{"slug":"fasting-glucose","name":"Fasting glucose","aliases":["Fasting plasma glucose","FPG","Fasting blood sugar"],"kind":"biomarker","system":"metabolomics","unit":"mg/dL","unitNote":"To convert to mmol/L, divide by 18.","answer":"A fasting glucose below 100 mg/dL is normal by the diagnostic cutoff, but in cohorts that followed healthy adults for a decade or more, the risk of later diabetes began rising from about 87 mg/dL and was about twice as high at 95 to 99 as below 85, while all-cause mortality was lowest at about 80 to 94 and rose again below about 70 to 80.","summary":"Fasting glucose is the diagnostic test for diabetes, and the cutoffs it carries (100 and 126 mg/dL) are agreed by guideline. Inside the normal range the number still carries information: large cohorts place the lowest risk of later diabetes in the low 80s and below, and the lowest mortality in the 80s and low 90s. It is also a late marker, moving years after insulin has.","whatItIs":[{"text":"Fasting plasma glucose is the concentration of sugar in the blood after at least 8 hours without calories. It is held in a narrow band by insulin from the pancreas and by the liver's release of stored glucose overnight. Diabetes is diagnosed by demonstrating increased glucose in venous plasma or an increased hemoglobin A1c, and the fasting value is the single most used test.","cites":["ada2026","sacks2023"],"grade":"A"},{"text":"Glucose is a late marker. In the Whitehall II cohort of 6,538 British civil servants followed for a median of 9.7 years, people who went on to develop diabetes showed a steep fall in insulin sensitivity during the 5 years before diagnosis and a steep rise in fasting glucose only in the final 3 years, from about 104 mg/dL (5.79 mmol/L) to 133 (7.40). In a separate study of 515 normoglycemic Israeli adults, a fasting insulin in the top fifth was the strongest predictor of dysglycemia 24 years later, independent of weight, blood pressure and triglycerides.","cites":["tabak2009","dankner2009"],"grade":"B"},{"text":"In 153 healthy, nonobese people aged 7 to 80 wearing a continuous glucose monitor for up to 10 days, mean glucose across the day was 98 to 99 mg/dL under age 60 and 104 above it, with a median of 96 percent of the time spent between 70 and 140 and about 1 percent of the time below 70. A fasting draw samples one point on that curve.","cites":["shah2019"],"grade":"C"}],"labRange":{"typical":"About 70 to 99 mg/dL, with 100 to 125 flagged as impaired fasting glucose and 126 or higher as the diabetes range","claims":[{"text":"Unlike most reference ranges, the fasting glucose cutoffs are diagnostic thresholds set by consensus, not a statistical interval from a laboratory's own population. The American Diabetes Association defines diabetes by a fasting plasma glucose of 126 mg/dL (7.0 mmol/L) or higher, with fasting meaning no caloric intake for at least 8 hours, and impaired fasting glucose as 100 to 125 mg/dL. In the absence of unequivocal hyperglycemia, diagnosis requires two abnormal results, from different tests or the same test on two occasions.","cites":["ada2026"],"grade":"A"},{"text":"The lower limit a laboratory prints, usually about 65 or 70 mg/dL, is a population interval rather than a diagnostic rule. The Endocrine Society recommends evaluating hypoglycemia only when Whipple's triad is documented: symptoms consistent with low glucose, a low measured plasma glucose at the time, and relief when the glucose is raised. A low number on a routine fasting draw in a person without symptoms does not meet that standard.","cites":["cryer2009"],"grade":"A"}]},"evidence":{"headline":"Risk of later diabetes rose continuously through the normal range, from about 87 mg/dL upward in young men and roughly doubling at 95 to 99 versus below 85 in a large US cohort. All-cause mortality was lowest at about 80 to 94 and vascular risk was flat between about 70 and 100; below 70 to 80, mortality rose again in several