Assessing the relationship between markers of glycemic control through flexible copula regression models.

Glycated haemoglobin (HbA1c) is a sensitive marker of blood glucose in patients with diabetes. However, levels can vary considerably, even amongst individuals with similar mean blood glucose concentrations. Other glycated proteins, such as fructosamine, can also act as blood sugar markers, but estimating HbA1c and fructosamine via independent models may lead to errors of interpretation regarding disease severity. From a clinical standpoint, it would be of great interest to know the factors that affect the mean concentration of both HbA1c and fructosamine, which influence the variability in the concentrations of these glycated markers and cause HbA1c/fructosamine discordance. Flexible models are required to illustrate the behaviour of these variables as well as the association between them. This work reviews existing models that might serve in this regard. Flexible copula regression models using splines were used to provide a better understanding of the behaviour of both glycated proteins and the relationship between them under the possible influence of different covariates. This work shows the usefulness of this type of models in practise and provides a basis for their clinical interpretation by means of an understandable case study. Ultimately, to better understand the effects of each continuous covariate, they are represented at the true scale of the response variables.

Interindividual differences in the clinical effectiveness of liraglutide in Type 2 diabetes: a real-world retrospective study conducted in Spain.

AIMS: To study the response of clinical variables (HbA1c , body weight, lipid profile and blood pressure) over 24 months of liraglutide treatment in a real-world clinical setting, and to describe the evolution of HbA1c and body weight reduction in response to liraglutide treatment by employing generalized additive mixed models (GAMMs). METHODS: We included people aged ≥ 18 years with Type 2 diabetes mellitus that initiated liraglutide treatment between November 2011 and May 2015. Demographic and clinical data were retrieved retrospectively over 24 months from electronic medical records with a median duration of observation of 7.0 (IQR 3.0-12.0) months. RESULTS: Individuals that initiated liraglutide therapy were obese (BMI 39.1 kg/m2 ), with inadequate HbA1c (68 mmol/mol [8.4%]), blood pressure and lipid levels. Upon liraglutide treatment, HbA1c , body weight, mean systolic and diastolic blood pressure, and lipid levels decreased gradually. GAMMs demonstrated that longer treatment with liraglutide was a predictor of improved HbA1c response, whereas higher baseline HbA1c , longer Type 2 diabetes duration and treatment with insulin were predictors of worse HbA1c response. Higher baseline weight, longer treatment with liraglutide and the interaction between metformin and time were predictors of improved weight response. CONCLUSIONS: In this real-world study, we showed the effectiveness of liraglutide in improving body weight, HbA1c , mean systolic and diastolic blood pressure, and lipid levels. GAMMs indicated that baseline HbA1c and weight, time of treatment with liraglutide, diabetes duration and the use of metformin or insulin are predictors of clinical response to liraglutide.

Optimum Sample Size to Estimate Mean Parasite Abundance in Fish Parasite Surveys.

To reach ethically and scientifically valid mean abundance values in parasitological and epidemiological studies this paper considers analytic and simulation approaches for sample size determination. The sample size estimation was carried out by applying mathematical formula with predetermined precision level and parameter of the negative binomial distribution estimated from the empirical data. A simulation approach to optimum sample size determination aimed at the estimation of true value of the mean abundance and its confidence interval (CI) was based on the Bag of Little Bootstraps (BLB). The abundance of two species of monogenean parasites Ligophorus cephali and L. mediterraneus from Mugil cephalus across the Azov-Black Seas localities were subjected to the analysis. The dispersion pattern of both helminth species could be characterized as a highly aggregated distribution with the variance being substantially larger than the mean abundance. The holistic approach applied here offers a wide range of appropriate methods in searching for the optimum sample size and the understanding about the expected precision level of the mean. Given the superior performance of the BLB relative to formulae with its few assumptions, the bootstrap procedure is the preferred method. Two important assessments were performed in the present study: i) based on CIs width a reasonable precision level for the mean abundance in parasitological surveys of Ligophorus spp. could be chosen between 0.8 and 0.5 with 1.6 and 1x mean of the CIs width, and ii) the sample size equal 80 or more host individuals allows accurate and precise estimation of mean abundance. Meanwhile for the host sample size in range between 25 and 40 individuals, the median estimates showed minimal bias but the sampling distribution skewed to the low values; a sample size of 10 host individuals yielded to unreliable estimates.

