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PubMed1981

A genetic analysis of taste threshold for phenylthiocarbamide.

Taste threshold for phenylthiocarbamide (PTC) was measured in 393 offspring from the families of 85 monozygotic (MZ) twin pairs. PTC scores were bimodally distributed with modes at one and eight and the antimode at five. Because of the non-normality of the distribution, a jackknife procedure was used to obtain 95% confidence intervals for the estimates of genetic, maternal, and environmental parameters. Analyses which assumed no epistasis and which included additive genetic effects revealed that 37.9% of the observed variation in PTC threshold was due to additive genetic effects, 16.6% was due to dominance effects, 14.2% was due to maternal effects, 13.7% was due to a common sibship environment, and 17.6% was due to random environmental effects, yielding a broad sense heritability of 0.55 for the threshold ability to taste PTC. Analyses which did not include additive genetic effects revealed 26.6% of the observed variance was due to dominance effects, 23.6% to maternal effects, and 49.8% to environmental effects at the 0.67 confidence levels, but that environmental factors accounted for 72.4% and dominance effects for 23.6% of the observed variation at the 95% level.

Adolescent↗
PubMed1994

International Lp(a) standardization.

Two international surveys for Lp(a) measurements were organized from 1989 to 1991. The results of the first survey led to the conclusion that the lack of a common primary standard was the main cause of the large inter-laboratory variation observed. No major effects of techniques or antisera were observed. The same findings were confirmed during the second survey, which was extended to include more samples and a larger number of participants. During the second survey, no consistent effect due to freezing or lyophilization could be demonstrated, although there was a trend towards lower Lp(a) values in lyophilized samples. The inter- and intra-laboratory coefficients of variation did not vary significantly for the different Lp(a) phenotypes, and variability was comparable for lyophilized, liquid and frozen materials. Large intra-assay coefficients of variation were observed during both surveys. Results obtained in different laboratories using the same commercial reagents and standards also showed a large variation. These initial results demonstrate that the lack of a primary standard and poor assay precision are the main factors responsible for the high inter-laboratory variation observed during these surveys.

Analysis of Variance↗
PubMed1999

The recognition of molecules from fourth-stage larvae of Ostertagia circumcincta by IgA from infected sheep.

The recognition of antigens from fourth-stage Ostertagia circumcincta by plasma IgA was studied in a group of 30, ten-month-old Scottish Blackface sheep which had been naturally, then deliberately infected. Western blotting revealed 49 bands that were recognized by antibody from one or more of the 30 sheep. There was a heterogeneous pattern of antigen recognition amongst the sheep. No individual recognized all the 49 bands and only one of the 49 bands was recognized by all sheep. Two antigens with approximate molecular weights 87,000 Da and 129,000 Da were significantly associated with a reduction in mean adult worm lengths. The observed variation in recognition of these two antigens on fourth-stage larval preparations accounted, in a statistical sense, for nearly 40% of the total variation in worm length. In addition to the variation in antibody mediated recognition of these two parasite molecules, three other components have been implicated in regulating worm length. They are a 37,000 Da band from adult worms, the amount of fourth-stage larval specific IgA in the abomasal mucosa and the density-dependent influence of adult worm burden. Together, these components and their interactions accounted for over 90% of the observed variation in worm length. These results indicate that the parasite-specific IgA response, or something extremely closely associated with it, is the major immunological mechanism controlling worm length.

Animals↗
PubMed1985

Identifying severe aortic valvular stenosis by bedside examination.

