HCN channels in the heart: lessons from mouse mutants

Hyperpolarization-activated cation channels generate the I(f) current in the heart. In the sino-atrial node (SAN), I(f) is thought to play an essential role in setting the heart rate and mediating its autonomic control. This review focuses on the role of I(f) in pacemaking and non-pacemaking cardiomyocytes and the resulting therapeutic implications. HCN4 represents the principal isoform underlying sino-atrial I(f) , but other isoforms may also be of importance. To examine the functional role of cardiac channels, several mouse mutants, most of them targeting HCN4, have been generated by different groups. Unexpectedly, these lines display greatly different and as yet unexplained phenotypes. We provide an overview about these HCN mutants and suggest an interpretation of the functional significance of I(f) in the SAN in light of these studies. HCN channels are also present in ventricular myocytes, and an up-regulation of I(f) in the hypertrophic and failing heart may contribute to arrhythmogenesis. Inhibition of I(f) by HCN channel blockers is a novel approach in the treatment of cardiac disorders, and ivabradine is approved for treatment of stable angina pectoris. Remarkably, a recent clinical trial assessing this substance in heart failure showed a significantly improved outcome. The mechanism underlying this beneficial effect is not yet clear and might lie beyond heart rate slowing. Thus, the growing knowledge about cardiac HCN channels will undoubtedly promote the development of the promising class of HCN channel blockers.

The cardiovascular risk factor profile in the study area Augsburg. Results from the first MONICA survey 1984/85

The main objective of the first survey was the investigation of the prevalence and distribution of hypertension, hypercholesterolemia and cigarette smoking in the study area. The data-collection phase lasted from October 1984 to May 1985. A two-stage cluster sample of 5312 persons of German nationality was drawn from a population of 282,279 inhabitants, aged 25-64. The data were gathered through interview, physical examination and self-administered questionnaire. A response of 79% was achieved. Sixteen percent of men and 10% of women had high blood pressure (BP) values (greater than or equal to 160/95 mmHg). Only 16% of male and 34% of female hypertensives had controlled BP values. The prevalence of hypercholesterolemia (greater than or equal to 6.72 mmol/L = greater than or equal to 260 mg/dl) was 26% in men and 22% in women. Forty percent of men and 22% of women reported they were current cigarette smokers. Among participants, aged 25-44, cigarette smoking was the most prevalent risk factor in men and women. Thirty-seven percent of men and 52% of women, aged 25-64, had none of the three major risk factors.

MesP1 drives vertebrate cardiovascular differentiation through Dkk-1-mediated blockade of Wnt-signalling

ES-cell-based cardiovascular repair requires an in-depth understanding of the molecular mechanisms underlying the differentiation of cardiovascular ES cells. A candidate cardiovascular-fate inducer is the bHLH transcription factor MesP1. As one of the earliest markers, it is expressed specifically in almost all cardiovascular precursors and is required for cardiac morphogenesis. Here we show that MesP1 is a key factor sufficient to induce the formation of ectopic heart tissue in vertebrates and increase cardiovasculogenesis by ES cells. Electrophysiological analysis showed all subtypes of cardiac ES-cell differentiation. MesP1 overexpression and knockdown experiments revealed a prominent function of MesP1 in a gene regulatory cascade, causing Dkk-1-mediated blockade of canonical Wnt-signalling. Independent evidence from ChIP and in vitro DNA-binding studies, expression analysis in wild-type and MesP knockout mice, and reporter assays confirm that Dkk-1 is a direct target of MesP1. Further analysis of the regulatory networks involving MesP1 will be required to preprogramme ES cells towards a cardiovascular fate for cell therapy and cardiovascular tissue engineering. This may also provide a tool to elicit cardiac transdifferentiation in native human adult stem cells.

Induced abnormality in Mir- and Earth grown Super Dwarf wheat

Super-dwarf wheat grown on the Mir space station using the Svet "Greenhouse" exhibited morphological, metabolic and reproductive abnormalities compared with Earth-grown wheat. Of prominent importance were the abnormalities associated with reproductive ontogeny and the total absence of seed formation on Mir. Changes in the apical meristem associated with transition from the vegetative phase to floral initiation and development of the reproductive spike were all typical of 'Super-Dwarf' wheat up to the point of anthesis. Observation of ruptured anthers from the Mir-grown plants revealed what appeared to be normally developed pollen. These pollen gains, however, contained only one nuclei, while normal viable pollen is tri-nucleate. A potentially important difference in the flight experiment, compared with ground reference studies, was the presence of a high level of atmospheric ethylene (1,200 ppb). Ground studies conducted by exposing 'Super-Dwarf' wheat to ethylene just prior to anthesis resulted in manifestation of the same abnormalities observed in the space flight samples.

Do siblings of myocardial infarction patients have a specific management of hypertension?

The aim of this study was to determine whether the management of hypertension differs between siblings of myocardial infarction patients and the general population. Siblings aged 35 to 74 years, unaffected by myocardial infarction, were drawn from the Augsburg Family Heart Study, conducted in 1996-1997 in southern Germany (n = 524). The reference group consisted of participants of the third MONICA population-based survey conducted in 1994-1995 in the same area, who were aged 35 to 74 years and also unaffected by myocardial infarction (n = 3802). Prevalence, awareness, treatment and control of hypertension (defined by blood pressure > or = 140/90 mm Hg or use of antihypertensive medication) were compared between the two groups. The result was that the prevalence of hypertension was higher in the siblings (men: age-adjusted OR = 1.31, 95% CI: 0.99-1.75; women: age-adjusted OR = 1.83, 95% CI: 1.39-2.41). Male hypertensive siblings were more often aware and treated for hypertension than male hypertensives of the reference group whereas the level of awareness and treatment was comparable between female hypertensives of the two groups. In both genders, no difference in the degree of control was shown between hypertensives of the two groups. In conclusion the siblings and their physicians should pay more attention to the family history of myocardial infarction in order to improve the management of hypertension in this high risk group.

[Epidemiology of limb fractures]

To analyze age- and sex-specific frequencies of peripheral fractures, we used data from the third MONICA-Augsburg Survey (1994/95). The study comprises 2404 male and 2450 female participants (age 25 to 74 years) who were questioned regarding fracture history. We investigated fracture prevalence, age-specific incidence rates, and the circumstances under which the fractures occurred. The age-standardized, cumulative fracture prevalence among men (m) 25 to 74 years of age was 45% and among women (w) of the same age 31%. Fracture prevalence among women was more than 10% lower than among men in the younger age groups (age 25 to 64 years), but after an significant increase in the 65 to 74-year-olds the fracture prevalence corresponded to that of men (m: 42%, w: 40%). A peak of incidence rates was found among men at age 15-24 (overall incidence rate: 2017 fractures/100,000 person-years) and at age 45-54 (overall incidence rate: 1640 fractures/100,000 PY), respectively, and among women at age 65-74 (overall incidence rate: 3214 fractures/100,000 PY). The prevalence of self-reported osteoporosis (age 25 to 74 years) was higher in women (7%) than in men (1%). Falls caused 43% (w: 59%, m: 33%) of all fractures, external violence 40% (m: 47%, w: 29%), and sports activities 15% (m: 18%, w: 10%). Further investigation of risk factors related to fractures can contribute to the development of specific preventive measures in that field. In the future, the prevention and efficient treatment of an existing or an often undiagnosed osteoporosis and also the prevention of falls in elderly persons should be an important public health concern.

