Sickle Cell Trait, European Ancestry, and Longitudinal Tracking of HbA1c Among African Americans: The Jackson Heart Study.
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ABSTRACT:
SUBMITTER: Echouffo-Tcheugui JB
PROVIDER: S-EPMC6754235 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
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Sickle Cell Trait, European Ancestry, and Longitudinal Tracking of HbA<sub>1c</sub> Among African Americans: The Jackson Heart Study.
Echouffo-Tcheugui Justin B JB Mwasongwe Stanford E SE Sims Mario M Dagogo-Jack Samuel S Golden Sherita H SH Correa Adolfo A Musani Solomon K SK
Diabetes care 20190820 10
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Project description:AimsTo examine the association of HbA1c and glucose levels with incident diabetic retinopathy according to black African or white European ancestry.MethodsIn this retrospective cohort study of 202 500 US Veterans with diabetes (2000-2014), measures included HbA1c , outpatient random serum/plasma glucose, and incident retinopathy [conversion from negative to ≥2 positive evaluations (ICD-9 codes), without a subsequent negative].ResultsAt baseline, the study population had a mean age of 59.3 years, their mean BMI was 31.9 kg/m2 , HbA1c level was 57 mmol/mol (7.4%) and glucose level was 8.8 mmol/l, and 77% were of white European ancestry (white individuals) and 21% of black African ancestry (black individuals). HbA1c was 0.3% higher in black vs white individuals (P < 0.001), adjusting for baseline age, sex, BMI, estimated glomerular filtration rate (eGFR), haemoglobin, and average systolic blood pressure and glucose. Over 11 years, incident retinopathy occurred in 9% of black and 7% of white individuals, but black individuals had higher HbA1c , glucose, and systolic blood pressure (all P < 0.001); adjusted for these factors, incident retinopathy was reduced in black vs white individuals (P < 0.001). The population incidence of retinopathy (7%) was associated with higher mean baseline HbA1c in individuals with black vs white ancestry [63 mmol/mol (7.9%) vs 58 mmol/mol (7.5%); P < 0.001)], but with similar baseline glucose levels (9.0 vs 9.0 mmol/l; P = 0.660, all adjusted for baseline age, sex and BMI).ConclusionsSince retinopathy occurs at higher HbA1c levels in black people for a given level of average plasma glucose, strategies may be needed to individualize the interpretation of HbA1c measurements.
| S-EPMC10241067 | biostudies-literature
Project description:BackgroundCombining HbA1c with glycated albumin (GA) may improve detection of dysglycaemia. As BMI correlates positively with HbA1c and negatively with GA, HbA1c may be more effective in obese and GA in nonobese individuals.MethodsTo relate these findings to Africans, we assessed in 1274 South Africans living in CapeTown (male 26%; age 48±16y; BMI 28.7 kg/m2 (range 15.6-73.8); obesity 39.9% and no prior diabetes history) the: (1) correlation of BMI with HbA1c and GA, (2) ability of HbA1c and GA separately and jointly, to detect OGTT-diagnosed dysglycaemia (diabetes plus prediabetes). Data collection took place between 2014 and 2016 in the City of Cape Town. Dysglycaemia was diagnosed by glucose criteria for the OGTT. Youden index was used to optimize diagnostic thresholds for HbA1c and GA.FindingsNormal glucose tolerance, prediabetes and diabetes occurred in 76%, 17% and 7%, respectively. BMI positively correlated with HbA1c [r = 0·34 [95%CI: 0·29,0·39)] and negatively with GA [-0·08 (0·13,0·03)]. For HbA1c the optimal threshold by Youden-index for dysglycaemia diagnosis was: 6·0% (95%CI: 5·8,6·2) and for GA: 13·44% (12·72,14·71). In the nonobese, obese and total cohort, HbA1c-alone detected: 51% (42-60), 72% (65,78), 63% (57,68), respectively; GA-alone detected 55% (52% (46,63), 52% (44, 59) and 53% (47,53), respectively; whereas: HbA1c+GA detected: 69% (60,76), 82% (75,87) and 76% (71, 81). Therefore, for the total cohort detection of dysglycaemia HbA1c-alone vs HbA1c+GA detected 63% (57,68) vs 76% (71,81).InterpretationThe opposite correlations of HbA1c and GA with BMI have now been demonstrated in an African-based population. Improving detection of dysglycaemia by combining HbA1c and GA has important implications for diabetes risk screening.FundingAES is supported by the intramural programs of the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Minority Health and Health Disparities of the National Institutes of Health (NIH, Bethesda, Maryland, USA). DBS is supported by the intramural program of the Clinical Center of NIH. The South African Medical Research Council (SAMRC) funded the VMH study with funds from the National Treasury under its Economic Competitiveness and Support Package (MRC-RFA-UFSP-01-2013/VMH Study).