cohorts.","scale":{"min":50,"max":130,"ticks":[50,60,70,80,90,100,110,120,130]},"bands":[{"label":"Common laboratory reference range","low":70,"high":99,"tone":"lab","source":"ADA 2026; typical US laboratories"},{"label":"Higher mortality and stroke risk below 70 in cohorts","low":50,"high":69,"tone":"caution","source":"Wei 2000; Park 2013"},{"label":"Lowest later-diabetes risk: below about 85 to 87","low":70,"high":86,"tone":"evidence","source":"Tirosh 2005; Nichols 2008"},{"label":"Lowest all-cause mortality in 12.5 million adults","low":80,"high":94,"tone":"evidence","source":"Yi 2017"},{"label":"Diabetes risk rising; mortality still near its lowest","low":87,"high":94,"tone":"neutral","source":"Tirosh 2005; Nichols 2008; Yi 2017"},{"label":"High-normal: about twice the diabetes risk and 1.5 times the cardiovascular risk of the low-normal range","low":95,"high":99,"tone":"caution","source":"Nichols 2008; Shaye 2012"},{"label":"Impaired fasting glucose: higher mortality in pooled cohorts","low":100,"high":125,"tone":"caution","source":"ADA 2026; Seshasai 2011; Yi 2017"},{"label":"Diabetes range, confirmed on repeat testing","low":126,"high":130,"tone":"caution","source":"ADA 2026"}],"claims":[{"text":"In 13,163 Israeli army men aged 26 to 45 with a fasting glucose below 100 mg/dL, followed for 74,309 person-years, the risk of type 2 diabetes rose progressively from a fasting glucose of 87 mg/dL upward compared with the bottom fifth (below 81), after adjusting for age, family history, body mass index, activity, smoking and triglycerides. Men with a glucose of 91 to 99 and triglycerides of 150 or more had 8.2 times the risk of men with a glucose below 86 and lower triglycerides. An association in a cohort of young men, not a trial.","cites":["tirosh2005"],"grade":"B"},{"text":"In 46,578 Kaiser Permanente members with a fasting glucose below 100 mg/dL and no prior diabetes, followed for a mean of 81 months, each additional milligram per deciliter raised the adjusted risk of a diabetes diagnosis by 6 percent. Compared with people below 85, those at 90 to 94 were 49 percent more likely and those at 95 to 99 were 2.3 times as likely to develop diabetes, after adjustment for age, sex, body mass index, blood pressure, lipids and smoking. Fewer than 1 percent per year progressed overall, so the absolute risk at any normal value stayed low.","cites":["nichols2008"],"grade":"B"},{"text":"Cardiovascular risk also tracks the normal range. In 10,913 adults screened at an Israeli preventive-medicine institute and followed for a mean of 4.3 years, a fasting glucose of 95 to 99 mg/dL carried 1.5 times the cardiovascular event rate of a value below 80, and the gradient persisted after adjustment for age, sex, blood pressure, body mass index, smoking and lipids. In 1,973 healthy Norwegian men followed for 22 years, those in the top quartile of fasting whole-blood glucose (above 85 mg/dL, which corresponds to a plasma value of about 94 because plasma reads about 11 percent higher) had 1.4 times the cardiovascular mortality of the lower three quartiles after adjustment; non-cardiovascular deaths were unrelated to glucose.","cites":["shaye2012","bjornholt1999","sacks2023"],"grade":"B"},{"text":"Pooled across 102 prospective studies and 698,782 people without prior vascular disease, fasting glucose was non-linearly related to vascular risk, with no significant association between 70 and 100 mg/dL (3.90 to 5.59 mmol/L). Relative to that span, coronary risk was 1.11 times higher at 101 to 110 (5.60 to 6.09 mmol/L) and 1.17 times at 110 to 126 (6.10 to 6.99), and adding fasting glucose to conventional risk factors did not meaningfully improve prediction in people without diabetes. In the same collaboration's analysis of 820,900 people and 123,205 deaths, fasting glucose above 100 mg/dL was associated with death, while values of 70 to 100 were not.","cites":["erfc2010","seshasai2011"],"grade":"A"},{"text":"The largest single cohort, 12,455,361 Korean adults examined in 2001 to 