A1C less than 4% increased mortality

Low hemoglobin A1c and risk of all-cause mortality among US adults without diabetes.
Carson AP, Fox CS, McGuire DK, Levitan EB, Laclaustra M, Mann DM, Muntner P.

Department of Epidemiology, University of Alabama at Birmingham, 35294-0022, USA. apcarson@uab.edu

Abstract
BACKGROUND: Among individuals without diabetes, elevated hemoglobin A1c (HbA1c) has been associated with increased morbidity and mortality, but the literature is sparse regarding the prognostic importance of low HbA1c.

METHODS AND RESULTS: National Health and Nutrition Examination Survey III (NHANES III) participants, 20 years and older, were followed up to 12 years (median follow-up, 8.8 years) for all-cause mortality. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the association between HbA1c levels and all-cause mortality for 14 099 participants without diabetes. There were 1825 deaths during the follow-up period. Participants with a low HbA1c (<4.0%) had the highest levels of mean red blood cell volume, ferritin, and liver enzymes and the lowest levels of mean total cholesterol and diastolic blood pressure compared with their counterparts with HbA1c levels between 4.0% and 6.4%. An HbA1c <4.0% versus 5.0% to 5.4% was associated with an increased risk of all-cause mortality (HR, 3.73; 95% CI, 1.45 to 9.63) after adjustment for age, race-ethnicity, and sex. This association was attenuated but remained statistically significant after further multivariable adjustment for lifestyle, cardiovascular factors, metabolic factors, red blood cell indices, iron storage indices, and liver function indices (HR, 2.90; 95% CI, 1.25 to 6.76).

CONCLUSIONS: In this nationally representative cohort, low HbA1c was associated with increased all-cause mortality among US adults without diabetes. Additional research is needed to confirm these results and identify potential mechanisms that may be underlying this association.

A1c concentrations less than 5% had the lowest rates of cardiovascular disease and mortality.

Ann Intern Med. 2004 Sep 21;141(6):413-20.

Association of hemoglobin A1c with cardiovascular disease and mortality in adults: the European prospective investigation into cancer in Norfolk.
Khaw KT, Wareham N, Bingham S, Luben R, Welch A, Day N.

University of Cambridge, School of Clinical Medicine, Medical Research Council Epidemiology Unit, Addenbrooke's Hospital, Cambridge, United Kingdom. kk101@medschl.cam.ac.uk.

Comment in:

Ann Intern Med. 2004 Sep 21;141(6):I12.
Ann Intern Med. 2004 Sep 21;141(6):475-6.
ACP J Club. 2005 Mar-Apr;142(2):52.

Abstract
BACKGROUND: Increasing evidence suggests a continuous relationship between blood glucose concentrations and cardiovascular risk, even below diagnostic threshold levels for diabetes.

OBJECTIVE: To examine the relationship between hemoglobin A1c, cardiovascular disease, and total mortality.

DESIGN: Prospective population study.

SETTING: Norfolk, United Kingdom.

PARTICIPANTS: 4662 men and 5570 women who were 45 to 79 years of age and were residents of Norfolk.

MEASUREMENTS: Hemoglobin A1c and cardiovascular disease risk factors were assessed from 1995 to 1997, and cardiovascular disease events and mortality were assessed during the follow-up period to 2003.

RESULTS: In men and women, the relationship between hemoglobin A1c and cardiovascular disease (806 events) and between hemoglobin A1c and all-cause mortality (521 deaths) was continuous and significant throughout the whole distribution. The relationship was apparent in persons without known diabetes. Persons with hemoglobin A1c concentrations less than 5% had the lowest rates of cardiovascular disease and mortality. An increase in hemoglobin A1c of 1 percentage point was associated with a relative risk for death from any cause of 1.24 (95% CI, 1.14 to 1.34; P < 0.001) in men and with a relative risk of 1.28 (CI, 1.06 to 1.32; P < 0.001) in women. These relative risks were independent of age, body mass index, waist-to-hip ratio, systolic blood pressure, serum cholesterol concentration, cigarette smoking, and history of cardiovascular disease. When persons with known diabetes, hemoglobin A(1c) concentrations of 7% or greater, or a history of cardiovascular disease were excluded, the result was similar (adjusted relative risk, 1.26 [CI, 1.04 to 1.52]; P = 0.02). Fifteen percent (68 of 521) of the deaths in the sample occurred in persons with diabetes (4% of the sample), but 72% (375 of 521) occurred in persons with HbA1c concentrations between 5% and 6.9%.

