Improved clinical utility of preimplantation genetic testing through the integration of ploidy and common pathogenic microdeletions analyses.

STUDY QUESTION: Can chromosomal abnormalities beyond copy-number aneuploidies (i.e. ploidy level and microdeletions (MDs)) be detected using a preimplantation genetic testing (PGT) platform? SUMMARY ANSWER: The proposed integrated approach accurately assesses ploidy level and the most common pathogenic microdeletions causative of genomic disorders, expanding the clinical utility of PGT. WHAT IS KNOWN ALREADY: Standard methodologies employed in preimplantation genetic testing for aneuploidy (PGT-A) identify chromosomal aneuploidies but cannot determine ploidy level nor the presence of recurrent pathogenic MDs responsible for genomic disorders. Transferring embryos carrying these abnormalities can result in miscarriage, molar pregnancy, and intellectual disabilities and developmental delay in offspring. The development of a testing strategy that integrates their assessment can resolve current limitations and add valuable information regarding the genetic constitution of embryos, which is not evaluated in PGT providing new level of clinical utility and valuable knowledge for further understanding of the genomic causes of implantation failure and early pregnancy loss. To the best of our knowledge, MDs have never been studied in preimplantation human embryos up to date. STUDY DESIGN, SIZE, DURATION: This is a retrospective cohort analysis including blastocyst biopsies collected between February 2018 and November 2021 at multiple collaborating IVF clinics from prospective parents of European ancestry below the age of 45, using autologous gametes and undergoing ICSI for all oocytes. Ploidy level determination was validated using 164 embryonic samples of known ploidy status (147 diploids, 9 triploids, and 8 haploids). Detection of nine common MD syndromes (-4p=Wolf-Hirschhorn, -8q=Langer-Giedion, -1p=1p36 deletion, -22q=DiGeorge, -5p=Cri-du-Chat, -15q=Prader-Willi/Angelman, -11q=Jacobsen, -17p=Smith-Magenis) was developed and tested using 28 positive controls and 97 negative controls. Later, the methodology was blindly applied in the analysis of: (i) 100 two pronuclei (2PN)-derived blastocysts that were previously defined as uniformly euploid by standard PGT-A; (ii) 99 euploid embryos whose transfer resulted in pregnancy loss. PARTICIPANTS/MATERIALS, SETTING, METHODS: The methodology is based on targeted next-generation sequencing of selected polymorphisms across the genome and enriched within critical regions of included MD syndromes. Sequencing data (i.e. allelic frequencies) were analyzed by a probabilistic model which estimated the likelihood of ploidy level and MD presence, accounting for both sequencing noise and population genetics patterns (i.e. linkage disequilibrium, LD, correlations) observed in 2504 whole-genome sequencing data from the 1000 Genome Project database. Analysis of phased parental haplotypes obtained by single-nucleotide polymorphism (SNP)-array genotyping was performed to confirm the presence of MD. MAIN RESULTS AND THE ROLE OF CHANCE: In the analytical validation phase, this strategy showed extremely high accuracy both in ploidy classification (100%, CI: 98.1-100%) and in the identification of six out of eight MDs (99.2%, CI: 98.5-99.8%). To improve MD detection based on loss of heterozygosity (LOH), common haploblocks were analyzed based on haplotype frequency and LOH occurrence in a reference population, thus developing two further mathematical models. As a result, chr1p36 and chr4p16.3 regions were excluded from MD identification due to their poor reliability, whilst a clinical workflow which incorporated parental DNA information was developed to enhance the identification of MDs. During the clinical application phase, one case of triploidy was detected among 2PN-derived blastocysts (i) and one pathogenic MD (-22q11.21) was retrospectively identified among the biopsy specimens of transferred embryos that resulted in miscarriage (ii). For the latter case, family-based analysis revealed the same MD in different sibling embryos (n = 2/5) from non-carrier parents, suggesting the presence of germline mosaicism in the female partner. When embryos are selected for transfer based on their genetic constitution, this strategy can identify embryos with ploidy abnormalities and/or MDs beyond aneuploidies, with an estimated incidence of 1.5% (n = 3/202, 95% CI: 0.5-4.5%) among euploid embryos. LIMITATIONS, REASONS FOR CAUTION: Epidemiological studies will be required to accurately assess the incidence of ploidy alterations and MDs in preimplantation embryos and particularly in euploid miscarriages. Despite the high accuracy of the assay developed, the use of parental DNA to support diagnostic calling can further increase the precision of the assay. WIDER IMPLICATIONS OF THE FINDINGS: This novel assay significantly expands the clinical utility of PGT-A by integrating the most common pathogenic MDs (both de novo and inherited ones) responsible for genomic disorders, which are usually evaluated at a later stage through invasive prenatal testing. From a basic research standpoint, this approach will help to elucidate fundamental biological and clinical questions related to the genetics of implantation failure and pregnancy loss of otherwise euploid embryos. STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for this study. S.C., M.F., F.C., P.Z., I.P., L.G., C.P., M.P., D.B., J.J.-A., D.B.-J., J.M.-V., and C.R. are employees of Igenomix and C.S. is the head of the scientific board of Igenomix. A.C. and L.P. are employees of JUNO GENETICS. Igenomix and JUNO GENETICS are companies providing reproductive genetic services. TRIAL REGISTRATION NUMBER: N/A.