2004 and followed to 2013, found a J-shaped curve with the lowest all-cause mortality at 80 to 94 mg/dL regardless of sex and age; hazard ratios began to rise at around 95 to 100 and again from around 80 downward. Within the impaired-fasting-glucose range, each 18 mg/dL increase carried 30 to 32 percent higher mortality in adults under 45 but 10 percent in those over 75. In 1,197,384 Korean adults followed for a mean of 16 years, cardiovascular risk was lowest at 85 to 99 with a nadir near 90, and a fasting glucose below 70 carried a small but significant excess of stroke (hazard ratios 1.06 in men and 1.11 in women).","cites":["yi2017","park2013"],"grade":"B"},{"text":"The low end is not benign in the older cohorts either. Among 40,069 adults at the Cooper Clinic, fasting glucose below 70 mg/dL carried 3.3 times, and 70 to 79 carried 2.4 times, the cardiovascular mortality of 80 to 109 after multivariate adjustment, and all-cause mortality rose in parallel. In the pooled European DECODE cohorts of 25,364 adults, mortality rose with the 2-hour glucose after a glucose load within every fasting category, which means a normal fasting value does not exclude the post-meal abnormality that carried most of the excess risk.","cites":["wei2000","decode1999"],"grade":"B"},{"text":"Some of the glucose-heart link appears causal rather than a bystander effect. In a Mendelian randomization analysis of 133,010 people for fasting glucose and 63,746 coronary cases, 12 variants that raise fasting glucose without raising diabetes risk carried 1.43 times the odds of coronary artery disease per 18 mg/dL (1 mmol/L), and 1.33 after excluding variants that act through lipids, blood pressure or obesity.","cites":["merino2017"],"grade":"B"}]},"levers":[{"name":"Weight loss of about 7 percent with 150 minutes a week of activity","effect":"lowers progression to diabetes by more than half","claim":{"text":"In the Diabetes Prevention Program, 3,234 adults with elevated fasting and post-load glucose were randomized to placebo, a glucose-lowering medication or a lifestyle program aiming at 7 percent weight loss and 150 minutes of weekly activity. Over an average of 2.8 years, diabetes incidence was 11.0, 7.8 and 4.8 cases per 100 person-years: lifestyle cut it by 58 percent and the medication by 31 percent, and 6.9 people had to take part for three years to prevent one case. In the Da Qing trial, 577 Chinese adults with impaired glucose tolerance randomized to six years of diet or exercise counseling had 43 percent lower diabetes incidence over 20 years, though cardiovascular events and mortality did not differ significantly.","cites":["knowler2002","li2008"],"grade":"A"}},{"name":"Exercise, including interval training","effect":"lowers fasting glucose in people at risk","claim":{"text":"A meta-analysis of 50 studies found that high-intensity interval training reduced insulin resistance compared with no exercise (standardized mean difference -0.49) and lowered hemoglobin A1c by 0.19 percentage points; in participants at risk of or with type 2 diabetes it lowered fasting glucose by about 17 mg/dL (0.92 mmol/L) versus control. In people with normal glucose the fasting value itself changed little, which fits a marker that sits at the end of the chain.","cites":["jelleyman2015"],"grade":"A"}},{"name":"Sleep","effect":"short or broken sleep raises diabetes risk","claim":{"text":"Pooling 10 prospective studies of 107,756 adults followed for 4 to 32 years, sleeping 5 to 6 hours or less carried 1.28 times the risk of type 2 diabetes, difficulty falling asleep 1.57 times and difficulty staying asleep 1.84 times; sleeping more than 8 to 9 hours also carried higher risk (1.48). These are cohort associations, not trials.","cites":["cappuccio2010"],"grade":"B"}},{"name":"Stress, illness and the dawn effect","effect":"raise it temporarily","claim":{"text":"Acute illness raises glucose through stress hormones, a state defined by its resolution once the illness passes, so