Total antioxidant capacity from diet and risk of myocardial infarction: a prospective cohort of women

BACKGROUND

There are no previous studies investigating the effect of all dietary antioxidants in relation to myocardial infarction. The total antioxidant capacity of diet takes into account all antioxidants and synergistic effects between them. The aim of this study was to examine how total antioxidant capacity of diet and antioxidant-containing foods were associated with incident myocardial infarction among middle-aged and elderly women.

METHODS

In the population-based prospective Swedish Mammography Cohort of 49-83-year-old women, 32,561 were cardiovascular disease-free at baseline. Women completed a food-frequency questionnaire, and dietary total antioxidant capacity was calculated using oxygen radical absorbance capacity values. Information on myocardial infarction was identified from the Swedish Hospital Discharge and the Cause of Death registries. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazard models.

RESULTS

During the follow-up (September 1997-December 2007), we identified 1114 incident cases of myocardial infarction (321,434 person-years). In multivariable-adjusted analysis, the HR for women comparing the highest quintile of dietary total antioxidant capacity to the lowest was 0.80 (95% CI, 0.67-0.97; P for trend=0.02). Servings of fruit and vegetables and whole grains were nonsignificantly inversely associated with myocardial infarction.

CONCLUSIONS

These data suggest that dietary total antioxidant capacity, based on fruits, vegetables, coffee, and whole grains, is of importance in the prevention of myocardial infarction.

Changes in eye protection behavior following an occupational eye injury

This study investigated whether workers modify eye protection behavior following an occupational eye injury. Workers treated for work-related eye injuries were questioned regarding the use of protective eyewear for the work-month prior to their eye injuries and again 6 to 12 months later. Workers reported an increase in the proportion of work-time they used eye protection (from a median of 20% to 100%; p < .0001). The effect appeared to be driven by whether eye protection was used at the time of the injury. Most respondents (66%) indicated they were more likely to use eye protection since their injuries. Workers not using eye protection at the time of injury were more likely to use eye protection in the future. A variety of employer and employee factors may influence this change. Although many workers' behaviors changed, health care providers should embrace the teachable moment when treating occupational eye injuries to encourage continued use or more appropriate forms of eye protection.

Changes in eye protection behavior following an occupational eye injury

This study investigated whether workers modify eye protection behavior following an occupational eye injury. Workers treated for work-related eye injuries were questioned regarding the use of protective eyewear for the work-month prior to their eye injuries and again 6 to 12 months later. Workers reported an increase in the proportion of work-time they used eye protection (from a median of 20% to 100%; p < .0001). The effect appeared to be driven by whether eye protection was used at the time of the injury. Most respondents (66%) indicated they were more likely to use eye protection since their injuries. Workers not using eye protection at the time of injury were more likely to use eye protection in the future. A variety of employer and employee factors may influence this change. Although many workers' behaviors changed, health care providers should embrace the teachable moment when treating occupational eye injuries to encourage continued use or more appropriate forms of eye protection.

Habitual coffee consumption and risk of heart failure: a dose-response meta-analysis

BACKGROUND

There have been discrepant findings on the association between coffee consumption and risk of incident heart failure.

METHODS AND RESULTS

We conducted a systematic review and a dose-response meta-analysis of prospective studies that assessed the relationship between habitual coffee consumption and the risk of heart failure. We searched electronic databases (MEDLINE, Embase, and CINAHL) from January 1966 through December 2011, with the use of a standardized protocol. Eligible studies were prospective cohort studies that examined the association of coffee consumption with incident heart failure. Five independent prospective studies of coffee consumption and heart failure risk, including 6522 heart failure events and 140 220 participants, were included in the meta-analysis. We observed a statistically significant J-shaped relationship between coffee and heart failure. Compared with no consumption, the strongest inverse association was seen for 4 servings/day and a potentially higher risk at higher levels of consumption. There was no evidence that the relationship between coffee and heart failure risk varied by sex or by baseline history of myocardial infarction or diabetes.

CONCLUSIONS

Moderate coffee consumption is inversely associated with risk of heart failure, with the largest inverse association observed for consumption of 4 servings per day.

Relations between QRS|T angle, cardiac risk factors, and mortality in the third National Health and Nutrition Examination Survey (NHANES III)

On the surface electrocardiogram, an abnormally wide QRS|T angle reflects changes in the regional action potential duration profiles and in the direction of the repolarization sequence, which is thought to increase the risk of ventricular arrhythmia. We investigated the relation between an abnormal QRS|T angle and mortality in a nationally representative sample of subjects without clinically evident heart disease. We studied 7,052 participants ≥40 years old in the third National Health and Nutrition Examination Survey with 12-lead electrocardiograms. Those with self-reported or electrocardiographic evidence of a previous myocardial infarction, QRS duration of ≥120 ms, or history of heart failure were excluded. Borderline and abnormal spatial QRS|T angles were defined according to gender-specific 75th and 95th percentiles of frequency distributions. All-cause (1,093 women and 1,191 men) and cardiovascular (462 women and 455 men) mortality during the 14-year period was assessed through linkage with the National Death Index. On multivariate analyses, an abnormal spatial QRS|T angle was associated with an increased hazard ratio (HR) for cardiovascular mortality in women (HR 1.82, 95% confidence interval 1.05 to 3.14) and men (HR 2.21, 95% confidence interval 1.32 to 3.68). Also, the multivariate adjusted HR for all-cause mortality associated with an abnormal QRS|T angle was 1.30 (95% confidence interval 0.95 to 1.78) for women and 1.87 (95% confidence interval 1.29 to 2.7) for men. A borderline QRS|T angle was not associated with an increased risk of all-cause or cardiovascular mortality. In conclusion, an abnormal QRS|T angle, as measured on a 12-lead electrocardiogram, was associated with an increased risk of cardiovascular and all-cause mortality in this population-based sample without known heart disease.

Transitional probability-based model for HPV clearance in HIV-1-positive adolescent females

Background

HIV-1-positive patients clear the human papillomavirus (HPV) infection less frequently than HIV-1-negative. Datasets for estimating HPV clearance probability often have irregular measurements of HPV status and risk factors. A new transitional probability-based model for estimation of probability of HPV clearance was developed to fully incorporate information on HIV-1-related clinical data, such as CD4 counts, HIV-1 viral load (VL), highly active antiretroviral therapy (HAART), and risk factors (measured quarterly), and HPV infection status (measured at 6-month intervals).

Methodology and Findings

Data from 266 HIV-1-positive and 134 at-risk HIV-1-negative adolescent females from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort were used in this study. First, the associations were evaluated using the Cox proportional hazard model, and the variables that demonstrated significant effects on HPV clearance were included in transitional probability models. The new model established the efficacy of CD4 cell counts as a main clearance predictor for all type-specific HPV phylogenetic groups. The 3-month probability of HPV clearance in HIV-1-infected patients significantly increased with increasing CD4 counts for HPV16/16-like (p<0.001), HPV18/18-like (p<0.001), HPV56/56-like (p = 0.05), and low-risk HPV (p<0.001) phylogenetic groups, with the lowest probability found for HPV16/16-like infections (21.60±1.81% at CD4 level 200 cells/mm³, p<0.05; and 28.03±1.47% at CD4 level 500 cells/mm³). HIV-1 VL was a significant predictor for clearance of low-risk HPV infections (p<0.05). HAART (with protease inhibitor) was significant predictor of probability of HPV16 clearance (p<0.05). HPV16/16-like and HPV18/18-like groups showed heterogeneity (p<0.05) in terms of how CD4 counts, HIV VL, and HAART affected probability of clearance of each HPV infection.

