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Biomedical subjects

A Gouveia-Oliveira

Publications and source records attributed to A Gouveia-Oliveira.

At least 19 recordsLinked to original sources

Effects of mouse ovarian tissue cryopreservation on granulosa cell-oocyte interaction.

BACKGROUND: Current ovarian tissue cryopreservation protocols have yet to be assessed in terms of somatic-germ cell interaction. Accordingly, post-thaw analysis of antral follicles can yield relevant data on the disruption of the granulosa-oocyte interface. METHODS: We compared fresh mouse ovarian tissue with tissues that had been either cryopreserved using dimethylsulphoxide (DMSO) or glycerol as cryoprotectants, or exposed to such cryoprotectants without freezing. The assessed parameters were: number of immature oocytes retrieved per ovary, allocation of the oocytes to different classes regarding antral follicle size and oocyte-granulosa cell adhesion, and the relative density of transzonal processes containing filamentous actin (TZPs-Act). RESULTS: Although cryopreservation reduces the average number of oocytes retrieved per ovary, it increases the relative distribution of granulosa-free oocytes while decreasing that of granulosa-enclosed ones. Additionally, a post-thaw decrease in TZPs-Act density was recorded. This decrease was also observed after cryoprotectant exposure without freezing, although at a lower level. For the assessed parameters, DMSO was more effective than glycerol as a cryoprotectant. CONCLUSIONS: In situ cryopreservation of granulosa-oocyte complexes with current protocols disrupts the granulosa-oocyte interface. The different patterns of granulosa cell adhesion and interaction in oocytes derived from different-sized antral follicles further suggests that the granulosa-oocyte interface may be developmentally regulated.

Actins↗

Isolated systolic hypertension--epidemiology and impact in clinical practice.

OBJECTIVE: To study the frequency, distribution and determinants of isolated systolic hypertension (ISH). DESIGN: Cross-sectional study, in two stages. First, consecutive patients of the Portuguese national health system aged 60 or over were selected (1999). The second stage covered people aged up to 60 years (2000). SETTING: Health Centers--primary care (Regional Health Administration--Lisbon). PARTICIPANTS: 3228 patients, 1100 male (439 aged up to 60 years and 661 aged > or = 60 years) and 2128 female (860 aged up to 60 years and 1268 aged > or = 60 years). MEASUREMENTS: Categories of hypertension. Risk stratification. Cardiovascular morbidity. Predictors of isolated systolic hypertension. RESULTS: The definition and staging of hypertension changed between 1988 and 1997/99 and as a consequence, there has been, in hypertensives, an increase in ISH frequency from 13% to 44% (2.4 times greater). This form of hypertension is far more frequent than grades 1 (mild hypertension = 22%), 2 (moderate hypertension = 15%) or 3 (severe hypertension = 7%). The proportion of hypertensives with ISH increases from 19% in people aged up to 40, to 30% in the fourth decade, 34% in the fifth decade, 44% in the sixth decade, 51% in the seventh decade, and 57% in those over 80 years of age. In hypertensives aged up to 50, ISH is more frequent in females. However, in those over age 50 it is predominant in males. ISH represents 60% and 37% respectively of untreated and treated hypertensives. Among untreated hypertensives, age was associated with ISH (p < 0.001; OR = 1.051 and 95% CI 1.037-1.065). In the over-60 subgroup, the following factors were associated: age (p = 0.013; OR = 1.048 and 95% CI 1.010-1.087); gender--male (p = 0.004; OR = 2.578 and 95% CI 1.361-4.881) and height (p = 0.044; OR = 0.966 and 95% CI 0.933-0.999). CONCLUSIONS: Isolated systolic hypertension is the most common form of hypertension and the most often untreated. The constitutional characteristics associated with isolated systolic hypertension in the elderly are age, gender (male) and body mass index (height). The extent of the problem justifies more attention to control of systolic blood pressure, both in research (efficacy) and in clinical practice (effectiveness).

Adult↗

Prospective evaluation of the peptide-bound collagen type I cross-links N-telopeptide and C-telopeptide in predicting bone metastases status.