Microalbuminuria, central adiposity and hypertension in the non-diabetic urban population of the MONICA Augsburg survey 1994/95

OBJECTIVE

Microalbuminuria is a renal marker of general vascular endothelial damage and early atherosclerosis with adverse prognostic implications. Microalbuminuria is associated with diabetes, insulin resistance, central adiposity and hypertension. We evaluated the degree of the association of components of the metabolic syndrome with microalbuminuria in a subsample of a non-diabetic study population.

DESIGN

Men and women aged 25-74 living in the city of Augsburg, Germany, were interviewed and examined in a standardised manner at a population-based survey conducted in 1994/95. Persons with a history of diabetes or HbA1c level > or = 7% were excluded.

OUTCOME

Albumin and creatinine were determined quantitatively in a spot urine and defined as microalbuminuria via an albumin/creatinine ratio between 30 and 299 mg/g.

RESULTS

Among 920 men and 879 women, the age- standardised prevalence of microalbuminuria was 8.0% and 7.5%, respectively. While a graded, positive increase in prevalence of microalbuminuria across quintiles of waist-to-hip (WHR) was observed in non-hypertensive men and women, microalbuminuria was uniformly high among hypertensives. Multivariate logistic regression models showed that central adiposity (OR 3.3) or hypertension (OR 4.0) alone significantly increased the odds of microalbuminuria while their joint presence (OR 3.6) did not add to the occurrence of microalbuminuria. While obesity was not associated with microalbuminuria once central adiposity was taken into account, elevated percent body fat remained associated with microalbuminuria.

CONCLUSIONS

Signs of early endothelial dysfunction as manifested as microalbuminuria are strongly and independently associated with central adiposity and should be considered in the context of the metabolic or insulin resistance syndrome.

Comparative floral development of Mir-grown and ethylene-treated, earth-grown Super Dwarf wheat

To study plant growth in microgravity, we grew Super Dwarf wheat (Triticum aestivum L.) in the Svet growth chamber onboard the orbiting Russian space station, Mir, and in identical ground control units at the Institute of BioMedical Problems in Moscow, Russia. Seedling emergence was 56% and 73% in the two root-module compartments on Mir and 75% and 90% on earth. Growth was vigorous (produced ca. 1 kg dry mass), and individual plants produced 5 to 8 tillers on Mir compared with 3 to 5 on earth-grown controls. Upon harvest in space and return to earth, however, all inflorescences of the flight-grown plants were sterile. To ascertain if Super Dwarf wheat responded to the 1.1 to 1.7 micromoles mol-1 atmospheric levels of ethylene measured on the Mir prior to and during flowering, plants on earth were exposed to 0, 1, 3, 10, and 20 micromoles mol-1 of ethylene gas and 1200 micromoles mol-1 CO2 from 7 d after emergence to maturity. As in our Mir wheat, plant height, awn length, and the flag leaf were significantly shorter in the ethylene-exposed plants than in controls; inflorescences also exhibited 100% sterility. Scanning-electron-microscopic (SEM) examination of florets from Mir-grown and ethylene-treated, earth-grown plants showed that development ceased prior to anthesis, and the anthers did not dehisce. Laser scanning confocal microscopic (LSCM) examination of pollen grains from Mir and ethylene-treated plants on earth exhibited zero, one, and occasionally two, but rarely three nuclei; pollen produced in the absence of ethylene was always trinucleate, the normal condition. The scarcity of trinucleate pollen, abrupt cessation of floret development prior to anthesis, and excess tillering in wheat plants on Mir and in ethylene-containing atmospheres on earth build a strong case for the ethylene on Mir as the agent for the induced male sterility and other symptoms, rather than microgravity.

[Ten-year trend of analgesic drug use (1984 to 1995): results of three MONICA-based surveys in Augsburg)]

BACKGROUND AND OBJECTIVE

Use of drugs, especially analgesics, is thought to be responsible for the rising cost of the health system in Germany, but there are no published population data for analgesic intake in Germany. Data derived from the three MONICA surveys (Monitoring of Trends and Determinants of Cardiovascular Diseases) in Augsburg and its adjacent districts were analysed for the prevalence of analgesic usage between 1984 and 1995 (the first such survey for Germany).

PATIENTS AND METHODS

A total of 5,899 males and 6,005 females (aged 25-64 years), representative of the population, were selected and examined in 1984/85, 1989/90 and 1994/95 (participation rate of those selected, 75-79%). Using a standardized protocol, all analgesic drugs taken during the previous 7 days were recorded and classified. The analysis was standardized for age and classified according to sex.

RESULTS

Strong analgesics were not significantly used under the ambulatory conditions of this survey and were therefore excluded from the analysis. Intake prevalence of mild to moderately strong analgesics varied from 5.9-8.9% in males and 9.9-13.4% in females. Prevalence was significantly at its lowest in 1989/90, but similar at the beginning and end of the 10-year period. Changes in prevalence of analgesic usage were similar to those of on-demand medication. Salicylic acid preparations containing higher dosages of the active ingredient were the drugs most commonly used, followed by aniline preparations, heteroaryl- as well as aryl-acetate and propionic acid derivates, pyrazole derivates, oxicam and anthranylic acid derivates.

CONCLUSION

The prevalence of taking mild of moderately strong analgesics was at a similar low level at the beginning and end of the 10-year period.

Effects of air pollution on blood pressure: a population-based approach

OBJECTIVES

This analysis assessed the association between blood pressure, meteorology, and air pollution in a random population sample.

METHODS

Blood pressure measurements of 2607 men and women aged 25 to 64 years who participated in the Augsburg Monitoring of Trends and Determinants in Cardiovascular Disease survey were analyzed in association with 24-hour mean concentrations of air pollutants.

RESULTS

During the air pollution episode in Europe in January 1985, an association between blood pressure and air pollution was observed, which disappeared after adjustment for meteorology. Continuous concentrations of total suspended particulates and sulfur dioxide were associated with an increase in systolic blood pressure of 1.79 mm Hg (95% confidence interval [CI] = 0.63, 2.95) per 90 micrograms/m3 total suspended particulates and 0.74 mm Hg (95% CI = 0.08, 1.40) per 80 micrograms/m3 sulfur dioxide. In subgroups with high plasma viscosity levels and increased heart rates, systolic blood pressure increased by 6.93 mm Hg (95% CI = 4.31, 9.75) and 7.76 mm Hg (95% CI = 5.70, 9.82) in association with total suspended particulates.