Sixty-seven consecutive symptomatic patients with aortic valvular stenosis (AS) and no or slight aortic incompetence were prospectively examined bedside by a senior cardiologist before an invasive pre-operative investigation. A history of effort syncope had the highest predictive value (pos), 100%, for a significant degree of AS (defined as a calculated valve area less than or equal to 0.9 cm2 or a peak systolic pressure difference across the valve of greater than or equal to 40 mmHg). The absence of effort syncope had a predictive value (neg) of 40%. The corresponding figures for peak intensity of the murmur in mid-systole were 93 and 82%, respectively. For the combination of effort syncope and/or mid-systolic peak intensity of the murmur (borderline findings included) the predictive values were 90% (pos) and 94% (neg), respectively. No other combination of symptoms and physical finding was more discriminating. This combination of criteria for prediction of a significant stenosis was prospectively applied to the next 39 AS patients. The criteria were fulfilled by 29 patients and all were found to have a significant AS as were four of the 10 patients not fulfilling the criteria. These four falsely negative patients had a valve area/peak pressure difference of 0.5, 0.8, 0.8 cm2 and 43 mmHg. The inter-observer variation was studied in a third series by two senior cardiologists independently examining 22 AS patients. They were concordant in all with regard to a history of effort syncope and in all but one (0.6 cm2) with regard to the timing of the peak murmur. Bedside examination of an AS patient by an experienced cardiologist has a good predictivity for severity, and the inter-observer variation is low. Non-invasive laboratory investigations have only a supplementary role. However, as many patients have effort angina, a pre-operative invasive procedure including coronary arteriography is often unavoidable.

Adult↗
PubMed1997

The utilization of multidimensional scaling to identify forage characteristics associated with preference in sheep.

Forage preference is difficult to assess but is likely an important factor in determining DM intake. In two experiments, six sheep (wethers, Exp. 1; ewes, Exp. 2) were used to obtain preference ratings on nine hays (Exp. 1) or nine fresh forages (Exp. 2). The statistical procedure of multidimensional scaling was used to develop orthogonal dimensions to account for the observed variation in preference for hays and fresh forages. This analysis produced three dimensions that accounted for 54% of the variation in mean 3-d preference for hays (Exp. 1). The three dimensions were subsequently associated by regression analysis with seven compositional variables. These were IVDMD and concentrations of monosaccharides, short-chain polysaccharides (SCP), and disaccharides in dimension 1(R2 = .99); acid detergent insoluble ash (ADIA) concentration, monosaccharide and SCP concentrations, and masticate NDF in dimension 2 (R2 = .99); and disaccharide and starch concentrations in dimension 3 (R2 = .65). Three dimensions accounting for 51% of the variation in fresh forage preference were found and related to four variables by regression analysis. These were disaccharide concentration and median particle size in dimension 1 (R2 = .76) and starch and monosaccharide + disaccharide concentrations in dimension 3 (R2 = .97). No physicochemical variables analyzed in this study were found to be significantly associated with the coordinates for the forages in dimension 2. Multidimensional scaling accounted for more than half the observed variation in animal preference and, in all but one case, these dimensions could be associated with physicochemical characteristics of the forages.

Algorithms↗
PubMed1994

[Changes in lipid availability in Venezuela, 1970-1992].

The authors carry out a research focused on the quantification and analysis of the main changes in feeding and nutrition in Venezuela between 1970 and 1992. Such research started with the review and adjustment of the Food Balance Sheets (Hojas de Balance de Alimentos) elaborated by the Instituto Nacional de Nutrición (National Nutrition Institute) between 1970 and 1979 in order to homogenize them in a methodological way to make them similar to those elaborated by that institution and the Fundación Polar for the 1980-90 period. Estimates were made about the daily and per person availability of food for human consumption (DCH) for 1991 and 1992. This report, a partial product of that research, characterizes the evolution of the lipidic DCH in Venezuela for the 1970-1992 period. This period has been divided in seven stages of the evolution of the total energetic DCH, as this reflects well the course of the daily and per person Food Purchasing Power (PCA); there is a direct and strong functional relationship between these two variables. Along those stages the behaviour of the lipidic DCH is studied and we try to view possible relationships between the evolution of the Venezeluans economical situation and the absolute and relative variations observed in the level and the structure of the lipidic DCH. This structure is analyzed from several points of view: groups of food sources, origin, "visibility", and place of origin. One purpose is to determine also which food groups are mainly responsible for the venezuelan's external lipidic dependence. A general picture of the evolution of the DCH for saturated fatty acids and cholesterol is made, as well as of the variations experienced by the P/S and M/S relationships. It was found that the most dynamic elements, those that can explain a very high percentage of the variations observed in the level and the structure of the lipidic DCH were: the groups of foods of Visible Fats, Milk and dairy products, and Meats; vegetal lipids; vegetal-visible and animal-invisible lipidic fractions; imported lipids or lipids of food products which raw materials were imported (oily raw materials to make oils and edible solid fats, and raw materials to make food for poultry and hogs). The importance of the food groups Visible Fats, Milk and dairy products, and Meats, as sources or saturated fatty acids in the diet of the Venezuelans was made evident (89-91% of the respective total DCH), as well as the importance of the food groups Eggs, Meats, Fish and Seafood, and Milk and dairy products, as sources of cholesterol (82-89% of the available total). It was found that the lipid-originated calories account for less than 30% of the total energetic DCH; saturated fatty acids account for less than 10% of the available calories/person/day; the DCH for cholesterol did not reach the level of 300 mg/p/d; the P/S and M/S relationships remained close to 1. These last four facts are considered favorable for the health of the human being.