| S-EPMC9249545 | biostudies-literature
Project description:IntroductionThis exploratory post hoc analysis investigated the relative changes in glycated haemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM) treated with dulaglutide versus active comparators across a continuous range of baseline HbA1c values using data from three phase III randomised controlled trials.MethodsData from patients receiving once-weekly dulaglutide 0.75 and 1.5 mg, once-daily sitagliptin 100 mg, once-daily liraglutide 1.8 mg or twice-daily exenatide 10 μg in the intent-to-treat populations in the AWARD-5, AWARD-6 and AWARD-1 trials were analysed using last observation carried forward analysis of covariance. Starting with the predefined statistical model from each study, the type of association between HbA1c baseline and change at 26 weeks was modelled. Consistency of treatment effect was assessed via treatment-by-baseline HbA1c interaction terms.ResultsImprovements in HbA1c occurred in all treatment groups across the entire baseline HbA1c range. The relationship between HbA1c baseline and magnitude of change was linear in all treatment groups, with greater reductions in patients with higher baseline HbA1c values. Across the continuum of baseline HbA1c values, patients treated with dulaglutide 1.5 mg achieved a similar mean HbA1c reduction to patients receiving liraglutide 1.8 mg and a greater reduction than patients receiving twice-daily exenatide or sitagliptin. In AWARD-5, the treatment-by-baseline HbA1c interaction P value (0.001) demonstrated progressively greater HbA1c reduction in dulaglutide-treated compared with sitagliptin-treated patients as baseline HbA1c increased.ConclusionOur results suggest that dulaglutide is an appropriate therapeutic option for patients with T2DM across a wide range of baseline HbA1c values, including those with poor metabolic control.FundingEli Lilly and Company. Plain language summary available for this article.
| S-EPMC6531505 | biostudies-literature
Project description:Aims/hypothesisThe aim of the study was to evaluate longitudinal associations between HbA1c levels, diabetes status and subsequent cognitive decline over a 10 year follow-up period.MethodsData from wave 2 (2004-2005) to wave 7 (2014-2015) of the English Longitudinal Study of Ageing (ELSA) were analysed. Cognitive function was assessed at baseline (wave 2) and reassessed every 2 years at waves 3-7. Linear mixed models were used to evaluate longitudinal associations.ResultsThe study comprised 5189 participants (55.1% women, mean age 65.6 ± 9.4 years) with baseline HbA1c levels ranging from 15.9 to 126.3 mmol/mol (3.6-13.7%). The mean follow-up duration was 8.1 ± 2.8 years and the mean number of cognitive assessments was 4.9 ± 1.5. A 1 mmol/mol increment in HbA1c was significantly associated with an increased rate of decline in global cognitive z scores (-0.0009 SD/year, 95% CI -0.0014, -0.0003), memory z scores (-0.0005 SD/year, 95% CI -0.0009, -0.0001) and executive function z scores (-0.0008 SD/year, 95% CI -0.0013, -0.0004) after adjustment for baseline age, sex, total cholesterol, HDL-cholesterol, triacylglycerol, high-sensitivity C-reactive protein, BMI, education, marital status, depressive symptoms, current smoking, alcohol consumption, hypertension, CHD, stroke, chronic lung disease and cancer. Compared with participants with normoglycaemia, the multivariable-adjusted rate of global cognitive decline associated with prediabetes and diabetes was increased by -0.012 SD/year (95% CI -0.022, -0.002) and -0.031 SD/year (95% CI -0.046, -0.015), respectively (p for trend <0.001). Similarly, memory, executive function and orientation z scores showed an increased rate of cognitive decline with diabetes.Conclusions/interpretationSignificant longitudinal associations between HbA1c levels, diabetes status and long-term cognitive decline were observed in this study. Future studies are required to determine the effects of maintaining optimal glucose control on the rate of cognitive decline in people with diabetes.
| S-EPMC6448974 | biostudies-literature
Project description:Glycated haemoglobin (HbA1c) is considered the gold standard for predicting glycaemia-associated risks for the microvascular and macrovascular complications of diabetes mellitus over 5-10 years. The value of HbA1c in the care of patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) is unassailable, yet HbA1c targets remain contentious. Guidelines from diabetes care organizations recommend conflicting HbA1c targets - generally between 6.5% and 8%. However, all such organizations advocate for individualization of HbA1c targets, leaving both health-care providers and their patients confused about what HbA1c target is appropriate in an individual patient. In this Review, we outline the landmark T1DM and T2DM trials that informed the current guidelines, we discuss the evidence that drives individualized HbA1c targets, we examine the limitations of HbA1c, and we consider alternatives for monitoring glycaemic control. Ultimately, in synthesizing this literature, we argue for an HbA1c target of <7% for most individuals, but emphasize the importance of helping patients determine their own personal goals and determinants of quality of life that are independent of a particular glycaemic target. We also recognize that as newer technologies and anti-hyperglycaemic therapies emerge, glycaemic targets will continue to evolve.
