Extent of regression dilution for established and novel coronary risk factors: results from the British Regional Heart Study

Factors Associated With Myocardial Infarction Reoccurrence

BACKGROUND

As recurrent myocardial infarctions (MIRs) constitute almost a third of the annual incidence of myocardial infarction, identifying the traditional and novel variables related to MIR is important.

OBJECTIVE

The aim of this study was to examine modifiable cardiac risks, adiposity, symptoms associated with inflammation (fatigue, depression, sleep) and inflammatory cytokines, and MIR by sex and race.

METHODS

Using a cross-sectional descriptive design, we recruited a convenience sample of adults (N = 156) discharged with first myocardial infarction or had MIR in the last 3 to 7 years. Surveys measured demographics, cardiac risk factors, depression, sleep, and fatigue. Anthropometric measures and cytokines tumor necrosis factor-α, interleukin-6, and high-sensitivity C-reactive protein (hsCRP) were obtained. A maximum likelihood regression was calculated to predict MIR.

RESULTS

The sample included 57% male and 30% Black participants, and the mean (SD) age was 65 (12) years. The hsCRP was the only cytokine related to symptoms: fatigue ( r = 0.309, P < .001) and depression ( r = 0.255, P = .002). An MIR was not associated with race despite White participants reporting better sleep ( t146 = -3.25, P = .002), lower body mass index ( t154 = -3.49, P = .001), and fewer modifiable risk factors ( t152 = -2.05, P = .04). An MIR was associated with being male, higher hsCRP and tumor necrosis factor-α levels ( P < .001), and higher inflammatory symptoms of fatigue ( P = .04), depression ( P = .01), and poor sleep ( P < .001).

CONCLUSION

Further examination of biomarkers to understand the mechanisms associated with inflammatory symptoms of fatigue, depression, and poor sleep and MIR is needed.

Association between levels of high-sensitivity C-reactive protein in plasma and freezing of gait in Parkinson's disease

This study explored the potential relationship between levels of high-sensitivity C-reactive protein (hs-CRP) in plasma and freezing of gait (FOG) in Parkinson's disease (PD) in China. A total of 72 healthy subjects, 62 PD patients with FOG, and 83 PD patients without FOG from our center were enrolled in this prospective study. Patients with FOG showed significantly higher hs-CRP levels than controls, but patients without FOG did not. Binary logistic regression analysis identified levels of hs-CRP in plasma to be an independent risk factor for FOG among the patients in our cohort (OR 6.371, 95% CI 2.589-15.678, p < 0.001). In fact, a cut-off level of 0.935 mg/L distinguished patients with or without FOG [area under the ROC curve (AUC) = 0.908, sensitivity 87.1%, specificity 89.2%]. Our study suggests that high levels of hs-CRP in plasma are associated with the occurrence of FOG in PD. The pooled data combined with a previous study carried out in Spain also indicate a positive association between plasma hs-CRP levels and FOG in PD. However, more research is still needed to verify the plasma hs-CRP as a potential biomarker of FOG.

Synergistic Impact of Body Mass Index and Cognitive Function on All-Cause Mortality in Older Adults: A Nationwide Longitudinal Study

BACKGROUND

Body mass index (BMI) and cognitive function are independent predictors of mortality risk. However, little is known about the combined impact of BMI and cognitive function on the risk of all-cause mortality in older adults. In this study, we aimed to examine the associations between BMI, cognitive function, and all-cause mortality, including between-factor interactions, in the general population of older adults in China.

METHODS

We used the data between 2011 and 2018 from the Chinese Longitudinal Healthy Longevity Survey that included adults aged ≥65 years residing in the 23 provinces of China. The association between BMI and cognitive function on all-cause mortality was examined with the Cox proportional hazards regression model.

RESULTS

The study included 8,293 Chinese older adults. Low BMI (underweight) and cognitive impairment were associated with the highest risk of death after adjustments [hazard ratio (HR) = 2.18; 95% confidence interval (CI), 1.96-2.41]; this combined effect was more prominent among adults aged <100 years and women. In addition, there was an interaction effect of BMI and cognitive impairment on all-cause mortality (P <0.001). Concurrently, among older adults with normal cognition, the risk of mortality related to underweight was higher than among their cognitively impaired counterparts [55% (normal cognition) vs. 38% (cognitive impairment)].

CONCLUSIONS

Low BMI (underweight) and cognitive impairment were independently and jointly associated with increased risk of all-cause mortality among Chinese older adults, and females showed a stronger effect in this association. The association between BMI and mortality was more pronounced in the participants with normal cognition than in their cognitively impaired counterparts.

Combined associations of hs-CRP and cognitive function with all-cause mortality among oldest-old adults in Chinese longevity areas: a prospective cohort study

BACKGROUND

Inflammatory markers, such as high sensitivity C-reactive protein (hs-CRP), and cognitive impairment (CI) are associated with mortality; CRP is related to the deterioration of CI. However, it is still unknown whether these two indices predict mortality independent of each other. Furthermore, their joint effect on all-cause mortality has not been well established, especially in oldest-old adults.

METHODS

Based on data from the 2012 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), we included 1447 oldest-old adults (mean age 84.7 years and 58.7% were female, weighted) with information on hs-CRP (stratified by a cutoff value of 3.0 mg/L) and cognition (quantified by Mini-Mental Status Examination (MMSE) scored according to the personal educational level) at baseline. Mortality was assessed in followed 2014 and 2017 waves. Cox proportional hazards regression models were used, with adjustment for hs-CRP and cognition (mutually controlled) and several traditional mortality risk factors.

RESULTS

During a median follow-up period of 32.8 months (Q1-Q3, 9.7-59.0 months), 826 participants died. Hs-CRP [HR > 3.0 mg/L vs ≤ 3.0 mg/L: 1.64 (95% CI, 1.17, 2.30)] and cognition [HR CI vs normal: 2.30 (95% CI, 1.64, 3.21)] each was independent predictor of all-cause mortality, even after accounting for each other and other covariates. Monotonic and positive associations were observed in combined analyses, in which the highest mortality risk was obtained in elders with both high hs-CRP> 3.0 mg/L and CI [HR: 3.56 (95% CI, 2.35, 5.38)].The combined effects were stronger in male and younger oldest-old (aged 80-89 years).

CONCLUSION

High hs-CRP and CI, both individually and jointly, were associated with increased all-cause mortality risks in Chinese oldest-old. Intervention strategies for preventing inflammation and maintaining adequate cognitive function may be more important in male and younger oldest-old for reducing mortality risk.

Probabilistic Quantitative Assessment of Coronary Heart Disease Risk From Dietary Exposure to Industrially Produced Trans-Fatty Acids in Partially Hydrogenated Oils

We conducted a probabilistic evaluation of changes in coronary heart disease (CHD) risk and public health burdens from industrially produced trans-fatty acids (IP-TFAs) exposure from the uses of partially hydrogenated oils in food. Our analyses used four quantitative methods based on human studies considering the uncertainty associated with risk parameters for CHD and IP-TFA daily dietary exposure of 0.05% of energy. Method 1 used experimental controlled feeding trial data for changes in low-density lipoprotein cholesterol; Method 2 used changes in both low-density lipoprotein cholesterol and high-density lipoprotein cholesterol; Method 3 used changes in a combination of three emerging CHD risk factor biomarkers; and method 4 used prospective observational studies of CHD cases associated with long-term dietary exposure of trans-fatty acids. We estimated mean percent changes in CHD risk and annual CHD cases in U.S. adults, with lower and upper 95% uncertainty intervals. Our results show that consuming 0.05% of energy from IP-TFA, instead of cis-monounsaturated fatty acids, can cause annual mean increases in CHD cases of 814 (510–1151, method 1), 1502 (990–2043, method 2), or 6877 (3611–10 694, method 4) in U.S. adults. Results for method 3 were intermediate between those for methods 2 and 4. Sensitivity analyses using alternate risk parameters or an alternate exposure scenario resulted in minor changes in public health burden estimates. The results demonstrate that IP-TFA exposure as low as 0.05% of energy from partially hydrogenated oil uses in food can cause substantial public health burdens in the United States from increased CHD risk.

Relationships between markers of inflammation and bone density: findings from the Hertfordshire Cohort Study

Among 365 Hertfordshire Cohort Study participants (aged 59-71 years at baseline), higher adiponectin and adiponectin to leptin ratios were associated with lower baseline lumbar spine and femoral neck bone mineral density (BMD). Lower IL-10 was associated with accelerated decline in lumbar spine BMD. This suggests that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.

INTRODUCTION

The aim of this study was to examine the association between indices of inflammation and BMD in a population-based cohort of older adults in the UK.

METHODS

Analyses were based on a sample of 194 men and 171 women of the Hertfordshire Cohort Study (community-living, older adults). Dual energy X-ray absorptiometry (DXA) was performed at the lumbar spine and proximal femur at baseline and repeated at a median of 4.5 years (inter-quartile range 3.6 to 5.2). Inflammatory markers (CRP, TNF, IL-1β, IL-6, IL-8, IL-10, adiponectin and leptin) were ascertained at baseline using enzyme-linked immunosorbent assay (ELISA) techniques and Bio-Plex Pro Assays. Gender-adjusted linear regression was used to examine the associations between markers of inflammation and outcomes with and without adjustment for anthropometric and lifestyle factors.

RESULTS

The mean (SD) ages at baseline were 64.4 (2.5) and 66.5 (2.7) years for men and women respectively. Higher levels of adiponectin and adiponectin to leptin ratios were each associated with lower baseline lumbar spine and femoral neck BMD in gender-adjusted (p < 0.01) and fully adjusted (p < 0.05) analyses. Lower levels of IL-10 and TNF were each associated with accelerated decline in lumbar spine BMD in both gender-adjusted (p ≤ 0.05) and fully adjusted (p < 0.05) analyses.