Cholesterol, Dietary↗
PubMed1994

Dietary myristic, palmitic, and linoleic acids modulate cholesterolemia in gerbils.

Previous studies with cebus monkeys and review of published human data indicated that 85% to 90% of the variation in plasma cholesterol (TC) could be explained on the basis of dietary myristic (14:0) and linoleic (18:2) acid intake in the absence of cholesterol, and that 16:0 contributed to cholesterolemia as dietary cholesterol was increased. Because monkeys are a limited resource, a more convenient, sensitive model was sought for investigating these dietary fatty acid and plasma lipid relationships. Accordingly, this report describes the results of multiple regression analysis of the TC response to dietary fatty acids based on 319 young, male Mongolian gerbils fed a total of 59 purified diets supplying about 40% energy as fat from single or blended fat sources. Gerbils (6-16 animals per dietary group) were fed purified diets (21 with 0.01 to 0.08% cholesterol and 38 cholesterol-free) for 4-week periods. When cholesterol-free diets were fed, dietary 14:0 and 18:2 together accounted for 89% of the observed variation in TC. Although 14:0 consumption increased TC in a linear manner, the independent ability of 18:2 to lower cholesterol was nonlinear and exhibited a threshold effect at 5-6% dietary energy, above which further lowering of TC was less remarkable. In gerbils consuming cholesterol-supplemented diets, 87% of the observed variation in TC could be accounted for by a regression equation that included 14:0, palmitic acid (16:0), and a log function of 18:2 plus dietary cholesterol itself. These results demonstrate the applicability of gerbils for such studies and confirm previous observations in monkeys and humans that dietary 14:0 and 18:2 are the main fatty acids modulating plasma cholesterol under normocholesterolemic circumstances (i.e., when consuming low-cholesterol diets and lipoprotein metabolism is normal) whereas 16:0 also appears modestly hypercholesterolemic when LDL receptors are compromised (i.e., when dietary cholesterol or certain metabolic factors have encumbered lipoprotein metabolism).

Animals↗
PubMed1995

Maximum single leg force production: cockroaches righting on photoelastic gelatin

