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J Llorca

Publications and source records attributed to J Llorca.

At least 55 records · Page 3Linked to original sources
PubMed1999

Increase in cervical cancer mortality in Spain, 1951-1991.

BACKGROUND: The trend in cervical cancer mortality in Spain from 1951 to 1991 is examined. METHODS: Analysis of national mortality statistics calculating age standardised mortality rates and an age-period cohort analysis. A fit to the Gompertz function was made to estimate the influence of the environmental factors on the mortality rates evolution. MAIN RESULTS: The age standardised mortality rate in Spain is lower than in other developed countries (USA or Estonia) and equal to Norwegian and Finland rates; but whereas in these countries the trend is to decrease, the Spanish rate has increased during this period, because of a cohort effect. A misclassification bias could be responsible for the trend in women aged 40 and older but the increasing trend in younger women could not be interpreted as espurious. The Gompertzian analysis suggests an increase in environmental factors causing cervical cancer. CONCLUSIONS: Cervical cancer mortality rates are increasing in Spain because of environmental factors.

Adult↗
PubMed1999

[Mortality due to multiple sclerosis in Spain, 1951-1992].

UNLABELLED: FOUNDATIONS: In this work, multiple sclerosis mortality trend in Spain from 1951 to 1992 is displayed. The purpose is to identify the pattern of age-adjusted mortality evolution and to measure the effect of environmental factors. METHODS: Multiple sclerosis mortality is standardized by age using the world standard population. In each year from 1951 to 1992, age-specific mortality rates are transversely fitted to the Gompertz law. The Longitudinal Gompertzian analysis is applied to the obtained coefficients to quantify the effects of competing risks and environmental factors. RESULTS: Multiple sclerosis age-adjusted mortality increased from 1951 to 1968; a step-down is produced in 1969 (coinciding with change from 7th to 8th revision of the International Classification of Diseases) and a stability from 1970 on. Multiple sclerosis in Spain is a Gompertzian disease. Adjusting mortality for R0 (which in the Gompertz function represents the addition of the environmental factors acting in a point near the beginning of the life and the competing risks of death) the result was almost constant throughout the whole analyzed period. CONCLUSIONS: It is suggested that multiple sclerosis mortality trend in Spain is due to changes in some environmental factor acting early and in a point; on the other hand, diet or other environmental factors acting for long time or genetic factors have and little or no influence in this trend.

Adult↗
PubMed1998

Risk factors for surgical site infections diagnosed after hospital discharge.

A prospective cohort study on 1103 consecutive patients undergoing general surgery with a follow-up of up to 30 days was undertaken to analyse the risk factors for surgical-site infection (SSI). Relative risks (RRs), crude and multiple-risk factors adjusted for by logistic regression analysis, and their 95% confidence intervals were calculated. One hundred and four patients (9.4%) developed infection, 81 in hospital and 23 at home. Predictors for in-hospital SSI differed from those for post-discharge SSI. In a crude analysis, an increased risk of post-discharge SSI occurred after clean-contaminated surgery (but not contaminated surgery). Stepwise logistic regression failed to identify any significant predictor for post-discharge SSI.

Adult↗
PubMed1998

[Gompertzian analysis of ischemic cardiopathy mortality in Spain, 1951-1992].

INTRODUCTION AND OBJECTIVES: In Spain ischemic heart disease mortality was increasing prior to 1975 and has decreased since 1975. This trend is common to both genders. The goal of this paper is to separate the genetic, environmental and competitive risk factors influencing this evolution. METHODS: The Gompertz function was adjusted cross-sectionally to age-specific mortality due to ischemic heart disease for each year from 1951 to 1992. The Gompertzian longitudinal analysis was applied to the coefficients obtained to estimate the effect due to environmental and competitive factors. RESULTS: Ischemic heart disease in Spain is a Gompertzian disease with an intersection point at 67 years for men and 40 years for women. Environmental factors were increasing before 1975 and have decreased since then. However, the competitive factors decreased in men since 1980 and in women since 1951 on. CONCLUSION: The evolution of risk factors (smoking, hypercholesterolemia and hypertension) is responsible for the major proportion of ischemic disease mortality changes. Treatment of instaured ischemic disease has a low influence.