Conclusions

This new model predicts the 3-month probability of HPV infection clearance based on CD4 cell counts and other HIV-1-related clinical measurements.

Within-visit variability of blood pressure and all-cause and cardiovascular mortality among US adults

The association between within-visit variability of systolic blood pressure (SBP) and diastolic blood pressure (DBP) and all-cause and cardiovascular (CVD) mortality was examined using the Third National Health and Nutrition Survey (n=15,317). Three SBP and DBP readings were taken by physicians during a single medical evaluation. Within-visit variability for each participant was defined using the standard deviation of SBP and DBP across these measurements. Mortality was assessed over 14 years (n=3848 and n=1684 deaths from all causes and CVD, respectively). After age, sex, and race-ethnicity adjustment, the hazard ratios (95% confidence intervals) for all-cause mortality associated with the 4 highest quintiles of within-visit standard deviation of SBP (2.00-2.99 mm Hg, 3.00-3.99 mm Hg, 4.00-5.29 mm Hg, and ≥5.30 mm Hg) compared with participants in the lowest quintile of within-visit standard deviation of SBP (<2.0 mm Hg) were 1.04 (0.87-1.26), 1.09 (0.92-1.29), 1.06 (0.88-1.28), and 1.13 (0.95-1.33), respectively (P=.136). The analogous hazard ratios for CVD mortality were 0.95 (0.69-1.32), 0.96 (0.67-1.36), 0.95 (0.74-1.23), and 1.04 (0.80-1.35), respectively (P=.566). No association with mortality was present after further adjustment and when modeling within-visit standard deviation of SBP as a continuous variable. Standard deviation of DBP was not associated with mortality.

Prevalence and prognosis of unrecognized myocardial infarctions in chronic kidney disease

BACKGROUND

Unrecognized myocardial infarctions (UMIs) are common in the general population but have not been well studied in patients with chronic kidney disease (CKD). The purpose of this study was to determine the prevalence and prognosis for mortality of UMI among adults with CKD.

METHODS

The current study included 18 864 participants in the population-based REasons for Geographic And Racial Differences in Stroke (REGARDS) study who completed a baseline examination including a 12-lead electrocardiogram (ECG). UMI was defined as the presence of myocardial infarction (MI) by Minnesota ECG classification in the absence of self-reported or recognized MI (RMI). Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation and albuminuria using albumin-to-creatinine ratio from a spot urine sample. All-cause mortality was assessed over a median 4 years of follow-up.

RESULTS

The prevalence of UMI was 4, 6, 6 and 13% among participants with eGFR levels of ≥ 60, 45-59.9, 30-44.9 and <30 mL/min/1.73 m(2), respectively, and 4, 5, 7 and 10% among participants with albuminuria levels of <10, 10-29.9, 30-299.9 and ≥ 300 mg/g, respectively. Compared to those with no MI, the multivariable adjusted hazard ratio for all-cause mortality associated with UMI and RMI was 1.65 [95% confidence interval (CI): 1.09-2.49] and 1.65 (95% CI: 1.20-2.26), respectively, among individuals with an eGFR <60 mL/min/1.73 m(2) and 1.49 (95% CI: 1.03-2.16) and 1.88 (95% CI: 1.40-2.52) among individuals with albuminuria ≥ 30 mg/g. Conclusion UMIs are common among individuals with an eGFR <60 mL/min/1.73 m(2) and albuminuria and associated with an increased mortality risk.

Comparison of concurrent complications of CKD by 2 risk categorization systems

BACKGROUND

Using both estimated glomerular filtration rate (eGFR) and proteinuria to classify the severity of chronic kidney disease (CKD) has been proposed. The utility of a staging system incorporating both eGFR and proteinuria for guiding the evaluation of concurrent CKD complications is not known.

STUDY DESIGN

Cross-sectional analysis.

SETTING & PARTICIPANTS

30,528 participants in the US National Health and Nutrition Examination Survey conducted in 1988-1994 and 1999-2006 (n = 8,242 for hyperparathyroidism).

PREDICTORS

Classification system that uses both eGFR and proteinuria (alternative) and a system that primarily uses eGFR (NKF-KDOQI [National Kidney Foundation's Kidney Disease Outcomes Quality Initiative]).

OUTCOMES

Prevalence of anemia, acidosis, hyperphosphatemia, hypoalbuminemia, hyperparathyroidism, and hypertension.

MEASUREMENTS

GFR estimated from the CKD Epidemiology Collaboration (CKD-EPI) equation and proteinuria assessed using urine albumin-creatinine ratio.

RESULTS

Prevalences of hypoalbuminemia, hypertension, and hyperparathyroidism increased with more severe CKD using the NKF-KDOQI system. For example, the prevalence of hyperparathyroidism was 9.1%, 11.1%, 28.2%, and 72.5% for stages 1, 2, 3 and 4, respectively. Similarly, prevalences of anemia, acidosis, and hyperphosphatemia increased progressively from stage 2 through 4. With the alternative system, prevalences of anemia, hyperphosphatemia, hypertension, and hyperparathyroidism were lower in stage 3 than in stage 2. For example, the prevalence of hyperparathyroidism was 13.5%, 40.3%, 22.2%, and 63.4% for stages 1, 2, 3 and 4, respectively. Applying the alternative system, participants without each complication were more likely to be reclassified appropriately to lower stages (eg, overall net reclassification index of -6.5% for hyperparathyroidism). However, participants with complications (except for hypoalbuminemia) were more likely to be reclassified inappropriately to lower stages.

LIMITATIONS

Use of a single creatinine measurement to estimate GFR and single measurement to assess albumin-creatinine ratio. Small number of participants with CKD stage 4.

CONCLUSIONS

The NKF-KDOQI system may better identify patients with certain concurrent CKD complications compared with systems using eGFR and proteinuria.

Baseline values of candidate urine acute kidney injury biomarkers vary by gestational age in premature infants

Acute kidney injury (AKI) is common in premature infants and is associated with poor outcomes. Novel biomarkers can detect AKI promptly. Because premature infants are born with underdeveloped kidneys, baseline biomarker values may differ. We describe baseline values of urinary neutrophil gelatinase-associated lipocalin (NGAL), IL-18, kidney injury molecule-1 (KIM-1), osteopontin (OPN), beta-2 microglobulin (B2mG), and Cystatin-C (Cys-C). Next, we test the hypothesis that these biomarkers are inversely related to GA. Candidate markers were compared according to GA categories in 123 infants. Mixed linear regression models were performed to determine the independent association between demographics/interventions and baseline biomarker values. We found that urine NGAL, KIM-1, Cys-C, and B2mG decreased with increasing GA. With correction for urine creatinine (cr), these markers and OPN/cr decreased with increasing GA. IL-18 (with or without correction for urine creatinine) did not differ across GA categories. Controlling for other potential clinical and demographic confounders with regression analysis shows that NGAL/cr, OPN/cr, and B2mG/cr are independently associated with GA. We conclude that urine values of candidate AKI biomarkers are higher in the most premature infants. These findings should be considered when designing and analyzing biomarker studies in newborn with AKI.