Integrating studies of mechanics, neural control and isolated muscle function are possible using arthropod legs. To evaluate leg performance, we measured the ground reaction forces generated by individual legs of the six-legged cockroach Blaberus discoidalis (3.1 g), during an emergency behavior, righting or over-turning. We used a photoelastic method to measure the forces generated by individual legs simultaneously. A gelatin track placed between crossed polarizing filters was illuminated from below, and a high-speed video camera recorded the stress-induced optical signals from above. The size and skew of the optical patterns were found to be related to the magnitude and direction of the force. We discovered that the ground reaction forces generated during the righting behavior of the death-head cockroach were eight times greater than those observed during high-speed running, supporting the possibility that relative leg forces (leg force per unit body weight) during running and maximal leg activity differ more in small arthropods than in larger vertebrates. Non-geometric scaling of relative leg force (i.e. scaling to less than body mass-0.33), along with the reduced force-generating ability of a single leg in animals with many legs, may help to explain why the maximum relative leg force production by six-legged cockroaches, as well as by some other small insects, can be similar to the relative single leg forces produced by two- and four-legged vertebrates that are almost 1000 times more massive. Leg number and body mass alone, however, appear to be insufficient to explain the variation observed in relative leg force production at a given body mass, because enormous diversity in musculo-skeletal parameters exists. The maximal relative leg force of the cockroach B. discoidalis during righting was at the low end of a 100-fold variation observed for smaller insects wedging (pushing through a small crevice) and pulling loads. Thus, this cockroach can be characterized as a moderately strong insect with the capacity for relatively high speed. Results from the present study question the predictive strength of the simple geometric scaling arguments involving a strength:weight ratio as they are applied to small arthropods and encourage further consideration of the importance of leg number, muscle force production and mechanical advantage in the derivation of general principles of leg performance.

Journal Article↗
PubMedDate not supplied

Evaluation of regional myocardial perfusion in patients with severe left ventricular dysfunction: comparison of 13N-ammonia PET and 99mTc sestamibi SPECT.

OBJECTIVE: Positron emission tomography (PET) scanning with 13N-ammonia and 18FDG is well established for the detection of myocardial viability. Due to the limited availability of PET facilities, recent studies have combined technetium 99m sestamibi single photon emission computed tomography (SPECT) with 18FDG PET or 18FDG SPECT. This approach enables simultaneous assessment of regional myocardial blood flow and metabolism and substantially increases the capacity for viability detection. To validate whether 99mTc-Sestamibi SPECT can replace 13N-ammonia PET, we compared these two modalities in patients with severe left ventricular dysfunction due to coronary artery disease. MATERIALS AND METHODS: Thirty-one patients (mean age 57+/-8 years; mean ejection fraction 27%+/-8%) with angiographically verified coronary artery disease were included. In random order, ammonia-PET and sestamibi-SPECT scans were performed. In a 20-segment model of the left ventricle, two blinded observers scored a total of 610 segments on a five-point scale. In a subset of 20 patients, 400 segments were scored twice to evaluate the observer variations of the two techniques. Segmental score differences were used to compare the imaging modalities. The impact on viability detection was assessed by combining the two flow tracers with FDG PET. RESULTS: Segmental comparison of the PET and SPECT studies yielded similar (difference < or = 1) results in 74% of segments, reflecting regional concordance values in the lateral, apical, anterior, septal, and inferior myocardial walls of 86%, 82%, 71%, 66%, and 63%, respectively. The differences in the septal and inferior walls were primarily due to overestimation of perfusion defects by sestamibi SPECT, which yielded a higher proportion of mismatch patterns in those regions. The overall observer variations of the PET and SPECT studies were 7.5% and 5.8%. CONCLUSION: Myocardial perfusion imaging with 13N-ammonia PET and 99mTc-sestamibi SPECT yielded similar results in patients with severe left ventricular dysfunction, except for the septal and inferior regions. In these regions, SPECT tended to overestimate perfusion defects. Hence, attenuation correction should be considered when combining FDG PET and sestamibi SPECT for diagnosing myocardial viability to avoid overestimation of mismatch patterns in those regions.

Adult↗
PubMed2000

Pulse wave velocity. A new calculation method.

