Assessing the relationship between multimorbidity, NCD configurations, frailty phenotypes, and mortality risk in older adults

BACKGROUND

Older adults are increasingly susceptible to prolonged illness, multiple chronic diseases, and disabilities, which can lead to the coexistence of multimorbidity and frailty. Multimorbidity may result in various noncommunicable disease (NCD) patterns or configurations that could be associated with frailty and death. Mortality risk may vary depending on the presence of specific chronic diseases configurations or frailty.

METHODS

The aim was to examine the impact of NCD configurations on mortality risk among older adults with distinct frailty phenotypes. The population was analyzed from the Costa Rican Longevity and Healthy Aging Study Cohort (CRELES). A total of 2,662 adults aged 60 or older were included and followed for 5 years. Exploratory factor analysis and various clustering techniques were utilized to identify NCD configurations. The frequency of NCD accumulation was also assessed for a multimorbidity definition. Frailty phenotypes were set according to Fried et al. criteria. Kaplan‒Meier survival analyses, mortality rates, and Cox proportional hazards models were estimated.

RESULTS

Four different types of patterns were identified: 'Neuro-psychiatric', 'Metabolic', 'Cardiovascular', and 'Mixt' configurations. These configurations showed a higher mortality risk than the mere accumulation of NCDs [Cardiovascular HR:1.65 (1.07-2.57); 'Mixt' HR:1.49 (1.00-2.22); ≥3 NCDs HR:1.31 (1.09-1.58)]. Frailty exhibited a high and constant mortality risk, irrespective of the presence of any NCD configuration or multimorbidity definition. However, HRs decreased and lost statistical significance when phenotypes were considered in the Cox models [frailty + 'Cardiovascular' HR:1.56 (1.00-2.42); frailty + 'Mixt':1.42 (0.95-2.11); and frailty + ≥ 3 NCDs HR:1.23 (1.02-1.49)].

CONCLUSIONS

Frailty accompanying multimorbidity emerges as a more crucial indicator of mortality risk than multimorbidity alone. Therefore, studying NCD configurations is worthwhile as they may offer improved risk profiles for mortality as alternatives to straightforward counts.

Peptic ulcer as mediator of the association between risk of gastric cancer and socioeconomic status, tobacco smoking, alcohol drinking and salt intake

BACKGROUND

Peptic ulcer disease (PUD) and gastric cancer (GC) are more prevalent in individuals with low socioeconomic status (SES) and share several risk factors. The aim of this study was to investigate the mediating role of PUD in the association between established risk factors and GC.

METHODS

We conducted a pooled analysis of 12 studies from the Stomach Cancer Pooling Project Consortium, including a total of 4877 GC cases and 11 808 controls. We explored the mediating role of PUD in the association between SES, tobacco smoking, heavy alcohol drinking and salt intake, and GC. Also, we assessed the ORs and 95% CIs of the risk factors and both PUD and GC.

RESULTS

PUD mediated 36% of the smoking effect mainly among men. Other risk factors were only slightly mediated by PUD (SES, 5.3%; heavy alcohol drinking, 3.3%; and salt intake, 2.5%). No significant difference was found when excluding PUD diagnosed within 2 years from GC.

CONCLUSIONS

Our study provides innovative information on the mechanism of stomach mucosal damage leading to PUD and GC, with respect to the effect of tobacco smoking in particular.

The utility of the Edmonton Obesity Staging System for the prediction of COVID-19 outcomes: a multi-centre study

BACKGROUND

Patients with obesity have an increased risk for adverse COVID-19 outcomes. Body mass index (BMI) does not acknowledge the health burden associated this disease. The performance of the Edmonton Obesity Staging System (EOSS), a clinical classification tool that assesses obesity-related comorbidity, is compared with BMI, with respect to adverse COVID-19 outcomes.

METHODS

1071 patients were evaluated in 11 COVID-19 hospitals in Mexico. Patients were classified into EOSS stages. Adjusted risk factors for COVID-19 outcomes were calculated and survival analysis for mechanical ventilation and death was carried out according to EOSS stage and BMI category.

RESULTS

The risk for intubation was higher in patients with EOSS stages 2 and 4 (HR 1.42, 95% CI 1.02-1.97 and 2.78, 95% CI 1.83-4.24), and in patients with BMI classes II and III (HR 1.71, 95% CI 1.06-2.74, and 2.62, 95% CI 1.65-4.17). Mortality rates were significantly lower in patients with EOSS stages 0 and 1 (HR 0.62, 95% CI 0.42-0.92) and higher in patients with BMI class III (HR 1.58, 95% CI 1.03-2.42). In patients with a BMI ≥ 25 kg/m², the risk for intubation increased with progressive EOSS stages. Only individuals in BMI class III showed an increased risk for intubation (HR 2.24, 95% CI 1.50-3.34). Mortality risk was increased in EOSS stages 2 and 4 compared to EOSS 0 and 1, and in patients with BMI class II and III, compared to patients with overweight.

CONCLUSIONS

EOSS was associated with adverse COVID-19 outcomes, and it distinguished risks beyond BMI. Patients with overweight and obesity in EOSS stages 0 and 1 had a lower risk than patients with normal weight. BMI does not adequately reflect adipose tissue-associated disease, it is not ideal for guiding chronic-disease management.

Fibroblast growth factor 21 is associated with increased serum total antioxidant capacity and oxidized lipoproteins in humans with different stages of chronic kidney disease

BACKGROUND AND AIMS

Oxidative stress (OS) induces the production of fibroblast growth factor 21 (FGF21). Previous data have revealed that FGF21 protects cells from OS injury and death, making it a potential therapeutic option for many diseases with increased OS. However, the association of this growth factor with OS markers in humans with chronic kidney disease (CKD) remains unknown. This study aims to evaluate the association of serum FGF21 with serum total antioxidant capacity (TAC) and oxidized low-density lipoproteins (OxLDL) in subjects in different stages of kidney disease.

METHODS

This is a cross-sectional study that included 382 subjects with different stages of CKD, irrespective of type 2 diabetes (T2D) diagnosis. Associations of serum FGF21 with OxLDL, TAC, sex, age, body mass index (BMI), fasting plasma glucose, estimated glomerular filtration rate (eGFR), T2D, and smoking, were evaluated through bivariate and partial correlation analyses. Independent associations of these variables with serum FGF21 were evaluated using multiple linear regression analysis.