Characterization of endocrine features and genotype-phenotypes correlations in blepharophimosis-ptosis-epicanthus inversus syndrome type 1.

OBJECTIVE: Blepharophimosis syndrome (BPES) is an autosomal dominant genetic condition resulting from heterozygous mutations in the FOXL2 gene and clinically characterized by an eyelid malformation associated (type I) or not (type II) with premature ovarian failure. The distinction between the two forms is critical for female patients, as it may allow to predict fertility and to plan an appropriate therapy. Identifying an underlying causative mutation is not always predictive of the clinical type of BPES since genotype-phenotype correlations are not yet fully delineated. Here, we describe the clinical and hormonal phenotypes of three female patients with BPES type 1 from two novel families, correlate their phenotypes with identified mutations, and investigate the effects of hormone replacement therapy (HRT). METHODS: Clinical, biochemical, and genetic evaluation were undertaken in all the patients and genotype-phenotype correlation was analyzed. The effects of substitutive hormonal therapy on secondary sexual characteristics development and induction of menarche were evaluated. RESULTS: All patients presented with primary amenorrhea or other signs of ovarian dysfunction. Two distinct mutations, a missense p.H104R change and an in-frame p.A222_A231dup10 duplication in the FOXL2 gene were identified. Observed phenotypes were not in accordance with the prediction based on the current genotype-phenotype correlations. HRT significantly improved secondary sexual characteristics development, as well as the induction of menarche. CONCLUSIONS: This study highlights the importance of early recognition of BPES and emphasizes the need of personalized therapy and follow-up in female patients carrying distinct FOXL2 mutations.

Unbiased next generation sequencing analysis confirms the existence of autosomal dominant Alport syndrome in a relevant fraction of cases.

The mode of inheritance of Alport syndrome (ATS) has long been controversial. In 1927, the disease was hypothesized as a dominant condition in which males were more severely affected than females. In 1990, it was considered an X-linked (XL) semidominant condition, due to COL4A5 mutations. Later on, a rare autosomal recessive (AR) form due to COL4A3/COL4A4 mutations was identified. An autosomal dominant (AD) form was testified more recently by the description of some large pedigrees but the real existence of this form is still questioned by many and its exact prevalence is unknown. The introduction of next generation sequencing (NGS) allowed us to perform an unbiased simultaneous COL4A3-COL4A4-COL4A5 analysis in 87 Italian families (273 individuals) with clinical suspicion of ATS. In 48 of them (55%), a mutation in one of the three genes was identified: the inheritance was XL semidominant in 65%, recessive in 4% and most interestingly AD in 31% (15 families). The AD form must therefore be seriously taken into account in all pedigrees with affected individuals in each generation. Furthermore, a high frequency of mutations (>50%) was shown in patients with only 1 or 2 clinical criteria, suggesting NGS as first-level analysis in cases with a clinical suspicion of ATS.