Adult↗
PubMed1998

Age differential mortality in Spain, 1900-1991.

STUDY OBJECTIVE: To analyse the interindividual inequalities in mortality in Spain through the 20th century using the Gini coefficient, widely used as an income concentration index. DESIGN: Age mortality data were obtained from official publications of vital statistics and age and sex compositions were obtained from population census. The Gini coefficient was estimated. It can take values between 0 and 1. Zero represents the situation in which all subjects die at the same age, whereas when all but one subject dies at 25 the index reaches a figure of 1. MAIN RESULTS: In both men and women there was a trend to decrease age differential mortality (from 0.26 to 0.16 for men and from 0.26 to 0.12 for women). Nevertheless, transitory increases were produced in 1918 (influenza epidemic), and in the period of the Civil War of Spain, showing a more important increase in the mortality of young people than that of the elderly. A new increase was observed through the second half of eighties; it resulted from an AIDS epidemic and motor vehicle injuries. CONCLUSION: Inequalities in mortality in Spain have decreased through the 20th century.

Adult↗
PubMed1997

Separation by FPLC chromatofocusing of UDP-glucosyltransferases from three developmental stages of Drosophila melanogaster.

Variation of UDP-glucosyltransferase activity, during Drosophila melanogaster development, was analyzed. The endogenous metabolite xanthurenic acid and the xenobiotic compounds 1-naphthol and 2-naphthol were used as substrates. Developmentally regulated differences were observed for the three substrates, suggesting the presence of UDP-glucosyltransferase isoenzymes. This was further confirmed by FPLC chromatofocusing on a Mono P column: seven peaks of UDP-glucosyltransferase activity (pHs: > or = 6.3, 5.8, 5.5, 4.9, 4.5, 4.2, < or = 4.0) with either single or overlapping substrate specificity were detected. A single xanthurenic acid:UDP-glucosyltransferase activity (pl 5.8) was found throughout development. In contrast, a gradual increase in the number of 2-napthol:UDP-glucosyltransferase-isoenzymes (pl from 6.3 to 4.0) was observed during development, whereas no isoenzymes specific for 1-naphthol were resolved. Based on the distribution and substrate specificity of the eluted peaks in the three developmental stages analyzed, the presence of seven or possibly eight UDP-glucosyltransferase isoenzymes is proposed.

Animals↗
PubMed1996

Longitudinal Gompertzian and Weibull analyses of adult mortality in Spain (Europe), 1900-1992.

Mortality data from Spain, 1900 to 1992, were analyzed using Gompertzian and Weibull functions. Longitudinal Gompertzian analysis demonstrated that annual age-specific mortality rate distributions were determined by a fixed intersection point (in men: 84.3 years, in women: 89.3 years). Two methods of longitudinal Gompertzian analysis were applied. The method based on linear regression indicated that environmental influences upon age-related mortality were constant. The method based on a rough estimate of first derivative suggested that environmental influences have been decreasing. Both of these methods suggested that genetic influence upon age-related mortality is greater for men that for women. Analysis of Spanish mortality data from 1900 to 1992 suggest that the Gompertz function fits age-specific mortality rate distributions in adult men and women better than the Weibull function.

Adult↗
PubMed1996

Nosocomial infections in patients having cardiovascular operations: a multivariate analysis of risk factors.

A total of 970 adult patients undergoing cardiovascular operations during a 1-year period were eligible for a case-control study on the risk factors for nosocomial infection. Cases were defined as patients in whom a postoperative infection developed. Every case was paired with one uninfected subject. Nosocomial infection occurred in 89 (9.2%) patients. A total of 120 episodes of infection were diagnosed (1.3 episodes per patient). The infection ratio was 12.4%. Surgical site infection was the most common (5.6%), followed by pneumonia (3.2%), urinary tract infection requiring the use of intravenous antibiotics (1.8%), deep surgical site (0.9%), and bacteremia (0.7%). Advanced age, urgent intervention, duration of surgical procedure, blood transfusion, and use of invasive procedures (urinary catheter, chest tubes, nasogastric tube passage) were significantly associated with infection in the bivariate analysis. Nosocomial infection resulted in a significant increase in the length of hospital stay. Cases showed an almost fivefold greater risk of death than controls (odds ratio, 4.73; 95% confidence interval, 1.11 to 6.83; p = 0.009). Age older than 65 years, female sex, and mode of surgical intervention were selected in the multivariate analysis for patients undergoing cardiac operations, whereas general anesthesia or assisted ventilation, central venous catheter, and blood transfusion were the variables selected for patients undergoing operation for vascular disorders. In summary, the recognition of risk factors for postoperative infection in patients undergoing cardiovascular surgical procedures may contribute to improve their prognosis and to more organized surveillance and control activities in the hospital environment.

