Prognostic cut-off values of caffeine and cardiovascular events in a cohort of unselected men and women from general population

Background

Several studies focused on the effect of caffeine on the cardiovascular (CV) system and on CV outcome, with fairly contrasting results. Dietary caffeine is usually taken into consideration as a continuous variable, but researcher would prefer to use cut-off values more useful in clinical setting.

Purpose

The present study is aimed at defining in epidemiological setting and in population-based context the cut-off values of caffeine, if any, having a CV prognostic values, to confirm them in men and women of general population, and to establish whether caffeine of food origin contained in multiple sources used in everyday life.

Methods

The study cohort was represented by 1,668 unselected men and women aged 59.6±17.1 years living in an area in North-East Italy and sharing homogeneous lifestyle, randomly taken from general population. Multivariate dichotomic Cox regression models having fatal and morbid CV event as dependent variables, adjusted for age, sex, basal heart rate, body mass index, LDLC, individualized FEV1, β-blocking therapy, ethanol intake, diabetes mellitus, arterial hypertension, smoking, smoking, blood pressure were preliminarily used to search for an association between caffeine as a continuous variable and incident CV event. Prognostic cut-off values, identified by means of receiver operating curves (ROC) and able to discriminate between subjects doomed to develop the CV event, were then used as independent predictors to divide people into those <cut-off>cut-off in further multivariate Cox models adjusted for the confounders listed above.

Results

Daily intake of caffeine over a specific cut-off determined via the ROC curve analysis are associated to lower incidence of CV events in a 20-year follow-up period. This cut-off corresponds, for each events, to an interval between two groups of quintiles of caffeine intake. The cerebrovascular events and those due to heart failure and arrhythmias were reduced also in multivariate models adjusted for confounders. On the contrary, intake of caffeine over the cut-off was only apparently associated to lower incidence of coronary disease, but this unadjusted crude association was wales and not confirmed after adjustment.

Conclusions

In men but not in women, higher voluntary daily consumption of caffeine from any source reduces significantly and to a considerable extent, in a long follow-up, the incidence of cerebrovascular events, heart failure and arrhythmias. To have preventive effects on events the consumption of caffeine must be higher than a cut-off that corresponds to 280, 230 and 280 mg/day respectively, cut-off values always falling between the third and fourth quintile of caffeine consumption. No prognostic cut-off can be identified in women and in any sex in the case of coronary events. Specific studies will be mandatory to understand the reason of this sex-specific difference.

Funding Acknowledgement

Type of funding sources: None.

Hyperuricemia and Risk of Cardiovascular Outcomes: The Experience of the URRAH (Uric Acid Right for Heart Health) Project

The latest European Guidelines of Arterial Hypertension have officially introduced uric acid evaluation among the cardiovascular risk factors that should be evaluated in order to stratify patient's risk. In fact, it has been extensively evaluated and demonstrated to be an independent predictor not only of all-cause and cardiovascular mortality, but also of myocardial infraction, stroke and heart failure. Despite the large number of studies on this topic, an important open question that still need to be answered is the identification of a cardiovascular uric acid cut-off value. The actual hyperuricemia cut-off (> 6 mg/dL in women and 7 mg/dL in men) is principally based on the saturation point of uric acid but previous evidence suggests that the negative impact of cardiovascular system could occur also at lower levels. In this context, the Working Group on uric acid and CV risk of the Italian Society of Hypertension has designed the Uric acid Right for heArt Health project. The primary objective of this project is to define the level of uricemia above which the independent risk of CV disease may increase in a significantly manner. In this review we will summarize the first results obtained and describe the further planned analysis.

P1566Identification of the cardiovascular threshold limit for serum uric acid. Analysis from a general Italian population

Background

Serum uric acid (SUA) is increasingly recognised as an important predictor of cardiovascular disease (CVD) and total mortality. However, the levels of SUA that discriminate across the different strata of risk for CVD and total mortality remain unknown, complicating the identification of subjects at high or low mortality risk for SUA in clinical practice.

Purpose

In this study we used a large Italian population comprising >3ehz748.0326 subjects to assess the threshold of SUA that increases the risk of total and CVD mortality.

Methods

The URic Acid Right for heArt Health (URRAH) study is a regional-basis multicentre cohort study which collected data from prospective studies and databases from different hypertension centres, including subjects with at least one measure of SUA and a follow-up of about 20 years. Total mortality was defined as mortality for any causes, cardiovascular mortality as death due to fatal myocardial infraction, stroke or heart failure. Multivariate dichotomic logistic and Cox regression models were used to confirm the relationship between SUA and mortality status both from cardiovascular and any causes, while ROC curves were used to identify the threshold of SUA that better discriminated people at higher or lower mortality risk.