CONCLUSIONS

The observed increase in systolic blood pressure associated with ambient air pollution could be related to a change in cardiovascular autonomic control.

A single histidine residue determines the pH sensitivity of the pacemaker channel HCN2

Hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels control the rhythmic activity of heart and neuronal networks. The activation of these channels is regulated in a complex manner by hormones and neurotransmitters. In addition it was suggested that the channels may be controlled by the pH of the cytosol. Here we demonstrate that HCN2, a member of the HCN channel family, is directly modulated by the intracellular pH in the physiological range. Protons inhibit HCN2 channels by shifting the voltage dependence of channel activation to more negative voltages. By using site-directed mutagenesis, we have identified a single histidine residue (His-321) localized at the boundary between the voltage-sensing S4 helix and the cytoplasmic S4-S5 linker of the channel that is a major determinant of pH sensitivity. Replacement of His-321 by either arginine, glutamine, or glutamate results in channels that are no longer sensitive to shifts in intracellular pH. In contrast, cAMP-mediated modulation is completely intact in mutant channels indicating that His-321 is not involved in the molecular mechanism that controls modulation of HCN channel activity by cyclic nucleotides. Because His-321 is conserved in all four HCN channels known so far, regulation by intracellular pH is likely to constitute a general feature of both cardiac and neuronal pacemaker channels.

Cellular expression and functional characterization of four hyperpolarization-activated pacemaker channels in cardiac and neuronal tissues

Hyperpolarization-activated cation currents (I(h)) have been identified in cardiac pacemaker cells and a variety of central and peripheral neurons. Four members of a gene family encoding hyperpolarization-activated, cyclic nucleotide-gated cation channels (HCN1--4) have been cloned recently. Native I(h) currents recorded from different cell types exhibit distinct activation kinetics. To determine if this diversity of I(h) currents may be caused by differential expression of HCN channel isoforms, we investigated the cellular distribution of the transcripts of HCN1--4 in the murine sinoatrial node, retina and dorsal root ganglion (DRG) by in situ hybridization. In the sinoatrial node, the most prominently expressed HCN channel is HCN4, whereas HCN2 and HCN1 are detected there at moderate and low levels, respectively. Retinal photoreceptors express high levels of HCN1, whereas HCN2, 3 and 4 were not found in these cells. In DRG neurons, the dominant HCN transcript is HCN1, followed by HCN2. We next determined the functional properties of recombinant HCN1--4 channels expressed in HEK293 cells. All four channel types gave rise to I(h) currents but displayed marked differences in their activation kinetics. Our results suggest that the heterogeneity of native I(h) currents is generated, at least in part, by the tissue-specific expression of HCN channel genes.

Assessing hypertension management in the community: trends of prevalence, detection, treatment, and control of hypertension in the MONICA Project, Augsburg 1984-1995

OBJECTIVE

To assess trends in prevalence and detection, treatment and control of hypertension in a German population between 1984 and 1995.

SETTING AND PARTICIPANTS

Independent random samples of the population were examined in cross-sectional surveys with identical methods in 1984/85 (age range 25 to 64 years, n = 4022 participants), 1989/90 (age range 25 to 74 years, n = 4940) and 1994/95 (age range 25 to 74 years, n = 4856).

MAIN OUTCOME MEASURES

Prevalence of hypertension and proportions of hypertensives detected, treated and controlled. Hypertension was defined as blood pressure above 140/90 mm Hg or taking antihypertensive medication.

RESULTS

The prevalence of hypertension did not change significantly over the 10 years (25--64 years, age-standardised 1984/85: 37.8% in men and 24.6% in women; 1994/95: 39.3% and 24.8%, respectively). Rates of detection, treatment and control of hypertension did not change much either. Of all hypertensives in 1994/95, 54% were detected in men and 64% in women, the treatment rates were 23% and 32%, and the proportions of those with controlled hypertension (below 140/90 mm Hg with treatment) were as low as 7% and 13%, respectively. Rates were higher in the older age groups, however, control rates never exceeded 20% at any age.

CONCLUSIONS

Despite considerable changes in the pharmacological treatment of hypertension there was a disappointing stagnation with regard to the management of this important risk factor in the community. The reasons for this unfavourable trend need clarification and appropriate public health action. Journal of Human Hypertension (2001) 15, 27-36

Mutations in the S4 domain of a pacemaker channel alter its voltage dependence

In an attempt to study the functional role of the positively charged amino acids present in the S4 segment of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels, we have introduced single and sequential amino acid replacements throughout this domain in the mouse type 2 HCN channel (mHCN2). Sequential neutralization of the first three positively charged amino acids resulted in cumulative shifts of the midpoint voltage activation constant towards more hyperpolarizing potentials. The contribution of each amino acid substitution was approximately -20 mV. Amino acid replacements to neutralize either the first (K291Q) or fourth (R300Q) positively charged amino acid resulted in the same shift (about 20 mV) towards more hyperpolarized potentials. Replacing the first positively charged amino acid with the negatively charged glutamic acid (K291E) produced a shift of approximately -50 mV in the same direction. None of the above amino acid substitutions had any measurable effect on the time course of channel activation. This suggests that the S4 domain of HCN channels critically controls the voltage dependence of channel opening but is not involved in regulating activation kinetics. No channel activity was detected in mutants with neutralization of the last six positively charged amino acids from the S4 domain, suggesting that these amino acids cannot be altered without impairing channel function.

Increases in heart rate during an air pollution episode

This paper assesses whether air pollution increases resting heart rates in 2,681 men and women aged 25-64 years who participated in the MONICA (monitoring of trends and determinants in cardiovascular disease) Augsburg cohort. Increases in heart rate were observed during the air pollution episode in January 1985 compared with non-episode days adjusted for cardiovascular risk factors and meteorologic parameters. Consistently, heart rates were also elevated at high concentrations of sulfur dioxide, total suspended particulates, or carbon monoxide. Acceleration in heart rates indicates an altered autonomic control of the heart in association with air pollution, which may contribute to the observed health effects in association with air pollution.

Population trends in antihypertensive drug use: results from the MONICA Augsburg Project 1984 to 1995

Trends in antihypertensive drug use were assessed among 25- to 64-year-old participants of three independent surveys of the MONICA Augsburg region in 1984/85, 1989/90, and in 1994/95. Despite constant prevalences of hypertension, the percentage of hypertensives taking medication increased over the study period. The latter was mainly due to significant rises in antihypertensive monotherapy. By contrast, the use of combination treatments with two or more agents remained constant; however, although combinations composed of only two drugs were taken more often in 1995, those with three or more agents and fixed-dose preparations decreased substantially. Beta-blockers were most frequently, and with a rising tendency, taken as antihypertensive monotherapy. Newer drug classes like calcium channel blockers and ACE-inhibitors were introduced as monotherapy more hesitantly. Diuretics persisted as the basis of antihypertensive combination therapy. The use of combination therapies containing obsolete drugs, like reserpine, declined significantly with corresponding increases in drug combinations of, in particular, calcium channel blockers or ACE-inhibitors. We conclude that monotherapies account for most of the rising antihypertensive treatment rates and probably reflect intensified therapy of borderline hypertensives. The trends in antihypertensive drug classes and treatment regimens reflect a less rapid adoption of novel therapeutic concepts but a fairly close adherence to national and international guidelines.