CONCLUSIONS

In a cohort of older adults, high levels of adiponectin and adiponectin to leptin ratios were both associated with lower BMD at the lumbar spine and femoral neck at baseline, and lower IL-10 was associated with accelerated decline in BMD at the lumbar spine. This adds weight to the theory that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.

Relationships Between Markers of Inflammation and Muscle Mass, Strength and Function: Findings from the Hertfordshire Cohort Study

We investigated the longitudinal relationships between inflammation markers and the following outcomes in a UK cohort study: appendicular lean mass (ALM); walking speed; level and change in grip strength; and sarcopenia defined by the European Working Group on Sarcopenia in Older People. Analyses were based on 336 community-dwelling older men and women (aged 59-70 years) who participated in the Hertfordshire Cohort Study (HCS). Inflammation markers were ascertained at baseline using enzyme-linked immunosorbent assay techniques and Bio-Plex Pro Assays. Grip strength was measured at baseline and follow-up [median follow-up time: 10.8 years (inter-quartile range 10.2-11.6)] and change in grip strength was ascertained using a residual change approach. At follow-up, ALM was ascertained using dual-energy X-ray absorptiometry, customary walking speed was measured and sarcopenia status was ascertained. Gender-adjusted linear and Poisson regression was used to examine the associations between inflammation markers and outcomes with and without adjustment for anthropometric and lifestyle factors. Higher C-reactive protein was associated (p < 0.04) with lower grip strength and accelerated decline in grip strength from baseline to follow-up. Higher cortisol was associated with lower ALM (p < 0.05). Higher interleukin-8 (IL-8) was associated with lower ALM (p < 0.05) and increased risk of sarcopenia [fully-adjusted relative risk per SD increase in IL-8: 1.37 (95% CI 1.10, 1.71), p = 0.005]. All associations were robust in fully-adjusted analyses. Inflammation markers were associated with measures of muscle mass, strength and function in HCS. Further work is required to replicate these associations and to delineate the underlying mechanisms.

Personalized Antidepressant Selection and Pathway to Novel Treatments: Clinical Utility of Targeting Inflammation

Major depressive disorder (MDD) is a chronic condition that affects one in six adults in the US during their lifetime. The current practice of antidepressant medication prescription is a trial-and-error process. Additionally, over a third of patients with MDD fail to respond to two or more antidepressant treatments. There are no valid clinical markers to personalize currently available antidepressant medications, all of which have similar mechanisms targeting monoamine neurotransmission. The goal of this review is to summarize the recent findings of immune dysfunction in patients with MDD, the utility of inflammatory markers to personalize treatment selection, and the potential of targeting inflammation to develop novel antidepressant treatments. To personalize antidepressant prescription, a c-reactive protein (CRP)-matched treatment assignment can be rapidly implemented in clinical practice with point-of-care fingerstick tests. With this approach, 4.5 patients need to be treated for 1 additional remission as compared to a CRP-mismatched treatment assignment. Anti-cytokine treatments may be effective as novel antidepressants. Monoclonal antibodies against proinflammatory cytokines, such as interleukin 6, interleukin 17, and tumor necrosis factor α, have demonstrated antidepressant effects in patients with chronic inflammatory conditions who report significant depressive symptoms. Additional novel antidepressant strategies targeting inflammation include pharmaceutical agents that block the effect of systemic inflammation on the central nervous system. In conclusion, inflammatory markers offer the potential not only to personalize antidepressant prescription but also to guide the development of novel mechanistically-guided antidepressant treatments.

Repeated measurements of carotid atherosclerosis and future risk of venous thromboembolism: the Tromsø Study

Essentials The relationship between atherosclerosis and venous thromboembolism (VTE) is controversial. In total, 10 426 participants recruited from the general population were included. Carotid intima media thickness and total plaque area was not associated with VTE. There was no association between plaque initiation or plaque progression and subsequent VTE.

SUMMARY

Background Whether a relationship between atherosclerosis and subsequent venous thromboembolism (VTE) exists is controversial. Objective To investigate the association between carotid atherosclerosis and VTE by using repeated measurements of intima media thickness (IMT) and total plaque area (TPA) in participants recruited from the general population. Methods Participants were recruited from the fourth (1994-1995), fifth (2001-2002) and sixth (2007-2008) surveys of the Tromsø Study. In total, 10 426 participants attended, for whom measurements of carotid IMT and TPA and potential confounders were updated at each available survey. Time-varying Cox regression models were used to calculate hazard ratios (HRs) of VTE across various levels of IMT and TPA adjusted for age, sex, and body mass index. Results There were 368 incident VTE events during a median follow-up of 10.8 years. Participants with increasing IMT were, on average, older and had a less favorable cardiovascular risk profile. There was no association between tertiles of increasing TPA and the risk of VTE in the time-varying model, and increasing IMT was not associated with an increased risk of VTE (HR 0.96, 95% confidence interval [CI] 0.86-1.07). Neither plaque formation nor plaque progression was associated with the risk of VTE (respectively: HR 1.00, 95% CI 0.98-1.02; and HR 0.96, 95% CI 0.84-1.11). Conclusion Carotid IMT and TPA were not associated with an increased risk of VTE in time-varying analyses. Furthermore, there was no association between plaque initiation or plaque progression and subsequent VTE.

Can C-reactive protein inform antidepressant medication selection in depressed outpatients? Findings from the CO-MED trial

OBJECTIVE

Currently, no valid measures inform treatment selection for depressed patients. Whether C-reactive protein (CRP) in particular and two other acute phase reactants (inflammatory markers) could differentiate between patients responding to either of two treatments with different mechanisms of action was assessed.

METHOD

Subjects included Combining Medications to Enhance Depression Outcomes (CO-MED) trial participants randomly assigned to either escitalopram plus placebo (SSRI monotherapy, n=51) or bupropion plus escitalopram combination (bupropion-SSRI combination, n=55) with baseline plasma samples. CRP, serum amyloid P component, and alpha-2-macroglobulin were measured using the Bioplex Pro™ human acute-phase 4-plex panel. We conducted mixed model analyses of depressive symptom (Quick Inventory of Depressive Symptomatology Self-Report) and side-effect burden (Frequency, Intensity, and Burden of Side-Effects Rating Scale) obtained weekly or every other week over the 12-week acute-phase of CO-MED trial to evaluate the relationship between these outcomes and baseline CRP and other acute-phase reactants.

RESULTS

The treatment arms did not differ in depressive symptom or side effect outcomes. Most participants (69.8%, 74/106) had baseline CRP levels greater than 1mg/L (indicative of systemic inflammatory activity). Higher baseline CRP levels were associated lower depression severity (correlation coefficient=-0.63) with bupropion-SSRI combination but not with SSRI monotherapy (correlation coefficient=0.40). The overall remission rate was 41.5%. The estimated remission rate with CRP threshold based assignment (SSRI monotherapy for <1mg/L and Bupropion-SSRI for ≥1mg/L) was 53.1%, with a number needed to treat of 8.6. Side effect burden was unrelated to any baseline inflammatory marker.

CONCLUSIONS

Baseline CRP levels relate differentially to antidepressant treatment outcomes in persons with major depressive disorder. Clinicaltrials.gov identifier: NCT00590863.

The Longer, the Better? An Empirical Study of the Extent and Mechanisms of Attenuating Biomarker Associations in Cardiovascular Patient Cohorts

BACKGROUND

Identifying novel risk markers in cardiovascular patients remains a research priority. Longer follow-up generally is considered favorable in such studies, but associations of interest may become attenuated with increasing follow-up. This issue has not been adequately addressed in the context of patient cohorts. The current study analyzed the extent and mechanisms of attenuating associations in a cardiovascular patient cohort.

METHODS

The associations of numerous biomarkers with all-cause mortality were estimated by multiple Cox regression in the Langzeiterfolge der KARdiOLogischen Anschlussheilbehandlung (KAROLA) prospective cohort study of 1204 patients who had participated in an inpatient rehabilitation program after an acute coronary syndrome (ACS) or coronary bypass operation. Hazard ratios were estimated based on the entire follow-up period (13 years), and after truncation at previous follow-up times (3, 4.5, 6, 8, 10 years).

RESULTS

For the majority of markers, a clear and sometimes very pronounced attenuation of the hazard ratios could be observed with increasing follow-up duration. Differential attrition generally was not a sufficient explanation for this phenomenon, whereas further analyses suggested a role for reverse causality for some of the markers. Power analyses showed that the relationship of follow-up duration and statistical power can be counterintuitive in the presence of realistic amounts of attenuation.

CONCLUSIONS

The attenuation of estimates of association in patient cohorts is a much more substantial and complex issue than currently appreciated. This has important implications for the design and interpretation of prognostic, as well as etiologic, studies which may be particularly relevant in the case of patient cohorts defined by an initial acute event.