Results

A total of 22.275 subjects had SUA and mortality information. Logistic regression identified a direct and strong association between SUA and an increased risk of total (OR 1.176, 95% CI 1.127–1.227) and CVD (OR 1.147, 95% CI 1.093–1.203) mortality, independently of other CVD risk factors (age, BMI, LDL cholesterol, diagnosis of diabetes, hypertension, chronic kidney disease, alcohol consumption and smoking). Cox models confirmed the presence of an independent association between SUA and any causes (HR 1.123, 95% CI 1.090–1.567) and CVD (HR 1.124, 95% CI 1.081–1.169) mortality. ROC curve analysis identified a cut-off value od SUA [(4.79 mg/dL (95% CI 4.7–5.4 mg/dl)] able to discriminate total mortality status, and a different one [(5.60 mg/dL (95% CI 5.09–5.89 mg/dl)] able to identify CVD mortality status. Multivariate Cox analysis adjusted for confounders confirmed that subjects with SUA >4.79 mg/dl had a significantly higher total mortality (HR 1.293, 95% CI 1.181–1.416) compared to those with SUA <4.79 mg/dl, independently of covariables. Similarly, subjects with SUA >5.60 mg/dl had a significantly higher CVD mortality (HR 1.428, 95% CI 1.273–1.600) than those with SUA <5.60 mg/dl after adjustment for the same confounders.

Conclusion

Levels of SUA that increase the risk of total and CVD mortality are significantly lower than those commonly used for the definition of hyperuricemia in clinical practice. Our data provide the first large evidence of a level of “cardiovascular” SUA that might be used in clinical practice to identify subjects at greater risk of total and CVD mortality.

The C825T GNB3 polymorphism, independent of blood pressure, predicts cerebrovascular risk at a population level

BACKGROUND

The role of C825T polymorphism of the candidate GNB3 gene in predicting cerebrovascular outcome has been poorly explored in longitudinal setting at a population level.

METHODS

In an epidemiological setting, 1,678 men and women from general population were genotyped for C825T polymorphism of GNB3 gene and follow-up for 10 years to detect nonfatal and fatal cerebrovascular events (CE). Established cerebrovascular risk factors were used to adjust the multivariate Cox analysis for confounders.

RESULTS

Seventy-three nonfatal and 30 fatal CE were recorded. Incidence of CE was higher in TT than in C-carriers (fatal: 2.6 vs. 1.7%, P < 0.03; nonfatal: 7.8 vs. 3.9%, P < 0.03; fatal recurrences: 1.6 vs. 0.6%, P < 0.03). In Cox analysis, the TT genotype predicted nonfatal (hazard ratio 1.99, 95% confidence interval 1.05-3.79, P = 0.03), fatal (2.91, 1.05-8.12, P = 0.04), and fatal recurrent CE (6.82, 1.50-31.1, P = 0.02) also after adjustment for age, gender, systolic and diastolic blood pressure, body adiposity, atherogenetic blood lipids, serum uric acid, diabetes, calories, caffeine and ethanol intake, and coronary events at baseline. Further adjustment for historical CE made the association between TT genotype and incident fatal CE nonsignificant (hazard ratio 2.72, 95% confidence interval 0.96-7.22, P = 0.06).

CONCLUSIONS

The TT genotype of GNB3 gene predicts incident CE independent of blood pressure and other established risk factors at a population level. Further studies are needed to clarify the nature and pathways of this association.

Glycaemic fall after a glucose load. A population-based study

BACKGROUND AND AIMS

A blood glucose (BG) fall after an oral glucose load has never been described previously at a population level. This study was aimed at looking for a plasma glucose trend after an oral glucose load for possible blood glucose fall if any, and for its impact on coronary mortality at a population level.

METHODS AND RESULTS

In subjects from an unselected general population, BG and insulin were detected before and 1 and 2h after a 75-g oral glucose load for insulin sensitivity and β-cell function determination. Blood pressure, blood examinations and left ventricular mass were measured, and mortality was monitored for 18.8±7.7 years. According to discriminant analysis, the population was stratified into cluster 0 (1-h BG < fasting BG; n=497) and cluster 1 (1-h BG ≥ fasting BG; n=1733). To avoid any interference of age and sex, statistical analysis was limited to two age-gender-matched cohorts of 490 subjects from each cluster (n=940). Subjects in cluster 0 showed significantly higher insulin sensitivity and β-cell function, lower visceral adiposity and lower blood pressure values. Adjusted coronary mortality was 8 times lower in cluster 0 than 1 (p<0.001). The relative risk of belonging to cluster 1 was 5.40 (95% CI 2.22-13.1).