Cone Beam Computed Tomography evaluation of palatal bone thickness for miniscrew placement in Down's syndrome.

OBJECTIVES: To quantify palatal bone thickness (PBT) in Down's syndrome (DS) patients in order to identify the best areas for miniscrew placement. DESIGN: The study group was formed of 40 DS patients (25 male and 15 female) with a mean age of 18.4±6.3 years (range, 9-40 years). A control group of 40 non-syndromic age- and sex-matched individuals was selected. Maxillary CBCT images were available for all participants. Coronal sections of the hard palate were selected at 4, 8, 16 and 24mm posterior to the distal wall of the incisive foramen. PBT measurements were performed at 20 selected points on these coronal sections at the midline and at 3 and 6mm to right and left of the suture. RESULTS: Overall, PBT was similar in DS and controls and it was not affected by age or sex. In both groups PBT decreased progressively with increasing distance from the posterior wall of the nasopalatine foramen in an anteroposterior direction, except along the median palatal suture. PBT along the suture was lower in DS than in controls in all the paracoronal image planes (P=0.02, 0.007, 0.01 and 0.02 at 4mm, 8mm, 16mm and 24mm, respectively, from the incisive foramen). PBT at the most anterior paramedian locations was also lower in DS than in controls (P=0.02 and 0.03, respectively, 3mm to the right and left of midline). CONCLUSIONS: In DS individuals, the most suitable area for miniscrew placement in terms of bone volume is the median palatal suture, irrespective of age or sex, as occurs in the general population, followed by the paramedian sites closest to the incisive foramen.

Epidemiology, mortality rate and survival in a homogeneous population of hypopituitary patients.

INTRODUCTION: Hypopituitarism is associated with higher prevalence of cardiovascular risk factors and premature death. Furthermore, some clinical and therapeutic features of hypopituitarism have been associated with a worse prognosis. OBJECTIVE: We reviewed, retrospectively, a large series of adult patients with hypopituitarism using stringent epidemiological criteria. Prevalence, association with cardiovascular risk factors, mortality and survival have been analysed. DESIGN AND METHODS: Two hundred and nine adult hypopituitary patients (56·9% females) from a population of 405 218 inhabitants, followed for 10 years. RESULTS: Prevalence of hypopituitarism at the end of the study was 37·5 cases/100 000 inhabitants. Incidence of hypopituitarism was 2·07 cases/100 000 inhabitants and year. Thirty-two patients died during the period of the study. Standardized mortality rate (SMR) was 8·05, higher in males (8·92 vs 7·34) and in younger patients (84·93 vs 5·26). Diagnosis of acromegaly (P = 0·033), previous radiotherapy (P = 0·02), higher BMI (P = 0·04), diabetes mellitus (P = 0·03) and cancer (P < 0·0001) were associated with mortality. A lower survival was associated with older age at diagnosis, nontumoural causes, previous radiotherapy, diabetes mellitus with poor metabolic control and malignant disease. CONCLUSIONS: Prevalence of hypopituitarism was 37·5 cases/100 000 inhabitants, and annual incidence was 2·07 cases/100 000 inhabitants. SMR was 8 times higher in hypopituitarism than in general population and was also higher in males and younger patients. Reduced survival was significantly related to cancer, nontumoural causes of hypopituitarism, older age at diagnosis, previous radiotherapy and diabetes mellitus with poor metabolic control.

A study of neurotoxic biomarkers, c-fos and GFAP after acute exposure to GSM radiation at 900 MHz in the picrotoxin model of rat brains.