High-Sensitivity C-Reactive Protein and Risk of Stroke in Atrial Fibrillation (from the Reasons for Geographic and Racial Differences in Stroke Study)

The relation between inflammation and prothrombotic state in atrial fibrillation (AF) is well recognized. This suggests a potential role for high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation, in improving prediction of stroke in participants with AF. Cox proportional hazard analysis was used to examine the risk of stroke in 25,841 participants (40% black and 55% women) with and without AF who were enrolled in the Reasons for Geographic and Racial Differences in Stroke study from 2003 to 2007. Baseline AF (n = 2,132) was ascertained by electrocardiogram and self-reported history of previous physician diagnosis. Stroke events were identified and adjudicated during 8.3 years of follow-up. A total of 655 incident strokes occurred during follow-up. In a model adjusted for sociodemographics, traditional stroke risk factors, and use of aspirin and warfarin, higher levels of hs-CRP were associated with increased overall stroke risk (hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.10 to 1.54, and HR 1.06, 95% CI 1.01 to 1.12 for hs-CRP >3 mg/L and per 1-SD increase, respectively). Higher levels of hs-CRP continued to be associated with incident stroke in participants without AF (HR 1.31, 95% CI 1.09 to 1.57, and HR 1.06, 95% CI 1.01 to 1.12 for hs-CRP >3 mg/L and per 1-SD increase, respectively) but not in those with AF (HR 1.22, 95% CI 0.78 to 1.91, and HR 1.01, 95% CI 0.82 to 1.23 for hs-CRP >3 mg/L and per 1-SD increase, respectively). In conclusion, although hs-CRP was significantly associated with stroke risk in this population, it seems to be limited to those without AF. These findings suggest a limited value of hs-CRP in improving stroke risk stratification in subjects with AF.

Atherosclerotic Risk Factors and Risk of Myocardial Infarction and Venous Thromboembolism; Time-Fixed versus Time-Varying Analyses. The Tromsø Study

Background

Single measurements of modifiable risk factors may underestimate associations with outcomes in cohorts. We aimed to compare risk estimates of myocardial infarction (MI) and venous thromboembolism (VTE) by atherosclerotic risk factors during long follow-up using time-fixed analyses without and with correction for regression dilution and time-varying analyses.

Methods

The study included 5970 subjects enrolled in the fourth survey of the Tromsø Study (1994/95). Blood pressure, lipid levels, body mass index (BMI), diabetes and smoking status were measured at baseline, and subjects still alive at the fifth (2001/02, n = 5179) and sixth (2007/08, n = 4391) survey were re-measured. Incident events of MI (n = 714) and VTE (n = 214) were recorded until December 2010. Time-fixed and time-varying Cox regression models were used to estimate hazard ratios (HR) for MI and VTE adjusted for age and sex.

Results

Variations in BMI, blood pressure and lipid levels were small, and did not alter the risk estimates when time-varying analyses were compared to time-fixed analyses. For MI, variables that changed considerably over time yielded the greatest changes in risk estimates (HR for smoking changed from 1.80 (95% CI 1.55–2.10) to 2.08 (95% CI 1.78–2.42)). For VTE, only BMI was associated with increased risk in both time-fixed and time-varying analysis, but the risk estimates weakened in the time-varying analysis. Correction of time-fixed HRs with Rosner´s method tended to overestimate risk estimates compared to time-varying analysis.

Comment

For MI and VTE, risk estimates based on baseline and repeated measures corresponded well, whereas correction for regression dilution tended to overestimate risks.

Baseline Plasma C-Reactive Protein Concentrations and Motor Prognosis in Parkinson Disease

Background

C-reactive protein (CRP), a blood inflammatory biomarker, is associated with the development of Alzheimer disease. In animal models of Parkinson disease (PD), systemic inflammatory stimuli can promote neuroinflammation and accelerate dopaminergic neurodegeneration. However, the association between long-term systemic inflammations and neurodegeneration has not been assessed in PD patients.

Objective

To investigate the longitudinal effects of baseline CRP concentrations on motor prognosis in PD.

Design, Setting, and Participants

Retrospective analysis of 375 patients (mean age, 69.3 years; mean PD duration, 6.6 years). Plasma concentrations of high-sensitivity CRP were measured in the absence of infections, and the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-III) scores were measured at five follow-up intervals (Days 1–90, 91–270, 271–450, 451–630, and 631–900).

Main Outcome Measure

Change of UPDRS-III scores from baseline to each of the five follow-up periods.

Results

Change in UPDRS-III scores was significantly greater in PD patients with CRP concentrations ≥0.7 mg/L than in those with CRP concentrations <0.7 mg/L, as determined by a generalized estimation equation model (P = 0.021) for the entire follow-up period and by a generalized regression model (P = 0.030) for the last follow-up interval (Days 631–900). The regression coefficients of baseline CRP for the two periods were 1.41 (95% confidence interval [CI] 0.21–2.61) and 2.62 (95% CI 0.25–4.98), respectively, after adjusting for sex, age, baseline UPDRS-III score, dementia, and incremental L-dopa equivalent dose.

Conclusion

Baseline plasma CRP levels were associated with motor deterioration and predicted motor prognosis in patients with PD. These associations were independent of sex, age, PD severity, dementia, and anti-Parkinsonian agents, suggesting that subclinical systemic inflammations could accelerate neurodegeneration in PD.

Baseline C-Reactive Protein Levels and Life Prognosis in Parkinson Disease

Background

C-reactive protein (CRP) is a biomarker of inflammation, and high levels of CRP correlate with vascular death. Chronic inflammation is considered to be involved in neurodegeneration, although there is no evidence linking it with the process of neurodegenerative diseases.

Objective

To determine the role of baseline CRP levels in the prognosis of patients with Parkinson disease (PD).

Methods

A cohort of 313 patients with a mean age of 69.1 and mean PD duration of 7.9 years was retrospectively followed for a mean observation time of 1,753 days. CRP was measured when patients were not diagnosed with any infections, and levels were repetitively measured to investigate a tendency of “regression to mean.” The primary outcome measure was a survival time from study enrollment to death.

Results

During the observation period 56 patients died. Baseline CRP was log-linearly associated with a risk of death in PD. Mean survival time was 3,149 (95% confidence interval; 3,009-3,289) days in patients with CRP ≤ 0.8mg/L (lower two thirds) and 2,620 (2,343-2,897) days in those with CRP > 0.8 mg/L (top third, p < 0.001, log-rank test). The adjusted hazard ratio (HR) per two-fold higher CRP concentration for all deaths was 1.29 (1.10-1.52), and after excluding PD-unrelated deaths, such as cancer or stroke, HR was 1.23 (1.01-1.49) (adjusted for age, sex, PD duration, modified Hohen-Yahr stages, MMSE scores, and serum albumin).

Conclusions

Baseline CRP concentrations were associated with the risk of death and predicted life prognosis of patients with PD. The associations were independent from PD duration, PD severity, cognitive function, ages, and nutritional conditions, suggesting the possibility that subclinical chronic inflammation is associated with a neurodegenerative process in PD.

Coenzyme Q10 benefits symptoms in Gulf War veterans: results of a randomized double-blind study

We sought to assess whether coenzyme Q10 (CoQ10) benefits the chronic multisymptom problems that affect one-quarter to one-third of 1990-1 Gulf War veterans, using a randomized, double-blind, placebo-controlled study. Participants were 46 veterans meeting Kansas and Centers for Disease Control criteria for Gulf War illness. Intervention was PharmaNord (Denmark) CoQ10 100 mg per day (Q100), 300 mg per day (Q300), or an identical-appearing placebo for 3.5 ± 0.5 months. General self-rated health (GSRH), the primary outcome, differed across randomization arms at baseline, and sex significantly predicted GSRH change, compelling adjustment for baseline GSRH and prompting sex-stratified analysis. GSRH showed no significant benefit in the combined-sex sample. Among males (85% of participants), Q100 significantly benefited GSRH versus placebo and versus Q300, providing emphasis on Q100. Physical function (summary performance score, SPS) improved on Q100 versus placebo. A rise in CoQ10 approached significance as a predictor of improvement in GSRH and significantly predicted SPS improvement. Among 20 symptoms each present in half or more of the enrolled veterans, direction-of-difference on Q100 versus placebo was favorable for all except sleep problems; sign test 19:1, p=0.00004) with several symptoms individually significant. Significance for these symptoms despite the small sample underscores large effect sizes, and an apparent relation of key outcomes to CoQ10 change increases prospects for causality. In conclusion, Q100 conferred benefit to physical function and symptoms in veterans with Gulf War illness. Examination in a larger sample is warranted, and findings from this study can inform the conduct of a larger trial.

Physical activity in older men: longitudinal associations with inflammatory and hemostatic biomarkers, N-terminal pro-brain natriuretic peptide, and onset of coronary heart disease and mortality

OBJECTIVES

To examine associations between habitual physical activity (PA) and changes in PA and onset of coronary heart disease (CHD) and the pathways linking PA to CHD.

DESIGN

British Regional Heart Study population-based cohort; men completed questionnaires in 1996 and 1998 to 2000, attended rescreen in 1998 to 2000, and were followed up to June 2010.

SETTING

Community.

PARTICIPANTS

Of 4,252 men recruited from primary care centers (77% of those invited and eligible) who were rescreened in 1998 to 2000, 3,320 were ambulatory and free from CHD, stroke, and heart failure and participated in the current study.

MEASUREMENTS

Usual PA (regular walking and cycling, recreational activity and sport). Outcome was first fatal or nonfatal myocardial infarction.

RESULTS

In 3,320 ambulatory men, 303 first and 184 fatal CHD events occurred during a median of 11 years of follow-up; 9% reported no usual PA, 23% occasional PA, and 68% light or more-intense PA. PA was inversely associated with novel risk markers C-reactive protein, D-dimer, von Willebrand Factor and N-terminal pro-brain natriuretic peptide (NT-proBNP). Compared with no usual PA, hazard ratios (HRs) for CHD events, adjusted for age and region, were 0.52 (95% confidence interval (CI) = 0.34-0.79) for occasional PA, 0.47 (95% CI = 0.30-0.74) for light PA, 0.51 (95% CI = 0.32-0.82) for moderate PA, and 0.44 (95% CI = 0.29-0.65) for moderately vigorous or vigorous PA (P for linear trend = .004). Adjustment for established and novel risk markers somewhat attenuated HRs and abolished linear trends. Compared with men who remained inactive, men who maintained at least light PA had an HR for CHD events of 0.73 (95% CI = 0.53-1.02) and men whose PA level increased had an HR of 0.86 (95% CI = 0.55-1.35).