PURPOSE: The objective assessment of bone metastases is currently based on serial changes in skeletal survey. We performed a prospective study to determine whether a correlation exists between the biochemical markers of bone turnover and x-ray evaluation of bone metastases in patients with or without bisphosphonate therapy, and whether bone markers are influenced by extraskeletal disease. PATIENTS AND METHODS: Patients with either bone or extraskeletal metastases were consecutively enrolled and World Health Organization response criteria were applied for both bone and extraosseous disease every 3 to 4 months. Serum levels of bone-specific alkaline phosphatase (B-AP) and C-telopeptide (ICTP) and urine levels of N-telopeptide (NTX) were measured monthly. The data were analyzed by generalized estimation equation regression. RESULTS: We studied 97 patients with bone metastases (52 also with extraskeletal metastases) and 26 with extraosseous disease only. Median time on study was 153 days, and 281 objective evaluations (171 in bone) were performed. With bisphosphonates (49 patients receiving pamidronate and three receiving clodronate), percent change from levels without therapy was 47% for NTX (P <.001) and 69% for B-AP (P =.008). With disease progression in bone, percent change from mean levels during stable disease was 152% for NTX (P <.001) and 144% for ICTP (P <.001) regardless of bisphosphonate therapy. NTX had the highest positive predictive value (71%) for the diagnosis of bone metastases progression. Extraskeletal disease had no significant effect on bone markers. CONCLUSION: Urinary NTX may be a valuable bone marker to assess the antiresorptive effect of bisphosphonate therapy and to evaluate the progression of bone metastases.

Adult↗

A critical approach to nutritional assessment in critically ill patients.

BACKGROUND AND AIMS: Nutritional assessment enhances quality of nutritional care, however, its practice bemuses professionals. This prospective study aimed to identify a feasible/informative nutritional parameter in intensive care. METHODS: 44 patients (APACHE II: 23.8+/-10.1), age 58.4+/-18.6 years, were evaluated at admission: clinical data, height, weight, body mass index (BMI), tricep skinfold thickness, mid-arm circumference (MAC), mid-arm muscle circumference (MAMC), albumin, total protein and lymphocyte count. Anthropometric parameters' performance was evaluated isolated or assembled according to Blackburn and McWhirter criteria. RESULTS: Oedema increased %IW and BMI (P<0.01); muscle depletion was frequent and agreed with MAC or MAMC ranked by both criteria, P=0.02. %IW and BMI overestimated well-nourished/overweight patients, whilst arm anthropometry, mostly MAC/MAMC, shifted towards +/-50% malnutrition. Patients were not equally ranked by both criteria; McWhirter's by using percentiles clarified the distribution and showed agreement between MAC and MAMC, P=0.007, unlike Blackburn's. Mortality was higher in patients with MAC<5th percentile, P=0.003; MAC;<15th percentile was able to predict mortality and major complications. In invasive ventilated patients, severe muscle depletion was associated with mortality, P=0.05. CONCLUSION: In intensive care most nutritional assessment methods are useless; MAC is simple, feasible and if classified by percentiles may prove functional with prognostic value.

APACHE↗

Towards a common framework for clinical trials information systems.

This work describes the strategies for data modeling and implementation and the general architecture of COATI, a Clinical Trials information system that has been in production for more than three years. We discuss how the ICH guidelines influenced the system design, how we used conventional relational and EAV tables and how we integrated third-party software packages into our system. We describe a new architecture that forms the basis of a common framework for Clinical Trials information systems. This structure is based on the concept of a Common Information Framework (CIF). We have defined standard objects and corresponding methods for the CIF as an essential step towards the development of Clinical Trials Informatics.

Clinical Trials as Topic↗

Three-dimensional environments preserve extracellular matrix compartments of ovarian follicles and increase FSH-dependent growth.

In this study we performed a systematic comparative analysis of two culture environments-flat/adhesive liquid and three-dimensional collagen gel-upon in vitro ovarian follicle development. We paid particular attention to the effects of in vitro environments upon the preservation of follicular structure and of peri- and intra-follicular extracellular matrix. We show that flat/adhesive environment leads to an obvious distortion of follicle morphology, marked extracellular matrix modifications and high rates of spontaneous, i.e., FSH-independent, follicle disruption. In contrast, three-dimensional collagen gel environments are able to maintain follicular structure with an in vivo-like basal lamina architecture, minimizing spontaneous disruption. Follicle distortions found in flat/adhesive culture systems include a pronounced flattening, causing the follicle horizontal diameters not to adequately reflect follicle volume. Our volume data, based on three-axis follicle diameter measurements, indicate that three-dimensional collagen gel environments increase follicle growth, particularly in response to FSH. This study demonstrates that preservation of both peri- and intra-follicular extracellular matrix compartments during the in vitro growth and differentiation of ovarian follicles is highly desirable, and is now possible through the use of appropriate three-dimensional collagen gel culture environments. This system allows a better understanding of the specific roles played by each of the follicle compartments during development.