The acute effects of microwave exposure from the Global System for Mobile Communication (GSM) were studied in rats, using 900MHz radiation at an intensity similar to mobile phone emissions. Acute subconvulsive doses of picrotoxin were then administered to the rats and an experimental model of seizure-proneness was created from the data. Seventy-two adult male Sprague-Dawley rats underwent immunochemical testing of relevant anatomical areas to measure induction of the c-fos neuronal marker after 90min and 24h, and of the glial fibrillary acidic protein (GFAP) 72h after acute exposure to a 900MHz electromagnetic field (EMF). The experimental set-up facilitated measurement of absorbed power, from which the average specific absorption rate was calculated using the finite-difference time-domain (FDTD) 2h after exposure to EMF radiation at 1.45W/kg in picrotoxin-treated rats and 1.38W/kg in untreated rats. Ninety minutes after radiation high levels of c-fos expression were recorded in the neocortex and paleocortex along with low hippocampus activation in picrotoxin treated animals. Most brain areas, except the limbic cortical region, showed important increases in neuronal activation 24h after picrotoxin and radiation. Three days after picrotoxin treatment, radiation effects were still apparent in the neocortex, dentate gyrus and CA3, but a significant decrease in activity was noted in the piriform and entorhinal cortex. During this time, glial reactivity increased with every seizure in irradiated, picrotoxin-treated brain regions. Our results reveal that c-fos and glial markers were triggered by the combined stress of non-thermal irradiation and the toxic effect of picrotoxin on cerebral tissues.

Prevalence of metabolic syndrome in Galicia (NW Spain) on four alternative definitions and association with insulin resistance.

The present study evaluated the prevalence of the metabolic syndrome (MS) in a representative sample (no.=2860) of adults from the Spanish region of Galicia using the definitions of a) the World Health Organization; b) the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults; c) the European Group for Study of Insulin Resistance; and d) the International Diabetes Federation. In addition, we assess concordance among the different definitions, and the relationships of MS with insulin resistance (IR) as assessed by the homeostatic model assessment (HOMA-IR) index. Our results indicate a high prevalence of MS under all 4 definitions. MS prevalence was higher in men than women on all 4 definitions, and increased significantly with body mass index and age. IR was high among subjects with MS, and the HOMA index was a good discriminator of MS and non-MS on all 4 definitions, suggesting that HOMA index may be a useful predictive tool in clinical practice.

Distance of the contact glide in the closing masticatory stroke during mastication of three types of food.

This study was designed to characterize the distance of the contact glide in the closing masticatory stroke in healthy adult subjects, during chewing of three types of food (crustless bread, chewing gum and peanuts). Mandibular movements (masticatory movements and laterality movements with dental contact) were registered using a gnathograph (MK-6I Diagnostic System) on the right and left side during unilateral chewing of the three food types. Length of dental contact was measured in masticatory cycle, which is defined as where the terminal part of the chewing cycles could be superimposed on the pathways taken by the mandible during lateral excursions with occlusal contacts. The length of dental contact during mastication of chewing gum is 1.46 +/- 1 mm, during chewing of soft bread is 1.38 +/- 0.7 mm and during chewing of peanuts is 1.45 +/- 0.9 mm. There is no significant difference in the lengths of dental contact during mastication of three types of foods that enable direct tooth gliding.

The action of pulse-modulated GSM radiation increases regional changes in brain activity and c-Fos expression in cortical and subcortical areas in a rat model of picrotoxin-induced seizure proneness.

The action of the pulse-modulated GSM radiofrequency of mobile phones has been suggested as a physical phenomenon that might have biological effects on the mammalian central nervous system. In the present study, GSM-exposed picrotoxin-pretreated rats showed differences in clinical and EEG signs, and in c-Fos expression in the brain, with respect to picrotoxin-treated rats exposed to an equivalent dose of unmodulated radiation. Neither radiation treatment caused tissue heating, so thermal effects can be ruled out. The most marked effects of GSM radiation on c-Fos expression in picrotoxin-treated rats were observed in limbic structures, olfactory cortex areas and subcortical areas, the dentate gyrus, and the central lateral nucleus of the thalamic intralaminar nucleus group. Nonpicrotoxin-treated animals exposed to unmodulated radiation showed the highest levels of neuronal c-Fos expression in cortical areas. These results suggest a specific effect of the pulse modulation of GSM radiation on brain activity of a picrotoxin-induced seizure-proneness rat model and indicate that this mobile-phone-type radiation might induce regional changes in previous preexcitability conditions of neuronal activation.