Two pacemaker channels from human heart with profoundly different activation kinetics

Cardiac pacemaking is produced by the slow diastolic depolarization phase of the action potential. The hyperpolarization-activated cation current (If) forms an important part of the pacemaker depolarization and consists of two kinetic components (fast and slow). Recently, three full-length cDNAs encoding hyperpolarization-activated and cyclic nucleotide-gated cation channels (HCN1-3) have been cloned from mouse brain. To elucidate the molecular identity of cardiac pacemaker channels, we screened a human heart cDNA library using a highly conserved neuronal HCN channel segment and identified two cDNAs encoding HCN channels. The hHCN2 cDNA codes for a protein of 889 amino acids. The HCN2 gene is localized on human chromosome 19p13.3 and contains eight exons spanning approximately 27 kb. The second cDNA, designated hHCN4, codes for a protein of 1203 amino acids. Northern blot and PCR analyses showed that both hHCN2 and hHCN4 are expressed in heart ventricle and atrium. When expressed in HEK 293 cells, either cDNA gives rise to hyperpolarization-activated cation currents with the hallmark features of native If. hHCN2 and hHCN4 currents differ profoundly from each other in their activation kinetics, being fast and slow, respectively. We thus conclude that hHCN2 and hHCN4 may underlie the fast and slow component of cardiac If, respectively.

Classical risk factors and their impact on incident non-fatal and fatal myocardial infarction and all-cause mortality in southern Germany. Results from the MONICA Augsburg cohort study 1984-1992. Monitoring Trends and Determinants in Cardiovascular Diseases

BACKGROUND

The MONICA (Monitoring Trends and Determinants in Cardiovascular Diseases) project in Augsburg provides the first population-based cohort study in Germany to quantify the associations of the risk factors hypertension, hypercholesterolaemia and smoking with incident non-fatal and fatal myocardial infarction and all-cause mortality, and to assess their impact at the population level.

METHODS

The cohort comprises 1074 men and 1013 women aged 45-64 years; they were followed over 8 years from 1984-1992. In the men, there were 61 non-fatal and fatal myocardial infarctions and 92 all-cause mortality events over this period; in the women the number of deaths from all causes was 45. Incidence rates, hazard rate ratios, population attributable fractions and rate advancement periods were calculated.

RESULTS

Adjusting for confounders, the myocardial infarction hazard rate ratios for men with hypertension, or a total cholesterol/HDL-cholesterol ratio > or =5.5, or smoking > or =20 cigarettes/day, were 2.0 (95% CI 1.2-3.5), 2.9 (95%, CI 1.7-5.0), and 2.7 (95% confidence interval (CI) 1 4-5.0), respectively. The risk factor combination total cholesterol/HDL cholesterol ratio > or = 5.5 and cigarette smoking was particularly hazardous. The three risk factors contributed 65% of the burden of myocardial infarction in the population. The rate advancement period for myocardial infarction associated with hypertension, total cholesterol/HDL cholesterol ratio > or =5.5 or smoking > or =20 cigarettes/day was 8.3, 12.4 and 11.5 years, respectively. In women, these risk factors were similarly predictive of all-cause mortality. Comparing the cohort data from Augsburg with those of two occupational cohorts from Germany reveals higher absolute myocardial infarction risks in the Augsburg population; however, the relative risk estimates in the Augsburg and the two occupational cohorts were very similar.

CONCLUSION

Our results confirm the important contribution of the classical risk factors to the risk of myocardial infarction and all-cause mortality in Germany. The results pertaining to the concept of rate advancement periods particularly demonstrate the great potential for prevention.

[Use of vitamins and minerals all food supplements from the MONICA cross-sectional study of 1994/95 from the Augsburg study region]

The intake of vitamin and mineral supplements was examined in a southern German population. Analyses are based on data from the 3rd survey of the MONICA Project Augsburg which took place from 1994 to 1995. The study population were 4,856 persons aged 25 to 74 years of a representative sample (net response 74.9%). During a standardized interview, participants were asked about their intake of vitamin or mineral supplments in the previous week (information available from 4,854 persons). To evaluate this information, a database on vitamin and mineral contents of about 500 supplements was established. The prevalence of supplement users is significantly higher among women than among men: more than a quarter of women (27.5%) versus nearly a fifth of men (18.1%). With increasing age women take supplements more frequently, especially minerals. Male supplement usage increases up to the age group 35-44 years and then remains constant. Vitamin C (women 12.8%, men 9.4%), magnesium (women 12.4%, men 8.7%), vitamin E (women 9.8%, men 7.8%), and calcium (women 10.7%, men 4.9%) are the vitamins and minerals supplemented most often. Among supplement users, 46.5% of women and 52.1% of men reported taking vitamin C. The median daily intake of vitamins--except biotin and niacin in men and folic acid and biotin in women--is at least 100% of the recommendations of the German Society for Nutrition for both men and women. All of the median intake values for minerals were less or equal than 100% of the recommendations.

[Family status and social integration as predictors of mortality: a 5-year follow-up study of 55- to 74-year-old men and women in the Augsburg area]

The relation between marital status, social integration and the mortality from all causes was examined in a population based cohort study. The 5-year-cohort consisted of 1,030 men and 957 women, aged 55-74 years who participated in the second MONICA Survey Augsburg, F.R.G., 1989/90 (MONICA = Monitoring of trends and determinants of cardiovascular disease). They were followed for mortality until 1995. Altogether 120 men and 45 women had died. Social integration was measured by an index of social ties. The index of social ties examined in these analyses includes (a) presence of a spouse, (b) number of close friends and relatives, (c) reported contact with close friends and relatives. Age standardized mortality rates (per 10,000 person years) were computed for men and women. Sex-specific Cox-proportional hazard models were used and hazard rate ratios (HRR) were calculated adjusting for age, hypertension, cigarette smoking, cholesterol, drinking alcohol, number of chronic diseases and self-reported health. Mortality rates were higher for men who were living alone (437.3) than for married men (235.3). Respectively in women the rates were 121.6 compared to 80.7. After controlling for age and self-reported health a HRR of 1.5 (95% CI: 1.0-2.4) was observed for single, divorced or widowed men and a HRR of 1.6 (95% CI: 0.8-3.0) for women living alone. Low mortality rates were observed in people with many social ties (men: 180.1, women: 29.9). Mortality rates of people who gave no informations about social ties (men: 349.5, women: 124.9) were similar to those who had only few social ties (men: 321.1, women: 132.5). The findings showed that people with few social ties were more likely to die in the follow-up period than those with more extensive contacts. After adjusting for age and self-reported health the HRR for those with few ties compared to those with many social ties were 1.6 (95% CI: 1.1-2.5) for men and 2.7 (95% CI: 1.1-6.6) for women. Similar results were found for people who gave no informations about their social ties (men: HRR = 1.4, 95% CI: 0.9-2.3; women: HRR = 2.6, 95% CI: 1.0-6.9). Social relationships were shown to be important predictors of mortality in elderly women and men. These findings confirm the need for further research, which enables to take steps against high mortality of the social isolated elderly.