Development and validation of a self-assessment tool for albuminuria: results from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

BACKGROUND

The prevalence of albuminuria in the general population is high, but awareness of it is low. Therefore, we sought to develop and validate a self-assessment tool that allows individuals to estimate their probability of having albuminuria.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

The population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study for model development and the National Health and Nutrition Examination Survey (NHANES) 1999-2004 for model validation. US adults 45 years or older in the REGARDS Study (n = 19,697) and NHANES 1999-2004 (n = 7,168).

PREDICTOR

Candidate items for the self-assessment tool were collected using a combination of interviewer- and self-administered questionnaires.

OUTCOME

Albuminuria was defined as a urinary albumin to urinary creatinine ratio ≥30 mg/g in spot samples.

RESULTS

8 items were included in the self-assessment tool (age, race, sex, current smoking, self-rated health, and self-reported history of diabetes, hypertension, and stroke). These items provided a C statistic of 0.709 (95% CI, 0.699-0.720) and good model fit (Hosmer-Lemeshow χ(2)P = 0.49). In the external validation data set, the C statistic for discriminating individuals with and without albuminuria using the self-assessment tool was 0.714. Using a threshold of ≥10% probability of albuminuria from the self-assessment tool, 36% of US adults 45 years or older in NHANES 1999-2004 would test positive and be recommended for screening. Sensitivity, specificity, and positive and negative predictive values for albuminuria associated with a probability ≥10% were 66%, 68%, 23%, and 93%, respectively.

LIMITATIONS

Repeated urine samples were not available to assess the persistency of albuminuria.

CONCLUSIONS

8 self-report items provide good discrimination for the probability of having albuminuria. This tool may encourage individuals with a high probability to request albuminuria screening.

Ethnic differences in hypertension incidence among middle-aged and older adults: the multi-ethnic study of atherosclerosis

The prevalence of hypertension is higher among blacks than whites. However, inconsistent findings have been reported on the incidence of hypertension among middle-aged and older blacks and whites, and limited data are available on the incidence of hypertension among Hispanics and Asians in the United States. Therefore, this study investigated the age-specific incidence of hypertension by ethnicity for 3146 participants from the Multi-Ethnic Study of Atherosclerosis. Participants, age 45 to 84 years at baseline, were followed for a median of 4.8 years for incident hypertension, defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or the initiation of antihypertensive medications. The crude incidence rate of hypertension, per 1000 person-years, was 56.8 for whites, 84.9 for blacks, 65.7 for Hispanics, and 52.2 for Chinese. After adjustment for age, sex, and study site, the incidence rate ratio (IRR) for hypertension was increased for blacks age 45 to 54 (IRR: 2.05 [95%CI: 1.47 to 2.85]), 55 to 64 (IRR: 1.63 [95% CI: 1.20 to 2.23]), and 65 to 74 years (IRR: 1.67 [95% CI: 1.21 to 2.30]) compared with whites but not for those 75 to 84 years of age (IRR: 0.97 [95% CI: 0.56 to 1.66]). Additional adjustment for health characteristics attenuated these associations. Hispanic participants also had a higher incidence of hypertension compared with whites; however, hypertension incidence did not differ for Chinese and white participants. In summary, hypertension incidence was higher for blacks compared with whites between 45 and 74 years of age but not after age 75 years. Public health prevention programs tailored to middle-aged and older adults are needed to eliminate ethnic disparities in incident hypertension.

Coffee consumption and incidence of heart failure in women

BACKGROUND

Previous studies of the relationship between coffee consumption and incidence of heart failure (HF) have not been consistent, with both potential benefit and potential harm reported. We therefore examined the association between coffee consumption and HF hospitalization or mortality in women.

METHODS AND RESULTS

We conducted a prospective, observational study of 34 551 participants of the Swedish Mammography Cohort who were 48 to 83 years old and did not have HF, diabetes, or myocardial infarction at baseline. Diet was measured using food-frequency questionnaires. Cox models were used to calculate hazard ratios of HF hospitalization or death from HF as the primary cause, as determined through the Swedish inpatient and cause-of-death registers between January 1, 1998, and December 31, 2006. Over 9 years of follow-up, 602 HF events occurred. Women who consumed ≥5 cups of coffee per day did not have higher rates of HF events than those who consumed <5 cups per day (multivariable-adjusted hazard ratio, 0.93; 95% confidence interval, 0.72 to 1.20). Compared with women who consumed ≤1 cup of coffee per day, hazard ratios were 1.01, 0.82, 0.94, and 0.87 for women who consumed 2, 3, 4, and ≥5 cups per day, respectively (P for trend=0.23). Further adjustment for self-reported hypertension did not change the results.

CONCLUSIONS

In this population of middle-aged and older women, we did not find an association between coffee consumption and incidence of HF events.

Acute kidney injury reduces survival in very low birth weight infants

Acute kidney injury (AKI) independently predicts mortality in children and adults. Our understanding of the epidemiology of AKI in very LBW (VLBW) infants is limited to retrospective studies. After adjustment for demographics, comorbidities, and interventions, infants with AKI have decreased survival compared with those without AKI. The study was conducted in regional quaternary care NICU of the University of Alabama at Birmingham. VLBW infants were followed prospectively and were classified into a serum creatinine (SCr)-based classification for AKI. Forty-one of 229 (18%) VLBW infants developed AKI. Those with AKI were more likely to have umbilical artery catheters, assisted ventilation, blood pressure medications, and lower 1-and 5-min Apgar scores. Of the infants with AKI, 17 of 41 (42%) died compared with 9 of 188 (5%) of those without AKI (p < 0.001). AKI was associated with mortality with a crude hazard ratio (HR) of 9.3 (95% CI, 4.1-21.0). After adjusting for potential confounders, those with AKI had higher chance of death as the adjusted HR was 2.4 (95% CI 0.95-6.04). AKI is associated with mortality in VLBW infants. Efforts to prevent and ameliorate the impact of AKI may improve the outcomes in this vulnerable population.

Physical activity and onset of acute ischemic stroke: the stroke onset study

Regular physical activity is known to decrease the risk of cardiovascular disease, but the risk of ischemic stroke immediately following moderate or vigorous physical activity remains unclear. The authors evaluated the risk of acute ischemic stroke immediately following physical activity and examined whether the risk was modified by regular physical activity. In a multicenter case-crossover study, the authors interviewed 390 ischemic stroke patients (209 men, 181 women) at 3 North American hospitals between January 2001 and November 2006. Physical activity during the hour before stroke symptoms arose was compared with usual frequency of physical activity over the prior year. Of the 390 subjects, 21 (5%) reported having engaged in moderate or vigorous physical activity during the hour before ischemic stroke onset, and 6 subjects had lifted an object weighing at least 50 pounds (≥23 kg) during that hour. The rate ratio for ischemic stroke was 2.3 (95% confidence interval (CI): 1.5, 3.7; P < 0.001) for moderate or vigorous physical activity in the previous hour and 2.6 (95% CI: 1.1, 5.9; P = 0.02) for lifting 50 pounds or more. People who reported engaging in moderate or vigorous physical activity at least 3 times per week experienced a 2-fold increased risk (95% CI: 1.2, 3.3) with each bout of physical activity, as compared with a 6.8-fold risk (95% CI: 2.5, 18.8) among more sedentary subjects (P for homogeneity = 0.03).