a fasting value drawn during or soon after an infection, injury or surgery does not describe baseline. Glucose also climbs before waking: in 248 people with type 2 diabetes on continuous monitoring, the median rise from the overnight low to the pre-breakfast value was 16 mg/dL. The size of that dawn rise in people without diabetes has not been as well measured.","cites":["dungan2009","monnier2013"],"grade":"C"}}],"caveats":[{"text":"A single fasting glucose is less noisy than most metabolic markers but not precise. In 685 US adults tested twice about 2 weeks apart, the within-person coefficient of variation was 5.7 percent for fasting glucose, against 16.7 percent for the 2-hour post-load glucose and 3.6 percent for hemoglobin A1c; only 70 percent of people at 126 or higher on the first draw were still there on the second. The laboratory guideline puts the 95 percent band around a true value of 126 at about 110 to 142, which is why a diagnosis needs a repeat and why a change of a few points between draws means little.","cites":["selvin2007","sacks2023"],"grade":"A"},{"text":"The tube matters. Red and white cells keep consuming glucose after the draw at about 5 to 7 percent (roughly 10 mg/dL) an hour at room temperature, and sodium fluoride alone does not stop it for up to 4 hours; in a Quest Diagnostics study, glucose fell 4.6 percent at 2 hours in fluoride-oxalate tubes but 0.3 percent in acidified citrate-fluoride tubes. The guideline asks for the sample to sit in an ice-water slurry and be separated within 30 minutes, or for citrate tubes. A draw that sat at room temperature can read several points low.","cites":["sacks2023","gambino2009"],"grade":"A"},{"text":"Fasting duration matters less than expected, other things more. In 28,024 German primary-care patients, mean glucose differed by only about 2 mg/dL (0.1 mmol/L) between people fasting 8 hours or more and those fasting less, and after 3 hours the difference had shrunk to about 1.4 mg/dL (0.08 mmol/L); age, time of day, physical activity and spirits consumed the day before moved the value more.","cites":["moebus2011"],"grade":"C"},{"text":"A normal fasting glucose can hide a high fasting insulin and an abnormal post-meal curve. Insulin sensitivity was already falling 5 years before diagnosis in Whitehall II while fasting glucose moved slowly, and in DECODE the excess mortality attached to the 2-hour glucose within each fasting category. Fasting glucose is best read beside fasting insulin, triglycerides, hemoglobin A1c and waist size.","cites":["tabak2009","decode1999","dankner2009"],"grade":"B"}],"seeAPhysician":["A fasting glucose of 126 mg/dL or higher on any draw, or 100 to 125 on two draws, which calls for confirmation and a plan rather than a watchful wait.","A low glucose with shakiness, sweating, confusion or palpitations that improve with eating, the pattern the hypoglycemia guideline asks to be evaluated.","Increased thirst, frequent urination, blurred vision or unexplained weight loss, whatever the fasting number.","Any glucose result during pregnancy, or while taking steroids, antipsychotics or other medications that raise blood sugar.","A fasting glucose that has climbed steadily across repeated draws from the same laboratory, even inside the normal range."],"openQuestions":["No randomized trial has moved healthy adults from a high-normal to a low-normal fasting glucose and measured outcomes; the thresholds on this page describe where risk sat in cohorts, not a tested goal.","The diabetes cohorts place the lowest risk below about 85 to 87 mg/dL while the mortality cohorts place it at about 80 to 94, and the oldest data show excess cardiovascular mortality at 70 to 79. Whether a value in the 70s is protective, neutral or a marker of frailty and illness is unresolved; the J-shape at the low end may be reverse causation.","Nearly all of the cohorts are of men, young Israelis, Koreans or white Europeans and Americans measured on older methods; how the