RESULTS

Serum FGF21 was significantly and positively correlated with age (r = 0.236), TAC (lnTAC) (r = 0.217), and negatively correlated with eGFR (r = -0.429) and male sex (r = -0.102). After controlling by age, sex, BMI, T2D, smoking, and eGFR; both TAC and OxLDL were positively correlated with FGF21 (r = 0.117 and 0.158 respectively, p < 0.05). Using multiple linear regression analysis, eGFR, male sex, T2D, OxLDL, and TAC were independently associated with serum FGF21 (STDβ = -0.475, 0.162, -0.153, 0.142 and 0.136 respectively; p < 0.05 for all) adjusted for age, BMI, smoking, and fasting plasma glucose.

CONCLUSION

A positive association between serum FGF21 and OS has been found independently of renal function in humans. Results from the present study provide novel information for deeper understanding of the role of FGF21 in OS in humans with CKD and T2D; mechanistic studies to explain the association of serum FGF21 with oxidative stress in CKD are needed.

Desigualdad social en México en el uso de servicios de tamizaje en adultos: un análisis de las encuestas nacionales de salud 2006 y 2012

Objetivo. Medir la desigualdad en el uso de servicios de tamizaje en adultos de 20 a 59 años, a partir de las encuestas nacionales de salud y nutrición 2006 y 2012. Material y métodos. A partir de la selección de cinco indicadores de tamizaje en adultos (detección de diabetes, hipertensión y cánceres de mama, cérvicouterino y de próstata) se estimaron el índice de Kuznets, el índice de desigualdad de la pendiente y el índice de concentración de salud, considerando como indicadores sociales la escolaridad, etnicidad, desempleo, nivel socioeconómico y tipo de protección en salud. Resultados. Las coberturas de las cinco pruebas se incrementaron, sin embargo, la desigualdad observada disminuyó únicamente en las intervenciones en mujeres; en el caso de la detección de cáncer de próstata se incrementó. Conclusión. Si bien es importante monitorear el desempeño de los servicios curativos, persiste el reto de asegurar el acceso efectivo y equitativo a servicios de diagnóstico temprano.

Stature in adults as an indicator of socioeconomic inequalities in Mexico

Objective

To estimate the association between stature in Mexican adults and some sociodemographic factors.

Methods

We studied a sample of 30 970 subjects, using anthropometric data from the 2012 National Health and Nutrition Survey (ENSANUT 2012). The first quartile was used as the cutoff to define short stature. We analyzed differences among stature strata for sociodemographic variables by using the Kruskal-Wallis test. We estimated odds ratios to measure the association between stature and sociodemographic variables, controlling for potential confounders.

Results

Persons from the southern region of the country were some three times as likely to be of short stature than were subjects in the northern region. The stature difference between the Mexican states with the highest and the lowest average stature was larger than the average difference in stature between Mexico and the United States of America. Adults who had had less than six years of schooling presented the highest prevalence of short stature, regardless of sex, region of the country, place of residence (rural or urban), or the proportion of indigenous language speakers in a state. In addition, the stratum with the highest marginalization (percentage of the population lacking education and services, with a low income, and living in a small community) showed the highest prevalence of short stature.

Conclusion

In Mexico, adults who are of short stature have unequal living conditions when compared to those of average or high stature, and this could drive increases in health inequity.

Terremotos y salud en México: atención de la emergencia en el Istmo de Tehuantepec

 El día 7 de septiembre del 2017 se registró un sismo de intensidad 8.2 grados en la escala de Richter, con mayor afec­tación en la región del Istmo de Tehuantepec. El mecanismo de respuesta por parte del sector salud fue implementado de manera inmediata a través del Operativo para la Seguridad en Salud. Las acciones prioritarias estuvieron enfocadas en el restablecimiento de la capacidad local de atención médica, en la identificación de enfermedades prevalentes y en llevar a cabo acciones de salud pública. Sin embargo, pese a las experiencias obtenidas en 1985, aún se vislumbra escasez de planeación y asignación de responsabilidades.

Analysis of spatial mobility in subjects from a Dengue endemic urban locality in Morelos State, Mexico

INTRODUCTION

Mathematical models and field data suggest that human mobility is an important driver for Dengue virus transmission. Nonetheless little is known on this matter due the lack of instruments for precise mobility quantification and study design difficulties.

MATERIALS AND METHODS

We carried out a cohort-nested, case-control study with 126 individuals (42 cases, 42 intradomestic controls and 42 population controls) with the goal of describing human mobility patterns of recently Dengue virus-infected subjects, and comparing them with those of non-infected subjects living in an urban endemic locality. Mobility was quantified using a GPS-data logger registering waypoints at 60-second intervals for a minimum of 15 natural days.

RESULTS

Although absolute displacement was highly biased towards the intradomestic and peridomestic areas, occasional displacements exceeding a 100-Km radius from the center of the studied locality were recorded for all three study groups and individual displacements were recorded traveling across six states from central Mexico. Additionally, cases had a larger number of visits out of the municipality´s administrative limits when compared to intradomestic controls (cases: 10.4 versus intradomestic controls: 2.9, p = 0.0282). We were able to identify extradomestic places within and out of the locality that were independently visited by apparently non-related infected subjects, consistent with houses, working and leisure places.

CONCLUSIONS

Results of this study show that human mobility in a small urban setting exceeded that considered by local health authority's administrative limits, and was different between recently infected and non-infected subjects living in the same household. These observations provide important insights about the role that human mobility may have in Dengue virus transmission and persistence across endemic geographic areas that need to be taken into account when planning preventive and control measures. Finally, these results are a valuable reference when setting the parameters for future mathematical modeling studies.