Invited commentary: dietary fiber, estradiol, and cholesterol

The limitations of examining mediating factors by adjusting for them in standard regression models have been well-documented in the literature. Although alternative analytic models have been suggested, they are rarely used. In the accompanying article, Mumford et al. (Am J Epidemiol. 2010;173(2):145-156) use marginal structural linear mixed models to determine the association between dietary fiber intake and cholesterol through pathways that do not involve estradiol. Their findings suggest that overall high fiber intake decreases levels of total and low density lipoprotein (LDL) cholesterol and that there are multiple pathways through which fiber can act. The estradiol-mediated pathway seems to lead to increases in total and LDL cholesterol which are more than counterbalanced by pathways leading to decreases in total and LDL cholesterol. In addition to answering a scientifically interesting question, this work provides a concrete example of the use of marginal structural models for examination of direct effects and may serve as a guide to future researchers.

Multivitamin use and the risk of myocardial infarction: a population-based cohort of Swedish women

BACKGROUND

Dietary supplements are widely used in industrialized countries.

OBJECTIVE

The objective was to examine the association between multivitamin use and myocardial infarction (MI) in a prospective, population-based cohort of women.

DESIGN

The study included 31,671 women with no history of cardiovascular disease (CVD) and 2262 women with a history of CVD aged 49-83 y from Sweden. Women completed a self-administered questionnaire in 1997 regarding dietary supplement use, diet, and lifestyle factors. Multivitamins were estimated to contain nutrients close to recommended daily allowances: vitamin A (0.9 mg), vitamin C (60 mg), vitamin D (5 μg), vitamin E (9 mg), thiamine (1.2 mg), riboflavin (1.4 mg), vitamin B-6 (1.8 mg), vitamin B-12 (3 μg), and folic acid (400 μg).

RESULTS

During an average of 10.2 y of follow-up, 932 MI cases were identified in the CVD-free group and 269 cases in the CVD group. In the CVD-free group, use of multivitamins only, compared with no use of supplements, was associated with a multivariable-adjusted hazard ratio (HR) of 0.73 (95% CI: 0.57, 0.93). The HR for multivitamin use together with other supplements was 0.70 (95% CI: 0.57, 0.87). The HR for use of supplements other than multivitamins was 0.93 (95% CI: 0.81, 1.08). The use of multivitamins for ≥5 y was associated with an HR of 0.59 (95% CI: 0.44, 0.80). In the CVD group, use of multivitamins alone or together with other supplements was not associated with MI.

CONCLUSIONS

The use of multivitamins was inversely associated with MI, especially long-term use among women with no CVD. Further prospective studies with detailed information on the content of preparations and the duration of use are needed to confirm or refute our findings.

Low hemoglobin A1c and risk of all-cause mortality among US adults without diabetes

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.

Prospective population studies of incident heart failure without data on baseline left ventricular ejection fraction

INTRODUCTION

Left ventricular ejection fraction (LVEF) is a predictor of incident heart failure (HF). However, baseline LVEF is often unavailable in population studies of HF. METERIAL AND METHODS: Of the 5324 Cardiovascular Health Study (CHS) participants free of baseline HF, 143 (3%) had LVEF < 45% and 1091 (21%) developed HF during 13 years of follow-up. Using public-use copies of the CHS data, we compared two predictor models of incident HF, with and without adjustment for baseline LVEF.

RESULTS

Baseline impaired LVEF was a strong independent predictor of incident HF (adjusted hazard ratio, 2.78; P < 0.001) but had no impact on the direction, magnitude or significance of independent associations of the other predictors of incident HF such as age, sex, race, coronary artery disease, hypertension and diabetes.

CONCLUSION

Baseline LVEF is an important predictor for incident HF but is not essential in population studies of risk factors for incident HF.

Chocolate intake and incidence of heart failure: a population-based prospective study of middle-aged and elderly women

BACKGROUND

Randomized clinical trials have shown that chocolate intake reduces systolic and diastolic blood pressure, and observational studies have found an inverse association between chocolate intake and cardiovascular disease. The aim of this study was to investigate the association between chocolate intake and incidence of heart failure (HF).

METHODS AND RESULTS

We conducted a prospective cohort study of 31,823 women aged 48 to 83 years without baseline diabetes or a history of HF or myocardial infarction who were participants in the Swedish Mammography Cohort. In addition to answering health and lifestyle questions, participants completed a food-frequency questionnaire. Women were followed from January 1, 1998, through December 31, 2006, for HF hospitalization or death through the Swedish inpatient and cause-of-death registers. Over 9 years of follow-up, 419 women were hospitalized for incident HF (n=379) or died of HF (n=40). Compared with no regular chocolate intake, the multivariable-adjusted rate ratio of HF was 0.74 (95% CI, 0.58 to 0.95) for women consuming 1 to 3 servings of chocolate per month, 0.68 (95% CI, 0.50 to 0.93) for those consuming 1 to 2 servings per week, 1.09 (95% CI, 0.74 to 1.62) for those consuming 3 to 6 servings per week, and 1.23 (95% CI, 0.73 to 2.08) for those consuming ≥1 servings per day (P=0.0005 for quadratic trend).

CONCLUSIONS

In this population, moderate habitual chocolate intake was associated with a lower rate of HF hospitalization or death, but the protective association was not observed with intake of ≥1 servings per day.

The effect of rest days on injury rates

Despite the importance of recuperation, few have studied the impact of rest periods on injury prevention. We determined the effect of rest days (breaks) on injury rates and treatments using electronic injury records from an acrobatic circus company that employs former world-class athletes as acrobats. To account for accumulated fatigue, we considered breaks across SD3 (third consecutive week of 1-day rest) to SD6 as a single exposure level (SD3-6), and vacation and DD (2-day rest) as a single exposure level. Medical attention injury rates were increased post- vs pre-break {rate ratio 1.45 [95% confidence intervals (95% CI): 1.22-1.73]} with less of an effect for 1-day time loss [1.25 (95% CI: 0.58-2.67)] and 15-day time loss [1.10 (95% CI: 0.26-4.56)]. However, the increase in injury rate post break for SD3-6 was similar to that of DD-Vacation (P=0.48, 0.53, and 0.65) for medical attention, and both ≥1 day and ≥15 days time loss, respectively. The increase in the number of treatments post-break was less for SD3-6 vs DD-vacation. Our findings suggest that 2-day breaks every four to 6 weeks may be sufficient to avoid an increasing injury rate due to cumulative fatigue in professional acrobatic circus artists.