Ultraflexible vesicles, Transfersomes, have an extremely low pore penetration resistance and transport therapeutic amounts of insulin across the intact mammalian skin

New vehicles for the non-invasive delivery of agents are introduced. These carriers can transport pharmacological agents, including large polypeptides, through the permeability barriers, such as the intact skin. This capability depends on the self-regulating carrier deformability which exceeds that of the related but not optimized lipid aggregates by several orders of magnitude. Conventional lipid suspensions, such as standard liposomes or mixed lipid micelles, do not mediate a systemic biological effect upon epicutaneous applications. In contrast to this, the properly devised adaptable carriers, when administered on the intact skin, transport therapeutic amounts of biogenic molecules into the body. This process can be nearly as efficient as an injection needle, as seen from the results of experiments in mice and humans with the insulin-carrying vesicles. The carrier-mediated transcutaneous insulin delivery is unlikely to involve shunts, lesions or other types of skin damage. Rather than this, insulin is inferred to be transported into the body between the intact skin cells with a bio-efficiency of at least 50% of the s.c. dose action.

[Nonparticipation as a factor influencing the value of follow-up studies. Results of a telephone 5-year follow-up interview of 55-74-year-old participants of the Augsburg 1989/90 MONICA Survey]

In prospective cohort studies losses to follow-up are the major source of bias. This article describes the results of the investigation whether there are systematic differences in socio-economic and health-related factors between participants in a follow up study and those who are lost to follow-up. Subjects included were 1,030 men and 957 women aged 55-74 who participated in the second MONICA Survey Augsburg, F.R.G., 1989/90 (MONICA = Monitoring of trends and determinants of cardiovascular disease). They were reexamined in 1994-95. In 1994/95 910 men and 912 women of the baseline study were still alive, 1305 persons (663 men, 642 women) took part in the follow up by telephone. Altogether 120 men and 45 women had died since 1989/90. 144 persons were not eligible for the study (15 moved away, 5 severely ill persons, 124 without telephone). 373 persons were classified as eligible non-responders. The response rate was 77.8% concerning 1678 eligible persons (men 79.1%, women 76.4%). Non-response has led to an underrepresentation of the lower social class (workers, less than 10 years of education; household income less than 1500 DM) and of persons living alone (single, divorced, widowed; single-person households). In females, non-responders were overrepresented by "never employed persons" (odds ratio 3.02; 1.89-4.85). We found that the odds of being non-responder for single, divorced or widowed men was 3.40 (95 %-CI: 2.20-5.23) compared to married men. Men "without chronic diseases" at the baseline study compared with ill men had an odds for non-response of 1.54 (95%-CI: 1.00-2.37); the odds was 1.38 (95%-CI: 1.02-1.85) among women who had described their health status as "not so good/bad" in comparison with women with good self reported health. The reported distortions by non-response could be important in analyses of social conditions of morbidity and mortality. The underrepresentation of men without chronic diseases and women with bad self-assessment of their health is relevant for the estimates of morbidity as health outcome. Both aspects have to be taken into account in the interpretation of the results.

The relation of alcohol intake to coronary heart disease and all-cause mortality in a beer-drinking population

Epidemiologic studies indicate that light to moderate alcohol consumption from beer, wine, or spirits is associated with a reduction in all-cause mortality, owing primarily to a reduced risk of coronary heart disease (CHD). To find out whether this protective effect of small to moderate amounts of alcohol could be confirmed in Germany, where much of the alcohol consumed is taken in the form of beer, we studied the relation between alcohol and CHD and total mortality in a population of southern Germany. We conducted a prospective cohort study from 1984 to 1992 among 1,071 men and 1,013 women, age 45-64 years at baseline, from the Augsburg region. Eighty-seven per cent of men and 56% of women reported drinking alcohol at baseline. Among drinkers, men had an average alcohol intake of 42 gm per day, of which 33 gm per day came from beer. Women who drank had an average alcohol intake of 16 gm per day and derived about half of it from beer and the other half from wine. During the 8 years of follow-up, 96 deaths (all causes) and 62 incident CHD events (nonfatal and fatal) occurred in men, and 45 deaths (all causes) occurred in women. Adjusting for a number of potential confounders, in men the adjusted hazard rate ratio (HRR) of CHD events for drinkers as compared with nondrinkers was 0.51 [95% confidence interval (CI) = 0.27-0.95]; this protective effect starts with the 0.1-19.9 gm per day alcohol category and does not change much with higher intake. In men, the adjusted total mortality HRR for drinkers as compared with nondrinkers was 0.59 (95% CI = 0.36-0.97). The total mortality HRRs for the different alcohol groups compared with nondrinkers show a U-shaped curve, with the lowest HRR of 0.46 (95% CI = 0.20-0.80) for the 20-39.9 gm per day alcohol group and an HRR of 1.04 (95% CI = 0.54-2.00) for the > or = 80 gm per day alcohol group. In women, the total mortality HRR for those drinking up to 19.9 gm per day as compared with nondrinkers was 0.46 (95% CI = 0.22-0.96).

The angiotensinogen T235 variant and the use of antihypertensive drugs in a population-based cohort

Variants of the angiotensinogen gene may increase the risk of developing arterial hypertension, but their effect on the use of antihypertensive medication in the general population remains unclear. Thus, we determined T174M and M235T allele status and angiotensinogen plasma levels in a cross-sectional sample of 634 middle-aged subjects (48.4% men) from the Monitoring Trends and Determinants in Cardiovascular Disease (MONICA) Augsburg cohort study. We found no association between T174M allele status and angiotensinogen levels, blood pressure, or use of antihypertensive drugs. In contrast, multivariate analysis revealed that individuals who carried at least one copy of the T235 allele (n = 418) had higher systolic and diastolic pressures (P = .007) and .008, respectively) and were more likely to use an antihypertensive drug (1.6-fold risk, P = .04) than homozygotes for the M235 allele (n = 216). The likelihood of taking two or more antihypertensive medications was 2.1-fold higher in carriers of the T235 allele (P = .02). Overall, 22.5% of all antihypertensive drugs taken appeared to be attributable to the excess risk associated with this allele. These associations were replicated in two previous surveys carried out on the same individuals over 10 years. Furthermore, the T235 allele was related to higher angiotensinogen plasma levels [15.5 +/- 0.31 versus 16.5 +/- 0.15 (nmol/L)/L in homozygotes for the M235 and T235 alleles, respectively; P < .01], which were also related to systolic pressure (P = .03) and more intensive antihypertensive medication (P = .03). We conclude that the angiotensinogen T235 allele accounts for a substantial proportion of antihypertensive drug use in this middle-aged, population-based group of white subjects.