absolute cutoffs transfer across ancestry, sex and age is only partly known, and the Korean data suggest the mortality gradient is steeper in younger adults.","Whether the 1-hour post-load glucose or continuous glucose monitoring in people without diabetes adds useful prognostic information to a fasting value is under active study, with no agreed thresholds for routine use.","How large the dawn rise is in people without diabetes, and whether a 7 a.m. draw and a 10 a.m. draw should be read on the same scale, has not been settled."],"questions":[{"q":"Is a fasting glucose of 98 normal?","a":"By the diagnostic cutoff, yes: normal is below 100 mg/dL. In the cohorts summarized here, 95 to 99 carried about twice the risk of later diabetes and about 1.5 times the cardiovascular risk of values in the low 80s, though the absolute yearly risk stayed under 1 percent. It is a reason to repeat the draw, check fasting insulin, triglycerides and hemoglobin A1c, and look at the trend, not a diagnosis."},{"q":"What is an optimal fasting glucose?","a":"No guideline defines one. The best evidence places the lowest risk of later diabetes below about 85 to 87 mg/dL and the lowest all-cause mortality at about 80 to 94, with risk rising again below about 70 to 80 in several cohorts. Those are descriptions of where risk was lowest, not targets proven by a trial."},{"q":"Why is my fasting glucose high when I eat well?","a":"Several reasons that are not diet. The liver releases glucose before waking, so an early draw can run higher; a recent illness, poor sleep or stress raises it; a sample that sat at room temperature reads lower, so the same person can look worse on a well-handled draw; and the draw itself varies about 6 percent from day to day. If it stays high on repeat, the usual cause is insulin resistance in the liver, which a fasting insulin and triglycerides help to show."}],"citations":[{"id":"ada2026","authors":"American Diabetes Association Professional Practice Committee","title":"2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2026","journal":"Diabetes Care","year":2026,"pmid":"41358893","doi":"10.2337/dc26-S002","type":"guideline","finding":"Diabetes at fasting plasma glucose 126 mg/dL or higher after at least 8 hours without calories; impaired fasting glucose 100 to 125; two abnormal results required absent unequivocal hyperglycemia.","url":"https://pubmed.ncbi.nlm.nih.gov/41358893/"},{"id":"sacks2023","authors":"Sacks DB, Arnold M, Bakris GL, et al.","title":"Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus","journal":"Diabetes Care","year":2023,"pmid":"37471273","doi":"10.2337/dci23-0036","type":"guideline","finding":"Glycolysis lowers sample glucose 5 to 7 percent an hour; plasma reads about 11 percent above whole blood; within-person CV 4.8 percent puts the band around 126 at 110 to 142.","url":"https://pubmed.ncbi.nlm.nih.gov/37471273/"},{"id":"tirosh2005","authors":"Tirosh A, Shai I, Tekes-Manova D, et al.","title":"Normal fasting plasma glucose levels and type 2 diabetes in young men","journal":"New England Journal of Medicine","year":2005,"pmid":"16207847","doi":"10.1056/NEJMoa050080","type":"cohort","finding":"Among 13,163 young men with fasting glucose below 100, diabetes risk rose progressively from 87 mg/dL upward versus below 81.","url":"https://pubmed.ncbi.nlm.nih.gov/16207847/"},{"id":"nichols2008","authors":"Nichols GA, Hillier TA, Brown JB","title":"Normal fasting plasma glucose and risk of type 2 diabetes diagnosis","journal":"American Journal of Medicine","year":2008,"pmid":"18501234","doi":"10.1016/j.amjmed.2008.02.026","type":"cohort","finding":"In 46,578 adults below 100 mg/dL, each mg/dL raised diabetes risk 6 percent; 95 to 99 carried 2.33 times the risk of below 85.","url":"https://pubmed.ncbi.nlm.nih.gov/18501234/"},{"id":"tabak2009","authors":"Tabák AG, Jokela M, Akbaraly TN, Brunner EJ, Kivimäki M, Witte