CONCLUSION

It seems that two clusters exist in the general population with respect to their response to an oral glucose load, independent of age and gender. Subjects who respond with a BG decrease could represent a privileged sub-population, where insulin sensitivity and β-cell function are better, some risk factors are less prevalent, and coronary mortality is lower.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Serum uric acid shows a J-shaped trend with coronary mortality in non-insulin-dependent diabetic elderly people. The CArdiovascular STudy in the ELderly (CASTEL)

The relationship between serum uric acid (SUA) and risk of coronary heart disease (CHD) mortality remains controversial, particularly in diabetic subjects. The aim of the present study is to evaluate whether SUA independently predicts CHD mortality in non-insulin-dependent elderly people from the general population and to investigate the interactions between SUA and other risk factors. Five hundred and eighty-one subjects aged >/=65 years with non-insulin-dependent diabetes mellitus were prospectively studied in the frame of the CArdiovascular STudy in the ELderly (CASTEL). Historical and clinical data, blood tests and 12-year fatal events were recorded. SUA as a continuous item was divided into tertiles and, for each tertile, adjusted relative risk (RR) with 95% confidence intervals (CI) was derived from multivariate Cox analysis. CHD mortality was predicted by SUA in a J-shaped manner. Mortality rate was 7.9% (RR 1.28, CI 1.05-1.72), 6.0% (reference tertile) and 12.1% (RR 1.76, CI 1.18-2.27) in the increasing tertiles of SUA, respectively, without any difference between genders. In diabetic elderly subjects, SUA independently predicts the risk of CHD mortality in a J-shaped manner.

Pulse hypertension: a new component of the metabolic syndrome in elderly women?

The classification of arterial hypertension (HT) to define metabolic syndrome (MS) is unclear in that different cutoffs of blood pressure (BP) have been proposed. We evaluated the categorization of HT most qualified to define MS in relationship with coronary heart disease (CHD) mortality at a population level. A total of 3257 subjects aged > or =65 years were followed up for 12 years. MS was defined according to the criteria of the National Education Cholesterol Program using three different categories of HT: MS-1 (systolic blood pressure (SBP) > or =130 and diastolic blood pressure (DBP) > or =85 mm Hg), MS-2 (SBP > or =130 or DBP > or =85 mm Hg) and MS-3 (pulse pressure (PP) > or =75 mm Hg in men and > or =80 mm Hg in women). Gender-specific adjusted hazard ratio (HR) with 95% confidence intervals (CI) for CHD mortality was derived from Cox analysis in the three MS groups, both including and excluding antihypertensive treatment. In women with MS untreated for HT, the risk of CHD mortality was always significantly higher than in those without MS, independent of categorization; the HR of MS was 1.73 (CI 1.12-2.67) using MS-1, 1.75 (CI 1.10-2.83) using MS-2 and 2.39 (CI 3.71-1.31) using MS-3. In women with MS treated for HT, the HR of CHD mortality was significantly increased only in the MS-3 group (1.92, CI 1.1-2.88). MS did not predict CHD in men. In conclusion, MS can predict CHD mortality in elderly women with untreated HT but not in those with treated HT; in the latter, PP is the most predictive BP value.

Intra-erythrocyte cation concentrations in relation to the C1797T beta-adducin polymorphism in a general population

Genetic variability in the ADD1 (Gly460Trp) and ADD2 (C1797T) subunits of the cytoskeleton protein adducin plays a role in the pathogenesis of hypertension, possibly via changes in intracellular cation concentrations. ADD2 1797CC homozygous men have decreased erythrocyte count and hematocrit. We investigated possible association between intra-erythrocyte cations and the adducin polymorphisms. In 259 subjects (mean age 47.7 years), we measured intra-erythrocyte Na(+) [iNa], K(+) [iK] and Mg(2+) [iMg], serum cations and adducin genotypes. Genotype frequencies (ADD1: GlyGly 61.5%, Trp 38.5%; ADD2: CC 80.4%, T 19.6%) complied with Hardy-Weinberg proportions. In men, ADD2 CC homozygotes (n=100) compared to T-carriers (n=23) had slightly lower iK (85.8 versus 87.5 mmol/l cells; P=0.107), higher iMg (1.92 versus 1.80 mmol/l cells; P=0.012), but similar iNa (6.86 versus 6.88 mmol/l cells; P=0.93). In men, iK, iMg and iNa did not differ according to ADD1 genotypes. In men, iK (R(2)=0.128) increased with age and serum Na(+), but decreased with serum total calcium and the daily intake of alcohol. iMg (R(2)=0.087) decreased with age, but increased with serum total calcium. After adjustment for these covariates (P<or=0.04 for all), findings in men for iK (CC versus T: 85.8 versus 87.3 mmol/l; P=0.14) and iMg (1.91 versus 1.82 mmol/l; P=0.03) remained consistent. In 136 women, none of the phenotype-genotype relations reached significance. Changes in intra-erythrocyte cations in ADD2 1797CC homozygous men might lead to osmotic fragility of erythrocytes, but to what extent they reflect systemic changes or are possibly involved in blood pressure regulation remains unknown.

Triglycerides + high-density-lipoprotein-cholesterol dyslipidaemia, a coronary risk factor in elderly women: the CArdiovascular STudy in the ELderly

BACKGROUND

The relationship between serum triglycerides (TG) level and the risk of coronary heart disease (CHD) mortality remains controversial.