BACKGROUND: The increase in aortic Pulse Wave Velocity (PWV) is considered a surrogate marker of vascular disease; it can be non-invasively assessed by means of an indirect method calculating the time that the pulse wave takes to travel a definite distance along the vasculature; the distance/time ratio corresponds to the velocity measure. The presentation of a new calculation method is the aim of the present study. METHODS: A duplex scanner at the common carotid artery, the abdominal aorta at the prebifurcation site and the femoral common artery levels, was performed on 127 out-patients with risk factors, 38 of which were affected by clinical vascular disease, and on 50 healthy subjects (control group). The spectral analysis from these three sites was registered simultaneously with an ECG trace and the interval between the R wave apex and the spectral complex systolic foot was measured. The Transit Time (TT) was calculated by the difference between the values obtained from the proximal and distal measurement sites and PWV dividing the distance between them by the TT (PWV = Distance/TT); statistical significance and intra and inter observer variation coefficient, expressed as mean +/- standard deviation, were calculated by the analysis of variance and Turkey test, the correlation with the major risk factors and the intima-media thickness by the multivariate analysis. RESULTS: The PWV is increased in the patients group compared to control group (p < 0.001). Multivariate analysis shows a positive correlation with age, hypercholesterolemia, arterial hypertension, diabetes mellitus, intima-media thickness and arterial disease, no correlation was found with the smoking habit. The "patients" group shows an increased PWV in those with atherosclerotic plaques and/or clinical vascular disease compared to non atherosclerotic patients with risk factors (p < 0.001); the intra and inter observer variation coefficient ranged between 4.87 +/- 1.82% and 8.06 +/- 3.16% respectively. CONCLUSIONS: The proposed PWV measurement method is simple, quick, reproducible and repeatable, it can separate healthy subjects from patients with risk factors, atherosclerotic plaques and clinical vascular disease. Due to the strong correlation with age, normal values in different age groups are necessary before the PWV can be used as a marker of vascular disease.

Adult↗
PubMed1992

Circadian variation in ischemic threshold. A mechanism underlying the circadian variation in ischemic events.

BACKGROUND: There is a circadian pattern in the occurrence of cardiac events in patients with coronary artery disease. Whether changes in coronary vascular tone contribute to these phenomena is unknown. We measured the ischemic threshold, defined as either the heart rate or rate-pressure product at 1-mm ST segment depression during treadmill exercise and used it as an index of the lowest coronary vascular resistance; the premise was that when ischemic threshold became lower, coronary vascular resistance was higher, and vice versa. METHODS AND RESULTS: Fifteen patients (group A) with stable coronary artery disease underwent four identical treadmill exercise tests in 24 hours, and ischemic threshold was measured as the heart rate at the onset of 1-mm ST depression. Before each treadmill test, postischemic forearm vascular resistance was measured after 5 minutes of forearm occlusion, using strain-gauge plethysmography. Sixteen additional patients (group B) underwent two treadmill tests at 8 AM and 1 PM, and ischemic threshold was measured as the heart rate-blood pressure product at 1-mm ST depression. A circadian variation was noted: In group A, the heart rate-derived ischemic threshold was lower at 8 AM and 9 PM compared with noon and 5 PM (p less than 0.03). Also, in group B, the rate-pressure product-derived ischemic threshold was 8 +/- 2% lower at 8 AM compared with 1 PM (p = 0.008). A circadian variation parallel to the observed variation in ischemic threshold was also noted in the postischemic forearm blood flow, which was lower in the morning and at night (p less than 0.004). There was a strong correlation between postischemic forearm blood flow and ischemic threshold (p less than 0.0001), such that ischemic threshold was lower at the time of day when postischemic forearm blood flow was lower, and vice versa. CONCLUSIONS: A lower ischemic threshold in the morning suggests that the ischemia-induced coronary vascular resistance is increased at this time, a finding supported by a similar variation in postischemic forearm vascular resistance. Parallel changes in forearm and coronary resistance suggest that generalized (neural or humoral factors) rather than local factors are responsible for the observed circadian changes. Increased coronary tone in the mornings may not only contribute to the higher incidence of transient ischemia but may help trigger acute cardiac events at this time.

Aged↗
PubMed2001

Type I collagen markers in cord serum of appropriate vs. small for gestational age infants born during the second half of pregnancy.