Animals↗

A database system for integrated clinical trial management, control, statistical analysis and ICH-compliant reporting.

Clinical trial management and quality assurance is a complex activity that, when manually executed, is prone to errors and delays, and organizations involved in the conduct of clinical drug trials must rely on database systems to ensure adequate data integrity and timely reporting. We report the design and implementation of an integrated computer system for the management and control of multiple phase II to IV clinical drug trials, and for automated generation of monitoring and statistical analysis reports that are fully compliant with international guidelines. This Windows-based system incorporates a number of third-party software tools and applications, and its major components are COATI (Control, Assessment and Tracking of Therapeutic Investigations), a client-server database application; DART (Data Analysis and Reporting Tool) for automated data abstraction and reporting; and PANDA (Data Analysis Package) for automated statistical analysis. The system is in production for two years and was used in 15 clinical trials in a diversity of medical conditions and study designs.

Clinical Trials as Topic↗

Age and gonadotropins control Ca2+-spike acquisition in mouse oocytes isolated from early preantral follicles.

The action of gonadotropins upon the oocyte is known to be crucial at later stages of follicular development in mammals. However, its influence on oocytes at early preantral stages is still a matter of debate. In the present study we evaluated the onset of mouse oocyte's capacity to exhibit calcium spikes during preantral stages of follicular development, prior to meiotic competence acquisition. In particular, through the use of confocal microscopy, we probed for the specific effects of age and gonadotropin stimulation upon the calcium dynamics of preantral follicle oocytes. We found that important developmental changes on the Ca2+ signalling mechanisms take place early during follicular development. Specifically we demonstrate that both age and gonadotropin stimulation increase the capacity of oocytes recovered from preantral follicles to exhibit calcium spikes. We propose that a strictly morphological staging of follicular development is insufficient to predict oocyte behaviour and must take in consideration animal age and gonadotropin environment.

Aging↗

[Risk factors for cerebrovascular stroke in a cohort of hypertensive patients].

OBJECTIVES: To identify stroke risk factors in hypertensive patients and the probability of stroke in relation to those risk factors and follow-up. STUDY DESIGN: A cohort study (patients with high blood pressure). MATERIAL AND METHODS: 707 hypertensive patients were studied (Hypertension Register) in what concerns stroke incidence until 1992 (n = 126), considering one case per individual. The following variables were analysed: age, sex, body mass index (Quetelet), systolic and diastolic blood pressure, heart rate, types of hypertension (JNC-IV), left ventricular hypertrophy, changes in ST segment and T wave (Minnesota Code), fundi, angina pectoris, heart failure, central nervous (neurological) disturbances, antihypertensive treatment, smoking, serum potassium, serum sodium, blood urea, creatinine, uric acid, blood sugar, diabetes and cholesterol, in the initial record. Individually, in relation to the control of hypertension, the subjects were classified according to the casual recording of normal blood pressure, the absence of drug treatment, diastolic pressure > 114 mmHg and, at the end of 1992, according to survival, causes of death and follow-up. Stroke risk factors have been identified by multivariate analysis (Cox regression model). The survival probability (without stroke) was defined by Kaplan-Meier method. RESULTS: It was possible to maintain the epidemiological surveillance, from 1975 to 1992, of 598 cases. From those, 109 hypertensive patients were victims of at least one episode of non transient cerebral ischaemia, during their follow-up of 10.5 years. From the characteristics studied, only five were identified at risk factors. The adjusted relative risks and confidence intervals (95% CI) were the following: age: 1.08 (1.06-1.10); diastolic pressure > 114 mmHg: 1.96 (1.32-2.91); neurological disturbances 4.64 (2.99-7.2); diabetes: 2.57 (1.62-4.05) and left ventricular hypertrophy: 1.34 (1.13-1.58). CONCLUSIONS: As far as stroke is concerned: a) Age, diabetes, a casual measurement of diastolic blood pressure > 114 mmHg and left ventricular hypertrophy (electrocardiogram) were the risk factors identified; b) Prevention should include blood pressure and diabetes control, although this disease has shown more risk than a casual measurement of severe hypertension; c) Its occurrence, in this model, has only partly been explained, therefore it has become necessary to deepen the study of the risk profile.