AIMS

To evaluate whether TG level is a risk factor for CHD in elderly people from general population, and to look for interactions between TG and other risk factors.

METHODS

3257 subjects aged >or= 65 years followed up for 12 years from the CArdiovascular STudy in the ELderly. Blood tests and anthropometric measurements were performed. Continuous items were divided into quintiles and, for each quintile, adjusted hazard ratio (HR) with 95% confidence interval (CI) for CHD mortality was derived by genders from Cox analysis.

RESULTS

In women, the HR of being in the fifth rather than in the first quintile of TG was 2.45 (CI 1.48-3.51). In turn, high-density-lipoprotein cholesterol (HDL-C) inversely predicted CHD mortality; the HR of being in the first rather than in the fifth quintiles of HDL-C was 1.52 (CI 1.24-2.36). The risk of CHD mortality further increased up to 3.81 (CI 1.62-5.43) when high TG and low HDL-C were combined. No predictive role for either TG or HDL-C was detected in men.

CONCLUSIONS

TG and HDL-C were independent predictors of CHD mortality in elderly women. The combination high TG + low HDL-C quadrupled the risk of CHD mortality in this gender only.

Context-dependency of the relation between left ventricular mass and AGT gene variants

In the European Project on Genes in Hypertension (EPOGH), we investigated in three populations to what extent in a family-based study, left ventricular mass (LVM) was associated with the C-532T and G-6A polymorphisms in the angiotensinogen (AGT) gene. We randomly recruited 221 nuclear families (384 parents and 440 offspring) in Cracow (Poland), Novosibirsk (Russia), and Mirano (Italy). Echocardiographic LVM was indexed to body surface area, adjusted for covariables, and subjected to multivariate analyses, using generalized estimating equations and quantitative transmission disequilibrium tests in a population-based and family-based approach, respectively. We found significant differences between the two Slavic centres and Mirano in left ventricular mass index (LVMI) (94.9 vs 80.4 g/m2), sodium excretion (229 vs 186 mmol/day), and the prevalence of the AGT -6A (55.7 vs 40.6%) and -532T (16.8 vs 9.4%) alleles. In population-based as well as in family-based analyses, we observed positive associations of LVMI and mean wall thickness (MWT) with the -532T allele in Slavic, but not in Italian male offspring. Furthermore, in Slavic male offspring, LVMI and MWT were significantly higher in carriers of the -532T/-6A haplotype than in those with the -532C/-6G or -532C/-6A allele combinations. In women, LVMI was neither associated with single AGT gene variants nor with the haplotypes (0.19 < P <0.98). In Slavic offspring carrying the AGT -532C/-6G or -532C/-6A haplotypes, LVMI significantly increased with higher sodium excretion (+3.5 g/m2/100 mmol; P=0.003), whereas such association was not present in -532T/-6A haplotype carriers (P-value for interaction 0.04). We found a positive association between LVMI and the AGT -532T allele due to increased MWT. This relation was observed in Slavic male offspring. It was therefore dependent on gender, age and ecogenetic context, and in addition it appeared to be modulated by the trophic effects of salt intake on LVM.

Should pulse pressure become part of the Framingham risk score?

An increased pulse pressure suggests aortic stiffening. New evidence also suggests that pulse pressure is a more sensitive measure of risk than other indexes of blood pressure in middle-aged and older persons. The objective of the study was to relate pulse pressure to the risk of cardiovascular events in the general population, and to assess whether pulse pressure could improve the Framingham risk prediction. A total of 378 men and 391 women over the age of 50 years (mean 62.7 years) were followed. Sex-specific Framingham cardiovascular risk scores were derived from age, systolic pressure, diastolic pressure, total and HDL cholesterol, smoking status and the presence or absence of diabetes mellitus. The cutoff points used to develop a pulse pressure score were calculated by determining the percentile points corresponding to the blood pressure categories in the Framingham risk score. We calculated relative hazard rates by multiple Cox regression. After a median follow-up of 7.2 years (range: 11 months-15 years), a total of 148 cardiovascular events occurred. In Cox regression analysis, a 10 mmHg higher pulse pressure was associated with 31% (P<0.0001) increase in the risk for cardiovascular events (fatal and nonfatal) after adjustment for sex, age, total and HDL cholesterol, smoking and the presence of diabetes mellitus. After adjustment for the aforementioned risk factors, a one-point increment in the blood pressure and pulse pressure scores was associated with a 40 and 48% (both P<0.0001) increase in the risk of fatal and nonfatal cardiovascular events, respectively. When both the blood pressure and pulse pressure scores were forced into a Cox model, only the pulse pressure score remained statistically significant (P<0.0001) with a relative hazard rate of 1.37 (CI: 1.16-1.69). These prospective data suggest that pulse pressure may improve the Framingham risk prediction among middle-aged and older individuals. Further studies, especially in the Framingham cohort, are warranted.