Prevalence, awareness, treatment and control of hypertension in Galicia (Spain) and association with related diseases.

The present study evaluated the prevalence of hypertension (HT) and its possible relationships with various risk factors in a representative sample (n=2884) of the adult population (>18 years old) of Galicia, a region of Spain. Subjects were selected by a two-step cluster sampling procedure from the Galician public health service database, which covers more than 95% of the population (2.7 million inhabitants). The overall prevalence of HT, defined as BP >140/90 mm Hg and/or current treatment with antihypertensive medication, was 25.5%, higher in men (31.1%) than in women (20.7%). Of the hypertensive subjects 50.6% were aware of the HT; of these, 72.0% were receiving treatment and 36.4% were treated and controlled. The prevalence of HT increased with age and was higher in subjects from urban areas than rural areas and higher in subjects with low educational level. Surprisingly, people with low educational level more frequently showed awareness of HT than people with high education level. Increased body mass index was related to increased prevalence of HT and close associations were observed between HT and cardiovascular diseases. Our data also show a linear upward trend in blood pressure from normal glucose metabolism to diabetes mellitus. Surprisingly, the prevalence of HT among people with known diabetes was higher than among people with undetected diabetes, which may indicate poor control of HT in diabetic subjects.

Iodine nutrition in the adult population of Galicia (Spain).

OBJECTIVE: To identify the current state of iodine nutrition in the adult population of Galicia (Spain), which is considered iodine sufficient based on results from studies carried out on schoolchildren. Urinary iodine concentration (UIC) and its relationship with different socio-demographic variables were assessed. DESIGN: A cross-sectional study was carried out on the population aged above 18 years in the Autonomous Community of Galicia (Spain) during 2004. The UICs were determined in an isolated urine sample using Dunn's colorimetric method. Iodine status was based on World Health Organization/International Council for the Control of Iodine Deficiency Disorders (WHO/ICCIDD) UIC. MAIN OUTCOME: A total of 2877 urine samples were taken. Median UIC for the total Galician population was 75.6 microg/L. About 30% of the population showed a UIC below 50 microg/L. Educational level, place of residence (coast vs. inland), and consumption of iodized salt were independent variables associated with the iodine nutrition of the adult population of Galicia. CONCLUSIONS: There is "mild" iodine deficiency (WHO) in the adult population of Galicia, which affects all the groups analyzed and which is particularly significant in the group of women of a fertile age. The data obtained on the state of iodine nutrition in school-age populations cannot be extended to the adult population.

[Factors determining the duration of temporary disability and return to work in a health district of Galicia]. / Determinantes de la duración de la incapacidad temporal y la vuelta al trabajo en un área sanitaria de Galicia.

OBJECTIVE: To determine the factors associated with the incidence and duration of temporary work incapacity (TWI) in a health district. DESIGN: Descriptive and retrospective study. SETTING: South health district of the province of Lugo, Spain. PARTICIPANTS: A random sample of 1513 cases was selected among the total of episodes of TWI, during 3 years period. MAIN MEASURES: The main factors analyzed are, on the one hand, the socio-demographic characteristics of the patient, his or her social security (SS) scheme, diagnosis that justifies the TWD, and the prescription date; and, on the other hand, the age, sex, specialised training, time in the post and years in practice of the physician who prescribes the TWI. The comparison of the means was carried out using variance analysis and the Kruskal-Wallis test. The relative effect of each variable on the probability of returning to the work was estimated through Cox regression models. RESULTS: The mean duration of the episodes of TWI was of 74+/-103 days. The most frequent diagnoses were those of the bones-muscles and joints (BMAJ), injuries and poisonings (IAP), and respiratory diseases (RD). The probability of returning to work is reduced with the increase of the age, with agrarian and autonomous SS affiliates, with diagnoses of mental disease or diagnoses of the circulatory system, and in cases prescribed by older doctors or less time in the post. CONCLUSIONS: The mean duration of the episodes of TWD is higher than that of other Spanish studies. The most influential factors in the return to work are the age of the patient, the SS scheme and the diagnosed illness.