| S-EPMC11653296 | biostudies-literature
Project description:IntroductionAlthough poor glycemic control is associated with dementia, it is unknown if variability in glycemic control, even in those with optimal glycosylated hemoglobin A1c (HbA1c) levels, increases dementia risk.MethodsAmong 171,964 people with type 2 diabetes, we evaluated the hazard of dementia association with long-term HbA1c variability using five operationalizations, including standard deviation (SD), adjusting for demographics and comorbidities.ResultsThe mean baseline age was 61 years (48% women). Greater HbA1c SD was associated with greater dementia hazard (adjusted hazard ratio = 1.15 [95% confidence interval: 1.12, 1.17]). In stratified analyses, higher HbA1c SD quintiles were associated with greater dementia hazard among those with a mean HbA1c < 6% (P = 0.0004) or 6% to 8% (P < 0.0001) but not among those with mean HbA1c ≥ 8% (P = 0.42).DiscussionGreater HbA1c variability is associated with greater dementia risk, even among those with HbA1c concentrations at ideal clinical targets. These findings add to the importance and clinical impact of recommendations to minimize glycemic variability.HighlightsWe observed a cohort of 171,964 people with type 2 diabetes (mean age 61 years). This cohort was based in Northern California between 1996 and 2018. We examined the association between glycosylated hemoglobin A1c (HbA1c) variability and dementia risk. Greater HbA1c variability was associated with greater dementia hazard. This was most evident among those with normal-low mean HbA1c concentrations.
| S-EPMC11350038 | biostudies-literature
Project description:ObjectivesTo examine the accuracy of glycated haemoglobin A1c (HbA1c) in detecting type 2 diabetes and impaired fasting glucose among adults living in Malawi.DesignA diagnostic validation study of HbA1c. Fasting plasma glucose (FPG) ≥7.0 mmol/L was the reference standard for type 2 diabetes, and FPG between 6.1 and 6.9 mmol/L as impaired fasting glucose.Participants3645 adults (of whom 63% were women) recruited from two demographic surveillance study sites in urban and rural Malawi. This analysis excluded those who had a previous diagnosis of diabetes or had history of taking diabetes medication.ResultsHbA1c demonstrated excellent validity to detect FPG-defined diabetes, with an area under the receiver operating characteristic (AUROC) curve of 0.92 (95% CI 0.90 to 0.94). At HbA1c ≥6.5% (140 mg/dL), sensitivity was 78.7% and specificity was 94.0%. Subgroup AUROCs ranged from 0.86 for participants with anaemia to 0.94 for participants in urban Malawi. There were clinical and metabolic differences between participants with true diabetes versus false positives when HbA1c was ≥6.5% (140 mg/dL).ConclusionsThe findings from this study provide justification to use HbA1c to detect type 2 diabetes. As HbA1c testing is substantially less burdensome to patients than either FPG testing or oral glucose tolerance testing, it represents a useful option for expanding access to diabetes care in sub-Saharan Africa.
| S-EPMC5942411 | biostudies-literature
Project description:BackgroundAfrican Americans have a higher prevalence of nocturnal hypertension and nondipping blood pressure than European Americans, but the genetic contribution to these racial differences remains unclear. We assessed the association of the percentage West African genetic ancestry with nocturnal hypertension and nondipping blood pressure in 932 African Americans from the Jackson Heart Study.MethodsUsing percentage West African ancestry determined from 389 ancestry informative markers, participants were categorized into tertiles (tertile 1 [low]: <79.3%, tertile 2: ≥79.3-86.3%, and tertile 3 [high]: >86.3%). Nocturnal hypertension was defined as mean nighttime (midnight-6 am) systolic (SBP)/diastolic blood pressure ≥120/70 mm Hg. Nondipping blood pressure was defined as mean nighttime-to-daytime (10 am-8 pm) SBP ratio >0.90.ResultsNocturnal hypertension was present in 57.9% of participants; 66.6% had nondipping blood pressure. The mean age was 59.4 years, 32.8% were male, and 56.0% were taking antihypertensive medication. The prevalence ratios (95% confidence interval) adjusted for age, sex, cardiovascular disease risk factors, and socioeconomic and psychosocial factors comparing participants with moderate and high to those with low percentage West African ancestry for nocturnal hypertension were 0.98 (0.87-1.10) and 0.95 (0.84-1.08), respectively, and for nondipping blood pressure was 0.96 (0.86-1.07) and 0.98 (0.88-1.09), respectively.ConclusionsWest African ancestry was not associated with nocturnal hypertension and nondipping blood pressure among African Americans. While rare genetic variants cannot be ruled out, these data highlight the need to better understand how environmental and behavioral factors contribute to differences in nocturnal blood pressure among African Americans compared with European Americans.