Adiposity and Blood Pressure in 110 000 Mexican Adults

Previous studies have reached differing conclusions about the importance of general versus central markers of adiposity to blood pressure, leading to suggestions that population-specific adiposity thresholds may be needed. We examined the relevance of adiposity to blood pressure among 111 911 men and women who, when recruited into the Mexico City Prospective Study, were aged 35 to 89 years, had no chronic disease, and were not taking antihypertensives. Linear regression was used to estimate the effects on systolic and diastolic blood pressure of 2 markers of general adiposity (body mass index and height-adjusted weight) and 4 markers of central adiposity (waist circumference, hip circumference, waist:hip ratio, and waist:height ratio), adjusted for relevant confounders. Mean (SD) adiposity levels were: body mass index (28.7±4.5 kg/m²), height-adjusted weight (70.2±11.2 kg), waist circumference (93.3±10.6 cm), hip circumference (104.0±9.0 cm), waist:hip ratio (0.90±0.06), and waist:height ratio (0.60±0.07). Associations with blood pressure were linear with no threshold levels below which lower general or central adiposity was not associated with lower blood pressure. On average, each 1 SD higher measured adiposity marker was associated with a 3 mm Hg higher systolic blood pressure and 2 mm Hg higher diastolic blood pressure (SEs <0.1 mm Hg), but for the waist:hip ratio, associations were only approximately half as strong. General adiposity associations were independent of central adiposity, but central adiposity associations were substantially reduced by adjustment for general adiposity. Findings were similar for men and women. In Mexican adults, often overweight or obese, markers of general adiposity were stronger independent predictors of blood pressure than measured markers of central adiposity, with no threshold effects.

Diabetes and Cause-Specific Mortality in Mexico City

BACKGROUND

Most large, prospective studies of the effects of diabetes on mortality have focused on high-income countries where patients have access to reasonably good medical care and can receive treatments to establish and maintain good glycemic control. In those countries, diabetes less than doubles the rate of death from any cause. Few large, prospective studies have been conducted in middle-income countries where obesity and diabetes have become common and glycemic control may be poor.

METHODS

From 1998 through 2004, we recruited approximately 50,000 men and 100,000 women 35 years of age or older into a prospective study in Mexico City, Mexico. We recorded the presence or absence of previously diagnosed diabetes, obtained and stored blood samples, and tracked 12-year disease-specific deaths through January 1, 2014. We accepted diabetes as the underlying cause of death only for deaths that were due to acute diabetic crises. We estimated rate ratios for death among participants who had diabetes at recruitment versus those who did not have diabetes at recruitment; data from participants who had chronic diseases other than diabetes were excluded from the main analysis.

RESULTS

At the time of recruitment, obesity was common and the prevalence of diabetes rose steeply with age (3% at 35 to 39 years of age and >20% by 60 years of age). Participants who had diabetes had poor glycemic control (mean [±SD] glycated hemoglobin level, 9.0±2.4%), and the rates of use of other vasoprotective medications were low (e.g., 30% of participants with diabetes were receiving antihypertensive medication at recruitment and 1% were receiving lipid-lowering medication). Previously diagnosed diabetes was associated with rate ratios for death from any cause of 5.4 (95% confidence interval [CI], 5.0 to 6.0) at 35 to 59 years of age, 3.1 (95% CI, 2.9 to 3.3) at 60 to 74 years of age, and 1.9 (95% CI, 1.8 to 2.1) at 75 to 84 years of age. Between 35 and 74 years of age, the excess mortality associated with previously diagnosed diabetes accounted for one third of all deaths; the largest absolute excess risks of death were from renal disease (rate ratio, 20.1; 95% CI, 17.2 to 23.4), cardiac disease (rate ratio, 3.7; 95% CI, 3.2 to 4.2), infection (rate ratio, 4.7; 95% CI, 4.0 to 5.5), acute diabetic crises (8% of all deaths among participants who had previously diagnosed diabetes), and other vascular disease (mainly stroke). Little association was observed between diabetes and mortality from cirrhosis, cancer, or chronic obstructive pulmonary disease.

CONCLUSIONS

In this study in Mexico, a middle-income country with high levels of obesity, diabetes was common, glycemic control was poor, and diabetes was associated with a far worse prognosis than that seen in high-income countries; it accounted for at least one third of all deaths between 35 and 74 years of age. (Funded by the Wellcome Trust and others.).

[Inequality in primary care interventions in maternal and child health care in Mexico]

OBJECTIVE

To analyze the principal indicators associated with maternal mortality and mortality in children under 1 year of age and evaluate coverage levels and variability among the federative entities of Mexico.

METHODS

Eight interventions in maternal and child primary health care (variables) were studied: complete vaccination series, measles vaccine, and pentavalent vaccine in children under 1 year of age; early breast-feeding; prenatal care with at least one check-up by trained staff; prevalence of contraceptive use among married women of reproductive age; obstetric care in delivery by trained staff; and the administration of tetanus toxoid (TT) to pregnant women. The average and standard deviation of national coverage for each variable was calculated. Within each federative entity the proportion of municipalities with high, medium, and low marginalization was determined. States were ranked by the proportion of municipalities with high marginalization (highest to lowest) and divided into quintiles. Absolute inequality was measured using the observed difference and relative inequality, using the ratio of each variable studied.

RESULTS

The average national coverage for the eight variables studied ranged from 86.5% to 97.5%, with administration of TT to pregnant women the lowest and administration of measles vaccine to children under 1 year of age the highest. Obstetric care in delivery, prevalence of contraceptive use, and prenatal checkup were the variables with less equitable coverage. In states with higher levels of marginalization, activities dependent on a structured health system-e.g., obstetric care in delivery-showed lower levels of coverage compared to preventive activities not requiring costly inputs or infrastructure-e.g., early breast-feeding.

CONCLUSIONS

Interventions exhibiting greater inequity are associated with the lack of medical infrastructure and are more accentuated in federative entities with higher levels of marginalization. Greater public health expenditure is urgently needed to implement feasible, effective alternatives in terms of access and health care. Intersectoral policies and activities should be implemented to create synergies that will equitably improve the health of Mexican mothers and children.

Modernización académica de la Escuela de Salud Pública de México: 1983-1995

Este artículo discute los esfuerzos por modernizar la Escuela de Salud Pública de México (ESPM). En la primera parte se abordan las condiciones en las que operaba la Escuela a principios de la década de los ochenta. En la segunda parte se describen los cambios introducidos entre 1983 y 1986, hasta  antes de la incorporación de la ESPM al Instituto Nacional de Salud Pública (INSP). En la tercera parte se revisa, sobre todo,  a renovación conceptual que dio sustento a los nuevos programas docentes que se implantaron a finales de los años ochenta y las iniciativas implantadas entre 1987 y 1995. En la cuarta parte se discute la construcción de la nueva sede del INSP y la mudanza a Cuernavaca. Este ensayo busca comunicar la importancia de las transformaciones por las que atravesó la ESPM y que la convirtieron en una institución verdaderamente académica que utiliza la investigación como motor de la formación de los recursos humanos en salud pública.