Dietary calcium and magnesium intake and mortality: a prospective study of men

The authors examined the association of dietary calcium and magnesium intake with all-cause, cardiovascular disease (CVD), and cancer mortality among 23,366 Swedish men, aged 45-79 years, who did not use dietary supplements. Cox proportional hazards regression models were used to estimate the multivariate hazard ratios and 95% confidence intervals of mortality. From baseline 1998 through December 2007, 2,358 deaths from all causes were recorded in the Swedish population registry; through December 2006, 819 CVD and 738 cancer deaths were recorded in the Swedish cause-of-death registry. Dietary calcium was associated with a statistically significant lower rate of all-cause mortality (hazard ratio (HR) = 0.75, 95% confidence interval (CI): 0.63, 0.88; P(trend) < 0.001) and a nonsignificantly lower rate of CVD (HR = 0.77, 95% CI: 0.58, 1.01; P(trend) = 0.064) but not cancer mortality (HR = 0.87, 95% CI: 0.65, 1.17; P(trend) = 0.362) when the highest intake tertile (mean = 1,953 mg/day; standard deviation (SD), 334) was compared with the lowest (990 mg/day; SD, 187). Dietary magnesium intake (means of tertiles ranged from 387 mg/day (SD, 31) to 523 mg/day (SD, 38) was not associated with all-cause, CVD, or cancer mortality. This population-based, prospective study of men with relatively high intakes of dietary calcium and magnesium showed that intake of calcium above that recommended daily may reduce all-cause mortality.

Fatty fish, marine omega-3 fatty acids and incidence of heart failure

Background

Marine omega-3 fatty acids have beneficial effects on cardiovascular risk factors. Consumption of fatty fish and marine omega-3 has been associated with lower rates of cardiovascular diseases.

Objective

We examined the association of fatty fish and marine omega-3 with heart failure (HF) in a population of middle-age and older women.

Methods

Participants in the Swedish Mammography Cohort aged 48–83 years completed 96-item food-frequency questionnaires. Women without history of HF, myocardial infarction, or diabetes at baseline (n= 36 234) were followed from January 1, 1998 until December 31, 2006 for HF hospitalization or mortality through Swedish inpatient and cause-of-death registers; 651 women experienced HF events. Cox proportional hazards models accounting for age and other confounders were used to calculate incidence rate ratios (RR) and 95% confidence intervals (CI).

Results

Compared to women who did not eat fatty fish, RR were 0.86 (95% CI: 0.67, 1.10) for <1 serving/week, 0.80 (95% CI: 0.63, 1.01) for 1 serving/week, 0.70 (95% CI: 0.53, 0.94) for 2 servings/week, and 0.91 (95% CI: 0.59, 1.40) for ≥3 servings/week (P_trend = 0.049). RR across quintiles of marine omega-3 fatty acids were 1 (reference), 0.85 (95% CI: 0.67, 1.07), 0.79 (95% CI: 0.61, 1.02), 0.83 (95% CI 0.65, 1.06), and 0.75 (95% CI: 0.58, 0.96) (P_trend = 0.04).

Conclusion

Moderate consumption of fatty fish (one to two servings per week) and marine omega-3 fatty acids were associated with a lower rate of first HF hospitalization or death in this population.

Dietary glycemic index, dietary glycemic load, and incidence of heart failure events: a prospective study of middle-aged and elderly women

OBJECTIVE

Dietary glycemic index (GI) and glycemic load (GL), measures of the propensity of dietary carbohydrate to increase blood glucose, have been associated with risk of coronary heart disease, but their association with incidence of heart failure (HF) is unknown. The authors therefore assessed whether dietary GI and GL were associated with rates of HF events.

METHODS

The authors conducted a prospective, observational study of 36,019 women 48-83 years old without baseline HF, diabetes, or myocardial infarction who were participants in the Swedish Mammography Cohort, a prospective cohort study. Diet was measured using food-frequency questionnaires. Women were followed from January 1, 1998, through December 31, 2006, for HF hospitalization or death through the Swedish inpatient and cause-of-death registers. Cox proportional hazards models adjusted for age and other risk factors were used to estimate incidence rate ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

Over 9 years of follow-up, 639 of 36,019 women died of HF (n = 54) or were hospitalized for HF for the first time (n = 585). The authors did not find statistically significant associations between dietary GI and HF events (RR comparing highest to lowest quartile = 1.12, 95% CI = 0.87-1.45, p for trend = 0.31) or between dietary GL and HF events (RR comparing highest to lowest quartile = 1.30, 95% CI = 0.87-1.93, p for trend = 0.16). Results were not significantly different in normal weight and overweight women.

CONCLUSIONS

In this population, dietary GI did not appear to be associated with incident HF events. There was a suggestion of an association between dietary GL and HF, which did not reach statistical significance.

Relation of consistency with the dietary approaches to stop hypertension diet and incidence of heart failure in men aged 45 to 79 years

The Dietary Approaches to Stop Hypertension (DASH) diet reduces blood pressure, and consistency with the DASH diet has been associated with lower rates of heart failure (HF) in women. We examined the association between consistency with the DASH diet and rates of HF hospitalization or mortality in 38,987 participants in the Cohort of Swedish Men aged 45 to 79 years. The diet was measured using food-frequency questionnaires, and scores were created to assess the consistency with DASH by ranking the intake of the DASH diet components. Cox models were used to calculate the rate ratios of HF (807 incident cases) determined through the Swedish in-patient and cause-of-death registers from January 1, 1998 to December 31, 2006. In multivariate-adjusted analyses, men in the greatest quartile of the DASH component score had a 22% lower rate of HF events than those in the lowest quartile (95% confidence interval 5% to 35%, p for trend = 0.006). In conclusion, greater consistency with the DASH diet was associated with lower rates HF events in men aged 45 to 79 years.

Coffee consumption and risk of heart failure in men: an analysis from the Cohort of Swedish Men

BACKGROUND

A previous study found that consuming 5 or more cups of coffee per day was associated with increased incidence of heart failure (HF). We sought to evaluate this association in a larger population.

METHODS

We measured coffee consumption using food frequency questionnaires among 37,315 men without history of myocardial infarction, diabetes, or HF. They were observed for HF hospitalization or mortality from January 1, 1998, until December 31, 2006, using record linkage to the Swedish inpatient and cause of death registries. Cox proportional hazards models adjusted for age, dietary, and demographic factors were used to calculate incidence rate ratios (RR) and 95% confidence intervals (CIs).

RESULTS

For 9 years of follow-up, 784 men experienced an HF event. Compared to men who drank <or=1 cup of coffee per day (unadjusted rate 29.9 HF events/10,000 person-years), RR were 0.87 (95% CI 0.69-1.11, unadjusted rate 29.2/10,000 person-years) for 2 cups/d, 0.89 (95% CI 0.70-1.14, unadjusted rate 25.1/10,000 person-years) for 3 cups/d, 0.89 (95% CI 0.69-1.15, unadjusted rate 25.0/10,000 person-years) for 4 cups/d, and 0.89 (95% CI 0.69-1.15, unadjusted rate 18.1/10,000 person-years) for >or=5 cups/d (P for trend in RR = .61).

CONCLUSIONS

This study did not support the hypothesis that high coffee consumption is associated with increased rates of HF hospitalization or mortality.