DR","title":"Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study","journal":"Lancet","year":2009,"pmid":"19515410","doi":"10.1016/S0140-6736(09)60619-X","type":"cohort","finding":"Insulin sensitivity fell steeply 5 years before diagnosis; fasting glucose rose steeply only in the last 3 years, from 5.79 to 7.40 mmol/L.","url":"https://pubmed.ncbi.nlm.nih.gov/19515410/"},{"id":"dankner2009","authors":"Dankner R, Chetrit A, Shanik MH, Raz I, Roth J","title":"Basal-state hyperinsulinemia in healthy normoglycemic adults is predictive of type 2 diabetes over a 24-year follow-up: a preliminary report","journal":"Diabetes Care","year":2009,"pmid":"19435961","doi":"10.2337/dc09-0153","type":"cohort","finding":"In 515 normoglycemic adults, top-quintile fasting insulin was the strongest independent predictor of dysglycemia 24 years later.","url":"https://pubmed.ncbi.nlm.nih.gov/19435961/"},{"id":"shah2019","authors":"Shah VN, DuBose SN, Li Z, et al.","title":"Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study","journal":"Journal of Clinical Endocrinology and Metabolism","year":2019,"pmid":"31127824","doi":"10.1210/jc.2018-02763","type":"cohort","finding":"In 153 healthy people, mean sensor glucose was 98 to 99 mg/dL (104 over age 60), 96 percent of time between 70 and 140, 1.1 percent below 70.","url":"https://pubmed.ncbi.nlm.nih.gov/31127824/"},{"id":"cryer2009","authors":"Cryer PE, Axelrod L, Grossman AB, et al.","title":"Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline","journal":"Journal of Clinical Endocrinology and Metabolism","year":2009,"pmid":"19088155","doi":"10.1210/jc.2008-1410","type":"guideline","finding":"Evaluate hypoglycemia only when Whipple's triad is documented: symptoms, a low measured plasma glucose, and relief when glucose is raised.","url":"https://pubmed.ncbi.nlm.nih.gov/19088155/"},{"id":"shaye2012","authors":"Shaye K, Amir T, Shlomo S, Yechezkel S","title":"Fasting glucose levels within the high normal range predict cardiovascular outcome","journal":"American Heart Journal","year":2012,"pmid":"22795290","doi":"10.1016/j.ahj.2012.03.023","type":"cohort","finding":"In 10,913 adults, fasting glucose 95 to 99 carried 1.53 times the cardiovascular event rate of below 80 over a mean 4.3 years.","url":"https://pubmed.ncbi.nlm.nih.gov/22795290/"},{"id":"bjornholt1999","authors":"Bjørnholt JV, Erikssen G, Aaser E, et al.","title":"Fasting blood glucose: an underestimated risk factor for cardiovascular death. Results from a 22-year follow-up of healthy nondiabetic men","journal":"Diabetes Care","year":1999,"pmid":"10333902","doi":"10.2337/diacare.22.1.45","type":"cohort","finding":"In 1,973 healthy men, fasting whole-blood glucose above 85 mg/dL carried 1.4 times the adjusted cardiovascular mortality over 22 years.","url":"https://pubmed.ncbi.nlm.nih.gov/10333902/"},{"id":"erfc2010","authors":"Emerging Risk Factors Collaboration; Sarwar N, Gao P, Seshasai SR, et al.","title":"Diabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies","journal":"Lancet","year":2010,"pmid":"20609967","doi":"10.1016/S0140-6736(10)60484-9","type":"meta-analysis","finding":"Across 698,782 people, vascular risk was flat between 3.90 and 5.59 mmol/L; coronary hazard ratios 1.11 at 5.60 to 6.09 and 1.17 at 6.10 to 6.99.","url":"https://pubmed.ncbi.nlm.nih.gov/20609967/"},{"id":"seshasai2011","authors":"Rao Kondapally Seshasai S, Kaptoge S, Thompson A, et al.; Emerging Risk Factors Collaboration","title":"Diabetes mellitus, fasting glucose, and risk of cause-specific death","journal":"New England Journal of Medicine","year":2011,"pmid":"21366474","doi":"10.1056/NEJMoa1008862","type":"meta-analysis","finding":"Across 820,900 people, fasting glucose above 100 mg/dL was associated with death; 70 to 100 was not.","url":"https://pubmed.ncbi.nlm.nih.gov/21366474/"},{"id":"decode1999","authors":"DECODE Study Group, European Diabetes Epidemiology Group","title":"Glucose tolerance and mortality: comparison of WHO and American Diabetes Association diagnostic criteria","journal":"Lancet","year":1999,"pmid":"10466661","type":"cohort","finding":"In 