[Academic modernization of Mexican School of Public Health: 1983-1995]

In this paper we discuss the recent efforts to modernize the School of Public Health of Mexico (ESPM). In the first part we analyze the conditions in which the ESPM operated at the beginning of the 1980s. In part two we describe the changes introduced in the ESPM between 1983 and 1986, up until its incorporation into the National Institute of Public Health (INSP). In part three we discuss the conceptual renovation which built the platform for the new academic programs introduced by the School between 1987 and 1995. In the fourth part we discuss the construction of the new facilities of INSP and the process of moving to the city of Cuernavaca. The main message of this paper is that the transformations witnessed by the ESPM in the final decades of the past century turned it into a true academic institution which uses research as the motor for training of human resources in public health.

[Some observations on high specialty medical care in Mexico]

OBJECTIVES

To put forth the concept of highly specialized medical care, in agreement with the nature of its practice, and evaluate the feasibility of creating a support service network.

METHODS

Qualitative study of the current practice and requirements for 39 selected medical specialties, using the technique of focused groups of experts in each specialty. In accordance with the "Grounded Theory", variables were systematized and categorized and then compared in order to identify relationships between categories and link them to consensus testimonial references. On the basis of the characteristics of each kind of practice, one key expert integrated and validated service portfolios.

RESULTS

We developed an integrated a concept for highly specialize medical care with 39 operational catalogs of those diagnoses that belong to each specialty, along with catalogs of the resources required by each specialty.

CONCLUSIONS

Highly specialized care is a desirable model for clinical practice, but does not constitute a different level of care. Currently, medical practice is constrained by the lack of well-defined boundaries and scarcity of resources in order to be conceptualized as high specialty. It is therefore more convenient to strengthen the concept of third level of care in order to identify opportunities for the establishment of high specialty areas that will in turn serve as the focal points for medical innovation.

[Direct cost analysis of hemodialysis units]

OBJECTIVE

To estimate and compare direct costs per hemodialysis session in public and private units in Mexico City.

MATERIAL AND METHODS

PAATI, a microcosting strategy, was used to determine total costs of four public and two private health hospitals in Mexico City. A "shadow study" approach was employed to collect the needed data. Charts containing the "PAATI" information for each session were developed in Microsoft Excel.

RESULTS

The average annual cost per patient undergoing hemodialysis in public units is $158 964.00 MX. The estimated cost for the care of all population estimated in need of renal replacement therapy (via hemodialysis) was estimated to be $10 921 788 072.00 MX.

CONCLUSION

Human resources and infrastructure availability in México are very limited for nephrology, and in consequence for offering hemodialysis services.

[The need of transforming the health system in Mexico]

In this article we review the need for the transformation of the Mexican health care system given the deformities that the system developed in the last 60 years. We start by the discussion of two main deformities: the segmented answer to the health right, and the development of a segmented health care system based on the method of payment (formal workers contributions); and the development of a health care model based on specialties and hospital care. These deformities have resulted in a health care system characterized by high costs and low effectiveness. Even though the correction of the deformities imply complex modifications that involve political economic and legal aspects, in the short term we have the conditions in Mexico for the creation of a universal primary health care system, given the human and financial resources available in the country.

[Calculating the optimum size of a hemodialysis unit based on infrastructure potential]

OBJECTIVE

To estimate the optimum size for hemodialysis units to maximize production given capital constraints.

MATERIALS AND METHODS

A national study in Mexico was conducted in 2009. Three possible methods for estimating a units optimum size were analyzed: hemodialysis services production under monopolistic market, under a perfect competitive market and production maximization given capital constraints.

RESULTS

The third method was considered best based on the assumptions made in this paper; an optimal size unit should have 16 dialyzers (15 active and one back up dialyzer) and a purifier system able to supply all. It also requires one nephrologist, five nurses per shift, considering four shifts per day.

CONCLUSION

Empirical evidence shows serious inefficiencies in the operation of units throughout the country. Most units fail to maximize production due to not fully utilizing equipment and personnel, particularly their water purifier potential which happens to be the most expensive asset for these units.

Modelling of the influenza A(H1N1)v outbreak in Mexico City, April-May 2009, with control sanitary measures

We use a time dependent modification of the Kermack and McKendrick model to study the evolution of the influenza A(H1N1)v epidemic reported in the Mexico City area under the control measures used during April and May 2009. The model illustrates how the sanitary measures postponed the peak of the epidemic and decreased its intensity. It provides quantitative predictions on the effect of relaxing the sanitary measures after a period of control. We show how the sanitary measures reduced the maximal prevalence of the infected population from 10% to less than 6% of the total population. We also show how the model predicts the time of maximal prevalence and explains the effect of the control measures.

On the spread of the novel influenza A (H1N1) virus in Mexico

A novel influenza A H1N1 virus of swine origin is responsible for the influenza epidemic affecting Mexico, the United States of America (USA), and 39 other countries. While the origin of this emerging pathogen remains uncertain, an increase in the reported incidence of respiratory diseases was noted during March 2009 at the town of La Gloria, in the southeastern state of Veracruz, Mexico. So far, this is the first community in which a case of novel influenza A H1N1 virus has been identified. Further cases were rapidly detected in other areas of Mexico and elsewhere. Initially, the atypical respiratory disease outbreak caused great uncertainty posing a challenge to the Mexican health system. Control measures such as social distancing, timely medical care, and personal hygiene have so far proven effective in containing the outbreak, resulting in a decline of the number of new cases. To the best of our knowledge, it appears that the virus might not be as virulent or contagious as previously thought. Here we provide a description of the influenza epidemic spread in Mexico. As the virus disseminates worldwide, there is concern about the possibility of a new reassortment resulting in a more pathogenic strain that will pose a threat for every country. The influenza epidemic provided lessons that underscore the importance of epidemiologic surveillance and preparedness. Further investigation to address questions about this new virus and conditions for its spread is warranted.

Likelihood ratios of clinical, laboratory and image data of pancreatic cancer: Bayesian approach

PURPOSE

The diagnosis of pancreatic cancer (PC) is most frequently established in advanced stages. The aim of this study is to estimate the likelihood ratios (LRs) of diagnostic data with regards to PC that could be used to approach an earlier diagnosis.