Effects of myostatin deletion in aging mice

Inhibitors of myostatin, a negative regulator of skeletal muscle mass, are being developed to mitigate aging-related muscle loss. Knock-out (KO) mouse studies suggest myostatin also affects adiposity, glucose handling and cardiac growth. However, the cardiac consequences of inhibiting myostatin remain unclear. Myostatin inhibition can potentiate cardiac growth in specific settings (Morissette et al., 2006), a concern because of cardiac hypertrophy is associated with adverse clinical outcomes. Therefore, we examined the systemic and cardiac effects of myostatin deletion in aged mice (27-30 months old). Heart mass increased comparably in both wild-type (WT) and KO mice. Aged KO mice maintained twice as much quadriceps mass as aged WT; however, both groups lost the same percentage (36%) of adult muscle mass. Dual-energy X-ray absorptiometry revealed increased bone density, mineral content, and area in aged KO vs. aged WT mice. Serum insulin and glucose levels were lower in KO mice. Echocardiography showed preserved cardiac function with better fractional shortening (58.1% vs. 49.4%, P = 0.002) and smaller left ventricular diastolic diameters (3.41 vs. 2.71, P = 0.012) in KO vs. WT mice. Phospholamban phosphorylation was increased 3.3-fold in KO hearts (P < 0.05), without changes in total phospholamban, sarco(endo)plasmic reticulum calcium ATPase 2a or calsequestrin. Aged KO hearts showed less fibrosis by Masson's Trichrome staining. Thus, myostatin deletion does not affect aging-related increases in cardiac mass and appears beneficial for bone density, insulin sensitivity and heart function in senescent mice. These results suggest that clinical interventions designed to inhibit skeletal muscle mass loss with aging could have beneficial effects on other organ systems as well.

Consistency with the DASH diet and incidence of heart failure

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet effectively reduces blood pressure. In observational studies, the association between diets consistent with DASH and risk of coronary heart disease and stroke has been examined with varying results. We hypothesized that diets consistent with the DASH diet would be associated with a lower incidence of heart failure (HF).

METHODS

We conducted a prospective observational study in 36 019 participants in the Swedish Mammography Cohort who were aged 48 to 83 years and without baseline HF, diabetes mellitus, or myocardial infarction. Diet was measured using food-frequency questionnaires. We created a score to assess consistency with the DASH diet by ranking the intake of DASH diet components and 3 additional scores based on food and nutrient guidelines. Cox proportional hazards models were used to calculate rate ratios of HF-associated hospitalization or death, determined using the Swedish inpatient and cause-of-death registers between January 1, 1998, and December 31, 2004.

RESULTS

During 7 years, 443 women developed HF. Women in the top quartile of the DASH diet score based on ranking DASH diet components had a 37% lower rate of HF after adjustment for age, physical activity, energy intake, education status, family history of myocardial infarction, cigarette smoking, postmenopausal hormone use, living alone, hypertension, high cholesterol concentration, body mass index (calculated as weight in kilograms divided by height in meters squared), and incident myocardial infarction. Rate ratios (95% confidence intervals) across quartiles were 1 [Reference], 0.85 (0.66-1.11), 0.69 (0.54-0.88), and 0.63 (0.48-0.81); P(trend) < .001. A similar pattern was seen for the guideline-based scores.

CONCLUSION

In this population, diets consistent with the DASH diet are associated with lower rates of HF.

Fish consumption, marine omega-3 fatty acids, and incidence of heart failure: a population-based prospective study of middle-aged and elderly men

AIMS

Fatty fish and marine omega-3 fatty acids were associated with lower rates of heart failure (HF) among US elderly, but this has not been confirmed in broader age ranges or other populations where source and type of fish may differ. We therefore conducted a population-based, prospective study of 39 367 middle-aged and older Swedish men.

METHODS AND RESULTS

Diet was measured using food-frequency questionnaires. Men were followed for HF through Swedish inpatient and cause-of-death registers from 1 January 1998 to 31 December 2004. We used proportional hazards models adjusted for age and other covariates to estimate hazard ratios (HR). Compared with no consumption, men who ate fatty fish once per week had an HR of 0.88 (95% CI 0.68-1.13). Hazard ratios for consumption two times per week and > or =3 times per week were 0.99 and 0.97, respectively. Hazard ratios across quintiles of marine omega-3 were 1, 0.94 (95% CI 0.74-1.20), 0.67 (95% CI 0.50-0.90), 0.89 (95% CI 0.68-1.16), 1.00 (95% CI 0.77-1.29).

CONCLUSION

In this population, moderate intake of fatty fish and marine omega-3 fatty acids was associated with lower rates of HF, though the association for fish intake was not statistically significant; higher intake was not associated with additional benefit.

Renal function predicts survival in patients with acute ischemic stroke

BACKGROUND

Among patients with acute ischemic stroke, impaired kidney function has been shown to increase the mortality risk, but the shape of this relationship has not been evaluated in detail.

METHODS

We estimated the glomerular filtration rate (eGFR) at the time of hospitalization in 1,175 consecutive patients hospitalized with acute ischemic stroke at the Beth Israel Deaconess Medical Center and examined the shape of the association between eGFR and all-cause mortality.

RESULTS

There were 508 deaths during a median follow-up of 40.3 months, resulting in a 'U'-shaped relationship between eGFR and all-cause mortality. The curve was relatively flat between 75 and 110 ml/min/1.73 m(2) but increased sharply at lower and higher levels of eGFR (test for nonlinearity: p < 0.0001).

CONCLUSIONS

Among patients with acute ischemic stroke, a reduced or highly elevated eGFR at hospital admission is associated with a higher mortality rate compared to patients with moderate levels of eGFR.

Adiposity and incidence of heart failure hospitalization and mortality: a population-based prospective study

BACKGROUND

Obesity is associated with heart failure (HF) incidence. We examined the strength of the association of body mass index (BMI) with HF by age and joint associations of BMI and waist circumference (WC).

METHODS AND RESULTS

Women aged 48 to 83 (n=36873) and men aged 45 to 79 (n=43487) self-reported height, weight, and WC. HF hospitalization or death (n=382 women, 718 men) between January 1, 1998, and December 31, 2004, was determined through administrative registers. Hazard ratios, from Cox proportional-hazards models, for an interquartile range higher BMI were 1.39 (95% CI, 1.15 to 1.68) at age 60 and 1.13 (95% CI, 1.02 to 1.27) at 75 in women. In men, hazard ratios were 1.54 (95% CI, 1.37 to 1.73) at 60 and 1.25 (95% CI, 1.16 to 1.35) at 75. A 10-cm higher WC was associated with 15% (95% CI, 2% to 31%) and 18% (95% CI, 4% to 33%) higher HF rates among women with BMI 25 and 30 kg/m(2), respectively; hazard ratios for 1 kg/m(2) higher BMI were 1.00 (95% CI, 0.96 to 1.04) and 1.01 (95% CI, 0.98 to 1.04) for WC 70 and 100 cm, respectively. In men, a 10-cm higher WC was associated with 16% and 18% higher rates for BMI 25 and 30 kg/m(2), respectively; a 1 kg/m(2) higher BMI was associated with 4% higher HF rates regardless of WC.

CONCLUSIONS

Strength of the association between BMI and HF events declined with age. In women, higher WC was associated with HF at all levels of BMI. Both BMI and WC were predictors among men.

Pooled analysis of patients with thunderclap headache evaluated by CT and LP: is angiography necessary in patients with negative evaluations?

BACKGROUND

Severe, abrupt onset headache raises concern for aneurysmal subarachnoid hemorrhage (SAH). The current standard work-up is brain CT scan followed by LP if the CT is non-diagnostic in patients with a normal neurological exam. Some have suggested that angiography is also indicated in this common clinical situation. Is evaluation with brain CT and LP for thunderclap headache to rule out SAH sufficient and is angiography needed?