Adult↗

Long-term prognosis of first-ever lacunar strokes. A hospital-based study.

BACKGROUND AND PURPOSE: Information concerning the long-term prognosis of lacunar strokes is still limited and has shown different results. The aim of this study was to investigate the long-term prognosis of first-ever lacunar strokes and the possible role of clinical prognostic factors and different pathogenic mechanisms. METHODS: Between March 1990 and November 1993, a cohort of consecutive patients presenting with first-ever lacunar infarcts was prospectively evaluated after stroke onset at day 0 to 3 and/or day 7, every 3 months up to 1 year, and every 6 months thereafter. All patients were studied according to a protocol that included demographic and clinical data, neurological examination, Toronto Stroke Scale, Barthel Index, Rankin Scale, CT scan, routine laboratory workup, electrocardiogram, carotid duplex scanning, and echocardiogram. More recently, patients have also been evaluated with transcranial Doppler ultrasonography. Recurrent strokes, myocardial infarction, and death were registered through direct observation, chart review, or interviews with the attending physician or family members. RESULTS: One hundred forty-five patients-94 (65%) with pure hemiparesis, 33 (23%) with sensorimotor stroke, 11 (8%) with ataxic hemiparesis, 5 (3%) with pure sensory stroke, and 2(1%) with dysarthria-clumsy hand syndrome-were followed for a median period of 39 months. During follow-up ther were 17 deaths (3 vascular), 30 recurrent strokes (1 fatal), and 4 myocardial infarctions. Five-year survival rate free of recurrent stroke was 63% (95% confidence interval [CI], 52% to 73%), while 5-year survival rate was 86% (95% CI, 78% to 91%). Cox proportional hazards analysis showed that age (p=.02) was the only significant predictor of survival free of recurrent stroke. Age (P<.001) and the degree of neurological dysfunction and functional disability at 7 days after the index stroke measured by the Toronto Stroke Scale (P=.05) and a Barthel Index score <40 (P=.04) were the only significant predictors of death. The 5-year probability rate of stroke-free recurrence was 72% (95% CI, 60% to 81%). Sixty-three percent of the first recurrent strokes were lacunar infarcts. When clinical, laboratory, and CT data as well as possible etiopathogenic mechanisms of lacunar strokes were considered, Cox proportional hazards analysis could not identify any predictor of stroke recurrence. CONCLUSIONS: Our study confirms that lacunar infarcts are associated with low stroke recurrence and mortality rates. In our series, the majority of first recurrent strokes were also lacunar infarcts. Age, degree of neurological dysfunction, and functional disability at day 7 after the index stroke were significant predictors of death.

Adult↗

Calcium regulation of colonic crypt cell kinetics: evidence for a direct effect in mice.

BACKGROUND & AIMS: Oral calcium supplementation is believed to decrease colonic hyperproliferation through neutralization of fatty acids and bile acids. In the present study, the effect of oral calcium, given with low-fat diets, in the early stages of colorectal carcinogenesis is evaluated. METHODS: In experiment A, mice received normal or low-calcium diets and were killed at 25 weeks. In experiment B, mice were fed the same diets but were submitted to six weekly injections of dimethylhydrazine and were killed at 10, 16, and 21 weeks. Cell proliferation was evaluated using bromodeoxyuridine immunohistochemistry. RESULTS: In experiment A, mice fed low-calcium diets showed a significant upward shift of the proliferative compartment (P = 0.04) (phase 2 defect) in the absence of hyperproliferation. In experiment B, besides a phase 2 defect, dimethylhydrazine-induced hyperproliferation was also significantly enhanced in animals fed low-calcium diets (phase 1 defect) as shown by an increased number of labeled cells per column and total labeling index (P = 0.01). CONCLUSIONS: Low-calcium diets induce an upward shift of the main proliferative compartment, which reflects an increased risk for malignant transformation. This effect was observed with a low-fat diet, suggesting a direct mechanism, rather than the usual indirect one, documented with high-fat diets.