BACKGROUND: The serum concentration of the N-terminal propeptide of type I procollagen (PINP) reflects the synthesis rate of type I collagen, whereas the corresponding C-terminal telopeptide (ICTP) mirrors its degradation. DESIGN: PINP and ICTP were measured in a total of 690 cord serum samples from 592 appropriate-for-gestational-age (AGA) infants and 98 smal-for-gestational-age (SGA) infants. These markers were compared between AGA and SGA infants of different gestational ages, ranging from 23 to 41 weeks, and birth weights, from 620 to 4555 g. RESULTS: Both PINP and ICTP levels were very high in the preterm AGA infants and declined significantly with advancing gestational age, paralleling the shape of the fetal growth velocity curve. Regardless of the quite large interindividual variations observed in these markers, PINP was significantly lower in both the preterm and term AGA infants than in the SGA infants. This was also the case for ICTP in the preterm infants of gestational age less than 36 weeks. In stepwise multiple regression analyses, gestational age, being either AGA or SGA and head circumference were significant factors to explain the levels of PINP and ICTP. The levels of PINP and ICTP were correlated with each other highly significantly in both the AGA and SGA infants (rs = 0.700 and 0.692, respectively; P < 0.001 in both). CONCLUSIONS: The levels of type I collagen markers seem to follow closely the shape of the fetal growth velocity curve during different stages of gestation. However, because of the large interindividual variations observed, further studies are needed before the significance of these markers for the assessment of normal and abnormal fetal growth can be established.

Biomarkers↗
PubMed1986

Follicular center cell lymphoma. Morphologic data relating to observer reproducibility.

Subjectivity and observer variation in non-Hodgkin's lymphoma continues to plague current classification schemes. It was thought important to assess objectively derived morphometric data to see if three categories of follicular center cell (FCC) lymphomas, follicular small cleaved cell, follicular mixed small cleaved and large cell, and diffuse and nodular large cell, actually fall into distinctly separate classes based on nuclear parameters. Mean nuclear area, contour index and invagination depth of neoplastic lymphocytes, and the percentage of invaginated and clefted nuclear profiles in each example of FCC lymphoma were evaluated by three different approaches. Results obtained from distribution of the morphometric data in scatter diagrams, calculation of the overlap index, and linear regression values, all revealed considerable (but variable) degrees of overlap between the three FCC subtypes regardless of the nuclear parameter employed. Where separation between FCC lymphomas was maximal, although still incomplete, there was no consistent correlation between the nuclear parameter and the pair of FCC lymphomas being compared. At least in terms of nuclear morphological features, non-Hodgkin's lymphomas of FCC type seem to represent a continuum of one disease process. The information provides a basis for understanding some reasons underlying the problem of observer variation in non-Hodgkin's lymphoma.

Cell Nucleus↗
PubMed1990

Histological grading of prostatic carcinoma in prostatectomy specimens. Comparison of prognostic accuracy of five grading systems.

The prognostic accuracy of 5 histological grading systems (Broders, Anderson, Mostofi, Gleason and Mostofi-Schroeder) was compared. Grading was performed on 50 prostatectomy specimens by 5 pathologists. The results were averaged so as to reduce the impact of inter-observer variation. The Cox proportional hazards model was used to estimate the relationship between average grading scores and both time-to-recurrence and time-to-death by prostatic carcinoma. Age at surgery was considered to be a possible confounding factor and adjusted accordingly. The prognostic impact of the 5 grading systems (related to both recurrence and death caused by prostatic carcinoma) was judged by the likelihood ratio (LR) test score (chi 2 distributed with 1 df); for time-to-recurrence for the Mostofi-Schroeder score the LR was 6.54 and for the Gleason system it was 1.79. A stepwise procedure demonstrated that the best prognostic performance was reached with the Mostofi-Schroeder and Broders systems used together (with Mostofi-Schroeder weighted 1.5 times larger than Broders). For time-to-recurrence the median grading result was also used, giving results similar to the mean grading result. For time-to-death from prostatic carcinoma the LR test scores for all grading systems were relatively low. In this analysis the outcome of the Gleason system showed a minimum of prognostic ability, whereas the Broders and Mostofi-Schroeder systems had a reasonable predictive ability. Since the inter-observer variation of the Mostofi-Schroeder system was large, the Broders system is preferable. The restrictions and implications of this study are discussed and a brief review of the prognostic importance of grading of prostatic carcinoma is presented.