Total cholesterol and mortality in the elderly

OBJECTIVE

To evaluate, at a population level, whether total cholesterol (TC) is a risk factor of mortality. To verify whether or not this is true for both genders.

DESIGN

Population-based, long-lasting, prospective study.

SETTING

Institutional epidemiology in primary care.

SUBJECTS

A total of 3257 subjects aged 65-95 years, recruited from Italian general population.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Total cholesterol was measured, analysed as a continuous variable and then divided into quintiles and re-analysed. For each quintile, the multivariate relative risk (RR) of mortality adjusted for confounders was calculated in both genders. Stratification of mortality risk by TC quintiles, body mass index and cigarette smoking was also performed in both genders.

RESULTS

Total cholesterol levels directly predicted coronary mortality in men [RR being in the fifth rather than in the first quintile: 2.40 (1.40-4.14)] and any other mortality in women. It also inversely predicted miscellaneous mortality in both genders. This trend was more evident when low cholesterol was associated with malnutrition or smoking.

CONCLUSIONS

High TC remains a strong risk factor for coronary mortality in elderly men. On the other hand, having a very low cholesterol level does not prolong survival in the elderly; on the contrary, low cholesterol predicts neoplastic mortality in women and any other noncardiovascular mortality in both genders.

Predictors of stroke mortality in elderly people from the general population. The CArdiovascular STudy in the ELderly

Stroke occurs particularly frequently in elderly people and, being more often disabling than fatal, entails a high social burden. The predictors of stroke mortality have been identified in 3282 subjects aged > or = 65 years, taking part in the CArdiovascular STudy in the ELderly (CASTEL), a population-based study performed in Northeast Italy. Historical and clinical data, blood tests and 14-year fatal events were recorded. Continuous items were divided into quintiles and, for each quintile, adjusted relative risk (RR) with 95% confidence intervals [CI] was derived from multivariate Cox analysis. Age, historical stroke (RR: 5.2; 95% CI: 3.18-8.6) and coronary artery disease (RR: 1.38; CI: 1.18-2.1), atrial fibrillation (RR: 2.40; CI: 1.42-4.0), arterial hypertension (RR: 1.33; CI: 1.15-1.76), systolic blood pressure > or = 163 mmHg (RR: 1.84; CI: 1.20-2.59), pulse pressure > or = 74 mmHg (RR: 1.50; CI: 1.13-2.40), cigarette smoking (RR: 1.60; CI: 1.03-2.47), electrocardiographic left ventricular hypertrophy (RR: 1.72; CI: 1.10-2.61), impaired glucose tolerance (IGT, RR: 1.83; CI: 1.10-3.0), uric acid (UA) > 0.38 mmol/l (RR: 1.61; CI: 1.14-2.10), serum potassium > or = 5 mEq/l (RR: 1.70; CI: 1.24-2.50) and serum sodium < or = 139 mEql/l (RR: 1.34; 1.10-2.10) increased the risk of stroke. In the CASTEL, stroke was the first cardiovascular cause of death. Some independent predictors usually unrelated to stroke mortality (namely pulse pressure, pre-diabetic IGT, UA and blood electrolytes disorders) have been identified.

Pulse pressure: an independent predictor of coronary and stroke mortality in elderly females from the general population

The aim of this paper is to evaluate whether pulse pressure is an independent risk factor for coronary and stroke mortality in 3282 subjects (1281 males and 2001 females) aged +/- 65 years, taking part in the CArdiovascular STudy in the Elderly (CASTEL). After dividing subjects into tertiles of pulse pressure, adjusted relative risk (RR) and confidence intervals (CI) for 14-year coronary and stroke mortality was evaluated for each tertile. Among females, coronary mortality rate was 2.7% in the first tertile of pulse pressure, 4.7% in the second (RR 1.38, 95% CI [1.15-2.66]) and 6.2% in the third (RR 2, CI [1.20-3.51]). Stroke mortality was 3.6%, 4.1% (RR 1.23, CI [1.02-2.23]) and 8.3% (RR 2.27, CI [1.37-3.74]), respectively. This trend was recognizable in normotensive, borderline and sustained hypertensive women, where mortality increased with rising pulse pressure. No relationship was found between pulse pressure and mortality in males. In elderly women, pulse pressure was a good predictor of coronary and stroke mortality, even superior to the label of hypertension. No matter how any given pulse pressure level was obtained, it was more predictive of both coronary and cerebrovascular mortality than belonging to a normo- or hypertensive category.