CONCLUSION

Even light PA was associated with significantly lower risk of CHD events in healthy older men, partly through inflammatory and hemostatic mechanisms and cardiac function (NT-proBNP).

Additive influence of genetic predisposition and conventional risk factors in the incidence of coronary heart disease: a population-based study in Greece

OBJECTIVES

An additive genetic risk score (GRS) for coronary heart disease (CHD) has previously been associated with incident CHD in the population-based Greek European Prospective Investigation into Cancer and nutrition (EPIC) cohort. In this study, we explore GRS-'environment' joint actions on CHD for several conventional cardiovascular risk factors (ConvRFs), including smoking, hypertension, type-2 diabetes mellitus (T2DM), body mass index (BMI), physical activity and adherence to the Mediterranean diet.

DESIGN

A case-control study.

SETTING

The general Greek population of the EPIC study.

PARTICIPANTS AND OUTCOME MEASURES

477 patients with medically confirmed incident CHD and 1271 controls participated in this study. We estimated the ORs for CHD by dividing participants at higher or lower GRS and, alternatively, at higher or lower ConvRF, and calculated the relative excess risk due to interaction (RERI) as a measure of deviation from additivity.

RESULTS

The joint presence of higher GRS and higher risk ConvRF was in all instances associated with an increased risk of CHD, compared with the joint presence of lower GRS and lower risk ConvRF. The OR (95% CI) was 1.7 (1.2 to 2.4) for smoking, 2.7 (1.9 to 3.8) for hypertension, 4.1 (2.8 to 6.1) for T2DM, 1.9 (1.4 to 2.5) for lower physical activity, 2.0 (1.3 to 3.2) for high BMI and 1.5 (1.1 to 2.1) for poor adherence to the Mediterranean diet. In all instances, RERI values were fairly small and not statistically significant, suggesting that the GRS and the ConvRFs do not have effects beyond additivity.

CONCLUSIONS

Genetic predisposition to CHD, operationalised through a multilocus GRS, and ConvRFs have essentially additive effects on CHD risk.

Protective Effect of Time Spent Walking on Risk of Stroke in Older Men

Background and Purpose—

Older adults have the highest risks of stroke and the lowest physical activity levels. It is important to quantify how walking (the predominant form of physical activity in older age) is associated with stroke.

Methods—

A total of 4252 men from a UK population-based cohort reported usual physical activity (regular walking, cycling, recreational activity, and sport) in 1998 to 2000. Nurses took fasting blood samples and made anthropometric measurements.

Results—

Among 3435 ambulatory men free from cardiovascular disease and heart failure in 1998 to 2000, 195 first strokes occurred during 11-year follow-up. Men walked a median of 7 (interquartile range, 3–12) hours/wk; walking more hours was associated with lower heart rate, D-dimer, and higher forced expiratory volume in 1 second. Compared with men walking 0 to 3 hours/wk, men walking 4 to 7, 8 to 14, 15 to 21, and >22 hours had age- and region-adjusted hazard ratios (95% confidence intervals) for stroke of 0.89 (0.60–1.31), 0.63 (0.40–1.00), 0.68 (0.35–1.32), and 0.36 (0.14–0.91), respectively, P (trend)=0.006. Hazard ratios were somewhat attenuated by adjustment for established and novel risk markers (inflammatory and hemostatic markers and cardiac function [N-terminal pro-brain natriuretic peptide]) and walking pace, but linear trends remained. There was little evidence for a dose–response relationship between walking pace and stroke; comparing average pace or faster to a baseline of slow pace, the hazard ratio for stroke was 0.65 (95% confidence interval, 0.44–0.97), which was fully mediated by time spent walking.

Conclusions—

Time spent walking was associated with reduced risk of onset of stroke in dose–response fashion, independent of walking pace. Walking could form an important part of stroke-prevention strategies in older people.

Distribution and determinants of C-reactive protein in the older adult population: European Prospective Investigation into Cancer-Norfolk study

BACKGROUND

C-reactive protein (CRP) is a well-documented predictor of cardiovascular diseases and mortality. We aimed to better understand the distribution and determinants of CRP in the population.

MATERIALS AND METHODS

Study participants were men and women aged 40-79 in the UK-based EPIC-Norfolk population-based cohort study. CRP was measured in 18 586 available serum samples (8334 men and 10 252 women) and remeasured in 6087 individuals on average 13 years later using a high-sensitivity assay.

RESULTS

In cross-sectional analyses, the range of serum CRP was 0.1-188.3 mg/L and the median 1.6 mg/L. A third of the population had serum CRP levels above 3 mg/L. Serum CRP levels were comparable in men and women who were not taking postmenopausal hormone replacement therapy (HRT). Women who were taking HRT had double CRP levels compared with HRT nonusers. Smoking was also strongly related to CRP in men and women. Serum CRP was positively and independently associated with age, body mass index and waist circumference and inversely with height. A stronger association with serum CRP measured concurrently than on average 13 years later indicated a short-term rather than long-term association with smoking and HRT use. Social class and alcohol intake were not independently related to CRP, but there was a strong inverse association with educational status.

CONCLUSION

The distribution of serum CRP in the population is similar in men and women after taking into account smoking and HRT use. Anthropometric factors as well as educational status are strongly related to serum CRP.

Metabolic factors associated with risk of renal cell carcinoma

Previous studies have shown that obesity and hypertension are associated with increased risk of renal cell carcinoma (RCC), but less is known about the association to other metabolic factors. In the Metabolic Syndrome and Cancer project (Me-Can) data on body mass index (BMI, kg/m2), blood pressure, and circulating levels of glucose, cholesterol, and triglycerides were collected from 560,388 men and women in cohorts from Norway, Austria, and Sweden. By use of Cox proportional hazard models, hazard ratios (HR) were calculated for separate and composite metabolic exposures. During a median follow-up of 10 years, 592 men and 263 women were diagnosed with RCC. Among men, we found an increased risk of RCC for BMI, highest vs. lowest quintile, (HR = 1.51, 95% CI 1.13–2.03), systolic blood pressure, (HR = 3.40, 95% CI 1.91–6.06), diastolic blood pressure, (HR = 3.33, 95% CI 1.85–5.99), glucose, (HR = 3.75, 95% CI 1.46–9.68), triglycerides, (HR = 1.79, 95% CI 1.00–3.21) and a composite score of these metabolic factors, (HR = 2.68, 95% CI 1.75–4.11). Among women we found an increased risk of RCC for BMI, highest vs. lowest quintile, (HR = 2.21, 95% CI 1.32–3.70) and the composite score, (HR = 2.29, 95% CI 1.12–4.68). High levels of the composite score were also associated with risk of death from RCC among both men and women. No multiplicative statistical or biological interactions between metabolic factors on risk of RCC were found. High levels of BMI, blood pressure, glucose and triglycerides among men and high BMI among women were associated with increased risk of RCC.

Prospective study of IL-18 and risk of MI and stroke in men and women aged 60-79 years: a nested case-control study

Aim

IL-18 is hypothesized to destabilise atherosclerotic plaques, leading to thrombotic events and epidemiologic studies suggest that IL-18 may increase risk of CHD or CVD.

We examined prospective associations between levels of serum IL-18 and new CHD and stroke events in older men and women from a general population.

Methods

A case-control study was nested within a prospective cohort of men and women aged 60–79 years recruited from general practices in 25 British towns in 1998–2000 and followed-up for 7.5 years for fatal and non-fatal MI and stroke. Baseline IL-18 was measured in stored serum samples of incident cases of MI (n = 364) or stroke (n = 300) and two controls per case.

Results

Geometric mean IL-18 levels were higher among the 364 MI cases than the 706 controls; 417.84 pg/mL (IQR 316.25, 537.44) compared to 386.90 pg/mL (IQR 296.54, 482.33), p(difference) = 0.002. IL-18 was positively associated with adverse lipid and inflammatory profiles. Men and women in the top third of baseline IL-18 levels had an age and sex-adjusted odds ratio (OR) for MI of 1.31 (95%CI 0.92, 1.85) compared with those in the lowest third; this attenuated to 1.05 (95%CI 0.72, 1.53) after additional adjustment for established vascular and inflammatory risk factors. Each doubling of IL-18 level was associated with an increased OR for MI 1.34 (95%CI 1.04, 1.72), which was attenuated on adjustment for established vascular and inflammatory risk factors; 1.09 (95%CI 0.83, 1.44).

Geometric mean IL-18 levels did not differ between stroke cases and controls. The OR for stroke associated with the highest compared to the lowest tertile of IL-18 was 1.24 (95%CI 0.84, 1.84). Results for MI and stroke did not differ by presence of pre-existing CVD, gender or age.

Conclusions

Circulating IL-18 levels were strongly associated with a range of established and novel risk factors but were not independently associated with risk of MI or stroke in our study.

Prospective study on metabolic factors and risk of prostate cancer

BACKGROUND

There are inconsistent data regarding the association between metabolic factors, separately and combined, and the risk of prostate cancer and death from prostate cancer.