1,2-Dimethylhydrazine↗

[The epidemiology of chronic venous insufficiency in Portugal].

The prevalence of chronic venous insufficiency (CVI) was investigated in 44,777 unselected primary care outpatient clinics in 17 of the 20 districts in Portugal, during 1993. The diagnosis of CVI was established clinically by 427 participating general practitioners. CVI was more prevalent in females, with a female to male ratio of 2.1:1. The disease affects all age groups, but in females its prevalence increases sharply between 15 and 20 years, while in males it begins to become important about 10 years later. The maximum age-specific prevalence is reached between 55 and 64 years in both sexes, when CVI is present in 58% of females and in 35% of males. Overall prevalence of CVI was calculated using the data from the population census of 1991, by the direct standardization method. The estimated prevalence of CVI in males is 17.8% and in females is 34.1%, corresponding to 812 thousand and 1,741 thousand cases in Portugal, respectively. In the population over 15 years old, the prevalence is 20.7% in males and 40.8% in females. These estimates have an error of +/- 2.5% with 95% confidence. The geographical distribution of the disease showed different patterns in males and in females. Prevalence decreases from coast to inland in males, and from south to north in females.

Adolescent↗

DNA methylation as an intermediate biomarker in colorectal cancer: modulation by folic acid supplementation.

Several studies have suggested that DNA hypomethylation is an early step in colorectal carcinogenesis. However, it is not clear at which stage in carcinogenesis this hypomethylation occurs, what promotes it, the extent to which it can be reversed and the consequences of such reversal in affecting tumour development. In an attempt to address some of these questions, we studied three groups of subjects with similar age and gender distributions: a group of 12 patients with colorectal carcinomas; a group of 12 patients with colorectal adenomas; and a group of eight healthy control subjects. Two experimental protocols were employed. In the first protocol, intrinsic DNA methylation was evaluated in neoplastic and in normal-appearing rectal mucosa of patients with colonic carcinomas or adenomas, compared with a group of healthy controls. In the second protocol, we examined, in a prospective and controlled fashion, the effect of folic acid supplementation (10 mg/day) on the degree of DNA methylation of rectal mucosa from those same patients after removal of the neoplasms. The degree of intrinsic DNA methylation was assessed on the basis of the capacity of the DNA isolates to serve as methyl acceptors in in vitro incubations that contained DNA methylase and [3H-methyl] S-adenosylmethionine. Intrinsic DNA methylation was significantly lower in carcinomas than in adenomas (P < 0.005). In addition, normal-appearing rectal mucosa from patients with carcinomas was significantly less methylated than in healthy controls (P < 0.005); the mean value found in the latter was also greater than the value observed in patients with adenomas, but not significantly so (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗

Computer education: attitudes and opinions of first-year medical students.

Students' attitudes toward medical informatics were evaluated with self-administered questionnaires, answered by 140 (77%) first-year medical and dental students. Fourteen per cent classified their computer literacy as negligible and 49% as deficient. Ninety-six per cent had used a computer before and 59% used one regularly. Nineteen per cent had computer education in secondary school and a further 16% attended courses given by a computer company. Only 16% read regularly about informatics. These results are similar to those observed in more industrialized countries, except that high-school education is more deficient. To 93% of these students, computer literacy is important for doctors, and to 85% computers may be very useful in many areas of health care. In the opinion of 66% of students, the computer-based patient record will be available within the next 3 to 10 years. Women showed lesser computer literacy (77% computer illiteracy to 39% in men), but there were no relevant differences in attitudes, behaviour and beliefs towards medical informatics between gender, for the same level of computer literacy. Computer education in the undergraduate curriculum was demanded by 92%, and 75% of these preferred an elective course. Weekly hours suggested for lectures should be 1 (54%) or 2 (42%), and for hands-on practice 2 (54%) or 4 (31%) hours. The curriculum should include medical applications (83% of students), information science theory and technology (44%), micro-informatics (44%), bibliographic database search (27%), programming languages (23%) and statistical packages (23%). Gender, computer literacy or course did not correlate significantly with students' opinions about the contents of undergraduate education.

Attitude of Health Personnel↗

A unified approach to the design of clinical reporting systems.