25,364 Europeans, mortality rose with 2-hour glucose within every fasting-glucose category; fasting glucose alone did not identify the excess risk.","url":"https://pubmed.ncbi.nlm.nih.gov/10466661/"},{"id":"wei2000","authors":"Wei M, Gibbons LW, Mitchell TL, Kampert JB, Stern MP, Blair SN","title":"Low fasting plasma glucose level as a predictor of cardiovascular disease and all-cause mortality","journal":"Circulation","year":2000,"pmid":"10790345","doi":"10.1161/01.cir.101.17.2047","type":"cohort","finding":"In 40,069 adults, fasting glucose below 70 carried 3.3 times, and 70 to 79 carried 2.4 times, the cardiovascular mortality of 80 to 109.","url":"https://pubmed.ncbi.nlm.nih.gov/10790345/"},{"id":"park2013","authors":"Park C, Guallar E, Linton JA, et al.","title":"Fasting glucose level and the risk of incident atherosclerotic cardiovascular diseases","journal":"Diabetes Care","year":2013,"pmid":"23404299","doi":"10.2337/dc12-1577","type":"cohort","finding":"In 1,197,384 Koreans over 16 years, cardiovascular risk was lowest at 85 to 99 with a nadir near 90; below 70 carried hazard ratios of 1.06 (men) and 1.11 (women) for stroke.","url":"https://pubmed.ncbi.nlm.nih.gov/23404299/"},{"id":"yi2017","authors":"Yi SW, Park S, Lee YH, Park HJ, Balkau B, Yi JJ","title":"Association between fasting glucose and all-cause mortality according to sex and age: a prospective cohort study","journal":"Scientific Reports","year":2017,"pmid":"28811570","doi":"10.1038/s41598-017-08498-6","type":"cohort","finding":"In 12,455,361 Korean adults, all-cause mortality was lowest at 80 to 94 mg/dL regardless of sex and age, rising from about 95 to 100 and from about 80 downward.","url":"https://pubmed.ncbi.nlm.nih.gov/28811570/"},{"id":"merino2017","authors":"Merino J, Leong A, Posner DC, et al.","title":"Genetically Driven Hyperglycemia Increases Risk of Coronary Artery Disease Separately From Type 2 Diabetes","journal":"Diabetes Care","year":2017,"pmid":"28298470","doi":"10.2337/dc16-2625","type":"mendelian-randomization","finding":"Twelve fasting-glucose-raising variants carried 1.43 times the odds of coronary disease per 1 mmol/L, 1.33 after removing pleiotropic variants, without raising diabetes risk.","url":"https://pubmed.ncbi.nlm.nih.gov/28298470/"},{"id":"knowler2002","authors":"Knowler WC, Barrett-Connor E, Fowler SE, et al.; Diabetes Prevention Program Research Group","title":"Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin","journal":"New England Journal of Medicine","year":2002,"pmid":"11832527","doi":"10.1056/NEJMoa012512","type":"rct","finding":"In 3,234 adults with elevated glucose, lifestyle cut diabetes incidence 58 percent and the medication arm 31 percent over 2.8 years; 6.9 needed to treat.","url":"https://pubmed.ncbi.nlm.nih.gov/11832527/"},{"id":"li2008","authors":"Li G, Zhang P, Wang J, et al.","title":"The long-term effect of lifestyle interventions to prevent diabetes in the China Da Qing Diabetes Prevention Study: a 20-year follow-up study","journal":"Lancet","year":2008,"pmid":"18502303","doi":"10.1016/S0140-6736(08)60766-7","type":"rct","finding":"Six years of lifestyle intervention in 577 adults lowered diabetes incidence 43 percent over 20 years; cardiovascular events and mortality did not differ significantly.","url":"https://pubmed.ncbi.nlm.nih.gov/18502303/"},{"id":"jelleyman2015","authors":"Jelleyman C, Yates T, O'Donovan G, et al.","title":"The effects of high-intensity interval training on glucose regulation and insulin resistance: a meta-analysis","journal":"Obesity Reviews","year":2015,"pmid":"26481101","doi":"10.1111/obr.12317","type":"meta-analysis","finding":"Across 50 studies, interval training reduced insulin resistance (SMD -0.49) and, in people at risk of or with diabetes, fasting glucose by 0.92 mmol/L.","url":"https://pubmed.ncbi.nlm.nih.gov/26481101/"},{"id":"cappuccio2010","authors":"Cappuccio FP, D'Elia L, Strazzullo P, Miller MA","title":"Quantity and