METHODS

A case-control study of 300 patients - 150 histological diagnosed cases of PC and 150 age-matched controls hospitalized for study of jaundice, abdominal pain, weight loss and/or chronic pancreatitis - was conducted. Bayesian probabilities in the form of LRs were estimated for PC predictions.

RESULTS

Probability of PC was associated with jaundice [odds ratio (OR) 2.89; confidence interval (CI) 1.71-4.85], glycemic disturbance (OR 5.64; CI 2.36-13.46), tobacco index >20 (OR 2.11; CI 1.08-4.09) and tumour marker CA 19-9 (OR 9.33; CI 1.36-63.95). Computed tomography showed the highest test performance with regards to PC when comparing with other diagnostic tests. LRs for variables relevant to PC were estimated, among the most relevant: jaundice LR + 1.92, CA 19-9 LR + 5.36 and computed tomography LR + 4.15. The prediction model with an endoscopic retrograde cholangiopancreatography at a tertiary referral hospital determined a 67% probability of detecting PC.

CONCLUSIONS

Through a Bayesian approach we can combine clinical, laboratory and imaging data to approximate to an earlier diagnosis of PC.

The Tape-Stripping Technique as a Method for Drug Quantification in Skin

Quantification of drugs within the skin is essential for topical and transdermal delivery research. Over the last two decades, horizontal sectioning, consisting of tape stripping throughout the stratum corneum, has become one of the traditional investigative techniques. Tape stripping of human stratum corneum is widely used as a method for studying the kinetics and penetration depth of drugs. This paper shows the applications of the tape stripping technique to quantify drug penetration through the skin, underlining its versatile application in the area of topical and transdermal drugs.

Assessing phytochemical intake in a group of Mexican women

OBJECTIVE

Identify the content of selected phytochemicals (PHYs) in Mexican foods and evaluate the reliability of a food frequency questionnaire (FFQ) in assessing PHYs intake among Mexican women.

MATERIAL AND METHODS

Values for PHYs content were obtained from four different data sets. PHYs intake was assessed in 50 women of reproductive age enrolled in a longitudinal cohort study. Values were obtained from a FFQ administered twice, one year apart in order to evaluate its reliability. Selected PHYs included flavonol (FOL), flavones (FES), flavanol (FAL), secoisolariciresinol (SE), matairesinol (MA), lariciresinol (LA), pinoresinol (PI), cynamic acid (CA) and coumestrol (CU).

RESULTS

Daily PHYs intake ranged from 1.3 microg +/- 0.9 for MA to 116.3 +/- 43.8 mg for CA. The adjusted correlation coefficients ranged from 0.17 for FAL to 0.47 for LA. Pinto beans, oranges, hot sauce, broccoli, apples and onions were the main sources of the selected PHYs daily intake.

DISCUSSION

The results of this study contribute to our understanding of the consumption of PHYs in the Mexican diet, and would help evaluate their potential health impact.

Cervical cancer: a qualitative study on subjectivity, family, gender and health services

Background

In 2002, cervical cancer was one of the leading causes of death in Mexico. Quantitative techniques allowed for the identification of socioeconomic, behavioral and biological characteristics that are part of its etiology.

However such characteristics, are inadequate to explain sufficiently the role that emotions, family networks and socially-constructed categories such as gender play in the demand and utilization of health services for cervical cancer diagnosis and treatment and neither the timely undertaking of preventive actions, such as getting a PAP smear or seeking adequate and continuons treatment.

Methods

A qualitative study was carried out to analyze the role of different social and cultural factors in the timely detection of cervical cancer. As part of a multi-level, multi-method research effort, this particular study was based on individual interviews with women diagnosed with cervical cancer (identified as the "cases"), their female friends and relatives (identified as the "controls") and the cases' husbands.

Results

The results showed that both: denial and fear are two important components that regulate the behavior of both the women and their partners. Women with a small support network may have limited opportunities for taking action in favor of their own health and wellbeing.

Conclusion

Women tend not to worry about their health, in general and neither about cervical cancer in particular, as a consequence of their conceptualizations regarding their body and feminine identify – both of which are socially determined. Furthermore, it is necessary to improve the quality of information provided in health services.

Dietary and genetic determinants of homocysteine levels among Mexican women of reproductive age

OBJECTIVE

To evaluate the independent and joint effects of dietary folate, vitamin B(12) consumption and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (677C>T and 1298A>C) on the circulating folate and homocysteine (Hcy) levels among Mexican women of reproductive age.

DESIGN

A cross-sectional, population-based study.

SUBJECTS

The first 130 healthy non-pregnant women (aged 16-34 years) who agreed to participate in a reproductive cohort in Morelos, Mexico.

MAIN OUTCOME MEASUREMENTS

Dietary intakes of vitamin B(12) and folate were estimated using a semiquantitative food frequency questionnaire. MTHFR 677C>T and 1298A>C polymorphisms were ascertained using the PCR-based method. Serum levels of Hcy and folate were determined using high-performance liquid chromatography and radioimmunoassay, respectively.

RESULTS

Genotype frequencies for the MTHFR 677C>T polymorphism were 21.5% (CC), 52.3% (CT) and 26.2% (TT) among Mexican women. Of the population, 22% had the MTHFR 1298AC genotype, while no individual carried the 1298CC genotype. We observed an increased level of Hcy among carriers of the 677TT genotype, compared to carriers of the 677CC genotype. The highest level of Hcy was observed among MTHFR 677TT carriers with low B(12) intake (<2.0 microg/day), which resulted with a significant interaction (P=0.01).

CONCLUSION

Vitamin B(12) is an important determinant of Hcy levels in Mexico. Supplementation of folic acid with vitamin B(12) may be preferable when the MTHFR 677T variant allele is prevalent.

Applications of thermo-reversible pluronic F-127 gels in pharmaceutical formulations

It is, sometimes, desirable to maintain a constant plasma drug concentration within the therapeutically effective concentration range. The use of high viscosity hydromiscible vehicles such as hydrophilic gels, is one of various approaches for controlled drug delivery, and represents an important area of pharmaceutical research and development. Of these systems, Pluronic F-127 (PF-127) provides the pharmacist with an excellent drug delivery system for a number of routes of administration and is compatible with many different substances. Gels containing penetration enhancers have proven to be especially popular for administering anti-inflammatory medications since they are relatively easy to prepare and very efficacious.

