Micro-inflammatory changes in asymptomatic healthy adults during bouts of respiratory tract infections in the community: Potential triggers for atherothrombotic events

Air temperature variability and high-sensitivity C reactive protein in a general population of China

BACKGROUND

Along with global climate change, the relationship between temperature variability (TV) and cardiovascular hospitalization and deaths have been well established. However, limited studies were conducted to reveal the underlying mechanism for TV-related cardiovascular diseases.

OBJECTIVES

In the current study, a novel TV calculation, taking account for both interday and intraday TV as well as lag effects, was used to investigate the effect of short-term TV on the level of high-sensitivity C reactive protein (hs-CRP), which is a crucial preclinical predictor for cardiovascular disease (CVD).

RESULTS

Among the 11,623 Chinese population (46.0% male; mean age 49.8 years), the average hs-CRP was 1.4 mg/ L (standard deviation 1.6 mg/L). Statistical significance between TV and hs-CRP was observed for different TV exposure days (TV01-TV07) in adjusted model, with highest effect for TV06. Specifically, per 1 °C increase in TV06 led to 2.241% (95%CI: 1.552%-2.935%) increase in hs-CRP. Female, obesity and elderly population were more susceptible to TV. The largest mediator for the association of TV and hs-CRP was lipoprotein(a), accounting for 8.68%, followed by smoking status (4.78%), alcohol use (3.95%) and systolic BP (3.20%).

CONCLUSION

Short-term TV will significantly increase the level of hs-CRP, suggesting hs-CRP to be the potential biologic mechanisms underlying the cardiovascular effects of TV. And more attention should be paid to unstable weather in the global climate change context. Further developing efficient public health policies on climate change may benefit for global heath.

Red blood cell distribution width and the risk of cardiovascular morbidity and all-cause mortality

Red blood cell distribution width (RDW) has been shown to predict cardiovascular mortality in various populations, but studies were less conclusive regarding cardiovascular morbidity. We aimed at evaluating the prognostic effect of RDW on cardiovascular morbidity and allcause mortality in the largest community cohort to date. We utilised the computerised database of a large community based healthcare maintenance organization (HMO) in Israel to identify a cohort of 225,006 eligible patients aged 40 or above who performed a blood count during 2006. We evaluated the relationship between 1% increments of RDW values and major cardiovascular events and all-cause mortality over a period of five years. A total of 21,939 incident cases of a major cardiovascular event and 4,287 deaths were documented during a total of six years of follow up, respectively. In comparison with patients with RDW level <13%, the hazard ratio for total mortality gradually increased to 4.57 (95% confidence interval [CI]: 3.35–6.24, p<0.001) among male patients and to 3.26 (95% CI: 2.49–4.28, p<0.001) among female patients with a RDW of 17% or above. Similar results were evident in anaemic and non-anaemic populations. RDW above 17% was also associated with a modest increased risk of major cardiovascular events in females 1.26 (95% CI: 1.03–1.52, p=0.021), while in men it was not significant, 1.08 (95% CI: 0.82–1.41, p=NS). In conclusion, increasing RDW levels significantly increased risk of cardiovascular morbidity and all-cause mortality. Our observation is evident in both anaemic and non-anaemic patients.

Winter Season Mortality: Will Climate Warming Bring Benefits?

Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

Effect of socioeconomic status on cardio-respiratory fitness: data from a health screening program

AIM

Lower socioeconomic status (SES) is associated with reduced cardio-respiratory fitness (CRF) and predicts adverse cardiovascular outcomes. We questioned whether this association remains significant among an apparently healthy population with a presumed higher SES.

METHODS

This cross-sectional study enrolled attendees of a health screening program between September 2002 and November 2010. Linear regression models included the metabolic equivalents achieved during an exercise treadmill stress test as the dependent variable and adjusted for self-reported SES parameters (level of education, occupational status, financial strain and a combined variable), cardiovascular risk factors, as well as to multiple potential confounders.

RESULTS

Data on 8471 individuals (5463 men and 3008 women) with a mean (SD) age of 44 (11) years were collected. We found a statistically significant difference in mean exercise capacity between the categories of SES, especially for the level of education and occupation, when adjusted for age, sex, cardiovascular risk factors, SES variables and multiple confounders.

CONCLUSIONS

Multiple factors affect CRF in apparently healthy screened individuals. When adjusted for those factors, SES correlates with CRF even within a more specific highly educated cohort.