METHODS

In the Metabolic Syndrome and Cancer Project (Me-Can), data on body mass index (BMI); blood pressure; and blood levels of glucose, cholesterol, and triglycerides were collected for 289,866 men. Cox proportional hazard models were used to calculate relative risks (RRs) by exposures in quintiles as well as for z scores (with a mean of 0 and a standard deviation of 1) together with a composite sum of scores to assess the combined effect of metabolic factors. RRs were corrected for random errors in measurement.

RESULTS

During a mean follow-up of 12 years, 6673 men were diagnosed with prostate cancer and 961 died of the disease. Men with high levels of glucose and triglycerides were found to have a decreased risk of prostate cancer: top versus bottom quintile of glucose: RR, 0.82 (95% confidence interval [95% CI], 0.62-1.08; P value for trend = .03) and top versus bottom quintile of triglycerides: RR, 0.88 (95% CI, 0.74-1.04; P value for trend = .001). High BMI, elevated blood pressure, and a high composite z score were found to be associated with an increased risk of death from prostate cancer: top versus bottom quintile of BMI: RR, 1.36 (95% CI, 1.08-1.71); systolic blood pressure: RR, 1.62 (95% CI, 1.07-2.45); and per 1-unit increase of the composite z score: RR, 1.13 (95% CI, 1.03-1.25).

CONCLUSIONS

The authors found no evidence of an association between high levels of metabolic factors and the risk of prostate cancer, but high BMI, elevated blood pressure, and a composite score of all metabolic factors were associated with an increased risk of death from prostate cancer.

Longitudinal associations between changes in physical activity and onset of type 2 diabetes in older British men: the influence of adiposity

OBJECTIVE

To determine how much physical activity (PA) is needed to protect against diabetes onset in older adults, whether protection is greater among overweight individuals, and whether taking up moderate activity in later life is beneficial.

RESEARCH DESIGN AND METHODS

Men (4,252) from a U.K. population-based cohort self-reported usual PA (regular walking and cycling, recreational activity, and sport) in 1996 and in 1998-2000, alongside other health behaviors and medical history. Fasting blood lipids were measured. Median follow-up was 7.1 years, during which 135 cases of type 2 diabetes (validated self-report) occurred.

RESULTS

Among 3,012 men free from cardiovascular disease and diabetes in 1998-2000, 9% reported no usual leisure-time PA, 23% occasional PA, and 15% vigorous PA. Compared with men reporting no activity, men reporting occasional, light, moderate, moderately vigorous, and vigorous PA had lower diabetes risks: hazard ratio (HR) 0.58 (95% CI 0.33-1.02), 0.39 (0.20-0.74), 0.38 (0.19-0.73), 0.39 (0.20-0.77), and 0.33 (0.16-0.70), respectively; P (trend) = 0.002, adjusted for age, social class, tobacco, alcohol, diet, and blood lipids. Adjustment for BMI, waist circumference, or fasting insulin attenuated HRs. HRs were stronger in men with BMI ≥28 vs. <28 kg/m(2) (interaction P = 0.02). Compared with men reporting light activity or less in 1996 and 2000, men who became at least moderately active by 2000 or remained at least moderately active at both times had adjusted HRs of 0.62 (0.34-1.12) and 0.51 (0.31-0.82), respectively.

CONCLUSIONS

Even light PA markedly reduced diabetes risk in older men, especially among the overweight or obese. Taking up or maintaining at least moderate PA in older adulthood strongly protected against diabetes.

Blood pressure and risk of cancer incidence and mortality in the Metabolic Syndrome and Cancer Project

Observational studies have shown inconsistent results for the association between blood pressure and cancer risk. We investigated the association in 7 cohorts from Norway, Austria, and Sweden. In total, 577799 adults with a mean age of 44 years were followed for, on average, 12 years. Incident cancers were 22184 in men and 14744 in women, and cancer deaths were 8724 and 4525, respectively. Cox regression was used to calculate hazard ratios of cancer per 10-mmHg increments of midblood pressure, which corresponded with 0.7 SDs and, for example, an increment of systolic/diastolic blood pressure of 130/80 to 142/88 mmHg. All of the models used age as the time scale and were adjusted for possible confounders, including body mass index and smoking status. In men, midblood pressure was positively related to total incident cancer (hazard ratio per 10 mmHg increment: 1.07 [95% CI: 1.04-1.09]) and to cancer of the oropharynx, colon, rectum, lung, bladder, kidney, malignant melanoma, and nonmelanoma skin cancer. In women, midblood pressure was not related to total incident cancer but was positively related to cancer of the liver, pancreas, cervix, uterine corpus, and malignant melanoma. A positive association was also found for cancer mortality, with HRs per 10-mmHg increment of 1.12 (95% CI: 1.08-1.15) for men and 1.06 (95% CI: 1.02-1.11) for women. These results suggest a small increased cancer risk overall in men with elevated blood pressure level and a higher risk for cancer death in men and women.

Effect of correcting for long-term variation in major coronary heart disease risk factors: relative hazard estimation and risk prediction in the Atherosclerosis Risk in Communities Study

PURPOSE

To examine the effect of correcting coronary heart disease (CHD) risk factors for long-term within-person variation on CHD risk.

METHODS

By using 5533 men and 7301 women from the Atherosclerosis Risk in Communities (ARIC) study, we compared models incorporating risk factors measured at a single visit and models incorporating additional measurements for systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol taken 3 years before baseline.

RESULTS

The largest change away from null was observed for systolic blood pressure, ie, hazard ratio (HR) 1.38 to 1.69 (+81%) in women and HR 1.26 to 1.41 (+56%) in men. HRs also decreased for age (-32% in women, -9% in men), race (-67% in women), the presence of diabetes (-13% in men and women), and medication use for hypertension (-27% in women, -26% in men) and cholesterol (-97% in women, HR 1.06-0.93 in men). The area under the ROC curve did not improve significantly in men or women, whereas reclassification was only significant in women (net reclassification improvement 5.4%, p = 0.016).

CONCLUSIONS

Modeling long-term variation in CHD risk factors had a substantial impact on HR estimates, with new effect estimates further from the null for some risk factors and closer for others including age and medication use, but only improved risk classification in women.

Metabolic risk factors and ovarian cancer in the Metabolic Syndrome and Cancer project

BACKGROUND

No studies have so far evaluated the impact of the metabolic syndrome (MetS) as an entity on ovarian cancer risk. The authors aimed to examine the association between factors in the MetS, individually and combined, and risk of ovarian cancer incidence and mortality.

METHODS

Altogether, 290,000 women from Austria, Norway and Sweden were enrolled during 1974-2005, with measurements taken of height, weight, blood pressure and levels of glucose, cholesterol and triglycerides. Relative risks (RRs) of ovarian cancer were estimated using Cox regression for each MetS factor in quintiles and for standardized levels (z-scores), and for a composite z-score for the MetS. RRs were corrected for random error in measurements.

RESULTS

During follow-up, 644 epithelial ovarian cancers and 388 deaths from ovarian cancer were identified. There was no overall association between MetS and ovarian cancer risk. Increasing levels of cholesterol [RR 1.52, 95% confidence interval (95% CI) 1.01-2.29, per 1-U increment of z-score] and blood pressure (RR 1.79, 95% CI 1.12-2.86) conferred, however, increased risks of mucinous and endometrioid tumours, respectively. In women below the age of 50 years, there was increased risk of ovarian cancer mortality for MetS (RR 1.52, 95% CI 1.00-2.30). Increasing levels of BMI (RR 1.17, 95% CI 1.01-1.37) conferred increased risk of ovarian cancer mortality in women above the age of 50 years.

CONCLUSION

There was no overall association between MetS and ovarian cancer risk. However, increasing levels of cholesterol and blood pressure increased the risks of mucinous and endometrioid tumours, respectively. Increasing levels of BMI conferred an increased risk of ovarian cancer mortality in women above the age of 50 years.

Study protocol: the empirical investigation of methods to correct for measurement error in biobanks with dietary assessment

Background

The Public Population Project in Genomics (P³G) is an organisation that aims to promote collaboration between researchers in the field of population-based genomics. The main objectives of P³G are to encourage collaboration between researchers and biobankers, optimize study design, promote the harmonization of information use in biobanks, and facilitate transfer of knowledge between interested parties. The importance of calibration and harmonisation of methods for environmental exposure assessment to allow pooling of data across studies in the evaluation of gene-environment interactions has been recognised by P³G, which has set up a methodological group on calibration with the aim of; 1) reviewing the published methodological literature on measurement error correction methods with assumptions and methods of implementation; 2) reviewing the evidence available from published nutritional epidemiological studies that have used a calibration approach; 3) disseminating information in the form of a comparison chart on approaches to perform calibration studies and how to obtain correction factors in order to support research groups collaborating within the P³G network that are unfamiliar with the methods employed; 4) with application to the field of nutritional epidemiology, including gene-diet interactions, ultimately developing a inventory of the typical correction factors for various nutrients.

Methods/Design

Systematic review of (a) the methodological literature on methods to correct for measurement error in epidemiological studies; and (b) studies that have been designed primarily to investigate the association between diet and disease and have also corrected for measurement error in dietary intake.

Discussion

The conduct of a systematic review of the methodological literature on calibration will facilitate the evaluation of methods to correct for measurement error and the design of calibration studies for the prospective pooling of biobanks. This could increase the efficiency of the design of such studies, improve statistical power, reduce bias, and aid in the assessment of gene-environment interaction effects in complex diseases. The systematic review of calibration of dietary intake information could inform gene-diet interaction investigations involving the pooling of results from studies with nutritional data collected in different ways.

