defects in the size permselectivity of the glomerular barrier but rather of changes in either glomerular charge selectivity or tubular handling of filtered proteins or of a combination of these two factors.

Adolescent↗

PubMedDate not supplied

Trends in heart disease death rates in diabetic and nondiabetic Pima Indians.

BACKGROUND: Secular trends over 34 years (1965-1998) in overall and cause-specific mortality were examined in 4,623 Pima Indians >or=35 years old. METHODS: The underlying and contributing causes of the 1,363 deaths were determined from a review of all available clinical records; 540 of the deaths occurred in the 2,528 nondiabetic participants and 823 in the 2,095 participants who had diabetes during all or part of the study period. Age/sex-adjusted death rates were calculated across four 8.5-year time intervals. RESULTS: In the nondiabetic participants, the rate of death from natural causes declined gradually over time (20.4, 17.3, 17.3, and 16.0 deaths per 1,000 persons/year; P=.11); deaths from ischemic heart disease (IHD) were uncommon (n=22), and the rate did not change appreciably, remaining as the fifth leading natural cause of death. In the diabetic participants, the rate of death from natural causes was unchanged over time, but the rate of death from IHD (n=141) increased nearly twofold (3.3, 4.2, 6.4, and 6.4 deaths per 1,000 persons/year; P<.01), becoming the leading cause of death in the third and fourth time intervals. CONCLUSIONS: The rate of death from IHD remained stable in nondiabetic Pima Indians but increased among those with diabetes. This finding suggests that, in the absence of diabetes, the underlying susceptibility to IHD in this population has not changed.

Adult↗