Computer-based Clinical Reporting Systems (CRS) for diagnostic departments that use structured data entry have a number of functional and structural affinities suggesting that a common software architecture for CRS may be defined. Such an architecture should allow easy expandability and reusability of a CRS. We report the development methodology and the architecture of SISCOPE, a CRS originally designed for gastrointestinal endoscopy that is expandable and reusable. Its main components are a patient database, a knowledge base, a reports base, and screen and reporting engines. The knowledge base contains the description of the controlled vocabulary and all the information necessary to control the menu system, and is easily accessed and modified with a conventional text editor. The structure of the controlled vocabulary is formally presented as an entity-relationship diagram. The screen engine drives a dynamic user interface and the reporting engine automatically creates a medical report; both engines operate by following a set of rules and the information contained in the knowledge base. Clinical experience has shown this architecture to be highly flexible and to allow frequent modifications of both the vocabulary and the menu system. This structure provided increased collaboration among development teams, insulating the domain expert from the details of the database, and enabling him to modify the system as necessary and to test the changes immediately. The system has also been reused in several different domains.

Artificial Intelligence↗

[Hypertension and well-being: a study with indapamide].

STUDY OBJECTIVE: Evaluate the clinical efficacy and quality of life of indapamide in patients with mild and moderate arterial systemic hypertension under indapamide. DESIGN: Open prospective design. SETTING: Outpatient clinics of the Instituto Nacional de Cardiologia Preventiva in Lisbon. PATIENTS: Thirty-two patients whose supine diastolic blood pressure was between 95 ans 115 mmHg without known secondary hypertension, unstable diabetes, cardiac, renal or hepatic failure, hypokalemia, coronary artery disease or stroke in the previous year. INTERVENTION: After a two week wash-out and four week placebo periods, indapamide has been given in a single daily dose of 2.5 mg at breakfast during 12 weeks. MEASUREMENTS AND MAIN RESULTS: The mean systolic/diastolic blood pressures was reduced from 155.7/103.7 to 138.6/86.1 mmHg (p < 0.0001). The mean standing systolic/diastolic blood pressure lowered from 160.2/103.7 to 141.6/85.9 mmHg (p < 0.0001). The questionnaires on quality of life and the analogic visual scale showed a progressive and significant improvement in general well-being. In the patient questionnaire the percentage of improvement was 80% (16/20 items) namely asthenia, headache, attention, dizziness, tinnitus and visual disturbance. In the physician questionnaire all the items improved. Biochemical acceptability was characterized by the stability of sodium, chlorine, glucose, creatinine, urea, cholesterol, triglycerides, uric acid and slight decrease in potassium from 4.38 to 4.14 mmol/l (p < 0.01) ranging in normal values. CONCLUSIONS: These results confirm the clinical efficacy of indapamide and its beneficial effects on quality of life in patients with mild and moderate hypertension when administered in monotherapy.

Adult↗

Formal representation of a conceptual data model for the patient-based medical record.

We present a general architecture for the patient-based medical record as it is being developed for the SAMS, a private social security system. The conceptual data model is described in a convenient formal notation, the entity-relationship diagram. Although following the original formulation of the problem-oriented medical record (POMR), the data model was designed with a level of generalization that, functionally, makes structural differences between conventional and POMR no longer apparent. The main features of this model are its adaptability to individual work practices and its problem-oriented structure, including the representation of problems' evolution. This structure will enable physicians to organize the data, mostly collected elsewhere, by explicitly relating the facts that constitute a particular patient record, which is a simple way to store context information and clinical knowledge that is not part of patient data.

Database Management Systems↗

[A multivariate analysis of the factors associated with the severity of chronic venous insufficiency].

Chronic Venous Insufficiency (CVI) affects a large proportion of individuals and, with the ageing of the population of Western Europe, its prevalence is expected to increase. Epidemiological data, particularly regarding risk factors, is scarce and controversial. The purpose of this study was to identify clinical factors that are associated with an increase in severity of CVI. Eighteen physicians observed 474 unselected patients with symptoms suggesting CVI. A multivariate model is forwarded in which age is a major risk factor. Other factors that are independently correlated with the severity of CVI are body weight, environmental heat, sedentariness, double heredity, high-dose oestrogen formulations, osteo-articular disease of the lower limbs, presence of troncular varices, involvement of the internal saphena, lymphedema or history of thrombophlebitis. Since most studies do not adjust for age when testing for risk factors, this may be an important reason for the multiplicity of reported factors and the lack of consistency of their results.

Adolescent↗