Cardiovascular risk factors, ECG abnormalities and quality of life in subjects with atrial fibrillation

In Central European regions epidemiologic findings for atrial fibrillation (AF) in a randomly selected population are not available. Therefore, information obtained by a standardized examination procedure including resting 12 lead ECG of 4003 participants (2014 men, 1989 women), aged 25 to 64 years, of the MONICA-Augsburg Survey 1984/85 were analysed. Reexamination of 3753 subjects took place three years later (Follow-up Study 1987/88). Persons with AF in the baseline survey (n = 13) were compared with an age-and sex-matched control group (n = 156) without AF, chosen from the same population sample, with regard to cardiovascular risk factors, associated disease and disturbances in the subjects' general well-being. In 1984/85 thirteen cases with AF (6 males, 7 females) were observed, giving an age-standardized prevalence of AF in males of 0.22% and in females of 0.34%. The age of men with AF ranged between 50 and 63 years and of women between 61 and 64 years. No significant differences were observed in persons with AF compared to the control group in risk factor levels and alcohol consumption; however, significant differences could be seen concerning disturbances in quality of life like self-reported health status (p < 0.001), sleep disturbances (p < 0.05), antihypertensive medication (p < 0.001). AF cases were found to have further ECG abnormalities significantly more often (left anterior hemiblock: p < 0.05; ventricular premature beats: p < 0.05). In all subjects with AF in the initial examination 1984/85 AF was found three years later (chronic AF). Overall 13 new cases (7 men, 6 women) were identified in the 1987/88 follow-up. The prevalence of AF in a South German population is comparable with AF prevalences reported from studies in other populations (e.g.) Framingham 1950, Reykjavik 1967/70). Associated ECG abnormalities were found more frequently in subjects with AF. Cases with AF have considerable disturbances in their general well-being.

Trends in alcohol intake in a southern German population from 1984-1985 to 1989-1990: results of the MONICA Project Augsburg

This study was undertaken to measure trends in alcohol intake from 1984-85 to 1989-90 in a southern German population. In the surveys of the MONICA Augsburg Project conducted in 1984-85 (Survey 1) and 1989-90 (Survey 2) data on alcohol intake (in grams/day) were gathered from two independent representative samples (Survey 1: 4,016; Survey 2: 3,960) of men and women, aged 25 to 64 years. A validated recall method was applied. Self-reported mean alcohol intake was high in Survey 1 (36 g/day in men; 11 g/day in women), but decreased from Survey 1 to Survey 2 in both men and women (32 g/day in men; 9 g/day in women). The decrease is reflected also in the median and 95th percentile values of alcohol intake and in an increase of the proportion of self-reported nondrinkers from Survey 1 to Survey 2. Alcohol intake in the MONICA Augsburg population is rather high in comparison to other countries, but a trend to lower intakes was observed from 1984-85 to 1989-90.

Five-year changes in population blood pressure and hypertension prevalence. Results from the MONICA Augsburg surveys 1984/85 and 1989/90

Two cardiovascular risk factor surveys were carried out in 1984/85 and 1989/90 in the Augsburg study region of the international World Health Organization (WHO) Monitoring Trends and Determinants of Cardiovascular Disease (MONICA) project. Independent random samples of the 25- to 64-year-old population were examined at each survey. Five-year changes in blood pressure (BP) and hypertension parameters were monitored in a population not targeted by any formal intervention program. Response rates in both surveys ranged close to 80%. Evaluation of selected quality indicators confirmed comparability of the two surveys in terms of BP measurement quality. Small but consistent decreases in mean systolic and diastolic BP were observed, particularly for women 35 years and older, whereas BP changes in men were less pronounced and inconsistent. Likewise, downward shifts of the 10th, 50th, and 90th percentiles of systolic and diastolic BP occurred in women and their slopes of BP rise with age decreased while such changes were less clear in men. The age-standardized prevalence of men and women with hypertensive BP (HBP; > or = 160/95 mm Hg) decreased slightly. This contrasted with rises in the prevalence of actual hypertension (those with HBP plus those taking antihypertensive drugs) for 45- to 64-year-old men, which originated from changes in hypertension management involving a more frequent drug treatment of borderline-hypertensive men (140 to 159/90 to 94 mm Hg) in 1989/90. There were notable overall increases in the awareness, treatment, and control of men and women with hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of education and professional position on changes in cigarette smoking and alcohol consumption: results of the MONIKA Augsberg cohort study]

This study examined the influence of educational achievement and occupational position on changes in risk behavior. Study population were 3753 men and women aged 25-64 years who were sampled by the first MONICA Augsburg Survey (Monitoring trends and determinants in cardiovascular disease). The subjects were sampled in 1984-85, were followed up for three years, and were reexamined in 1987-88. The baseline findings showed for both men and women a statistically significant inverse association between current cigarette smoking and educational level. During the follow-up period the differences between highest and lowest educational levels increased significantly among men. In 1987-88 only 21% of the best educated men were smokers compared to 38% of those with the lowest educational level. Men with low educational levels also drank more alcohol than better educated men, whereas among women those with lowest educational level drank less alcohol than the better educated. Statistically independent of education and age it was found that male civil servants and farmers had the lowest proportion of smokers in cross-sectional as well as longitudinal analyses. Among women, smoking was and remained most prevalent in simple white-collar occupations. In general, the findings indicate that the type of occupation and the actual working conditions have effects on life-style related risk factors which are in part independent of a social gradient. The results also suggest that the tendency to change unhealthy behavior is less pronounced in "high risk" groups.