Methylenetetrahydrofolate reductase 677C>T polymorphism and gastric cancer susceptibility in Mexico

This study investigated whether methylenetetrahydrofolate reductase MTHFR 677C>T polymorphism modified gastric cancer (GC) risk independently as well as in combination with folate intake and alcohol consumption. A hospital-based case-control study of 201 cases and 427 controls was conducted in three geographical areas of Mexico, between 1994 and 1996. The MTHFR 677T allele frequency was 51.0% in cases compared with 45.3% in controls. After controlling for dietary sources of folate, alcohol intake and other selected variables, a significant increase in GC risk was found among carriers of the 677TT genotype compared with those with the 677CC genotype (odds ratio (OR) 1.62, 95% confidence interval (CI) 1.00-2.59), with a significant trend (P = 0.048). There were no significant interactions between the MTHFR polymorphism and consumption of folate and alcohol. Our results suggest that the high prevalence of MTHFR 677T allele may be a contributor to the high rate of morbidity and mortality in GC in Mexico.

[Risk factors in invasive cervical cancer among Mexican women]

OBJECTIVE

To evaluate the association between invasive Cervical Cancer (CC) and high risk Human PapillomaVirus (HR-HPV) (viral load and type 16), along with other gynecological and socioeconomic factors.

MATERIAL AND METHODS

Individually matched case-control study (215 women with invasive CC and 420 controls). The study population was recruited between 2000 and 2001. A set of variables traditionally linked with CC (gynecological and socioeconomic factors) and two variables related to HPV infection (viral load and type 16) were assessed. Hybrid Capture II was used to detect HR-HPV DNA. Viral load was measured by light measurements expressed as relative light units (RLU) and they were categorized for analysis into four groups: negative (< 1 RLU), low viral load (1-49 RLU), middle load (50-499 RLU) and high load (>499 RLU). The analysis included univariate, bivariate and multivariate techniques being the final step the estimation of Odds Ratios (OR) by means of conditional logistic regression models. Results. The probability of having invasive CC was 78 times higher in patients with infection of HR-HPV. Risk increases with HPV type 16 (OR = 429.7) as compared with other types of HR-HPV (OR = 64.1). An important trend was observed with the increase of the viral load (from 46.6 with low viral load; to 250.7 with intermediate and 612.9 with high load). The findings also indicate significant diferences in the viral load between cases and controls according to age groups and HR-HPV types (16 versus others high risk types). Finally, the partner-demographic and obstetrical variables related to the disease increased the risk of invasive CC. No association between CC and smoking was observed in this population.

CONCLUSIONS

This study helps in identifying women at higher risk of developing invasive CC as a subset of those patients infected with HR-HPV. The findings point strongly to the importance of the viral load in HR-HPV as a co-factor in the development of this disease. This biomarker contributes to improving the prevention and early detection of this disease and also to identify women at higher risk who carry a high viral load of HR-HPV.

Frequency and Correlates of Adverse Events in a Respiratory Diseases Hospital in Mexico City

OBJECTIVES

To estimate the frequency of severe adverse events (AEs) during hospital stay as well as their type and correlates in a referral hospital for respiratory diseases, using methods similar to those used in the Harvard Medical Malpractice Study.

DESIGN

Retrospective review of medical records in a stratified sample of 836 patients drawn from a total of 4,555 hospital admissions registered during the year 2001.

SETTING

A referral tertiary-care hospital for patients with respiratory diseases located in Mexico City.

MAIN OUTCOME MEASURES

Weighted prevalence of AEs and odds ratios for correlates.

RESULTS

The overall weighted prevalence for AEs was 9.1% (95% confidence interval, 7.5 to 10.4%). Of these patients, 17% had a related transient disability, 52% had a prolonged hospital stay, and 26% had an AE that according to the reviewers contributed to their death. Of the total number of AEs, 74% were qualified as potentially preventable. Among all types of AEs, we identified as most relevant for a chest hospital the delayed surgical treatment of empyema, representing 11% of the total.

CONCLUSIONS

The frequency of AEs in a tertiary-care respiratory hospital is similar to that reported in general hospitals. A strategy to improve the treatment of empyema is needed.

[Breast feeding and the incidence of acute diarrhea during the first three months of life]

OBJECTIVE

To assess the effect of exclusive breastfeeding and its interactions with selected socioeconomic factors, on the incidence of acute infantile diarrhea during the first three months of life.

MATERIAL AND METHODS

A prospective cohort study with a follow up of three months was conducted in 327 mother and child pairs, living in the city of Durango, Mexico, between April and June 1994. Data analyses included simple univariate and bivariate cross-tabulations, as well as multivariate logistic regression models with random effects.

RESULTS

Infants who were not exclusively breastfed were at a significantly increased risk of having acute diarrhea during early infancy (ORcombined breastfeeding=3.23; 95% CI 1.84-5.68 and ORartificial breastfeeding=4.36; 95% CI 2.32-8.19). Moreover, the protective effect of breastfeeding was independent from the effects of the following factors: poor maternal education, lack of social support for baby care, and being an adolescent mother. However, lack of potable water and lack of sewerage were potential effect modifiers of type of lactation deltaG=9.26; p=0.09; ORno water/no sewerage= 2.58; 95% CI 1.10-6.03 in the final multivariate model), for simultaneous lack of potable water and sewerage, which is greater than the sum of the individual OR for each variable.

CONCLUSIONS

Similar to previous studies, exclusive breastfeeding was found to have great importance, since this practice protects the child's health and allows for a better development, despite unfavorable social and economic conditions. In particular, it seems that the protection conferred by breastfeeding is stronger when home conditions are poor, but this same condition presents an intervention opportunity, particularly the assurance of potable water provision for the infant when breastfeeding is not an option.