Prospective study of circulating soluble CD40 ligand concentrations and the incidence of cardiovascular disease in a nested prospective case-control study of older men and women

BACKGROUND

CD40 ligand(CD40L) is implicated in atherosclerotic plaque formation.

OBJECTIVES

We investigated prospective associations between circulating soluble CD40L and myocardial infraction (MI) or stroke in an older general population cohort, accounting for established and novel cardiovascular risk factors.

METHODS

Baseline serum CD40L (sCD40L) was measured in incident MI (n = 368) and stroke (n = 304) cases and two controls per case, 'nested' in prospective UK studies of 4252 men and 4286 women aged 60-79 years, sampled from general practices in Britain in 1998-2000, with 7-year follow-up for fatal and non-fatal MI and stroke.

RESULTS

sCD40L was higher in smokers and negatively associated with lung function and positively associated with total cholesterol and markers of inflammation, but not with other established cardiovascular disease (CVD) risk factors. Geometric mean sCD40L levels did not differ between MI cases and controls (5.94 ng mL(-1) vs. 5.82 ng mL(-1); P = 0.5) or between stroke cases and controls (5.61 ng mL(-1) vs. 5.28 ng mL(-1), P = 0.1). There was no strong evidence for elevated risk of MI or stroke in multivariable models comparing participants in the top to those in the bottom third of sCD40L. Age-adjusted odds ratios (ORs) were 1.39 [95% confidence interval (CI) 0.98, 1.96] for MI and 1.16 (0.78, 1.73) for stroke. These attenuated to 1.24 (95% CI 0.86, 1.79) and 1.18 (0.78, 1.78), respectively, after adjustment for established and novel CVD risk factors.

CONCLUSIONS

sCD40L is associated with other inflammatory markers but is not itself a strong independent risk marker for either stroke or MI.

Interleukin 18 and coronary heart disease: prospective study and systematic review

AIM

Previous studies suggest that circulating levels of interleukin-18 (IL-18) may be prospectively related to risk of coronary heart disease (CHD) in the general population. We report new data from the largest prospective study to date, which are combined with data from all published prospective studies in a meta-analysis.

METHODS

We measured baseline IL-18 levels in stored serum samples of subjects from a case-control study nested within a prospective study of 5661 men aged 40-59 years recruited from general practices in 18 British towns in 1978-1980 and followed-up for up to 16 years (median time to event 8.4 years) for fatal CHD and non-fatal myocardial infarction (595 cases, 1238 controls).

RESULTS

IL-18 concentrations were strongly related to cigarette smoking, triglyceride, HDL-cholesterol (inversely) and to circulating levels of several inflammatory and haemostatic markers. Men in the top third of baseline IL-18 levels had an age-adjusted odds ratio (OR) for CHD of 1.55 (95% CI 1.21, 1.98) compared with those in the lowest third; this was reduced to 1.30 (95% CI 0.99, 1.69) after additional adjustment for vascular risk factors and 1.12 (95% CI 0.84, 1.49) after further adjustment for CRP and IL-6. In meta-analyses of CVD, associations (or effect sizes) were consistent between studies; RRs were 1.64 [corrected] (95% CI 1.48, 1.83) [corrected] after age adjustment, 1.39 (95% CI 1.25, [corrected] 1.55) after additional risk factor adjustment and 1.34 (95% CI 1.17, 1.53) [corrected] after additional adjustment for inflammatory markers.

CONCLUSIONS

Circulating IL-18 is prospectively and independently associated with CVD risk.

Metabolic syndrome and risk of bladder cancer: prospective cohort study in the metabolic syndrome and cancer project (Me-Can)

There are little data on the putative association between factors in the metabolic syndrome (MetS) and risk of bladder cancer. In the Metabolic Syndrome and Cancer project (Me-Can), measurements of height, weight, blood pressure and circulating levels of glucose, cholesterol, and triglycerides had been collected from 578,700 subjects in cohorts in Norway, Austria, and Sweden. We used Cox proportional hazard models to calculate relative risks (RRs) of bladder cancer by exposures divided into quintiles, in categories according to the World Health Organisation (WHO) and as a continuous standardized variable (z-score with mean = 0 and standard deviation = 1) for each separate component and its standardized sum, a composite MetS score. RRs were corrected for random error in measurements. During a mean follow-up of 11.7 years (SD = 7.6), 1,587 men and 327 women were diagnosed with bladder cancer. Significant associations with risk were found among men per one unit increment of z-score for blood pressure, RR = 1.13 (95% CI 1.03-1.25), and the composite MetS score, RR = 1.10 (95% CI 1.01-1.18). Among women, glucose was nonsignificantly associated with risk, RR = 1.41 (95% CI 0.97-2.06). No statistically significant interactions were found between the components in the MetS in relation to bladder cancer risk. Hypertension and a composite MetS score were significantly but modestly associated with an increased risk of bladder cancer among men and elevated glucose was associated with a nonsignificant increase in risk among women.

Metabolic factors and the risk of colorectal cancer in 580,000 men and women in the metabolic syndrome and cancer project (Me-Can)

BACKGROUND

The metabolic syndrome (MetS) has been related to an increased risk of colorectal cancer, but the modest size of previous studies precluded detailed characterization of the role of individual MetS factors and their interaction on risk.

METHODS

In the Metabolic Syndrome and Cancer Project (Me-Can), data on body mass index (BMI), blood pressure, and blood levels of glucose, cholesterol, and triglycerides were available for 578,700 men and women. The mean age of participants at baseline was 44 years, and the mean follow-up was 12 years. Relative risks (RR) of colorectal cancer per 1 standard deviation increment in Z score of factors and for a combined MetS score, were calculated from Cox regression models, including adjustment for potential confounders.

RESULTS

During follow-up, 2834 men and 1861 women were diagnosed with colorectal cancer. The RR of colorectal cancer for the MetS score was 1.25 (95% confidence interval [CI], 1.18-1.32) in men, and 1.14 (95% CI, 1.06-1.22) in women. Significant associations also were observed in men for BMI (RR, 1.07; 95% CI, 1.02-1.13), blood pressure (RR, 1.10; 95% CI, 1.02-1.18), and triglycerides (RR, 1.17; 95% CI, 1.06-1.28) and, in women, for BMI (RR, 1.08; 95% CI, 1.01-1.15). There was no significant positive interaction between the metabolic factors on risk.

CONCLUSIONS

The combination of metabolic factors and some separate factors was related to an increased risk of colorectal cancer, but there was no interaction between metabolic factors.

Serum triglycerides and cancer risk in the metabolic syndrome and cancer (Me-Can) collaborative study

OBJECTIVE

To assess the association between serum triglyceride levels and cancer risk.

METHODS

The metabolic syndrome and cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included data on 257,585 men and 256,512 women. The mean age at study entry was 43.8 years for men and 44.2 years for women. The mean follow-up time was 13.4 years (SD = 8.5) for men and 11.9 years (SD = 7.2) for women. Excluding the first year of follow-up, 23,060 men and 15,686 women were diagnosed with cancer. Cox regression models were used to calculate relative risk (RR) of cancer for triglyceride levels in quintiles and as a continuous variable. RRs were corrected for random error by use of regression dilution ratio.

RESULTS

Relative risk for top quintile versus bottom quintile of triglycerides of overall cancer was 1.16 (95% confidence interval 1.06-1.26) in men and 1.15 (1.05-1.27) in women. For specific cancers, significant increases for top quintile versus bottom quintile of triglycerides among men were found for cancers of the colon, respiratory tract, the kidney, melanoma and thyroid and among women, for respiratory, cervical, and non-melanoma skin cancers.

CONCLUSION

Data from our study provided evidence for a possible role of serum triglycerides in cancer development.

Metabolic syndrome and breast cancer in the me-can (metabolic syndrome and cancer) project

BACKGROUND

Few studies have assessed the metabolic syndrome (MetS) as an entity in relation to breast cancer risk, and results have been inconsistent. We aimed to examine the association between MetS factors (individually and combined) and risk of breast cancer incidence and mortality.

METHODS

Two hundred ninety thousand women from Austria, Norway, and Sweden were enrolled during 1974-2005, with measurements of height, weight, blood pressure, and levels of glucose, cholesterol, and triglycerides. Relative risks (RR) of breast cancer were estimated using Cox proportional hazards regression for each MetS factor in quintiles and for standardized levels (z-scores) and for a composite z-score for the MetS.

RESULTS

There were 4,862 incident cases of breast cancer and 633 deaths from breast cancer identified. In women below age 50, there was a decreased risk of incident cancer for the MetS (per 1-unit increment of z-score; RR, 0.83; 95% confidence interval, 0.76-0.90) as well as for the individual factors (except for glucose). The lowest risks were seen among the heaviest women. In women above age 60, there was an increased risk of breast cancer mortality for the MetS (RR, 1.23; 95% confidence interval, 1.04-1.45) and for blood pressure and glucose. The strongest association with mortality was seen for increased glucose concentrations.

CONCLUSIONS

The MetS was associated with a decreased risk of incident breast cancer in women below age 50 with high body mass index, and with an increased risk of breast cancer mortality in women above 60.

IMPACT

Lifestyle interventions as recommended for cardiovascular disease prevention may be of value to prevent breast cancer mortality in postmenopausal women.