Determinantes de la duración de la incapacidad temporal y la vuelta al trabajo en un área sanitaria de Galicia / Factors determining the duration of temporary disability and return to work in a health district of Galicia

Objetivo. Determinar los factores asociados con la incidencia y la duración de la incapacidad temporal (IT) en un área sanitaria. Diseño. Descriptivo, retrospectivo. Emplazamiento. Área Sanitaria Sur de la provincia de Lugo. Participantes. Una muestra de 1.513 episodios de IT seleccionada aleatoriamente entre el total de éstos, durante un período de 3 años. Mediciones principales. Se analizaron las características sociodemográficas del paciente, el régimen de la seguridad social (SS), el diagnóstico que justifica la IT y la fecha de la prescripción; del médico prescriptor se analizaron la edad, el sexo, la formación especializada, la antigüedad en la plaza y los años de ejercicio. La comparación de medias se realizó mediante el análisis de la varianza y el test de Kruskal-Wallis. El efecto relativo de cada variable sobre la probabilidad de volver al trabajo se estimó mediante modelos de regresión de Cox. Resultados. La duración media de los episodios de IT fue de 74 ± 103 días. Los diagnósticos más frecuentes fueron los del sistema osteomioarticular (SOMA), las lesiones y envenenamientos (LYE) y las enfermedades respiratorias (NML). Se reduce la probabilidad de volver al trabajo con el incremento de la edad, en los regímenes de seguridad social autónomos y agrarios por cuenta propia, en los diagnósticos de enfermedades mentales y del aparato circulatorio, y cuando el médico prescriptor es de mayor edad o menos antiguo en la plaza. Conclusiones. La duración media de los episodios de IT es superior a la de otros estudios españoles. Los factores que más influyen en la reincorporación al trabajo son la edad del paciente, el régimen de la seguridad social y la enfermedad diagnosticada

Objective. To determine the factors associated with the incidence and duration of temporary work incapacity (TWI) in a health district. Design. Descriptive and retrospective study. Setting. South health district of the province of Lugo, Spain. Participants. A random sample of 1513 cases was selected among the total of episodes of TWI, during 3 years period. Main measures. The main factors analyzed are, on the one hand, the socio-demographic characteristics of the patient, his or her social security (SS) scheme, diagnosis that justifies the TWD, and the prescription date; and, on the other hand, the age, sex, specialised training, time in the post and years in practice of the physician who prescribes the TWI. The comparison of the means was carried out using variance analysis and the Kruskal-Wallis test. The relative effect of each variable on the probability of returning to the work was estimated through Cox regression models. Results. The mean duration of the episodes of TWI was of 74±103 days. The most frequent diagnoses were those of the bones-muscles and joints (BMAJ), injuries and poisonings (IAP), and respiratory diseases (RD). The probability of returning to work is reduced with the increase of the age, with agrarian and autonomous SS affiliates, with diagnoses of mental disease or diagnoses of the circulatory system, and in cases prescribed by older doctors or less time in the post. Conclusions. The mean duration of the episodes of TWD is higher than that of other Spanish studies. The most influential factors in the return to work are the age of the patient, the SS scheme and the diagnosed illness

Reproducibility of optic nerve head measurements obtained by optical coherence tomography.