Nectinopathies: an emerging group of ectodermal dysplasia syndromes.

Cleft Lip/Palate-Ectodermal Dysplasia and Ectodermal Dysplasia-Syndactyly Syndrome are rare congenital disorders caused by recessive mutations in the PVRL1 and PVRL4 genes, respectively. These genes encode nectins 1 and 4, an emerging class of molecules acting in cooperation with cadherins to form cell-cell adhesion especially at adherens junctions. Their role in skin, hair and teeth biology and in the fine-tuning morphogenesis of craniofacial (lip/palate) and limbs is yet to be outlined prompting future research. We propose refer to these entities (nectin 1-ED and nectin 4-ED) as "nectinopathies", which are likely to be underestimated/underdiagnosed ED syndomes.

First and second branchial arch involvement in mandibulofacial dysostosis Guion-Almeida type.

BACKGROUND: Mandibulofacial dysostosis Guion-Almeida Type (MFDGA; OMIM#610536) is a rare autosomal dominant genetic disorder caused by heterozygous pathogenic variants in the EFTUD2 gene. Mandibulofacial dysostoses are characterised by the core triad malar hypoplasia, maxillary hypoplasia and dysplastic ears, all derived by the impaired development of the first and second branchial arches. Differential diagnosis is often challenging. The early genetic diagnosis is extremely useful, not only for the correct management of cranial malformations, but also for the early diagnosis and treatment of the comorbidities associated to the disease, which greatly benefit from early treatment.

Potassium intake and risk of incident type 2 diabetes mellitus: the Coronary Artery Risk Development in Young Adults (CARDIA) Study.

AIMS/HYPOTHESIS: Serum potassium has been found to be a significant predictor of diabetes risk, but the effect of dietary potassium on diabetes risk is not clear. We sought to determine if dietary potassium is associated with risk of incident type 2 diabetes in young adults. METHODS: We used data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Potassium intake was measured by (1) an average of three 24 h urinary potassium collections at the 5-year study visit, and (2) the CARDIA dietary assessment instrument at baseline. Incident type 2 diabetes cases were ascertained on the basis of use of diabetes medication and laboratory measurements. Analyses were adjusted for relevant confounders including intake of fruit and vegetables and other dietary factors. RESULTS: Of 1,066 participants with urinary potassium measurements, 99 (9.3%) developed diabetes over 15 years of follow-up. In multivariate models, adults in the lowest urinary potassium quintile were more than twice as likely to develop diabetes as their counterparts in the highest quintile (HR 2.45; 95% CI 1.08, 5.59). Of 4,754 participants with dietary history measurements, 373 (7.8%) developed diabetes over 20 years of follow-up. In multivariate models, African-Americans had a significantly increased risk of diabetes with lower potassium intake, which was not found in whites. CONCLUSIONS/INTERPRETATION: Low dietary potassium is associated with increased risk of incident diabetes in African-Americans. Randomised clinical trials are needed to determine if potassium supplementation, from either dietary or pharmacological sources, could reduce the risk of diabetes, particularly in higher-risk populations.

A novel homozygous splice site mutation in the HPGD gene causes mild primary hypertrophic osteoarthropathy.