Environmental exposure to combustion-derived air pollution is associated with reduced functional capacity in apparently healthy individuals

Prior toxicological exposure reports demonstrated the decremental effect of several air pollutants on the metabolic equivalents achieved during exercise testing (METs). There are no prior large scale epidemiological reports about the effect of environmental air pollution exposure on those parameters. We analyzed a cohort of apparently healthy individuals attending a screening survey program held between 2003 and 2009. Participants were included if residing within an 11 km radius from the nearest air pollution monitoring station. Linear regression models were fitted for the metabolic equivalents and adjusted to short- and long-term air pollutant exposure (particulate matter under 10 micron, sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone). The models were adjusted for possible confounders that affect air pollution and stress testing measurements. The study population comprised 6,612 individuals (4,201 males and 2,411 females). We found a statistically significant short- and long-term negative correlation between air pollutants, mainly CO and NO2 and between the metabolic equivalents achieved. A similar short-term effect was found for SO2. We conclude that exposure to combustion-derived air pollutants has a short- and long-term decremental effect on cardiorespiratory fitness as measured by exercise stress testing. Our epidemiological data support previous toxicological reports.

Association of angiotensin-converting enzyme inhibitor therapy initiation with a reduction in hemoglobin levels in patients without renal failure

OBJECTIVE

To investigate whether treatment initiated with an angiotensin-converting enzyme inhibitor (ACE-I) or an angiotensin II receptor blocker (ARB) for patients with ischemic heart disease, hypertension, or diabetes causes a reduction in hemoglobin (Hb) levels.

PATIENTS AND METHODS

This was a retrospective cohort analysis using the computerized database of a large health maintenance organization. Included were all adults with a first purchase of an ACE-I, an ARB, or a calcium channel blocker (CCB) between January 1, 2004, and December 31, 2009, defined as the index date. Measures of Hb levels before and 1 year after the index date were reviewed, and the change was calculated. All the analyses were stratified by pharmaceutical class. The main exposure variables were the proportion of days covered (PDC) by these drugs and the mean enalapril dosage (for enalapril users only).

RESULTS

Levels of Hb before and after treatment were available for 14,754 patients taking ACE-Is, 751 taking ARBs, and 3087 taking CCBs. A high PDC was significantly associated with greater yearly reductions in Hb levels compared with a low PDC for CCB use, but was more pronounced for ACE-I and ARB use. A high PDC was also associated with a higher odds of developing anemia in ACE-I users (odds ratio [OR], 1.59; P<.001) and ARB users (OR, 2.21; P=.05). In nonanemic enalapril users, every 10-mg increment in daily dose was associated with an OR of 1.45 for the development of anemia (P<.001). The association remained after excluding nonadherent patients.

CONCLUSION

Levels of Hb are reduced during the first year of use of ACE-Is and to a lesser extent with use of ARBs. This association is dose dependent and is not explained by patient adherence.

Association of cold ambient temperature and cardiovascular markers

Cardiovascular mortality has been shown to increase in the winter. However, it is unclear whether cold temperature affects indicators known as cardiovascular markers. We evaluated the association between ambient temperature and cardiovascular markers using data collected retrospectively from 55,567 adults who had visited a health check-up clinic between 1995 and 2008. Non-parametric smoothing regressions were fitted to determine the shapes of association between temperature and cardiovascular markers such as blood pressure, lipid profiles, platelet count, and high sensitivity C-reactive protein (hsCRP). Mixed effect model was used to investigate the significance of the relationship between temperature and cardiovascular markers. Decreased ambient temperature was associated with an increase in systolic and diastolic blood pressures, platelet count and serum low density lipoprotein-cholesterol concentration. In contrast, high density lipoprotein-cholesterol level declined with decreasing temperature. The hsCRP level increased with decreasing temperature in the minimum temperatures below 0°C, but revealed a reverse association above. Our study suggests that excess cardiovascular mortality in cold weather might be associated with temperature-related variations of cardiovascular markers.

Vitamin D deficiency prevalence and cardiovascular risk in Israel

BACKGROUND

Accumulated data in the past years suggest that vitamin D deficiency has an adverse effect on cardiovascular (CVD) health and that its prevalence is significantly higher among patients with CVD risk factors, contributing to the pathogenesis of CVD.

MATERIALS AND METHODS

This is a cross-sectional analysis of a relatively large database derived from a health care maintenance organization. The population consisted of individuals 18 years and older who had undergone blood tests for vitamin D levels for any reason during 2001-2008.