PURPOSE: To evaluate reproducibility of optic nerve head (ONH) morphometry measurements obtained by optical coherence tomography (the fast optical disk protocol of the -Zeiss model 3000 OCT system) in normal and glaucomatous eyes. METHODS: Prospective instrument-evaluation study. ONH measurements for 20 eyes were obtained in eight scan sessions taken during two visits to an ophthalmology clinic (10 normal patients, 10 glaucoma patients, one eye per subject). At every one of the eight sessions for each eye, estimates of eight ONH morphometry variables (see Main outcome measures) were obtained. The first two sessions were performed by two operators, followed by a 30-minute break. The same operators then completed a third and fourth session. This sequence was duplicated on a second visit. Intrasession, intersession, intervisit, and interoperator reproducibility of the eight variables were calculated by the use of a components variance model. Intraclass correlation coefficients (ICC) were used to assess reliability. RESULTS: Vertical integrated rim area, horizontal integrated rim area, disk area, cup area, rim area, cup/disk area ratio, cup/disk horizontal ratio, cup/disk vertical ratio. With the exception of the horizontal integrated rim area and rim area in normal subjects, the factor subject was the most important source of variance for all variables. Reliability values as measured by ICC for normal eyes were above 81%, with the exception of measurements of the horizontal integrated rim area (23.1%), rim area (33.3%), and disk area (64.7%). For glaucomatous eyes all values were above 85%, with the exception of the disk area (68.1%). CONCLUSIONS: ONH measurements obtained using the fast optical disk protocol of the Zeiss 3000 OCT system show good reproducibility, for both normal and glaucomatous eyes.

Association between vitamin D receptor FokI. Polymorphism and serum parathyroid hormone level in patients with chronic renal failure.

We investigated the relationship between vitamin D receptor (VDR) start codon polymorphism and serum levels of PTH, calcidiol, and calcium in 64 Spanish patients with chronic renal failure (CRF). An exon 2 fragment of the VDR gene was amplified by PCR, and cleaved with the restriction enzyme FokI. The alleles were identified according to the digestion pattern obtained as F (absence of restriction site) and f (presence of restriction site). Genotype frequencies in the patient population were 54.7% FF, 28.1% Ff and 17.2% ff, vs 46.7% FF, 43.3% Ff and 10% ff in a healthy control population. The difference between the two populations was statistically significant (p<0.01). Within the patient population, mean serum PTH level in the FF group was significantly higher (159.77+/-25.69 pg/ml) than in both the Ff and ff groups (106.67+/-19.07 and 77.55+/-15.85 pg/ml, respectively; p<0.05). However there were no significant differences in serum levels of calcidiol or calcium among genotypes. These results suggest that FokI polymorphisms of the VDR gene may determine parathyroid response in CRF patients.

Assessing relationships between health-related quality of life and adherence to antiretroviral therapy.

OBJECTIVE: To investigate associations between health-related quality of life (HRQoL), as assessed using the multidimensional quality of life-HIV (MQOL-HIV) questionnaire, and adherence to antiretroviral treatment in HIV-infected subjects. DESIGN: Multicentre cross-sectional study in three institutional tertiary hospitals in northwest Spain. PATIENTS AND METHODS: The MQOL-HIV was completed by 235 HIV-infected adults undergoing antiretroviral treatment. Adherence to antiretroviral therapy was assessed by using patient's self-report. Information about sociodemographic characteristics and clinical variables was also collected. RESULTS: Good adherence (> or = 95% of prescribed pills correctly taken) was reported by 131 patients (55.7%). Univariate analyses indicated that the sociodemographic and clinical variables associated with adherence were age, educational level, income, employment, home stability, transmission route, history of previous antiretroviral therapy, and number of prescribed pills/day. Subscales of MQOL-HIV associated with adherence were mental health, cognitive functioning, financial status, medical care, partner intimacy, and (in men only) sexual functioning. Stepwise logistic regression showed that good adherence was more frequent in patients aged > 40 years (odds ratio, OR: 2.50; 95% confidence interval, CI: 1.15-5.61) and in patients with high cognitive functioning (OR: 2.26; 95% CI: 1.19-4.30). Conversely, poor adherence was more frequent in patients without stable home (OR: 2.96; 95% CI: 1.39-6.32), in patients required to take 14 or more pills/day (OR: 2.17; 95% CI: 1.18-4.28), in patients with low financial status (OR: 3.42; 95% CI: 1.57-7.45), and in patients reporting low medical care (OR: 2.07; 95% CI: 1.07-3.98). CONCLUSIONS: HRQoL dimensions, notably cognitive functioning, financial status and medical care, are closely associated with antiretroviral therapy adherence.

