OBJECTIVE: To estimate the global, regional, and national prevalence of prediabetes, defined by impaired glucose tolerance (IGT) or impaired fasting glucose (IFG). RESEARCH DESIGN AND METHODS: We reviewed 7,014 publications for high-quality estimates of IGT (2-h glucose, 7.8–11.0 mmol/L [140–199 mg/dL]) and IFG (fasting glucose, 6.1–6.9 mmol/L [110–125 mg/dL]) prevalence for each country. We used logistic regression to generate prevalence estimates for IGT and IFG among adults aged 20–79 years in 2021 and projections for 2045. For countries without in-country data, we extrapolated estimates from countries with available data with similar geography, income, ethnicity, and language. Estimates were standardized to the age distribution for each country from the United Nations. RESULTS: Approximately two-thirds of countries did not have high-quality IGT or IFG data. There were 50 high-quality studies for IGT from 43 countries and 43 high-quality studies for IFG from 40 countries. Eleven countries had data for both IGT and IFG. The global prevalence of IGT in 2021 was 9.1% (464 million) and is projected to increase to 10.0% (638 million) in 2045. The global prevalence of IFG in 2021 was 5.8% (298 million) and is projected to increase to 6.5% (414 million) in 2045. The 2021 prevalence of IGT and IFG was highest in high-income countries. In 2045, the largest relative growth in cases of IGT and IFG would be in low-income countries. CONCLUSIONS: The global burden of prediabetes is substantial and growing. Enhancing prediabetes surveillance is necessary to effectively implement diabetes prevention policies and interventions.

Quiz Ref ID The prevalence of prediabetes and diabetes increases substantially with age.¹ In the US, an estimated 25% of adults 65 years or older have diabetes, whereas more than 50% meet criteria for prediabetes depending on the definition used.² Despite the high prevalence of diabetes and prediabetes among older adults, progression of hyperglycemia over time (ie, the transition from normoglycemia to prediabetes or diabetes or transition from prediabetes to diabetes) is poorly characterized in this population.

Background: Heterogeneity in type 2 diabetes presentation and progression suggests that precision medicine interventions could improve clinical outcomes. We undertook a systematic review to determine whether strategies to subclassify type 2 diabetes were associated with high quality evidence, reproducible results and improved outcomes for patients. Methods: We searched PubMed and Embase for publications that used ‘simple subclassification’ approaches using simple categorisation of clinical characteristics, or ‘complex subclassification’ approaches which used machine learning or ‘omics approaches in people with established type 2 diabetes. We excluded other diabetes subtypes and those predicting incident type 2 diabetes. We assessed quality, reproducibility and clinical relevance of extracted full-text articles and qualitatively synthesised a summary of subclassification approaches. Results: Here we show data from 51 studies that demonstrate many simple stratification approaches, but none have been replicated and many are not associated with meaningful clinical outcomes. Complex stratification was reviewed in 62 studies and produced reproducible subtypes of type 2 diabetes that are associated with outcomes. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into clinically meaningful subtypes. Conclusion: Critical next steps toward clinical implementation are to test whether subtypes exist in more diverse ancestries and whether tailoring interventions to subtypes will improve outcomes.

Since 2000, there has been an increase in research on possible health benefits of vitamin D. However, a 2011 Institute of Medicine (IOM; now the National Academy of Medicine) report concluded that vitamin D was beneficial for bone health but evidence was insufficient for extraskeletal health.¹ Several large-scale trials are ongoing to evaluate the effect of vitamin D supplementation on extraskeletal outcomes.² The IOM report noted possible harm (eg, hypercalcemia, soft tissue or vascular calcification) for intakes above the tolerable upper limit, which is the highest level of intake likely to pose no risk of adverse effects for most adults.¹

The plasma proteome can be quantified using different types of highly multiplexed technologies, including aptamer-based and proximity-extension immunoassay methods. There has been limited characterization of how these protein measurements correlate across platforms and with absolute measures from targeted immunoassays. We assessed the comparability of (a) highly multiplexed aptamer-based (SomaScan v4; Somalogic) and proximity-extension immunoassay (OLINK Proseek^® v5003; Olink) methods in 427 Atherosclerosis Risk in Communities (ARIC) Study participants (Visit 5, 2011–2013), and (b) 18 of the SomaScan protein measurements against targeted immunoassays in 110 participants (55 cardiovascular disease cases, 55 controls). We calculated Spearman correlations (r) between the different measurements and compared associations with case-control status. There were 417 protein comparisons (366 unique proteins) between the SomaScan and Olink platforms. The average correlation was r = 0.46 (range: −0.21 to 0.97; 79 [19%] with r ≥ 0.8). For the comparison of SomaScan and targeted immunoassays, 6 of 18 assays (growth differentiation factor 15 [GDF15], interleukin-1 receptor-like 1 [ST2], interstitial collagenase [MMP1], adiponectin, leptin, and resistin) had good correlations (r ≥ 0.8), 2 had modest correlations (0.5 ≤ r < 0.8; osteopontin and interleukin-6 [IL6]), and 10 were poorly correlated (r < 0.5; metalloproteinase inhibitor 1 [TIMP1], stromelysin-1 [MMP3], matrilysin [MMP7], C-C motif chemokine 2 [MCP1], interleukin-10 [IL10], vascular cell adhesion protein 1 [VCAM1], intercellular adhesion molecule 1 [ICAM1], interleukin-18 [IL18], tumor necrosis factor [TNFα], and visfatin) overall. Correlations for SomaScan and targeted immunoassays were similar according to case status. There is variation in the quantitative measurements for many proteins across aptamer-based and proximity-extension immunoassays (approximately 1/2 showing good or modest correlation and approximately 1/2 poor correlation) and also for correlations of these highly multiplexed technologies with targeted immunoassays. Design and interpretation of protein quantification studies should be informed by the variation across measurement techniques for each protein.

Background: Elevated serum calcium has been associated with a variety of metabolic abnormalities and may be associated with a greater risk of diabetes