quality of sleep and incidence of type 2 diabetes: a systematic review and meta-analysis","journal":"Diabetes Care","year":2010,"pmid":"19910503","doi":"10.2337/dc09-1124","type":"meta-analysis","finding":"Across 107,756 adults, short sleep carried relative risk 1.28, long sleep 1.48, trouble falling asleep 1.57 and trouble staying asleep 1.84 for type 2 diabetes.","url":"https://pubmed.ncbi.nlm.nih.gov/19910503/"},{"id":"dungan2009","authors":"Dungan KM, Braithwaite SS, Preiser JC","title":"Stress hyperglycaemia","journal":"Lancet","year":2009,"pmid":"19465235","doi":"10.1016/S0140-6736(09)60553-5","type":"review","finding":"Stress hyperglycemia is defined as hyperglycemia that resolves spontaneously once acute illness passes.","url":"https://pubmed.ncbi.nlm.nih.gov/19465235/"},{"id":"monnier2013","authors":"Monnier L, Colette C, Dejager S, Owens D","title":"Magnitude of the dawn phenomenon and its impact on the overall glucose exposure in type 2 diabetes: is this of concern?","journal":"Diabetes Care","year":2013,"pmid":"24170753","doi":"10.2337/dc12-2127","type":"cross-sectional","finding":"In 248 people with type 2 diabetes on continuous monitoring, the median dawn rise from overnight nadir to pre-breakfast glucose was 16 mg/dL.","url":"https://pubmed.ncbi.nlm.nih.gov/24170753/"},{"id":"selvin2007","authors":"Selvin E, Crainiceanu CM, Brancati FL, Coresh J","title":"Short-term variability in measures of glycemia and implications for the classification of diabetes","journal":"Archives of Internal Medicine","year":2007,"pmid":"17646610","doi":"10.1001/archinte.167.14.1545","type":"laboratory","finding":"Within-person CV about 2 weeks apart: 5.7 percent for fasting glucose, 16.7 percent for 2-hour glucose, 3.6 percent for HbA1c; 70.4 percent of values at 126 or higher repeated there.","url":"https://pubmed.ncbi.nlm.nih.gov/17646610/"},{"id":"gambino2009","authors":"Gambino R, Piscitelli J, Ackattupathil TA, et al.","title":"Acidification of blood is superior to sodium fluoride alone as an inhibitor of glycolysis","journal":"Clinical Chemistry","year":2009,"pmid":"19282354","doi":"10.1373/clinchem.2008.121707","type":"laboratory","finding":"Glucose fell 4.6 percent at 2 hours in fluoride-oxalate tubes versus 0.3 percent in citrate-fluoride-EDTA tubes; fluoride alone takes up to 4 hours to stop glycolysis.","url":"https://pubmed.ncbi.nlm.nih.gov/19282354/"},{"id":"moebus2011","authors":"Moebus S, Göres L, Lösch C, Jöckel KH","title":"Impact of time since last caloric intake on blood glucose levels","journal":"European Journal of Epidemiology","year":2011,"pmid":"21822717","doi":"10.1007/s10654-011-9608-z","type":"cross-sectional","finding":"In 28,024 adults, glucose differed by about 0.1 mmol/L between fasting 8 hours or more and less; after 3 hours the difference was 0.07 to 0.08 mmol/L.","url":"https://pubmed.ncbi.nlm.nih.gov/21822717/"}],"written":"2026-10-07","updated":"2026-10-07","reviewed":true,"reviewedOn":"2026-10-10","related":{"essays":["fasting-insulin-of-12-what-it-means"],"glossary":["Fasting insulin","HbA1c","HOMA-IR","Insulin resistance","CGM","Glycemic variability","Reference range","Optimal range"],"symptoms":["weight-loss-resistance","food-cravings","fatigue","poor-sleep"],"entries":["fasting-insulin","hba1c","triglycerides","apob"]},"url":"https://taggehealth.com/labs/fasting-glucose","author":"Daniel Tagge, MD","publisher":"Tagge Health","license":"Free to read and cite with attribution to the URL above.","inPractice":"I like to see fasting glucose in the 70s to the mid 80s, and I read it beside fasting insulin, triglycerides and hemoglobin A1c rather than on its own. The ceiling is where the diabetes cohorts found risk beginning to rise. The floor is my judgment: the mortality data are quiet in the low 80s and less so in the 70s, so a value in the 70s earns a look at how the person feels and what else is moving, not a cheer. One high draw earns a repeat on a well-handled sample before it earns a label."}