[Results after treatment with sildenafil citrate in 100 patients with erectile dysfunction]. / Resultados tras el tratamiento con Citrato de Sildenafilo en 100 pacientes con disfunción eréctil.

OBJECTIVE: In order to know the efficiency, tolerance and acceptance of Sildenafil Citrate in our area as a new treatment for Eréctil Dysfunction (E.D.). MATERIAL AND METHODS: We include 100 patients with E.D. who were assisted in our medical office from November 1998 to February 2000 to evaluate them according to several predeterminated variables. RESULTS: The positive response index (E.D. improvement) was 69.9%. We only found side effects in 11.8% (headache 5.4%, flushing 4.3%, diarrhea/blurred vision 2.2%). The most widely used dose was 50 mgrs (65.6%). Only 50.5% of the patients had enough information about Sildenafil. The highest positive response index corresponded to the mild E.D. (76.1%). Also the best results were achieved with the mixed and psychological etiology (74.1%). The Sildenafil treatment was rejected (fear or its price) by the 46.2% of the patients. CONCLUSIONS: The Sildenafil Citrate is an effective treatment for the E.D. It hardly has any side effects. The 50 mgrs dose got the best results. Almost half of the patients complained about an insufficient information on this pharmaceutical. Sildenafil got a good response even when there were risk associated factors of E.D.

Application of nonparametric models for calculating odds ratios and their confidence intervals for continuous exposures.

Calculating odds ratios and corresponding confidence intervals for exposures that have been measured using a continuous scale presents important limitations in the traditional practice of analytical epidemiology. Approximations based on linear models require making arbitrary assumptions about the shape of the relation curve or about its breakpoints. Categorical analyses generally have low statistical efficiency, and cutpoints for the categories are in most cases arbitrary and/or opportunistic. The use of logistic generalized additive models to calculate odds ratios does not require these assumptions and allows great flexibility and adequate statistical efficiency. Based on the asymptotic normality of the logarithm of the odds ratio, the authors propose the use of an approximate analytical expression for the corresponding covariance matrix, which will allow the construction of confidence intervals for odds ratios that can be interpreted as in the classical parametric context. The authors illustrate this procedure by examining the relation between glycemia and risk of postoperative infection, using data obtained from a cohort study of patients undergoing surgery in Santiago, Spain (January 1996--March 1997). The authors found that glycemia values below 75 mg/dl and above 130 mg/dl were associated with increased risk of postoperative infection.

Sulindac in familial adenomatous polyposis: evaluation by nuclear morphometry.

OBJECTIVE: To find out if nuclear morphometry is a useful indicator of prognosis in patients with familial adenomatous polyposis (FAP) before and after treatment with sulindac. DESIGN: Open study. SETTING: Teaching hospital, Spain. SUBJECTS: 29 patients (17 women and 12 men) with FAP who had been treated by colectomy. There were two control groups: 17 people with healthy rectal mucosa and 10 patients with colorectal cancer. INTERVENTIONS: The 29 patients with FAP were treated with sulindac 150 mg orally twice daily for 6 months. MAIN OUTCOME MEASURES: Results of histological examination of biopsy specimens and nuclear morphometry. RESULTS: Before treatment, all patients with FAP had nuclei of cells in the rectal mucosa that were intermediate in size between those in healthy mucosa (small nuclei) and those in cancer (large nuclei). After 6 months' treatment with sulindac the patients with FAP no longer had any polyps and the size of the nuclei was similar to those in healthy mucosa. Only 1 patient failed to respond, and in this patient one of the polyps subsequently became malignant. CONCLUSIONS: Nuclear morphometry may be useful in identifying patients with FAP who are at high risk of malignant degeneration.