METHODS

We systematically searched for studies that followed neurologically-intact patients with thunderclap headache and normal CT and LP for at least 1 year. The primary outcome was SAH. We estimated the proportion of patients who developed SAH and the one-sided upper 95% confidence bound.

RESULTS

Seven studies including 813 patients were identified. None of the patients developed SAH during follow-up (pooled proportion=0, upper 95% confidence bound=0.004).

CONCLUSION

Although our methods have important limitations, we believe that this analysis will give clinicians better tools to decide whether or not to pursue further work-up with angiography in patients with thunderclap headache and normal neurological exam, CT, and LP.

Meta-analysis of the placebo response in ulcerative colitis

PURPOSE

The placebo response rate in randomized controlled trials (RCTs) in ulcerative colitis (UC) varies from 0 to 76%. The aims of this study were to quantify the pooled placebo response rate and identify the factors affecting it.

METHODS

We performed a meta-analysis of 110 RCTs carried out between 1955 and 2005 and published in English. Regression analysis was used to identify factors significantly modifying placebo response.

RESULTS

The pooled placebo remission rate was 23% (95%CI: 18.4-28%) and the pooled placebo improvement rate was 32.1% (95%CI: 28.1-36.3%). Multivariate analysis showed that the country where the study was performed (P = 0.025 for placebo remission and P = 0.0083 for placebo response rates) significantly influenced the placebo remission and response rates.

CONCLUSION

Placebo remission and response rates in RCTs of UC are highly variable and are significantly influenced by the country in which the RCT is performed.

Dietary glycemic index, dietary glycemic load, blood lipids, and C-reactive protein

Carbohydrate quantity and quality may influence the risk of cardiovascular disease through blood lipid concentrations and inflammation. We measured dietary glycemic index (GI) and dietary glycemic load (GL) among 18137 healthy women > or = 45 years old without diagnosed diabetes using a food-frequency questionnaire. We assayed fasting total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol; LDL/HDL cholesterol ratio; triacylglycerols (TG); and C-reactive protein (CRP). We evaluated associations with dietary GI and GL using a cross-sectional design, adjusting for age, body mass index, lifestyle factors, and other dietary factors. Dietary GI was significantly associated with HDL and LDL cholesterol, LDL/HDL cholesterol ratio, TG, and CRP (comparing top to bottom quintile difference in HDL cholesterol = -2.6 mg/dL, LDL cholesterol = 2.2 mg/dL, LDL/HDL cholesterol ratio = 0.16, TG = 12 mg/dL, and CRP = 0.21 mg/L). Dietary GL was associated with HDL cholesterol, LDL/HDL cholesterol ratio, and TG (comparing top to bottom quintile HDL cholesterol = -4.9 mg/dL, LDL/HDL cholesterol ratio = 0.24, and TG = 13 mg/dL). Differences in blood lipids and CRP between extreme quintiles of dietary GI and GL were small, but may translate into a clinically meaningful difference in cardiovascular risk.

HbA1c measured in stored erythrocytes and mortality rate among middle-aged and older women

AIMS/HYPOTHESIS

Diabetes is known to increase mortality rate, but the degree to which mild hyperglycaemia may be associated with the risk of death is uncertain. We examined the association between HbA1c measured in stored erythrocytes and mortality rate in women with and without diabetes.

METHODS

We conducted a cohort study of 27,210 women>or=45 years old with no history of cardiovascular disease or cancer who participated in the Women's Health Study, a randomised trial of vitamin E and aspirin.

RESULTS

Over a median of 10 years of follow-up, 706 women died. Proportional hazards models adjusted for age, smoking, hypertension, blood lipids, exercise, postmenopausal hormone use, multivitamin use and C-reactive protein were used to estimate the relative risk of mortality. Among women without a diagnosis of diabetes and HbA1c<5.60%, those in the top quintile (HbA1c 5.19-5.59%) had a relative risk of mortality of 1.28 (95% CI 0.98-1.69, p value for linear trend=0.14) compared with those with HbA1c 2.27-4.79%. Women with HbA1c 5.60-5.99% and no diagnosis of diabetes had a 54% increased risk of mortality (95% CI 1-136%) compared with those with HbA1c 2.27-4.79%. HbA1c was significantly associated with mortality across the range 4.50-7.00% (p value for linear trend=0.02); a test of deviation from linearity was not statistically significant (p=0.67). Diabetic women had more than twice the mortality risk of non-diabetic women.

CONCLUSIONS/INTERPRETATION

This study provides further evidence that chronic mild hyperglycaemia, even in the absence of diagnosed diabetes, is associated with increased risk of mortality. ClinicalTrials.gov ID no.: NCT00000479.

Dietary glycemic index, dietary glycemic load and mortality among men with established cardiovascular disease

BACKGROUND/OBJECTIVES

In men with established cardiovascular disease, the effect of diets with high glycemic index (GI) and glycemic load (GL) is unknown. We tested the hypothesis that diets with higher GI and GL are associated with increased mortality in men with established cardiovascular disease.

SUBJECTS/METHODS

We measured dietary GI and GL using food-frequency questionnaires in 4617 men, 45-79 years old, with a history of cardiovascular disease. The men were followed for cardiovascular mortality (6-year follow-up, 608 cases) and all-cause mortality (8-year follow-up, 1303 cases) using the Swedish cause-of-death and death registers. We used Cox models with age as the timescale and adjusted for body mass index, physical activity, history of hypertension and diabetes, family history of myocardial infarction, aspirin use, cigarette smoking and dietary factors to estimate incidence rate ratios (RRs).

RESULTS

Comparing top to bottom quartiles of dietary GI, the RR for cardiovascular mortality was 0.86 (95% confidence interval (CI) 0.67-1.10, P for linear trend=0.21), and the RR for all-cause mortality was 1.00 (95% CI 0.85-1.19, P for linear trend=0.87). Compared to quartile 1, the RR for men with dietary GL in quartile 4 was 1.02 (95% CI 0.70-1.49, P for linear trend=0.81) for cardiovascular and 1.15 (95% CI 0.89-1.49, P for linear trend=0.20) for all-cause mortality.

CONCLUSIONS

In this population of men with prior cardiovascular disease, dietary GI and GL were not associated with cardiovascular or all-cause mortality.

Dietary glycemic index, dietary glycemic load, and cardiovascular disease in middle-aged and older Swedish men

BACKGROUND

In women, dietary glycemic index (GI) and dietary glycemic load (GL) have been associated with cardiovascular disease; in men, however, the evidence for an association is weaker.

OBJECTIVE

We tested the hypothesis that men consuming diets high in GI or GL have a greater risk of cardiovascular disease.

DESIGN

At baseline, we assessed dietary GI and dietary GL by using food-frequency questionnaires in 36 246 Swedish men aged 45-79 y without diabetes or prior cardiovascular disease. Participants were followed through inpatient, cause-of-death, and death registries from 1 January 1998 until 31 December 2003 for myocardial infarction, ischemic stroke, hemorrhagic stroke, and cardiovascular mortality and until 31 December 2005 for all-cause mortality. We used Cox models with age as the time scale to estimate relative risks adjusted for cigarette smoking, body mass index, physical activity, demographic characteristics, and nutritional factors.