Aged↗
PubMed2001

Transrectal ultrasonography in male subfertility patients: an intra- and interobserver study.

The purpose of this paper was to examine whether ultrasound abnormalities of the prostate and seminal vesicles, which may be related to male accessory gland infection, are reproducible. Forty-seven men attending an infertility clinic were studied. Imaging findings of transrectal ultrasonography were recorded. Kappa (kappa)-values to determine the intra- and inter-observer variation were assessed. Calcifications have good intra-observer (kappa = 0.77; 95% CI: 0.59-0.96) and good inter-observer reproducibility (kappa = 0.73; 95% CI: 0.54-0.93). Dilatation of the peri-prostatic plexus had moderate intra-observer (kappa = 0.57; 95% CI: 0.33-0.80) and good inter-observer reproducibility (kappa = 0.74; 95% CI: 0.55-0.94). Other ultrasound abnormalities of the prostate were not reproducible. None of the ultrasound abnormalities of the seminal vesicles were reproducible. In our study the prevalence of ultrasound abnormalities which may be related to male accessory gland infection was as high as 96%. However, only calcifications and dilatation of the venous plexus had good reproducibility. Other observed ultrasound abnormalities of the prostate and seminal vesicles were poorly reproducible and are therefore of no use in the diagnosis of male accessory gland infection.

Adult↗
PubMed1998

Secular trends in blood pressure levels in Denmark 1964-1991.

BACKGROUND: Hypertension is an essential risk factor for development of cardiovascular diseases. Prospective studies show a reduction in risk of myocardial infarction with reduction of blood pressure. In Denmark there was a decrease in ischaemic heart disease mortality during the period (1968-1992) with around 34% in 30-65 year old men and 30% in women. OBJECTIVE: To assess the changes in casual blood pressure between 1964 and 1991 in seven cross-sectional population studies. SETTING: Centre of Preventive Medicine, University of Copenhagen, DK-2600 Glostrup. POPULATION: 10359 subjects, equal numbers of men and women, age exactly 30, 40, 50 and 60 years drawn as random samples from a background population of 300000 inhabitants and surveyed in 1964-1974 and five cross-sectional studies 1976, 1978, 1982-1984, 1986-1987 and 1991. METHODS: Blood pressure was measured according to WHO criteria by one technician in each survey. Alcohol consumption and physical activity were measured by a self-administered questionnaire. The weight and height were measured by standardized methods. Data on mortality from ischaemic heart disease were obtained from death certificates recorded by the National Board of Health. RESULTS: Blood pressure increased with increasing age in both genders and was significantly higher in men than in women. Median blood pressure in 50 year old men in 1964 was 135/85 mmHg and in 1991 it was 123/79, whereas in women in 1964 it was 140/85, against 119/74 in 1991. The prevalence of hypertensives among 30 and 40 year olds declined throughout the period. The performance of blood pressure measurements, technical variation, examination programme, seasonal variation and inter-observer variation were potential bias sources and influenced blood pressure levels, but cannot be shown to be responsible for the declining trend in blood pressure and hypertension. Women became a little more physical active in leisure time and men less active. Women consumed less alcohol than men, but the amounts slightly increased by the end of the period. Body mass index >25 was seen less frequently in women than in men and this increased in men over the period. Sale of antihypertensive drugs increased in Denmark over the 1964-1991 period. There seems to be good agreement between the changes in blood pressure in the population and the decline in mortality from stroke and coronary heart disease in Denmark, which is influenced by other risk factors as well. CONCLUSION: Blood pressure distributions have shifted towards lower values in 1964-1991. Prevalence of hypertension declined up to 1983. Risk factor changes as well as treatment for hypertension contribute to this.

Adult↗