Blood pressure, body size and prostate cancer risk in the Swedish Construction Workers cohort

Data from prospective studies on blood pressure and prostate cancer risk are limited, and results are inconclusive. Baseline measurements of height, weight and blood pressure were available in 336,159 men in the Swedish Construction Workers cohort. During an average of 22.2 years of follow-up, 10,002 incident cases and 2,601 fatal cases of prostate cancer were identified in National registers. For 5,219 cases, tumor characteristics were available; 2,817 tumors were classified as nonaggressive and 2,402 as aggressive. Relative risks of disease were estimated from Cox regression models, using attained age as time-scale, and adjusting for birth year, smoking status and body mass index (BMI). Top compared to bottom quintile level of systolic or diastolic blood pressure was associated with a significant 15-20% decreased risk of incident prostate cancer (p for trend: systolic < 0.0001, diastolic = 0.3), but blood pressure was not significantly associated with risk of fatal prostate cancer. BMI was not associated with prostate cancer incidence, but was positively associated with fatal prostate cancer; men in the top quintile had a 30% increased risk (p for trend = 0.0004). The associations between blood pressure and BMI and nonaggressive tumors were similar to those of incident prostate cancer, and associations with aggressive tumors were similar to those of fatal prostate cancer. Data from our study suggest that hypertension is associated with a decreased risk of incident prostate cancer, but the explanation for this finding is unclear. Our study support a positive association between overweight and risk of fatal prostate cancer.

Activation of Hemostasis and Decline in Cognitive Function in Older People

Objective— To determine whether activation of hemostatic function (thrombosis and fibrinolysis) is associated with cognitive decline in older people.

Methods and Results— We studied 5804 people (age, 70–82 years) in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). Mean follow-up was 3.2 years, including annual measurement of speed of information processing (letter, digit coding, and Stroop), verbal memory (picture–word naming), and basic and instrumental activities of daily living. Raised levels of markers of thrombin generation ( d -dimer and prothrombin fragment 1+2) were associated independently with increased rate of cognitive decline (eg, Stroop increased by 4.44 s [SEM, 0.68] in bottom tertile of d -dimer compared to 5.46 [SEM, 0.71] in highest tertile; P <0.05) and deterioration in activities of daily living. This increased rate of decline was attenuated but not removed when subjects with incident nonfatal stroke were omitted from the analysis. It also persisted when adjustments were made for inflammation (C-reactive protein and IL-6).

Conclusion— Older patients with increased markers of thrombin generation ( d -dimer and prothrombin fragment 1+2) are at increased risk for cognitive decline and deterioration in ability to perform activities of daily living. This is likely attributable to increased risk of cerebral ischemic damage (including covert disease) associated with prothrombotic states.

C-reactive protein concentration and risk of coronary heart disease, stroke, and mortality: an individual participant meta-analysis

BACKGROUND

Associations of C-reactive protein (CRP) concentration with risk of major diseases can best be assessed by long-term prospective follow-up of large numbers of people. We assessed the associations of CRP concentration with risk of vascular and non-vascular outcomes under different circumstances.

METHODS

We meta-analysed individual records of 160 309 people without a history of vascular disease (ie, 1.31 million person-years at risk, 27 769 fatal or non-fatal disease outcomes) from 54 long-term prospective studies. Within-study regression analyses were adjusted for within-person variation in risk factor levels.

RESULTS

Log(e) CRP concentration was linearly associated with several conventional risk factors and inflammatory markers, and nearly log-linearly with the risk of ischaemic vascular disease and non-vascular mortality. Risk ratios (RRs) for coronary heart disease per 1-SD higher log(e) CRP concentration (three-fold higher) were 1.63 (95% CI 1.51-1.76) when initially adjusted for age and sex only, and 1.37 (1.27-1.48) when adjusted further for conventional risk factors; 1.44 (1.32-1.57) and 1.27 (1.15-1.40) for ischaemic stroke; 1.71 (1.53-1.91) and 1.55 (1.37-1.76) for vascular mortality; and 1.55 (1.41-1.69) and 1.54 (1.40-1.68) for non-vascular mortality. RRs were largely unchanged after exclusion of smokers or initial follow-up. After further adjustment for fibrinogen, the corresponding RRs were 1.23 (1.07-1.42) for coronary heart disease; 1.32 (1.18-1.49) for ischaemic stroke; 1.34 (1.18-1.52) for vascular mortality; and 1.34 (1.20-1.50) for non-vascular mortality.

INTERPRETATION

CRP concentration has continuous associations with the risk of coronary heart disease, ischaemic stroke, vascular mortality, and death from several cancers and lung disease that are each of broadly similar size. The relevance of CRP to such a range of disorders is unclear. Associations with ischaemic vascular disease depend considerably on conventional risk factors and other markers of inflammation.

FUNDING

British Heart Foundation, UK Medical Research Council, BUPA Foundation, and GlaxoSmithKline.

Blood glucose and risk of incident and fatal cancer in the metabolic syndrome and cancer project (me-can): analysis of six prospective cohorts

BACKGROUND

Prospective studies have indicated that elevated blood glucose levels may be linked with increased cancer risk, but the strength of the association is unclear. We examined the association between blood glucose and cancer risk in a prospective study of six European cohorts.

METHODS AND FINDINGS

The Metabolic syndrome and Cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included 274,126 men and 275,818 women. Mean age at baseline was 44.8 years and mean follow-up time was 10.4 years. Excluding the first year of follow-up, 18,621 men and 11,664 women were diagnosed with cancer, and 6,973 men and 3,088 women died of cancer. We used Cox regression models to calculate relative risk (RR) for glucose levels, and included adjustment for body mass index (BMI) and smoking status in the analyses. RRs were corrected for regression dilution ratio of glucose. RR (95% confidence interval) per 1 mmol/l increment of glucose for overall incident cancer was 1.05 (1.01-1.10) in men and 1.11 (1.05-1.16) in women, and corresponding RRs for fatal cancer were 1.15 (1.07-1.22) and 1.21 (1.11-1.33), respectively. Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri, and stomach.

CONCLUSIONS

Data from our study indicate that abnormal glucose metabolism, independent of BMI, is associated with an increased risk of cancer overall and at several cancer sites. Our data showed stronger associations among women than among men, and for fatal cancer compared to incident cancer. Please see later in the article for the Editors' Summary.

Peripheral levels of fibrinogen, C-reactive protein, and plasma viscosity predict future cognitive decline in individuals without dementia

OBJECTIVE

To determine whether circulating levels of the biomarkers C-reactive protein (CRP), fibrinogen, plasma viscosity, and hematocrit were associated with cognitive decline in middle-aged to elderly people.

METHODS

Subjects consisted of 2312 men and women aged 50 to 80 years participating in the Aspirin for Asymptomatic Atherosclerosis Trial, all of whom were free of symptomatic cardiovascular disease at baseline. Biomarker levels and cognitive ability were measured at baseline with cognition assessed in all subjects using the Mill Hill Vocabulary Scale and in a subgroup of 504 persons using tests of memory, nonverbal reasoning, information processing speed, executive function, and mental flexibility. After 5 years, the five-test battery was administered to all participants and scores were used to derive a general cognitive ability factor.

RESULTS

Baseline CRP and fibrinogen levels were associated negatively with age and sex-adjusted follow-up scores on the majority of the cognitive tests, and the general cognitive ability factor (correlations = -0.054 to 0.105, p < .05). In analyses adjusting for baseline cognitive scores, asymptomatic atherosclerotic disease, and cardiovascular risk factors, both markers predicted decline in several cognitive domains (excluding memory). Baseline plasma viscosity, but not hematocrit, was associated negatively with follow-up test scores for general cognitive ability, information processing speed, and mental flexibility (correlations = -0.050 to -0.098, p < .05) and with decline across the same domains (p < .05).

CONCLUSIONS

Increased circulating levels of CRP, fibrinogen, and elevated plasma viscosity predicted poorer subsequent cognitive ability and were associated with age-related cognitive decline in several domains, including general ability.

Prospective study of matrix metalloproteinase-9 and risk of myocardial infarction and stroke in older men and women

OBJECTIVES

The endopeptidase matrix metalloproteinase-9 (MMP-9) is implicated in atherosclerotic plaque rupture. We investigate prospective associations between MMP-9 and MI or stroke in an older general population cohort, accounting for established and novel cardiovascular risk factors.

METHODS

Baseline serum MMP-9 was measured in incident MI (n=368) and stroke (n=299) cases and two controls per case, 'nested' in prospective studies of 4252 men and 4286 women aged 60-79 years, sampled from General Practices in Britain in 1998-2000, with 7-year follow-up for fatal and non-fatal MI and stroke.

RESULTS

Geometric mean MMP-9 was 528 ng/mL (IQR 397, 743) in MI cases compared to 501 ng/mL (IQR 370, 743) in controls, p=0.10. Participants in the top compared to bottom third of MMP-9 levels had an age-adjusted odds ratio for MI of 1.53 (95% CI 1.09, 2.13), which attenuated to 1.18 (95% CI 0.81, 1.70) after adjustment for established and novel cardiovascular risk factors. There was weak evidence that OR differed according to pre-existing CVD; the OR for MI in 187 participants with pre-existing CVD was 2.20 (1.04, 4.64) and 1.24 (0.84, 1.82) in 715 participants without (LR test for interaction p=0.06). Geometric mean MMP-9 levels were higher in stroke cases than controls; 522ng/mL (IQR 363, 673) vs 487 (IQR 393, 704), p=0.045; however adjustments similarly attenuated the associations.

CONCLUSIONS

While serum MMP-9 is univariately associated with risk of MI and stroke, it is not a strong independent risk marker for either.

Triglycerides and coronary heart disease: have recent insights yielded conclusive answers?

PURPOSE OF REVIEW

Despite over 50 years of research, the relevance of triglycerides to coronary heart disease risk remains uncertain.