RESULTS

Dietary GI and dietary GL were not associated with myocardial infarction (n = 1324), ischemic stroke (n = 692), cardiovascular mortality (n = 785), or all-cause mortality (n = 2959). Dietary GL was associated with hemorrhagic stroke [n = 165; relative risk = 1.44 comparing extreme quartiles (95% CI: 0.91, 2.27); P for trend = 0.047].

CONCLUSIONS

Dietary GI and dietary GL were not associated with ischemic cardiovascular disease or mortality, but dietary GL was associated with a greater risk of hemorrhagic stroke. Discrepancies between these findings and those of previous studies may be due to variations in the associations by sex or to differences in dietary contributions to GI and GL.

Reproducibility and validity of dietary glycemic index, dietary glycemic load, and total carbohydrate intake in 141 Swedish men

BACKGROUND

Although the associations of dietary glycemic index (GI) and dietary glycemic load (GL) with many chronic diseases have been examined in epidemiologic studies, information regarding the reproducibility and validity of these measures assessed with the use of food-frequency questionnaires (FFQs) is lacking.

OBJECTIVE

We examined the reproducibility and validity of dietary GI and dietary GL and of carbohydrate intake as assessed by using an FFQ.

DESIGN

Swedish men (n = 141) aged 40-74 y completed 2 FFQs 1 y apart and two 1-wk weighed diet records 6 mo apart. Dietary GI, dietary GL, and carbohydrate intake (starches and sugars) were calculated from both FFQs and diet records. We used intraclass correlations between the 2 FFQs to measure reproducibility and Pearson correlations between the diet records and the FFQs to assess the relative validity.

RESULTS

Reproducibility of the FFQs was 0.66 (95% CI: 0.56, 0.75) for dietary GI, 0.61 (95% CI: 0.50, 0.71) for dietary GL, and 0.61 (95% CI: 0.50, 0.71) for carbohydrate. The correlations between the FFQs and diet records were 0.62 (95% CI: 0.45, 0.74) for dietary GI, 0.77 (95% CI: 0.56, 0.88) for dietary GL, and 0.76 (95% CI: 0.55, 0.88) for carbohydrate after adjustment for within-person variation in the FFQs and diet records.

CONCLUSION

In this sample of men, an FFQ measured dietary GI, dietary GL, and carbohydrate with reproducibility and validity similar to other commonly studied nutritional factors.

Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials

AIMS

The aim of this study was to assess the evidence on the effect of oral magnesium supplementation on glycaemic control in patients with Type 2 diabetes.

METHODS

We searched the electronic databases of medline, embase and the Cochrane Controlled Trials Register up to January 2005. We identified nine randomized double-blind controlled trials with a total of 370 patients with Type 2 diabetes and of duration 4-16 weeks. The median dose of oral magnesium supplementation was 15 mmol/day (360 mg/day) in the treatment groups. The primary outcome was glycaemic control, as measured by glycated haemoglobin (HbA(1c)) or fasting blood glucose levels; the secondary outcomes included body mass index, blood pressure (BP) and lipids. Using a random-effects model, we calculated the weighted mean differences (WMD) and 95% confidence interval (CI).

RESULTS

After a median duration of 12 weeks, the weighted mean post-intervention fasting glucose was significantly lower in the treatment groups compared with the placebo groups [-0.56 mmol/l (95% CI, -1.10 to -0.01); P for heterogeneity = 0.02]. The difference in post-intervention HbA(1c) between magnesium supplementation groups and control groups was not significant [-0.31% (95% CI, -0.81 to 0.19); P for heterogeneity = 0.10]. Neither systolic nor diastolic BP was significantly changed. Magnesium supplementation increased on high-density lipoprotein (HDL) cholesterol levels [0.08 mmol/l (95% CI, 0.03 to 0.14); P for heterogeneity = 0.36] but had no effect on total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride.

CONCLUSIONS

Oral magnesium supplementation for 4-16 weeks may be effective in reducing plasma fasting glucose levels and raising HDL cholesterol in patients with Type 2 diabetes, although the long-term benefits and safety of magnesium treatment on glycaemic control remain to be determined.

Association between consumption of beer, wine, and liquor and plasma concentration of high-sensitivity C-reactive protein in women aged 39 to 89 years

Although cross-sectional studies have shown an inverse or U-shaped relation between alcohol consumption and plasma concentration of high-sensitivity C-reactive protein (hs-CRP), the associations between specific types of alcoholic beverages--beer, wine, and liquor--and hs-CRP concentrations are less clear. Plasma concentrations of hs-CRP were measured in 11,815 participants in the Women's Health Study who had never used postmenopausal hormones. Alcohol intake was measured using a semiquantitative food-frequency questionnaire. Alcohol consumption had an inverse association with geometric mean hs-CRP concentrations (nondrinkers 1.43 mg/L, 0.1 to 6 g alcohol/day 1.37 mg/L, 6.1 to 12 g alcohol/day 1.29 mg/L, >12 g alcohol/day 1.28 mg/L, p for trend = 0.003). In age-adjusted analyses, beverage preference was a significant predictor of geometric mean hs-CRP concentration. However, after adjustment for body mass index (BMI), beer drinkers who consumed 6.1 to 12 g alcohol/day had a geometric mean hs-CRP concentration of 1.03 mg/L, wine drinkers 1.09 mg/L, liquor drinkers 1.28 mg/L, and combination drinkers 1.09 mg/L (p = 0.43). The association between alcohol and hs-CRP concentration appears to be mediated primarily by ethanol and was independent of the type of alcoholic beverage consumed once BMI was taken into account.

Is nondiabetic hyperglycemia a risk factor for cardiovascular disease? A meta-analysis of prospective studies

BACKGROUND

Although hyperglycemia increases the risk of cardiovascular disease (CVD) in diabetic patients, the risk associated with blood glucose levels in the nondiabetic range remains unsettled.

METHODS

We identified 38 reports in which CVD incidence or mortality was an end point, blood glucose levels were measured prospectively, and the relative risk (RR) and information necessary to calculate the variance were reported comparing groups of nondiabetic people. These reports were prospective studies, published in English-language journals. First author, publication year, participant age and sex, study duration, CVD end points, glucose assessment methods, control for confounding, range of blood glucose levels, RR, and confidence intervals (CIs) or P values were extracted. Using a random effects model, we calculated pooled RRs and 95% CIs.

RESULTS

The group with the highest postchallenge blood glucose level (midpoint range, 150-194 mg/dL [8.3-10.8 mmol/L]) had a 27% greater risk for CVD compared with the group with the lowest level (midpoint range, 69-107 mg/dL [3.8-5.9 mmol/L]) (RR, 1.27 [95% CI, 1.09-1.48]). The results were similar when combining studies regardless of type of blood glucose assessment (RR, 1.36 [95% CI, 1.23-1.52]) and when using strict criteria for exclusion of diabetic subjects (RR, 1.26 [95% CI, 1.11-1.43]). Adjustment for CVD risk factors attenuated but did not abolish this relationship (RR, 1.19 [95% CI, 1.07-1.32]). The RR was greater in cohorts including women than in cohorts of men (RR, 1.56 vs 1.24 [P = .03]).

CONCLUSION

Blood glucose level is a risk marker for CVD among apparently healthy individuals without diabetes.