The association of antihypertensive treatment patterns and adverse lipid effects in population-based studies

We investigated the relationship between antihypertensive drug treatment of hypertensives and their mean serum lipid concentrations in population based studies in Germany. Data from three surveys (Luebeck Blood Pressure Study (LBS) of 1984, MONICA Augsburg Survey I of 1984/85, MONICA Augsburg Survey II of 1989/90), obtained on random samples of the population aged 25-64 years, were used for cross-sectional analyses. Moreover, prospective analyses were carried out on participants of the MONICA Augsburg cohort study of 1987/88 (3-year-follow-up of the MONICA Survey I). Blood pressure, non-fasting serum total cholesterol and HDL-cholesterol, and body height and weight were measured under strictly standardized conditions. Interview data were available on medical history including medication use, and on smoking and alcohol consumption. In cross-sectional and prospective analyses treated male and female hypertensives in each population had significantly lower crude mean HDL-C concentrations than untreated hypertensives, borderliners, or normotensives. Differences in mean HDL-C between untreated and treated hypertensives were attenuated but still significant after control of confounders and ranged from 1.8 to 6.1 mg/dl (i.e. in relative terms, -3.4 to -12.9%) in men and from 3.6 to 9.4 mg/dl (-5.7 to -14.9%) in women. By contrast, crude and multivariate associations of antihypertensive treatment with non-HDL-C (total minus HDL-C) levels were inconsistent and not significant. The inverse association of drug therapy with HDL-C was confirmed by prospective analyses in the MONICA cohort study supporting a causal relationship. Treatment patterns in a community (prevalence of prescribed drug classes) correlated with the magnitude and significance of HDL-C effects.(ABSTRACT TRUNCATED AT 250 WORDS)

[Drug interactions in the prescriptions of patients before and after a heart infarct: results of the MONICA Augsburg heart infarct registry]

The prescriptions of 603 patients who had survived acute myocardial infarction (AMI) for at least one year and were registered from 1 Oct 84 to 31 Dec 86 in the Coronary Event Register of the MONICA project Augsburg were analyzed for the presence of drug-drug interactions with the aid of a computerized drug information system (SMA). Prior to AMI, 59% of patients were treated (average of 2 active substance per patient), 100% were treated on release from hospital (4.5 active substances), and 96% one year after AMI (5.8 active substances). Potential drug-drug interactions were found in 18% of patients before AMI, 65% on discharge from hospital, and 66% one year after AMI. While the potential frequency and severity of interactions are minor on average, prescriptions frequently contain several interactions. Calculations show that at least 5-6% of all prescriptions after AMI will produce interactions, so that drug safety for this high-risk patient group can be enhanced by a drug information system. Beta-blockers are the substance group most frequently involved in potential interactions in AMI patients.

Blood rheology in healthy cigarette smokers. Results from the MONICA project, Augsburg

To investigate the relationship between cardiovascular risk factors and the fluidity of blood, a random sample of the population consisting of 4022 persons ages 25 to 64 years was investigated for plasma viscosity, hemoglobin, and total serum protein. A total of 567 healthy nonsmokers and 287 healthy smokers were identified and compared. Plasma viscosity was found to be elevated in male smokers; this was related to both the degree and the duration of cigarette abuse. Plasma viscosity proved to be age-dependent in smokers, but did not change with age in nonsmokers. Total serum protein decreased with age in nonsmokers, while it did not change in smokers. Hemoglobin increased only in female smokers. These findings suggest that blood fluidity is jeopardized in smokers. In men the hemorheological deficit is mostly due to a rise of plasma viscosity, which, in turn, may be caused by an elevation of plasma fibrinogen levels. In women it is predominantly due to an increase in hemoglobin. These alterations in hemorheological variables may be a marker for increased cardiovascular risk in smokers and could reduce blood flow and hinder microcirculatory function.

Social relations and smoking behavior: results from the first MONICA Survey Augsburg

This study examines the relationship between various aspects of social relations and the prevalence of smoking, using data from the first MONICA Survey, Augsburg, FRG, 1984/85. Study population of the survey was a two-stage cluster sample of 5312 men and women aged 25 to 64. The response was 79.4%. The measurement of social relations included a modified form of the Syme/Berkman social network scale, as used in the Alameda County Study. Analyses were carried out separately for the total four-level social network index in relation to smoking, and for specific components of that index (marital status, contacts with friends and relatives, activities in informal groups). The results showed for both men and women, that there was a significant association between the social network index and the prevalence of smoking: the more social ties and contacts, the lower the percentage of smokers. The results from multiple logistic regression analyses indicated an effect of social relations on smoking, that is at least partly independent of age, gender and educational level. In general, the findings may contribute to a better understanding of 'risk groups', and the possible pathways leading from social relations to health and disease.

Smoking habits and attitude to smoking in the study population of the MONICA Project Augsburg

Data concerning smoking habits were derived from the first MONICA-Augsburg survey 1984/85 based on a random two stage cluster sample of the 25-64 year old population of the city of Augsburg and the two surrounding rural districts (n = 5312). Data were gathered by a standardized interview. Response was 79%. Overall, about 36% of men and 18% of women are regular cigarette smokers (i.e. smoking more than one cigarette per day). In both sexes smoking decreases with increasing age. In men 43% of the 25-34 year old participants are regular smokers and 29% in the age group 55-64. In women 29% of the youngest age group but only 9% aged 55-64 are current regular smokers. In male regular cigarette smokers the mean amount of cigarettes consumed per day is 21, in women 14 cigarettes. The mean amount of nicotine and tar consumed per day is 17 mg and 277 mg in men, 10 mg and 159 mg in women. On the average men start smoking at the age of 18 and women at the age of 21. In both sexes the percentage of regular smokers, who are willing to change their smoking habits, is very high. In each age and sex group about 60% of all regular smokers affirmed their willingness to quit smoking in the future. It is hoped, that this willingness of the population to change their smoking behavior will be supported by suitable education and intervention programs.

Factors associated with measured differences between fourth and fifth phase diastolic blood pressure

Data from the Munich Blood Pressure Study I were used to investigate the distributions of fourth (D4) and fifth (D5) phase diastolic blood pressures in a population and to identify factors related to their difference. Muffling (in contrast to change of amplitude) of sounds was taken as the criterion for fourth phase Korotkoff sounds. D4 could not be detected (ie D4 = D5) in 33.7% of the 1032 men and in 42.1% of the 1163 women. The difference D4-D5 (mean +/- SEM) was 3.1 +/- 0.1 mmHg for male and 2.4 +/- 0.1 mmHg for female participants. Only 28.0% of D4-D5 differences were greater than 4 mmHg in men and 20.2% in women. D4-D5 varied considerably between the three measurements of each examination both related to participants and observers. Participant characteristics associated with greater D4-D5 were higher SBP, higher D4, and lower D5. Smoking was more common in men with greater D4-D5. Inter-observer variability was very strong. Non-detection of D4 ranged from 78.8% to 10.2% between observers. To assess the relative importance of participant and observer influence on the magnitude of D4-D5, we fitted a polychotomous logistic regression model. In this model, participant characteristics had only a weak effect on measured D4-D5. This was outweighted by potential observer effects several-fold stronger than the strongest participant effect. We conclude that for reliability reasons D5 should be given preference over D4 when measuring diastolic blood pressure in adults, whether for clinical or for epidemiological purposes.