OBJECTIVES: Homozygous mutations in HPGD gene, encoding 15-hydroxyprostaglandin dehydrogenase, have recently been associated with primary hypertrophic osteoarthropathy (PHO). So far, only 7 HPGD alterations are known. In order to expand this mutational spectrum and better delineate the HPGD-related phenotype, we report the clinical and molecular characterisation of a 13-year-old boy and compare his features to known mutated patients. METHODS: The HPGD gene exons 1-7 and exon-intron junctions were analysed by direct sequencing. Previously published HPGD-mutated patients were systematically reviewed based on the original clinical description. RESULTS: A novel homozygous c.217+1G>A mutation affecting the obligatory donor splice site of HPGD exon 2 was identified in our proband who showed a mild form of PHO. Review of HPGD-mutated patients outlined all patients manifested digital clubbing, periostosis and acro-osteolysis. Hyperhidrosis (92%), arthralgia (65%) and eczema (33%) were variably associated features. Pachydermia (54%) was mild and mostly limited to palms and sole; cutis vertigis gyrata, blepharoptosis and severe skin thickening were never observed. Besides digital clubbing, PHO infants often presented patent ductus arteriosus (PDA) (32%) and delayed cranial sutures closure (55%). CONCLUSIONS: The present findings broaden the allelic spectrum of HPGD gene to include a novel c.217+1G>A mutation. Mutated patients display a homogeneous phenotype mainly consisting in digital clubbing, periostosis, acro-osteolysis, hyperhidrosis and mild pachydermia. Earliest manifestations include delayed closure of the cranial sutures and PDA. In conclusion, the information reported herein would facilitate the diagnosis of PHO due to HPGD mutations.

Joubert syndrome with bilateral polymicrogyria: clinical and neuropathological findings in two brothers.

Joubert syndrome (JS) is characterized by hypotonia, ataxia, developmental delay, and a typical neuroimaging finding, the so-called "molar tooth sign" (MTS). The association of MTS and polymicrogyria (PMG) has been reported as a distinct JS-related disorder (JSRD). So far, five patients have been reported with this phenotype, only two of them being siblings. We report on one additional family, describing a living child with JS and PMG, and the corresponding neuropathological picture in the aborted brother. No mutations were detected in the AHI1 gene, the only so far associated with the JS + PMG phenotype. Moreover, linkage analysis allowed excluding all known gene loci, suggesting further genetic heterogeneity.

Normal cognitive functions in joubert syndrome.

Developmental delay and subsequent impaired cognitive functions are present in almost all patients with Joubert syndrome (JS). We report on a 20-year-old woman with mild clinical signs of JS (minimal truncal ataxia and oculomotor apraxia) but typical molar tooth sign on neuroimaging, normal full scale (IQ=93), verbal (IQ=93), and performance intelligence quotient (IQ=94). Only minor difficulties in visual-spatial organization and in some executive functions could be detected. This pattern of deficits is partly reminiscent of the cerebellar cognitive affective syndrome. Her diagnosis was only reached following the diagnosis of JS in two brothers with severe cognitive impairment. Molecular investigations demonstrated a homozygous mutation in the INPP5E gene. This exceptional observation confirms that normal cognitive functions are possible in JS and corroborates the well known intrafamilial variability.

Quantitative comparison and evaluation of software packages for assessment of abdominal adipose tissue distribution by magnetic resonance imaging.

OBJECTIVE: To examine five available software packages for the assessment of abdominal adipose tissue with magnetic resonance imaging, compare their features and assess the reliability of measurement results. DESIGN: Feature evaluation and test-retest reliability of softwares (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision) used in manual, semi-automated or automated segmentation of abdominal adipose tissue. SUBJECTS: A random sample of 15 obese adults with type 2 diabetes. MEASUREMENTS: Axial T1-weighted spin echo images centered at vertebral bodies of L2-L3 were acquired at 1.5 T. Five software packages were evaluated (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision), comparing manual, semi-automated and automated segmentation approaches. Images were segmented into cross-sectional area (CSA), and the areas of visceral (VAT) and subcutaneous adipose tissue (SAT). Ease of learning and use and the design of the graphical user interface (GUI) were rated. Intra-observer accuracy and agreement between the software packages were calculated using intra-class correlation. Intra-class correlation coefficient was used to obtain test-retest reliability. RESULTS: Three of the five evaluated programs offered a semi-automated technique to segment the images based on histogram values or a user-defined threshold. One software package allowed manual delineation only. One fully automated program demonstrated the drawbacks of uncritical automated processing. The semi-automated approaches reduced variability and measurement error, and improved reproducibility. There was no significant difference in the intra-observer agreement in SAT and CSA. The VAT measurements showed significantly lower test-retest reliability. There were some differences between the software packages in qualitative aspects, such as user friendliness. CONCLUSION: Four out of five packages provided essentially the same results with respect to the inter- and intra-rater reproducibility. Our results using SliceOmatic, Analyze or NIHImage were comparable and could be used interchangeably. Newly developed fully automated approaches should be compared to one of the examined software packages.