Aged↗
PubMed1995

Subtyping of Legionella pneumophila isolates by arbitrarily primed polymerase chain reaction.

Arbitrarily primed polymerase chain reaction (AP-PCR) was used to differentiate strains of Legionella pneumophila isolated from different water sources in a resort hotel in Benidorm, Alicante, Spain, where an outbreak of Legionnaires' disease occurred among a group of tourists between 65 and 80 years of age. All isolates were L. pneumophila serogroup 1, subtype Pontiac (Knoxville 1). Five different patterns (P1 to P5) were obtained by AP-PCR. The number of bands per pattern varied between 4 and 11. Patterns P1 and P2 represented 60 and 20% of L. pneumophila isolates, respectively. Since different subpopulations of L. pneumophila coexisted (up to three different AP-PCR patterns were identified in a single room), it was not possible to link an individual L. pneumophila strain to the occurrence of this outbreak.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Comparison of 2 methods for calculating uncertainty in laboratory analysis].

OBJECTIVE: To compare two methods in the estimation of the uncertainty in laboratory quality control. METHODS: A computerized simulation is performed to compare the delta method (suggested by the International Organization for Standardization and the Entidad Nacional de Acreditación) and a bootstrap-based method. The simulation includes several situations with different environmental conditions and different relationships between the analyzed variables. RESULTS: The mean in the coverage obtained by the estimated confidence intervals is higher and closer to the nominal using the bootstrap than using the delta method. The most important differences are observed in the coverage percent distribution: while using the bootstrap, a great number of simulations obtain coverage near the nominal of 95%; using the delta method the coverage are more dispersed, including coverage of 100% in some occasions and lesser than 80% in others. The bootstrap offers very similar results under different conditions, including in the presence of unknown and unmeasured variables or when the analyzed variables are correlated. The delta method shows poorer results in both situations. CONCLUSION: The uncertainty in the laboratory quality control can be estimated more accurately with bootstrapping than with the delta method.

Clinical Laboratory Techniques↗
PubMedDate not supplied

[Population attributable fraction: estimation and interpretation].

The goal of this paper is to revise the concept, estimation methods, and interpretations of the population attributable fraction. From the usual formula of the population attributable fraction: (Ip ­ I₀) / Ip, where Ip is the cumulative incidence in the overall population, and I₀ is the cumulative incidence in the non-exposed group, other formulae are presented for use in exposures with more than two levels, and in the presence of confounding factors. Differences in estimation methods between cohort and case-control studies are discussed, and equations to estimate confidence intervals are displayed. Finally, some interpretations -­including the concepts of «etiologic case» and «case in excess», suggested by Greenland and Robbins-­, and some habitual errors are discussed.

Case-Control Studies↗
PubMedDate not supplied

[Competing death risks].

The death of an individual is not a repetitive event, so if a cause of death overtakes another cause in producing death, mortality rates from the overtaken cause decrease. This phenomenon is known as competing risks of death and it must be taken into account in any cause-specific mortality analysis. In this work the competing risks concept is formalized and some historical data are described. The main parametric tools to analyze competing risks are displayed, with a special look at the Gompertz and Weibull functions. Regarding non-parametric models, the Chiang method is shown and its applicability on both dependent and independent causes of death is discussed. Finally, other tools specially useful in clinical epidemiology are enumerated, including Cox regression, Kaplan-Meier and log-rank methods, as well as the interactions between competing risks and misclassification and selection biases.