LIMITATIONS: Whether HbA1c concentrations and cardiovascular disease are causally related cannot be concluded from an observational study; intervention studies are needed to determine whether decreasing HbA1c concentrations would reduce cardiovascular disease.

CONCLUSIONS: The risk for cardiovascular disease and total mortality associated with hemoglobin A1c concentrations increased continuously through the sample distribution. Most of the events in the sample occurred in persons with moderately elevated HbA1c concentrations. These findings support the need for randomized trials of interventions to reduce hemoglobin A1c concentrations in persons without diabetes.

Glycated Hemoglobin Better Than Fasting Glucose for Predicting Cardiovascular Risk

Glycated hemoglobin levels, especially above 6.0%, are better than fasting glucose for predicting long-term cardiovascular risk, the New England Journal of Medicine reports.


Researchers measured glycated hemoglobin and fasting glucose in some 11,000 adults without diabetes or cardiovascular disease and followed them for a median of 14 years. Compared with hemoglobin levels of 5.0% to 5.5%, higher values — especially above 6% — were associated with significantly increased risks for diabetes, coronary heart disease, and stroke. Associations between hemoglobin and all-cause mortality were also significant, but formed a J-shaped curve, with the lowest and highest levels being predictive of death.


These findings held true even after adjustment for fasting glucose.


The authors say their findings "may add to the evidence supporting the use of glycated hemoglobin as a diagnostic test for diabetes."

obese smoker healthy health care costs chart

Fat/smokers excellent citizens

Fat People Cheaper to Treat, Study Says
By MARIA CHENG – 1 day ago

LONDON (AP) — Preventing obesity and smoking can save lives, but it doesn't save money, researchers reported Monday. It costs more to care for healthy people who live years longer, according to a Dutch study that counters the common perception that preventing obesity would save governments millions of dollars.

"It was a small surprise," said Pieter van Baal, an economist at the Netherlands' National Institute for Public Health and the Environment, who led the study. "But it also makes sense. If you live longer, then you cost the health system more."

In a paper published online Monday in the Public Library of Science Medicine journal, Dutch researchers found that the health costs of thin and healthy people in adulthood are more expensive than those of either fat people or smokers.

Van Baal and colleagues created a model to simulate lifetime health costs for three groups of 1,000 people: the "healthy-living" group (thin and non-smoking), obese people, and smokers. The model relied on "cost of illness" data and disease prevalence in the Netherlands in 2003.

The researchers found that from age 20 to 56, obese people racked up the most expensive health costs. But because both the smokers and the obese people died sooner than the healthy group, it cost less to treat them in the long run.

On average, healthy people lived 84 years. Smokers lived about 77 years, and obese people lived about 80 years. Smokers and obese people tended to have more heart disease than the healthy people.

Cancer incidence, except for lung cancer, was the same in all three groups. Obese people had the most diabetes, and healthy people had the most strokes. Ultimately, the thin and healthy group cost the most, about $417,000, from age 20 on.

The cost of care for obese people was $371,000, and for smokers, about $326,000.

The results counter the common perception that preventing obesity will save health systems worldwide millions of dollars.

"This throws a bucket of cold water onto the idea that obesity is going to cost trillions of dollars," said Patrick Basham, a professor of health politics at Johns Hopkins University who was unconnected to the study. He said that government projections about obesity costs are frequently based on guesswork, political agendas, and changing science.

"If we're going to worry about the future of obesity, we should stop worrying about its financial impact," he said.

Obesity experts said that fighting the epidemic is about more than just saving money.

"The benefits of obesity prevention may not be seen immediately in terms of cost savings in tomorrow's budget, but there are long-term gains," said Neville Rigby, spokesman for the International Association for the Study of Obesity. "These are often immeasurable when it comes to people living longer and healthier lives."

Van Baal described the paper as "a book-keeping exercise," and said that governments should recognize that successful smoking and obesity prevention programs mean that people will have a higher chance of dying of something more expensive later in life.

"Lung cancer is a cheap disease to treat because people don't survive very long," van Baal said. "But if they are old enough to get Alzheimer's one day, they may survive longer and cost more."

The study, paid for by the Dutch Ministry of Health, Welfare and Sports, did not take into account other potential costs of obesity and smoking, such as lost economic productivity or social costs.

"We are not recommending that governments stop trying to prevent obesity," van Baal said. "But they should do it for the right reasons."

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PLoS: http://medicine.plosjournals.org