RPGRIP1L mutations are mainly associated with the cerebello-renal phenotype of Joubert syndrome-related disorders.

Joubert syndrome-related disorders (JSRDs) are autosomal recessive pleiotropic conditions sharing a peculiar cerebellar and brainstem malformation known as the 'molar tooth sign' (MTS). Recently, mutations in a novel ciliary gene, RPGRIP1L, have been shown to cause both JSRDs and Meckel-Gruber syndrome. We searched for RPGRIP1L mutations in 120 patients with proven MTS and phenotypes representative of all JSRD clinical subgroups. Two homozygous mutations, the previously reported p.T615P in exon 15 and the novel c.2268_2269delA in exon 16, were detected in 2 of 16 families with cerebello-renal presentation ( approximately 12%). Conversely, no pathogenic changes were found in patients with other JSRD phenotypes, suggesting that RPGRIP1L mutations are largely confined to the cerebello-renal subgroup, while they overall represent a rare cause of JSRD (<2%).

Birth weight is not related to risk of diabetic retinopathy in type 2 diabetes: the Atherosclerosis Risk in Communities Study.

PURPOSE: Low birth weight has been suggested as a risk factor for diabetes. Whether it is related to diabetic retinopathy is unclear and is examined in this study. MATERIALS AND METHODS: We examined 609 adults with type 2 diabetes from the population-based Atherosclerosis Risk in Communities Study. Retinal photographs were graded for diabetic retinopathy. Birth weight was assessed by self-report. RESULTS: Retinopathy was present in 116 (19%) participants (113 non-proliferative and 3 proliferative). After adjusting for age, sex, race, education level, body mass index, fasting glucose, duration of diabetes, glycosylated hemoglobin A1c, family history of diabetes, serum total cholesterol, and blood pressure, there was no evidence of either a linear or non-linear relationship between birthweight and diabetic retinopathy. CONCLUSIONS: Birth weight was not associated with diabetic retinopathy.

Diffusion tensor imaging in Joubert syndrome.

BACKGROUND AND PURPOSE: Neuropathologic findings and preliminary imaging studies demonstrated the absence of pyramidal tract and superior cerebellar peduncular decussation in individual patients with Joubert syndrome (JS). We hypothesized that functional-structural neuroimaging findings do not differ between the genetic forms of JS. MATERIALS AND METHODS: MR imaging was performed with a 3T MR imaging-unit. Multiplanar T2- and T1-weighted imaging was followed by diffusion tensor imaging (DTI). Isotropic diffusion-weighted images, apparent diffusion coefficient maps, and color-coded fractional anisotropy maps, including tractography, were subsequently calculated. RESULTS: In all 6 patients studied, DTI showed that the fibers of the superior cerebellar peduncles did not decussate in the mesencephalon and the corticospinal tract failed to cross in the caudal medulla. The patients represented various genetic forms of JS. CONCLUSION: In JS, the fibers of the pyramidal tract and the superior cerebellar peduncles do not cross, irrespective of the underlying mutation.

Variants of the insulin receptor substrate-1 and fatty acid binding protein 2 genes and the risk of type 2 diabetes, obesity, and hyperinsulinemia in African-Americans: the Atherosclerosis Risk in Communities Study.