RESULTS

The study population consisted of 34,874 individuals: 26,699 (76·6%) were women at a mean ± SD age of 55 ± 15 and 8175 men (23·4%) aged 55 ± 17. The mean ± SD vitamin D level was 23·2 ± 10·1 and 22·7 ± 9·9 for men and women, respectively. The prevalence of vitamin D deficiency or insufficiency (vitamin D levels < 30 ng mL(-1)) for the entire study population was surprisingly high for men and women (79·2% and 77·5%, respectively). This remained consistent with only little variation when stratified by age. The group with vitamin D < 15 ng mL(-1) vs. the group with vitamin D levels ≥ 30 ng mL(-1) demonstrated a significant (P < 0·031) age-adjusted odds ratios for the presence of hypertension, diabetes mellitus, dyslipidemia, obesity and peripheral vascular disease for women (OR = 1·19; 1·65; 1·13; 2·28; 1·85, respectively), and the presence of all the above except hypertension in men (OR = 1·51; 1·28; 2·06; 1·73, respectively).

CONCLUSIONS

Vitamin D deficiency is associated with CVD and other risk factors in this Israeli study population. The prevalence of the deficiency in Israel is similar to the prevalence found in less sunny regions.

The effect of influenza vaccination on risk of acute myocardial infarction: self-controlled case-series study

Acute myocardial infarction (AMI) peaks in winter months, partly linked to epidemic influenza. This implies that influenza vaccination may prevent some cases of AMI. This study investigated the association between influenza vaccination and AMI using the self-controlled case-series method. We identified 8180 cases of first AMI aged 40 years and over at time of diagnosis. The incidence of AMI was significantly reduced in the 60 days following vaccination (compared with the baseline period), ranging from a reduction of 32% (IRR 0.68; 95% CI 0.60-0.78) at 1-14 days after vaccination, to 18% (IRR 0.82; 95% CI 0.75-0.90) at 29-59 days after vaccination. Reductions in AMI incidence were more pronounced for early seasonal vaccinations before mid-November.

The association of higher levels of within-normal-limits liver enzymes and the prevalence of the metabolic syndrome

Background

Metabolic syndrome (MetS) is frequently characterized by elevated liver enzymes, including gamma-glutamyl transferase (GGT) and alanine aminotransferase (ALT). Our objective was to evaluate the range of prevalence of MetS in apparently healthy individuals whose liver enzyme concentrations were all within-normal-range.

Methods

We have performed a cross sectional analysis on participants of the Tel-Aviv medical center inflammation survey (TAMCIS) recruited between the years 2003-2009. Analyzed were a cohort of 6,561 men and 3,389 women.

Results

The prevalence of MetS increased significantly from the first quintile to the fifth for both GGT and ALT, all the five quintiles being in the normal range. Logistic regression analysis for the presence of MetS showed crude odds ratios of 2.7 and 2.4 between the first and fourth quintiles and 3.6 and 3.2 for the fifth quintile in men and women respectively for ALT. For GGT the respective odds being 3.6 and 3.2 for the fourth quintile and 3.9 and 3.4 for the fifth quintile in men and women, respectively.

Conclusions

A relatively high prevalence of MetS was noted in a cohort of apparently healthy individuals with liver enzyme concentrations within-normal-limits. Practical consequences include the need to follow up these enzyme concentrations as continuous variables and to take into consideration that even relatively small elevations within the normal range might reflect the presence of dysmetabolism.

Elevated resting heart rate is associated with the metabolic syndrome

BACKGROUND

Increased resting heart rate (RHR) may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS) in a sample of apparently healthy individuals and those with cardiovascular risk factors.

METHODS

We performed a cross-sectional analysis in a large sample of apparently healthy individuals who attended a general health screening program and agreed to participate in our survey. We analyzed a sample of 7706 individuals (5106 men and 2600 women) with 13.2% of men and 8.9% of the women fulfilling the criteria for the MetS. The participants were divided into quintiles of resting heart rate. Multiple adjusted odds ratio was calculated for having the MetS in each quintile compared to the first.

RESULTS

The multi-adjusted odds for the presence of the MetS increased gradually from an arbitrarily defined figure of 1.0 in the lowest RHR quintile (<60 beats per minute (BPM) in men and <64 BPM in women) to 4.1 and 4.2 in men and women respectively in the highest one (>or=80 BPM in men and >or=82 BPM in women).

CONCLUSION

Raised resting heart rate is significantly associated with the presence of MetS in a group of apparently healthy individuals and those with an atherothrombotic risk. The strength of this association supports the potential presence of one or more shared pathophysiological mechanisms for both RHR and the MetS.