RECENT FINDINGS

Contrary to prevailing views, recent studies demonstrate that the long-term within-individual variability of triglyceride measurements is similar to that of other lipid fractions. Several prospective studies have reported on associations of circulating triglyceride levels with coronary heart disease risk, but it remains unclear whether observed associations are dependent on levels of conventional risk factors (especially other lipids) or are importantly modified under different circumstances (especially by fasting status). Ongoing large-scale studies should help clarify such outstanding uncertainties and assess whether measurement of triglyceride levels can better identify individuals at increased risk of coronary heart disease than measurement of conventional risk factors alone. Available interventions that lower levels of triglycerides are unable to judge causality as such interventions typically influence levels of several lipid fractions. Study of genetic variants that regulate triglyceride levels may provide an alternative approach to assess causality.

SUMMARY

Although recent studies have progressed our understanding of triglycerides and coronary heart disease, several outstanding uncertainties remain unresolved. Ongoing studies should help clarify these, including whether measurement of triglyceride levels can help improve coronary heart disease risk assessment, and study of genetic variants may help better understand any causal role.

Does fibrinogen add to prediction of cardiovascular disease? Results from the Scottish Heart Health Extended Cohort Study

Plasma fibrinogen is an established risk factor for cardiovascular disease (CVD), but it has not been established whether it adds predictive value to risk scores. In the Scottish Heart Health Extended Cohort Study, we measured plasma fibrinogen in 13 060 men and women, aged 30-74 years, initially free of CVD. After follow-up for a median of 19.2 years, 2626 subjects had at least one CVD event. After adjusting for classical CVD risk factors and socio-economic status, the hazard ratios (95% confidence interval) for a one unit (g/l) increase in plasma fibrinogen were 1.09 (1.02, 1.16) for men and 1.10 (1.02, 1.19) for women. Although fibrinogen added significantly to the discrimination of the Framingham risk score for women, it failed to do so for men. Fibrinogen did not add significantly to the ASSIGN risk score. Fibrinogen added between 1.3% and 3.2% to the classification of CVD status by the existing risk scores. We conclude that the added value of fibrinogen to two currently used risk scores is low; hence population screening with fibrinogen for this purpose is unlikely to be clinically useful or cost-effective.

Chronic exposure to outdoor air pollution and markers of systemic inflammation

BACKGROUND

Cohort studies suggest that long-term exposure to higher levels of outdoor air pollution increases risk of developing cardiovascular disease. One suggested mechanism is that air pollution, especially particulate matter, induces systemic inflammation, thereby increasing the risk of developing long-term pathologic changes in the cardiovascular system, We aimed to examine the association between long-term exposure to higher levels of air pollution and chronic systemic inflammation.

METHODS

We examined the relationship between 2 markers of systemic inflammation (fibrinogen and C-reactive protein) and measures of outdoor air pollution estimated for each postcode sector of residence, using models incorporating information on pollutant emissions from multiple sources, and atmospheric dispersion and processing, in 3 representative cross-sectional studies of the English population in 1994, 1998, and 2003. These included about 25,000 adults with fibrinogen measurements and 17,000 adults with C-reactive protein measurements. We used multilevel linear regression modeling and pooled the results from the 3 surveys using meta-analysis.

RESULTS

We found no associations between concentrations of fibrinogen or C-reactive protein and measures of outdoor air pollution (particulate matter <10 mum in diameter (PM10), nitrogen dioxide, sulfur dioxide, and ozone). Specifically, we found, for each 1-microg/m(3) [corrected] increase in PM(10) concentration, a change in fibrinogen concentrations of -0.08% (95% confidence interval = -0.25 to [corrected] 0.10) and in C-reactive protein concentrations of 0.14% (-1.00 to [corrected] 1.30).

CONCLUSIONS

Our findings do not support the hypothesis that the association between outdoor air pollution exposure and later cardiovascular disease is mediated by chronic systemic inflammation.

Leptin and coronary heart disease: prospective study and systematic review

OBJECTIVES

This study sought to better determine the link between leptin and coronary heart disease (CHD).

BACKGROUND

Circulating leptin is considered a risk factor for CHD but larger studies are needed.

METHODS

Leptin levels were measured in 550 men with fatal CHD or nonfatal myocardial infarction and in 1,184 controls nested within a prospective study of 5,661 British men and set in context with a meta-analysis.

RESULTS

Baseline leptin correlated with body mass index (BMI), blood pressure, total cholesterol, triglyceride, and inflammatory markers; correlations persisted after BMI adjustment. The within-person consistency of leptin values over 4 years (correlation coefficient: 0.79; 95% confidence interval [CI]: 0.73 to 0.83) was higher than those of some established cardiovascular risk factors. In a comparison of individuals in the top third with those in the bottom third of baseline leptin, the age- and town-adjusted odds ratio for CHD was 1.25 (95% CI: 0.96 to 1.62), decreasing to 0.98 (95% CI: 0.72 to 1.34) after adjustment for BMI. A systematic review identified 7 prospective reports with heterogeneous findings (I(2) = 60%, 13% to 82%). The combined adjusted risk ratio across all studies was 1.44 (95% CI: 0.95 to 2.16) in a comparison of extreme thirds of leptin levels. The inconsistency between studies was partially explained by sample size, with combined estimates from studies involving >100 CHD cases (1.28, 95% CI: 0.80 to 2.04) being somewhat weaker than those from smaller studies (1.81, 95% CI: 0.76 to 4.31).

CONCLUSIONS

Previous studies appear to have overestimated associations of leptin and CHD risk. Our results suggest a moderate association that is largely dependent on BMI.

Circulating TNFalpha levels in older men and women do not show independent prospective relations with MI or stroke

Background

Tumour necrosis factor alpha (TNFα) is a pro-inflammatory cytokine implicated in atherosclerotic plaque formation. We investigated whether circulating TNFα is prospectively associated with myocardial infarction (MI) or stroke in the older general population, independently of established cardiovascular risk factors and other inflammatory markers related to CHD risk.

Methods

We measured baseline TNFα concentrations in stored serum samples of 362 incident MI and 299 incident stroke cases and controls (2 per case, frequency matched by age, gender and town) who were ‘nested’ in parallel prospective studies of 4252 men and 4286 women aged 60–79 years assessed in general practices in 24 British towns in 1998–2000 and followed up for an average 7 years for fatal and non-fatal MI and stroke.

Results

TNFα levels were 11.4% (95% CI 9.5, 13.3%) higher among MI cases than controls; geometric mean 1.84 pg/mL compared to 1.63 pg/mL, p (difference) < 0.001. Participants in the top third of baseline TNFα levels had an age-adjusted odds ratio (OR) for MI of 1.75 (95%CI 1.22, 2.49) compared with those in the bottom third, which was reduced to 1.47 (95%CI 1.01, 2.14) after adjustment for established cardiovascular risk factors. However, further adjustment for C-reactive protein and interleukin-6 abolished the association OR 1.33 (95% CI 0.91, 1.66) and the linear trend. Excluding subjects with pre-existing CVD did not materially affect results. No significant association between TNFα and stroke was observed.

Conclusions

This study suggests that TNFα is not a strong independent risk marker for MI, and is not associated with risk of stroke.

Bone lead levels and blood pressure endpoints: a meta-analysis

BACKGROUND

Previous reviews have shown increases in blood pressure and hypertension associated with increases in lead levels in blood. We performed a meta-analysis of the association of bone lead levels with systolic blood pressure, diastolic blood pressure, and hypertension using published data.

METHODS

We searched Medline, Embase, and Toxline for epidemiologic studies on bone lead levels and blood pressure endpoints. We used inverse-variance weighted random-effects models to summarize the association of tibia or patella lead levels with blood pressure endpoints.

RESULTS

We summarized data from 3 prospective studies and 5 cross-sectional studies. All studies measured lead levels in tibia bone and 3 studies measured lead levels in patella. For a 10 microg/g increase in tibia lead, the cross-sectional summary increases in blood pressure were 0.26 mm Hg for systolic (95% confidence interval = 0.02 to 0.50) and 0.02 mm Hg for diastolic (-0.15 to 0.19). The summary odds ratio for hypertension was 1.04 (1.01 to 1.07). For a 10 microg/g increase in patella lead, the summary odds ratio for hypertension was 1.04 (0.96 to 1.12).

CONCLUSION

Systolic blood pressure and hypertension risk were associated with lead levels in tibia bone, but the magnitude of the summary estimates was small. These summary estimates, however, were based on published data and we could not evaluate nonlinear dose-response relationships, the relative contribution of bone and blood lead levels, or the influence of differences in study populations. A more detailed characterization of the association of bone lead levels and blood pressure endpoints would require a pooled analysis of individual participant data from existing studies.

Length of the QT interval: determinants and prognostic implications in a population-based prospective study of older men

OBJECTIVE

We examined potential determinants and prognostic value of the corrected QT interval (QTc).

DESIGN

A total of 4252 British men aged 60 to 79 years had a resting 12-lead electrocardiogram. Potential determinants of the QTc were assessed using multivariable regression. Men were followed up for 7 years.

RESULTS

A 1 standard deviation increase in QTc (26 milliseconds) was associated with increased all-cause mortality (hazard ratio, 1.13; 95% confidence interval, 1.05-1.22). Longer QTc was associated with increasing age, preexisting coronary heart disease, and a range of drugs. Shorter QTc was present in diabetics and smokers. Corrected QT interval was related inversely with serum potassium and calcium and positively with serum urate, sodium, and systolic blood pressure. The relation of QTc to all-cause mortality was independent of adjustment for these factors.

CONCLUSIONS

Age, preexisting coronary heart disease, certain medications and biochemical factors, and diabetes are independently associated with QTc. Corrected QT interval is an independent predictor of all-cause mortality.