We conducted a community-based case-control study of African-American men and women in the Atherosclerosis Risk in Communities Study. The allele frequencies of the Gly972Arg variant of the insulin receptor substrate-1 (IRS-1) gene and the Ala54Thr variant of the fatty acid binding protein 2 (FABP2) gene were compared in 992 normal control subjects and three patient groups: 1) 321 type 2 diabetic individuals, 2) 260 severely obese individuals, and 3) 258 markedly hyperinsulinemic individuals without diabetes. Allele frequencies of Gly972Arg IRS-1 and Ala54Thr FABP2 were 0.07 and 0.22, respectively; there were no differences in allele or genotype frequencies between patients and control subjects for either gene variant. In weighted linear regression of all patients and control subjects, the presence of the IRS-1 gene variant was associated with a 0.85 (0.42) kg/m2 higher BMI (P = 0.04). In addition, individuals with at least one IRS-1 Arg972 allele and two FABP2 Thr54 alleles had a BMI of 33.3 (7.9) kg/m2, compared with 30.0 (6.3) kg/m2 for those with neither allele (P = 0.05). These results suggest that in African-Americans, these variants in the IRS-1 and FABP2 genes are not associated with the risk of type 2 diabetes, severe obesity, or marked hyperinsulinemia, but that their independent and joint effects may be associated with small increases in BMI.

Glycemic control and sliding scale insulin use in medical inpatients with diabetes mellitus.

OBJECTIVE: To identify predictors of hypoglycemic and hyperglycemic episodes in hospitalized patients with diabetes with special attention to the effectiveness of sliding scale insulin regimens. DESIGN: Prospective cohort study. SETTING: Urban university hospital. PARTICIPANTS: One hundred seventy-one adults with diabetes mellitus as a comorbid condition admitted consecutively to medical inpatient services during a 7-week period. MEASUREMENTS: Demographic, clinical, and laboratory data from inpatient medical records. MAIN OUTCOMES: Rates of hypoglycemic (capillary blood glucose, < or = 3.3 mmol/L [< or = 60 mg/dL]) and hyperglycemic (capillary blood glucose, > or = 16.5 mmol/L [> or = 300 mg/ dL]) episodes. RESULTS: Of the patients, 23% experienced hypoglycemic episodes, and 40% experienced hyperglycemic episodes. The overall rates of hypoglycemic and hyperglycemic episodes were 3.4 and 9.8 per 100 capillary blood glucose measurements, respectively. Independent predictors of hypoglycemic episodes included African American race (relative risk [RR], 2.13) and low serum albumin level (RR, 1.92 per 100-g/L decrease); corticosteroid use was associated with a reduced risk of hypoglycemic episodes (RR, 0.32; P < .05). Independent predictors of hyperglycemic episodes included female gender (RR, 1.67), severity of illness (RR, 1.22 per 10 Acute Physiology and Chronic Health Evaluation III units), severe diabetic complications (RR, 2.32), high admission glucose level (RR, 1.33 per 5.5 mmol/L), admission for infectious disease (RR, 2.14), and corticosteroid use (RR, 3.74; P < .05). Of 171 patients, 130 (76%) were placed on a sliding scale insulin regimen. When used alone, sliding scale insulin regimens were associated with a 3-fold higher risk of hyperglycemic episodes compared with individuals following no pharmacologic regimen (RRs, 2.85 and 3.25, respectively; P < .05). CONCLUSIONS: Suboptimal glycemic control is common in medical inpatients with diabetes mellitus. The risk of suboptimal control is associated with selected demographic and clinical characteristics, which can be ascertained at hospital admission. Although sliding scale insulin regimens are prescribed for the majority of inpatients with diabetes, they appear to provide no benefit; in fact, when used without a standing dose of intermediate-acting insulin, they are associated with an increased rate of hyperglycemic episodes.

Effect of potassium supplementation on blood pressure in African Americans on a low-potassium diet. A randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet. DESIGN: Randomized, double-blind, placebo-controlled trial with two parallel arms. SETTING: Community-based research site. PARTICIPANTS: Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mm Hg. INTERVENTION: During the 21-day intervention period, all participants were provided with a low-potassium diet (32 to 35 mmol/d). In addition to this diet, they were randomly assigned to receive either potassium supplements (80 mmol/d) or placebo. MAIN OUTCOME MEASURE: Change in blood pressure in the potassium vs the placebo group, based on a total of nine blood pressure readings at three visits. Blood pressures were taken before and during the intervention by means of random-zero sphygmomanometry. RESULTS: At baseline, the placebo and potassium groups were similar for mean blood pressure (127/78 vs 125/77 mm Hg), 24-hour urinary potassium excretion (50 vs 44 mmol), and all other variables measured (all P > .05). During the intervention, the net difference in 24-hour urinary potassium excretion between groups was 70 mmol. Compared with the placebo group, the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg (95% confidence interval, -9.3 to -4.4 mm Hg; P < .001) and a decline in diastolic blood pressure of 2.5 mm Hg (95% confidence interval, -4.3 to -0.8 mm Hg; P = .004). Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates. CONCLUSIONS: Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium. Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension.