Treatment of hypertension. Patterns of drug utilization in a metropolitan population

In the Munich Blood Pressure Study (MBS), a cross-sectional study (MBS I) with follow-up (MBS II) of a random sample of 3,198 citizens aged 30-69 (response rate, 69.3%), treatment and control of hypertension were examined. Of the actual hypertensives 59% (221) in MBS II (373) were on drug treatment and about two-thirds (150) of those being treated had controlled blood pressure (BP). Women's BP was better controlled than men's. Of the 221 treated hypertensives 85% (188) received types of drugs or drug combinations which were in accordance with the recommendations of the German Hypertension League. However, this did not apply to the prescribed dosages of the various drugs. Of the treated hypertensives 52% were either on a diuretic, on a beta-blocker, or on a combination of both drugs. Rauwolfia alkaloids combined with a diuretic were given to 27%. In 79% of the participants who had received a beta-blocker either alone or in combination with other antihypertensive agents and who still had high BP values, the prescribed beta-blocker dosage was below the recommended daily dose. Fatigue was the most frequently reported symptom, possibly attributable to antihypertensive drug treatment. Electrocardiographic signs of left ventricular hypertrophy were found less frequently in controlled hypertensives, in comparison to treated but uncontrolled hypertensives or untreated hypertensives.

Oral contraceptive use and blood pressure in a German metropolitan population

The relationship between blood pressure (BP) and oral contraceptive (OC) use in women has been examined with the data from the Munich Blood Pressure Study (MBS), a cross-sectional study with follow-up of a random sample of 3198 Munich citizens aged 30-69 (response rate 69.3%). Multiple linear and logistic regression analyses were run with BP as the dependent variable and age, OC use, obesity, alcohol consumption, and smoking habit as the independent variables. All second and third order interactions between the independent variables were tested during a backward stepping procedure. OC use appeared as a significant main effect in most of the analyses. The coefficient of the OC variable was about 3 in the linear regression analyses for both systolic BP and diastolic BP, indicating an increase of about 3 mmHg in the systolic and diastolic BP of the OC users. An analysis of the change in BP after one year in relation to change in OC user status has also been made. It was observed that women ceasing to use OC had a clear decrease in BP while those starting to use OC had on average an increase in BP.

Screening for hypertension: results of the Munich Blood Pressure Program

The Munich Blood Pressure Program (MBP) is a community hypertension control program for the metropolitan area of Munich. It tries to improve "incidental screening" in doctors' offices in the city through continuing education programs for physicians and auxiliary personnel and, in addition, emphasizes worksite screening to bring high-risk hard-to-reach groups under treatment and control. Blood pressure (BP) is measured at the worksite under standardized conditions. Those with values greater than or equal to 140 mm Hg systolic BP and/or greater than or equal to 90 mm Hg diastolic BP at the first visit have BPs measured again within 1-5 days. If their BP values are still elevated, they are referred to their family physicians for further assessment. At the same time, they are given a postage-paid card on which their doctors are asked to note the BP value measured in their offices. This postcard is returned to the MBP for evaluation. A computer-based reminder system informs all MBP participants at certain time intervals to have their BP checked. The text of the letters and the time interval between them depend on the most recent BP and treatment status data available to the MBP. In 1983, screenings were performed in seven firms. Participation rates of up to 57% were achieved for this entirely voluntary examination (3,948 participants). Age- and sex-specific prevalence rates (for the pooled data of the seven firms) were similar to those of a random sample of the Munich population (Munich Blood Pressure Study I). Seventy-four percent of those with elevated BP at first visit participated in the remeasurement at a second visit. Only 58% of these showed elevated BP values the second time. More than half (n = 101) of those second-visit hypertensives (greater than or equal to 160/95 mm Hg; n = 183) returned at least one completed postcard. The examining physician confirmed the hypertensive BP values in 60 of those cases. Of the 101, 57 were under treatment, 19 controlled and 38 uncontrolled. The follow-up period considered here lasted until May 1984 and varied from 5 to 15 months according to the date of screening in the respective firm. Only the first returned card has been evaluated thus far.

[Quality assurance and quality control of blood pressure measurements. Experiences with the Munich blood pressure study]

More than 12 000 blood pressure measurements were taken in the Munich Blood Pressure Study (MBS). The reliability of these blood pressure measurements is reported. After consideration of possibilities for systematic and random measurement errors we present methods used in the MBS to control and assess the quality of the blood pressure readings over a long period of time: measures for standardizing the recording conditions and procedures; training and testing of the field staff using audio tape-recording and simultaneous measurements with a double stethoscope; analysis of inter- and intraobserver-variation relative to that of reference measurements; analysis of observer preferences for certain terminal digits. With the application of these methods one can indeed successfully reduce observer variability to a tolerable amount even over a considerable period of time.

[Epidemiology of digitalis medication. Results of the Munich blood-pressure study]

As part of a blood-pressure survey in Munich, some of its inhabitants aged 30-69 years were asked by questionnaire about any digitalis medication. Chemically defined glycosides were taken by 127 of 1827 persons (7%), two-thirds of them older than 60 years, for clinically compensated chronic heart failure. Using the equation of Cockcroft and Gault to calculate creatinine clearance, it was below 80 ml/min and thus indicative of early impairment of renal function in more than 50%. In 44% the prescribed daily dose of glycoside corresponded to the calculated maintenance dose, 29% had less and 27% had taken more. None had clinical signs of digitalis intoxication. ECG changes possibly due to digitalis were much less common than had been expected. Sinus rhythm was present in 93%. More than 50% did not know why they were taking digitalis and 80% were taking two or more drugs at the same time. Since more than half had signs of early renal function impairment, creatinine clearance should be taken into account when determining the dosage of a digoxin preparation especially in elderly patients; alternatively, digitoxin should be prescribed. The survey also showed that a large number of persons on glycoside medication did not take the drug regularly.

Alcohol consumption as a risk factor for high blood pressure. Munich Blood Pressure Study

The Munich Blood Pressure Study (MBS), a 1980-81 cross-sectional study (with follow-up) of a random sample of 3198 Munich citizens aged 30-69 years (response rate 69%), revealed hypertensive blood pressure (BP) values in 17.7% of men and 10.7% of women (WHO criteria). One of the main goals of the MBS was to search for social, behavioral, and environmental risk factors for hypertension. The relationship between BP and five possible risk factors--alcohol consumption (g/day), cigarette smoking, oral contraceptive use, years of education, obesity (BMI)--has been examined. The major emphasis of this report is the relationship of alcohol consumption to BP. Multiple linear and logistic regression analyses were run controlling for both age and sex. All second- and third-order interactions between the independent variables were tested during a backward-stepping procedure. Alcohol consumption appeared as a significant main effect in many of the analyses. The coefficient of the alcohol variable ranged from 0.02 to 0.06 for men and women in the separate linear regression analyses for systolic and diastolic BP. Thus, for example, according to the model, the daily consumption of 1 liter of beer (40 g alcohol) may cause an increase in diastolic BP in women of 2.4 mm Hg.