| S-EPMC5946866 | biostudies-literature
Project description:Aims/hypothesisThis study aimed to examine the relationship between average glucose levels, assessed by continuous glucose monitoring (CGM), and HbA1c levels in pregnant women with diabetes to determine whether calculations of standard estimated average glucose (eAG) levels from HbA1c measurements are applicable to pregnant women with diabetes.MethodsCGM data from 117 pregnant women (89 women with type 1 diabetes; 28 women with type 2 diabetes) were analysed. Average glucose levels were calculated from 5-7 day CGM profiles (mean 1275 glucose values per profile) and paired with a corresponding (±1 week) HbA1c measure. In total, 688 average glucose-HbA1c pairs were obtained across pregnancy (mean six pairs per participant). Average glucose level was used as the dependent variable in a regression model. Covariates were gestational week, study centre and HbA1c.ResultsThere was a strong association between HbA1c and average glucose values in pregnancy (coefficient 0.67 [95% CI 0.57, 0.78]), i.e. a 1% (11 mmol/mol) difference in HbA1c corresponded to a 0.67 mmol/l difference in average glucose. The random effects model that included gestational week as a curvilinear (quadratic) covariate fitted best, allowing calculation of a pregnancy-specific eAG (PeAG). This showed that an HbA1c of 8.0% (64 mmol/mol) gave a PeAG of 7.4-7.7 mmol/l (depending on gestational week), compared with a standard eAG of 10.2 mmol/l. The PeAG associated with maintaining an HbA1c level of 6.0% (42 mmol/mol) during pregnancy was between 6.4 and 6.7 mmol/l, depending on gestational week.Conclusions/interpretationThe HbA1c-average glucose relationship is altered by pregnancy. Routinely generated standard eAG values do not account for this difference between pregnant and non-pregnant individuals and, thus, should not be used during pregnancy. Instead, the PeAG values deduced in the current study are recommended for antenatal clinical care.
| S-EPMC6518090 | biostudies-literature
Project description:Rationale & objectiveApolipoprotein L1 (APOL1) high-risk variants are associated with an increased risk for chronic kidney disease (CKD) among African Americans. Less is known regarding the risk for the development of CKD and kidney failure (end-stage kidney disease [ESKD]) among African Americans with only 1 APOL1 risk variant or whether the risk is modified by sickle cell trait.Study designThe Jackson Heart Study is a community-based longitudinal cohort study.Setting & participantsSelf-reported African Americans in the Jackson Heart Study (n = 5,306).ExposuresAPOL1 G1 and G2 genotypes and sickle cell trait.OutcomesIncident CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2), albuminuria (urinary albumin-creatinine ratio ≥ 30 mg/g), continuous and rapid kidney function decline (≥30% decline), and incident ESKD.Analytical approachMultivariable linear and logistic regression, and Cox proportional hazards models adjusted for age, sex, hypertension, diabetes, ancestry informative markers, and sickle cell trait.ResultsOf 2,300 participants, 41.3% had zero, 45.1% had 1, and 13.6% had 2 APOL1 risk variants. Sickle cell trait was present in 8.5%. Compared with participants with zero APOL1 risk variants, those with 2 alleles had an increased risk for incident albuminuria (adjusted HR [aHR], 1.88; 95% CI, 1.04 to 3.40), ESKD (aHR, 9.05; 95% CI, 1.79 to 45.85), incident CKD (aHR, 1.65; 95% CI, 1.06 to 2.57), continuous decline (β = -1.90; 95% CI, -3.35 to -0.45), and rapid kidney function decline (OR, 2.21; 95% CI, 1.22 to 4.00) after adjustment for sickle cell trait, with similar results after adjustment for ancestry informative markers. Having 1 APOL1 risk variant was not associated with CKD outcomes and there was no interaction of APOL1 with sickle cell trait.LimitationsSingle-site recruitment of African American individuals with APOL1 and sickle cell trait.ConclusionsThe presence of 1 APOL1 risk allele was not associated with increased risk for CKD outcomes, whereas 2 risk alleles were associated with incident albuminuria, CKD, ESKD, and rapid and continuous kidney function decline. Additional studies are needed to determine factors that might alter the risk for adverse kidney outcomes among individuals with high-risk APOL1 genotypes.
| S-EPMC8664705 | biostudies-literature