Pulse pressure and coronary mortality in elderly men and women from general population

The aim of this work was to evaluate whether pulse pressure (PP) in elderly people is a better predictor of coronary mortality than systolic and diastolic blood pressure taken alone. For this aim, 3282 elderly subjects aged >or=65 years were studied in a population-based frame. Blood pressure was repeatedly measured and averaged; historical data, anthropometrics, blood tests and 14-year coronary mortality were recorded. Statistics included analysis of covariance, Cox analysis and bivariate vectorial analysis. Coronary mortality in women was predicted by PP (1.01 excess risk/mm Hg PP) and was significantly higher in the 3rd than in the 1st tertile of PP (relative risk 2.90); neither systolic nor diastolic pressure taken alone influenced mortality. When systolic and diastolic pressures were both entered into a Cox model, the former had a positive and the latter a negative effect on survival, confirming a prognostic role of PP. For any given level of systolic pressure, mortality was inversely associated with diastolic pressure. Finally, the mean vector representing both systolic and diastolic pressures of non-surviving women was characterised by higher systolic and lower diastolic components than in non-surviving. No significant trend of mortality in relation to either systolic blood pressure or PP was observed in men. In conclusion, the combination of systolic and diastolic pressure called PP is an independent predictor of coronary mortality in elderly females, and a better predictor than systolic or diastolic pressure alone.

Heritability of left atrial size in the Tecumseh population

BACKGROUND

Little is known about the determinants of atrial size, and no study has analyzed whether genetic factors are involved in the pathogenesis of LA enlargement.

MATERIALS AND METHODS

We studied the heritability of echocardiographic left atrial size in 290 parents from the Tecumseh Blood Pressure Study and 251 children from the Tecumseh Offspring Study. All data from the parents and children were obtained at the same field office in Tecumseh, USA. Left atrial dimension was determined echocardiographically in accordance with American Society of Echocardiography guidelines with the use of leading-edge-to-leading-edge measurements of the maximal distance between the posterior aortic root wall and the posterior left atrial wall at end systole.

RESULTS

For correlation between the left atrial dimensions of the parents and their offspring, several models were generated to adjust the atrial dimensions in both groups for an increasing number of clinical variables. After removing the effect of age, gender, height, weight, skinfold thickness, and systolic blood pressure, parent-child correlation for left atrial size was 0.19 (P = 0.007). Further adjustment for left ventricular mass and for measuring left ventricular diastolic function increased the correlation to 0.25 (P = 0.001).

CONCLUSIONS

The present data indicate that heredity can explain a small but definite proportion of the variance in left atrial dimension.

Weak effect of hypertension and other classic risk factors in the elderly who have already paid their toll

The aim of the CASTEL, a population-based (n=3282) prospective study which began 14 years ago, was to identify those items which had a prognostic impact in the elderly, and to evaluate whether the typical cardiovascular risk factors, particularly arterial hypertension, play a role after the age of 65 years. Initial screening, final follow-up and annual detection of mortality were performed. Mantel-Hanszel approach and multivariate Cox model were used for statistics. Cardiovascular mortality was 23.3% in normotensive, 23.3% in borderline, and 25% in the sustained hypertensive subjects (insignificant difference). In women, the incidence of stroke and coronary artery disease weakly depended on pulse pressure. Historical stroke and myocardial infarction predicted cardiovascular mortality in women; diabetes, uricaemia and high heart rate in men. In the very old, the predictors were less numerous, and blood pressure was not a predictor whatsoever; pulse blood pressure and murmurs at the neck were especially predictive in women, historical heart failure, proteinuria and tachycardia in men, historical stroke and myocardial infarction, pulmonary disease, left ventricular hypertrophy, diabetes and uricaemia in both genders. The elderly have a different cardiovascular risk pattern compared to younger people. Hypertension is not a predictor of coronary and stroke mortality. Prognosis depends on pulse pressure rather than on the label 'hypertension'. Hypercholesterolaemia is not a risk factor. This could simply indicate that elderly persons are the survivors in a population where significant mortality has already made its mark, eliminating those with the worst risk pattern. The two genders have a different risk profile due to sex-specific susceptibility to risk factors.

Genetic contribution to the variance in left ventricular mass: the Tecumseh Offspring Study

OBJECTIVE

To estimate the contribution of heredity to the variance in left ventricular mass (LVM), and to ascertain whether genetic factors may interact with non-genetic factors in promoting LVM growth.

SUBJECTS AND SETTING

The study population consisted of 290 healthy parents and 251 healthy children living in Tecumseh, Michigan, USA.

MAIN OUTCOME MEASURE

Correlation of parents' LVM with offspring's LVM adjusting for a number of clinical variables.

METHODS

LVM in parents and offspring was measured with M-mode echocardiography by the same investigators.

RESULTS

Parents unadjusted LVM was unrelated to offspring unadjusted LVM, but after removing the confounding effect of age, sex, anthropometric measurements, systolic blood pressure, plasma insulin and urinary sodium excretion, parent-child correlation for LVM was 0.28 (P = 0.006). The relative contribution of parental-adjusted LVM and of several offspring phenotypic and environmental variables on offspring LVM was evaluated by multivariable regression analysis. When age, gender, anthropometric measurements and systolic blood pressure were accounted for, adjusted LVM of parents explained only 1.6% of the total variance in offspring LVM. However, after inclusion of insulin and urinary sodium in the model heredity explained 7.6% of the total variance in offspring LVM, and its predictive power was second only to that of child's height. Furthermore, an interactive effect of parental LVM with offspring systolic blood pressure was found on child's left ventricular mass.