Helicobacter pylori-CagA seropositivity and nitrite and ascorbic acid food intake as predictors for Gastric Cancer

A hospital-based case-control study was carried out between 1994 and 1996 to evaluate the risk of gastric cancer (GC) according to Helicobacter pylori-CagA (+) seropositivity, nitrite and ascorbic acid intake. Three geographical areas of Mexico were selected on the basis of their contrasting dietary patterns and H. pylori seroprevalence. Nitrite and ascorbic acid consumption were estimated by interview among 211 cases and 454 matched controls. Serum antibodies against IgG H. pylori and CagA were detected by immunosorbent assays. The adjusted risk for GC was significantly higher among CagA+ subjects compared with those that were CagA negative (Odds Ratio (OR)=2.04 95% Confidence Interval (CI) 1.37-3.02 P for trend P < 0.001), this effect remained significant among diffuse GC cases (OR 2.05 95% CI 1.25-3-36). No significant effects due to nitrite and ascorbic consumption or interactions of these nutrients with CagA seropositivity were detected. Seropositivity to H. pylori CagA+ strains may be an independent factor for diffuse GC in Mexico.

Nutritional factors and breast cancer in Mexico

Breast cancer (BC) morbidity and mortality in Mexico are on the rise, affecting younger women with more frequency. Nutritional factors are often mentioned as determinants of BC but their relevance is not well established in Latin-American countries, where dietary habits show great variation. From a study population previously assembled in Mexico City, 141 histologically confirmed cases of BC were matched by age (+/-3 yr) to an equal number of hospital controls. A food frequency questionnaire was administered to all subjects and the risk of BC was estimated in relation to the intake of selected nutrients. The findings of this study show a protective effect against BC due to a high intake of polyunsaturated fat (odds ratio, OR = 0.10, 95% CI = 0.02-0.40, P for trend = 0.001) and vitamin E (OR = 0.10, 95% CI = 0.02-0.44, P for trend = 0.003) among postmenopausal women. In addition, our findings also suggest that a high intake of total fiber (OR = 0.29, 95% CI = 0.08-1.10, P for trend = 0.080) and carotenes (OR = 0.42, 95% CI = 0.16-1.14, P for trend = 0.088) lowers BC risk among premenopausal women. The relationship between the intake of nutrients and BC risk needs further confirmation.

Dichlorodiphenyldichloroethane burden and breast cancer risk: a meta-analysis of the epidemiologic evidence

The relationship of dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk has received increasing attention since the beginning of the 1990s. Contradicting published results regarding the relationship between body burden levels of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE)--the main DDT metabolite--and breast cancer, we argue that such differences stem from methodologic differences among those studies. We performed a meta-analysis of 22 articles using DerSimonian and Laird's method for random effects models. The Q-statistic was used to identify heterogeneity in the outcome variable across studies. The gradient of p,p'-DDE exposure in epidemiologic studies was homogenized to serum lipid bases (nanograms per gram). The potential for publication bias was examined by means of the Begg's test. We discuss methodologic features of the studies in an attempt to reconcile the findings. The summary odds ratio (OR) for selected studies was 0.97 (95% confidence interval, 0.87-1.09) and the gradient of exposure ranged from 84.37 to 12,948 ng/g. No overall heterogeneity in the OR was observed (chi-squared = 27.93; df = 23; p = 0.218). Neither the study design nor the lack of breast-feeding control or the type of biologic specimen used to measure p,p'-DDE levels were the causes of heterogeneity throughout the studies. Evidence for publication bias was not found (p = 0.253). Overall, these results should be regarded as a strong evidence to discard the putative relationship between p,p'-DDE and breast cancer risk. Nevertheless, the exposure to DDT during critical periods of human development--from conception to adolescence--and individual variations in metabolizing enzymes of DDT or its derivatives are still important areas to be researched in regard to breast cancer development in adulthood.

Capsaicin consumption, Helicobacter pylori positivity and gastric cancer in Mexico

Gastric cancer (GC) incidence has not declined in Mexico. We assessed whether the intake of capsaicin (CAP), the pungent compound of chili peppers, increases the risk of GC independently of H. pylori positivity (Hp). From 1994 to 1996, a hospital-based case-control study was performed in 3 areas of Mexico; 234 cases of GC and 468 matched controls were enrolled and their diet and other characteristics were inquired. Chili pepper intake was queried by interview and CAP content of chilies was determined in a separate analysis by gas chromatography to estimate CAP intake; IGg Hp serum antibodies were determined by ELISA. The risk of GC was increased (OR = 1.71; 95% CI = 0.76-3.88) among high-level consumers of CAP (90-250 mg of capsaicin per day, approximately 9-25 jalapeño peppers per day) as compared to low-level consumers (0-29.9 mg of capsaicin per day, approximately 0 to less than 3 jalapeño peppers per day; p for trend p = 0.026); this effect was independent of Hp status and other potential GC determinants and was higher among diffuse GC cases (OR = 3.64; 95% CI = 1.09-12.2; p for trend = 0.002) compared to intestinal GC cases (OR = 1.36; 95% CI = 0.31-5.89; p for trend = 0.493). No significant interaction was found between CAP intake and Hp on GC risk. Chili pepper consumption might be an independent determinant of GC in Mexico.

[Factors associated with quality of life parameters in older adults in Morelos]

OBJECTIVE

This study aimed to identify a set of factors related to quality of life across the dimensions of physical, social and emotional functioning and general health perception in an elderly population from the state of Morelos, Mexico.

MATERIAL AND METHODS

A cross-sectional study was carried out from March to September of 1997 in urban and rural areas of the state of Morelos. The sample was built from randomly selected 2,571 households in the study areas. Data for the study were collected by means of structures personal interviews, using a questionnaire applied to 869 subjects who were 60 years or older at the time of the interview. Quality of life was analyzed in four dimensions: physical, social and emotional functioning and general health perception. Independent variables were: gender, age, perceived morbidity, activity level, health check-up and hospitalization during the last year, tobacco consumption and family income. Statistical analyses went from descriptive statistics to the fitting of multivariate unconditional logistic regression models.

RESULTS

The factors associated with the dimensions of quality of life were: physical functioning; gender, illness in last year, age, tobacco consumption and activity level. In social functioning only health check up was significant, as protector factor of good social quality. In emotional functioning the associated factors were: gender, illness and medical check-up in last year. For the dimension health perception the variables were: gender, illness, hospitalization in last year and activity. All of them statistically significant p < 0.05.

CONCLUSIONS

The factors associated with quality of life vary according to each dimension. However; gender, morbidity, health check up and activity were common for the dimensions studied; so that these aspects should be considered for planning interventions to improve the quality of life in elderly people.