Body weight patterns from 20 to 49 years of age and subsequent risk for diabetes mellitus: the Johns Hopkins Precursors Study.

BACKGROUND: Obesity in middle age is a well-known risk factor for the development of type 2 diabetes mellitus. However, the importance of weight and weight gain at younger ages is less certain. OBJECTIVE: To determine the relationship of body weight patterns from 20 to 49 years of age with the subsequent risk for type 2 diabetes mellitus. SETTING: An ongoing longitudinal study of former medical students. PARTICIPANTS: Nine hundred sixteen white men without diabetes at 50 years of age. MEASUREMENTS: Weight and height measured in medical school, then assessed by mailed questionnaire to 49 years of age. MAIN OUTCOME: Incident type 2 diabetes mellitus based on physician self-report. RESULTS: During 14 255 person-years of follow-up, there were 35 incident cases of type 2 diabetes mellitus (2.5 per 1000 person-years). After simultaneous adjustment for age, physical activity, lifetime maternal history of diabetes, and smoking, body mass indexes (BMIs; calculated as weight in kilograms divided by the square of height in meters) at 25, 35, and 45 years of age were all strongly associated with diabetes risk (relative risks for overweight [BMI> or =25.0] vs. not overweight, >3.0; all Ps<.05), as were maximum and average BMI to 49 years of age. The relationship of BMI at 25 years of age to diabetes risk was substantially attenuated by adjustment for BMI at 45 years of age and average BMI, but was independent of weight change, weight variability, or maximum BMI. CONCLUSION: In men, overweight at 25 years of age strongly predicts diabetes risk in middle age, largely through its association with overweight at 45 years of age and high average BMI to 49 years of age.

A community-based study of explanatory factors for the excess risk for early renal function decline in blacks vs whites with diabetes: the Atherosclerosis Risk in Communities study.

CONTEXT: The explanation for the excess risk for diabetic renal disease in blacks is uncertain. OBJECTIVES: To compare the incidence of early renal function decline in black and white adults with diabetes and to examine possible explanatory factors for racial differences. DESIGN: Prospective cohort study. SETTING: Four US communities participating in the Atherosclerosis Risk in Communities study. PARTICIPANTS: Community-based sample of 1434 diabetic adults aged 45 to 64 years. MEASUREMENTS: Detailed baseline assessment using structured interview, results of physical examination, and laboratory measurements. MAIN OUTCOME: Development of early renal function decline defined by an increase in serum creatinine of at least 35.4 micromol/L (0.4 mg/dL) during 3 years of follow-up. RESULTS: During 3 years of follow-up, early renal function decline developed in 45 blacks (28.4 per 1000 person-years [PY]) and 25 whites (9.6 per 1000 PY). After adjustment for age, sex, and baseline serum creatinine level, early renal function decline was more than 3 times as likely to develop in blacks than whites (odds ratio, 3.15; 95% confidence interval, 1.86-5.33). Additional adjustment for education, household income, health insurance, fasting glucose level, mean systolic blood pressure, smoking history, and physical activity level reduced the relative odds in blacks to 1.38 (95% confidence interval, 0.71-2.69), corresponding to a 82% reduction in excess risk. CONCLUSIONS: These data suggest that early renal function decline is 3 times more likely to develop in blacks than whites and that potentially modifiable factors, including lower socioeconomic status, suboptimal health behaviors, and suboptimal control of glucose level and blood pressure, account for more than 80% of this disparity.