CONCLUSION

Heredity can explain a small, but definite proportion of the variance in LVM. Higher blood pressure favors the phenotypic expression of the genes that regulate LVM growth.

Cardiovascular mortality in non-insulin-dependent diabetes mellitus. A controlled study among 683 diabetics and 683 age- and sex-matched normal subjects

Although non-insulin-dependent diabetes mellitus (NIDDM) is considered a major cause of death, the role of some independent risk factors in diabetic patients is under debate. In fact the prognosis of NIDDM diabetes varies considerably in relation to the individual risk pattern, and the different studies are not directly comparable because of differences in size, age and geography of the samples, and type of statistical analysis. The aim of the study is to identify the independent predictors of mortality in a cohort of subjects with NIDDM, and to verify whether the relative risk (RR) of cardiovascular mortality is different in comparison to that of coeval non-diabetic subjects from a general population. The study includes 683 patients with NIDDM from the Northern Italian town of Pordenone, followed up for 6 years and age- and sex-matched to 683 non-diabetic subjects from a Northern Italian general population. When the two cohorts were compared, NIDDM turned out to be a strong risk factor for cardiovascular mortality (RR: 2.67). Age, coronary artery disease (RR: 1.78), arterial hypertension (RR: 1.39), macro- (RR: 2.97) and microalbuminuria (RR: 2.01) were independent predictors of cardiovascular mortality in the diabetics. In conclusion, survival of diabetic patients is worse than that of non-diabetic coeval subjects. Only few items are able to predict cardiovascular mortality in the diabetics, namely age, hypertension, CAD, macro- and microalbuminuria.

The 24-hour rhythm of blood pressure differs from that of leg hemodynamics in orthotopic heart transplant recipients

BACKGROUND

This study was aimed at investigating whether a circadian rhythm of peripheral resistance exists in patients with orthotopic cardiac transplantation (OCT) and whether it parallels that of blood pressure (BP).

METHODS

BP and leg flow and resistance (plethysmography) were monitored for 24 hours in 13 denervated OCT recipients and 13 control patients with native heart, matched for casual blood pressure.

RESULTS

On the basis of BP trend, control patients showed a BP reduction during sleep, whereas OCT recipients did not. Leg resistance was significantly lower and leg flow significantly higher during sleep than during waking in all patients, and the extent of the nocturnal decrease was similar in the two categories.

CONCLUSIONS

The decrease in leg resistance in patients confined to bed for 24 hours is caused by peripheral mechanisms and does not depend on the autonomic control of the heart. The nocturnal decline in BP depends, on the contrary, on cardiac control and is lost in patients with denervated heart.

Blood pressure and metabolic profile after surgical menopause: comparison with fertile and naturally-menopausal women

In 1978 a random sample (367 men and 568 women aged 18-65 years) taken from the general population of a north-eastern Italian town was screened for cardiovascular risk; 16 years later, the women were invited to a second screening. Three groups were identified at the initial screening (fertile, naturally menopausal and surgically menopausal) and four in the longitudinal study (137 remained fertile during the whole study, 205 became naturally menopausal, 56 were ovariectomised and 127 were already going through the menopause). The protocol included a questionnaire, blood pressure (BP) measurement, and blood exams. Continuous variables were adjusted for confounders. Systolic BP, prevalence of hypertension, cholesterol, glycaemia and uricaemia were similar, whereas diastolic and triglycerides (TG) were lower in surgically-menopausal than in fertile women (P < 0.001). No significant difference in 16 years' variation from baseline was observed between the four groups, although women who remained fertile showed the smallest increases. In particular, neither systolic or diastolic BP increases differed between the women who were oophorectimised and those who remained fertile. 'Fertile status' was rejected from the logistic equation of incidence of hypertension, and 'age of menopause' was also rejected when this analysis was repeated in ovariectomised women. New coronary artery disease (angina pectoris or myocardial infarction) was observed in one ovariectomised woman, in three naturally menopausal, and in 13 already menopausal women which seemed to reflect the age trend. No new cases were observed in women who remained fertile. In conclusion, in Italian women surgical menopause, similarly to natural menopause, is devoid of any negative prognostic effect. Journal of Human Hypertension (2000) 14, 799-805