Preterm birth in relation to maternal organochlorine serum levels

PURPOSE

To evaluate the associations of serum levels of p,pacute;-DDE and two other persistent organochlorine pesticides, beta-HCH and HCB, in relation to preterm birth.

METHODS

During 1995 we performed a case-cohort study and 233 mothers were recruited at three large maternity hospitals in Mexico City. Serum levels were obtained shortly after delivery.

RESULTS

A non-significant increased risk of preterm birth in relation to serum p,p'-DDE levels was observed. There was also a suggestion of an increased risk of preterm birth among women in the highest tertile of beta-HCH (adjusted odds ratio 1.85, 95% CI = 0.94-3.66, p value for test of trend p = 0.08) compared with the lowest tertile. No association was found between HCB serum levels and preterm births.

CONCLUSIONS

These findings suggest that p,pacute;-DDE and other organochlorine pesticides may pose a risk to preterm birth in countries that continue to use such insecticides for malaria control.

[Evaluation of the availability, utilization, and costs of computerized tomography in the state of Morelos, Mexico]

OBJECTIVE

To assess the availability, utilization, and costs of computerized tomography (CT scan) in private and public hospitals in Morelos State, Mexico.

MATERIAL AND METHODS

From January to April 1999, a cross-sectional study was carried out in two private and two public hospitals in Morelos, Mexico. Individual face-to-face interviews were conducted with directors, managers, radiologists, and heads of maintenance at each hospital. Statistical analysis was performed to describe the variables measuring availability, utilization, and costs of CT scans. A comprehensive assessment of CT scans was also performed. Emphasis was made on the variability of observed patterns among the participating hospitals.

RESULTS

CT scan technology has been used by hospitals in Morelos State for over ten years; programs for preventive or corrective maintenance of these equipments are available, although at high costs. No strategies for technology assessment are available for acquisition of CT scanners nor during their period of utilization. This study did not attempt to evaluate the appropriateness of the clinical use of CT nor its untoward effects.

CONCLUSIONS

Findings from the present study showed that: 1) a lack of mechanisms for technology assessment and management of CT scans prevented hospitals from managing CT scanning technologies efficiently; 2) technology assessment regulation is not available, even though it is necessary for the adequate selection of the best technologies, on the basis of their efficiency, effectiveness, safety, and availability.

Serum levels of beta-hexachlorocyclohexane, hexachlorobenzene and polychlorinated biphenyls and breast cancer in Mexican women

Information on the association between exposure to beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB) or polychlorinated biphenyls (PCBs) and the incidence of breast cancer is inconclusive. However, exposure to such compounds is a public health concern in Mexico and is subject to recent regulation. Serum levels of beta-HCH, HCB and PCBs were analysed in 95 histologically confirmed breast cancer cases and 95 hospital controls, 20-79 years of age, from Mexico City, enrolled between March 1994 and April 1996. After adjusting for established risk factors, there was no evidence of a relationship between beta-HCH, HCB and PCBs and breast cancer risk (OR for beta-HCH tertile 3 versus tertile 1: 1.05 95% CI 0.46-2.40; OR for HCB tertile 3 versus tertile 1: 0.46 95% CI 0.20-1.07; OR for PCBs 1.31 95% CI 0.33-5.21 for the high category of exposure). This study lends no support to the case for a role for beta-HCH, HCB or PCBs in breast cancer aetiology.

Food sources of phytoestrogens and breast cancer risk in Mexican women

We analyzed the intake of selected foods that contain phytoestrogens in relation to breast cancer (BC) risk using data from a hospital-based case-control study performed in Mexico City from 1994 to 1995. A total of 198 women with BC, aged 21-79 years, were individually age matched to an identical number of women with no breast disease. By a direct interview, information on socioeconomic characteristics and diet was obtained. A semiquantitative questionnaire was used to estimate the frequency of consumption of 95 foods. The effect of selected foods that contain phytoestrogens on BC risk was estimated using logistic regression models. The adjusted odds ratio for the consumption of more than one slice of onion per day and BC was 0.27 (95% confidence interval = 0.16-0.47), with a statistically significant trend (p < 0.001). This protective effect remained after adjustment for known risk factors of BC. Among premenopausal women, there was also a protective and significant effect due to the intake of lettuce and spinach and nonsignificant protective effects for the consumption of apples and herbal tea. Additional studies aimed at evaluating the potential protective effect of particular phytoestrogens on BC risk are needed.

[Identification of malignant breast lesions in Mexico]

OBJECTIVE

To evaluate the modes of detection of breast malignancies in Mexico City and to estimate the number of patients diagnosed in advanced stages.

MATERIAL AND METHODS

This cross-sectional study was conducted between 1994 and 1996, among 256 women with a histological diagnosis of breast cancer, at three tertiary level public hospitals in Mexico City. Personal interviews were conducted to collect data on reproductive characteristics, clinical history, and breast cancer modes of detection. Data analysis consisted of percentages, odds ratios, and 95% confidence intervals.

RESULTS

Ninety percent of women sought medical care after identifying a breast lump by themselves. Only 10% of patients had a stage-I tumor; all 27 cases first identified by a physician were in stage II-B and higher.

CONCLUSIONS

An increasing trend of breast cancer mortality in Mexico City will persist, unless a greater proportion of tumors in situ is detected; this would require enhancing breast cancer screening programs and conducting an intense educational intervention among women at risk.

[Prevalence of hearing loss and correlated factors in a cement plant]

OBJECTIVE

To assess the impact of occupational exposure to noise, as well as its relationship with other factors that can induce hearing loss.

MATERIAL AND METHODS

In January and February 1997, we conducted sonometry and dosimetry tests in a cement factory, as well as audiometric test in 85 cement workers, to identify sources of noise and evaluate the effect to noise exposure and other factors, of the prevalence of occupational hearing loss. Statistical analysis was conducted using measures of central tendency, bivariate analysis and polynominal regression models.

RESULTS

High noise levels were found in the crushing, crude milling, and cement milling sites. The highest individual dose corresponded to the packer job post. Fifty-five per cent of the study population presented some degree of hearing loss due to noise exposure. The cement processing area with the highest percentage of damaged workers was calcination.

CONCLUSIONS

Our results show that noise is a serious risk factor in particular sites of cement factories, and also that an elevated number of hearing loss cases are due to occupational noise exposure in this industry; Our findings underscore the need for designing and implementing hearing protection programs, to assure the health and safety of cement workers.