Bias↗
PubMedDate not supplied

DNA amplification fingerprinting for subtyping Neisseria gonorrhoeae strains.

BACKGROUND AND OBJECTIVES: DNA amplification fingerprinting is used in most epidemiologic studies as a substitute for conventional typing methods. DNA amplification fingerprinting and conventional typing methods were compared in this epidemiologic study of Neisseria gonorrhoeae. GOAL OF THIS STUDY: To differentiate 70 Neisseria gonorrhoeae isolates from untreated patients with urogenital gonococcal infection. STUDY DESIGN: Gonococcal strains were characterized by auxotyping, serotyping, plasmid profile, antibiotic sensitivity, and DNA amplification fingerprinting. The method of unweighted pair-group average linkage was used for cluster analysis. Discriminatory power was calculated applying Simpson's index. RESULTS: Amplification of Neisseria gonorrhoeae DNA with primers OPA-03 and OPA-13 produced well-resolved patterns of 15 and 22 DNA fragments, respectively, with a discriminatory power (0.978 with OPA-13 and 0.967 with OPA-03) comparable to that obtained with auxotyping/serotyping combination (D:0.968) or with auxotype/serotype/plasmid profile combination (D:0.983). Correlation between DNA amplification fingerprinting pattern and auxotype/serotype class was not always uniform. Some strains with the same auxotype/serotype/plasmid profile were subdivided by DNA amplification fingerprinting, and vice versa. CONCLUSION: Although auxotype/serotype class and DNA amplification fingerprinting can be used in the epidemiologic characterization of strains, DNA amplification fingerprinting offers a better discriminatory index than the separate serotyping. It is especially useful for differentiating serologically identical strains and nontypable strains. A combination of serotyping and DNA amplification fingerprinting seems to be the best way to differentiate Neisseria gonorrhoeae strains in epidemiologic studies, bringing together the most simple techniques and the best discriminatory power among isolates.

Bacterial Typing Techniques↗
PubMedDate not supplied

[The measurement of inequalities in age of death: calculating the Gini Index based on mortality tables].

The Gini index has been used to gauge the concentration of different variables, including income, the mortality distribution and the spread of physicians. The use of the Gini index for gauging the inequalities in the age of death based on actuarial mortality data. For this purpose, the 1990 age and gender-related mortality figures for each Autonomous Community were used. The inequalities in the number of years lived are greater among males than among females throughout all of the Autonomous Communities. The Communities showing the longest life expectancies are those which have also been revealed to involved the least degree of inequality in the number of years lived, which therefore makes in possible to pinpoint health-care priorities in some cases. The Gini index can be applied to age-related mortality for gauging the degree of inequality in the age of death and to pinpoint age groups on which to place priority with regard to health-care measures.

Adolescent↗
PubMedDate not supplied

Hypersensitivity vasculitis in adults: a benign disease usually limited to skin.

OBJECTIVES: To examine the clinical spectrum of hypersensitivity vasculitis (HV) in an unselected population of adults and establish differences between patients with HV limited to the skin and those with systemic involvement. METHODS: Retrospective study of adult patients (> 20 years) with biopsy-proven cutaneous leukocytoclastic vasculitis diagnosed as having HV, who were seen at the single hospital serving a well defined population between 1984 and 1998. Patients were classified as having HV according to the criteria of Michel et al. (9). To examine outcome and relapses of the disease only those patients with a follow-up of at least 1 year were included in this study. RESULTS: 64 patients with a mean follow-up of 4.9 +/- 3.5 (range: 1.1-13.6) years were studied. Ten (15.6%) had visceral involvement (3 gastrointestinal and 7 renal manifestations) during the course of the disease. The remaining patients had a leukocytoclastic vasculitis limited to the skin. When the study was concluded persistent hematuria and proteinuria was only observed in 1 patient and none developed renal insufficiency. Patients with a history of drug treatment and elevated ESR had more systemic complications but the difference was not statistically significant. The outcome was excellent in both patients with HV limited to the skin and in those with systemic complications during the course of the disease. CONCLUSIONS: In unselected adults HV is generally a benign disease confined exclusively to the skin. In those patients with systemic manifestations, visceral involvement is generally mild and transient.

Adult↗