Predictors of cancer mortality in elderly subjects

Cancer mortality was analysed in 3282 elderly subjects aged > or =65 years from 2 cohorts of general population having different life-style patterns. They took part in the CASTEL (CArdiovascular STudy in the ELderly), a 12-year lasting prospective Italian study. The aim of the present analysis was to identify the items able to influence cancer mortality. A biochemical profile and a questionnaire on lifestyle were collected. Continuous items were averaged and compared with analysis of variance, frequencies with the Pearson's chi2 test. Mortality was recorded yearly for 12 years from the Registrar's Office and causes of death double-checked by consulting medical case sheets and family doctors' files. The influence of items on mortality was evaluated with the Cox multivariate analysis. Relative risk (RR) of each item was adjusted for confounders. Age, gender, tobacco smoking, the presence of respiratory symptoms, low body mass index in males, serum alanine transaminase (ALT) and alkaline phosphatase (ALP), as well as the town of residence, were powerful predictors of cancer mortality. In the entire population, 12-year overall mortality was 49.4%, cardiovascular 22.8%, and neoplastic 11%; the latter was higher in males than in females (15.7% vs. 7.9%, p < 0.00001). In subjects with respiratory symptoms neoplastic mortality was 11.6% (RR: 1.47) vs. 9.7% in those without symptoms (p < 0.01). Subjects with very low cholesterol (< or = 178 mg/dl), those with high uric acid (> or =8.7 mg/ dl) and males with low body mass index (< or =22.7 kg/ m2) has an increased risk of cancer mortality. RR of cancer mortality increased with increasing ALT or ALP. It was approximately 1 in those having ALT and ALP between 9 and 41.2 U/I, 1.41 in those exceeding this latter level and < 1 in those below 9 U/I. RR of ALP had a similar trend, the best protective cut-off value being < 106 and the worst one > 177 U/I. When both serum enzymes were simultaneously raised, RR of cancer mortality increased to 2.84.

24-hour leg and forearm haemodynamics in transected spinal cord subjects

OBJECTIVE

A circadian rhythm of blood pressure has been demonstrated both in subjects who are physically active during the day and in those confined to bed. The study of the circadian rhythm of arterial flow and peripheral resistance, on the other hand, is limited to pioneer experiments. This paper is aimed at demonstrating that leg peripheral resistance has circadian fluctuations which are modulated by spinal neural traffic.

METHODS

Eleven normal (able-bodied) human subjects and 11 patients with spinal transection due to spinal cord injury (SCI) were studied. They were confined to bed for 24 h. Blood pressure and heart rate were monitored every 15 min with an automatic device and leg flow with an automatic strain-gauge plethysmograph synchronised to the pressurometer. Peripheral resistance was calculated at the same intervals.

RESULTS

In able-bodied subjects leg resistance was significantly higher during waking hours (when the sympathetic system is more activated) than during sleep, while in subjects with spinal cord injury no difference was detected between day-time and night-time.

CONCLUSIONS

The circadian rhythm is controlled by adrenergic fibres transmitted via the spinal cord.

Effects of caffeine on glucose tolerance: a placebo-controlled study

OBJECTIVE

The investigation was performed to study the effects of 200 mg oral caffeine on glucose tolerance.

DESIGN

Single-blind Latin square with active treatment (caffeine) and placebo.

SETTING

The University of Padova, Department of Internal Medicine.

SUBJECTS

30 nonsmoking healthy subjects aged 26-32 years who abstained not only from coffee but also from tea, chocolate and cola for 4 weeks and who had given their informed consent.

INTERVENTIONS

A 75 g oral glucose tolerance test (OGTT) was performed after giving caffeine or placebo (highly decaffeinated coffee).

RESULTS

The glycaemic curve was normal in all subjects and was similar in the two groups until the second hour; in subjects taking caffeine a shift towards the right was detected at the 2nd, 3rd and 4th hours in comparison to those taking the placebo. Blood insulin levels were comparable after caffeine and after placebo along the entire OGTT.

CONCLUSIONS

The data suggest that caffeine intake induces a rise in blood glucose levels that is insulin independent.

Should digoxin be proscribed in elderly subjects in sinus rhythm free from heart failure? A population-based study

Increased mortality in digoxin-treated subjects has been demonstrated in patients with recent myocardial infarction. Those with congestive heart failure (CHF) due to causes other than myocardial infarction seem to be free from this effect. No information is currently available concerning mortality in elderly people who are frequently prescribed digitalis even in the absence of CHF. The aim of this study was to investigate whether subjects improperly receiving digoxin were worse off than those not receiving this drug. This analysis is a part of CASTEL, a population-based prospective study that has enrolled a cohort of 2,254 subjects aged > or = 65 years. CHF was diagnosed in 187 subjects and atrial fibrillation (AF) in 90. The remaining 1,977 were free from CHF and in sinus rhythm, but 447 were treated with digitalis. Cumulative mortality and morbid events by digitalis treatment were calculated in all these categories. Among subjects free from CHF and AF (improper use), all-cause and cardiovascular mortality was significantly higher among those taking digitalis than in those who did not. Non-fatal events including CHF were also more apparent in the former than in the latter. Cox analysis confirmed digitalis as a predictor of mortality in these subjects. No effect of digitalis on survival was found in patients with CHF or AF (proper use). In elderly subjects without atrial fibrillation or CHF, the use of digitalis worsens morbidity and mortality.