Oral Bacterial Acid-Base Metabolism in Caries Screening: A Proof-Of-Concept Study.

The objective of this cross-sectional study was to clinically validate an array of biochemical tests for oral acid/alkali generation as caries screening instruments. 185 adult subjects (mean 33.6±10.6 years) were examined clinically for dental caries using the ICDAS criteria. Bitewing radiographs were used to confirm interproximal surfaces of posterior teeth. For the purposes of this study, subjects were classified as "caries-active" if they had at least one untreated caries lesion with ICDAS 4 or higher. Pooled supragingival plaque and unstimulated saliva samples were collected and assayed for pH changes from sucrose and urea metabolism using colorimetric tests. The validity of each test to discriminate between "caries-inactive" and "caries-active" subjects was assessed and compared to a commercial bacteriological caries-screening test using roc regression and logistic regression models. The AUCs of the plaque-urea (PU: 0.59 (0.51, 0.67)), plaque-urea-glucose (PUG: 0.59 (0.51, 0.67)) and saliva-urea-glucose (SUG: 0.59 (0.51, 0.67)) tests did not differ significantly from the bacteriological tests (CRT-mutans: 0.62 (0.54, 0.70); CRT-lactobacillus: 0.63 (0.56, 0.71) (P>0.05), but the plaque-glucose (SG), saliva-glucose (SG), saliva-urea (SU) and saliva-plaque-glucose (SPG) tests had significantly smaller AUCs (P<0.05). The AUCs for the PU, PUG, SUG, and the CRT-mutans tests were higher in subjects who had no existing dental restorations (PU: 0.90 (0.77, 1.04); PUG: 0.90 (0.79, 1.01); SUG: 0.89 (0.69, 1.08); CRT-mutans: 0.90 (0.73, 1.08)). The incorporation of the biochemical tests into a multidimensional bacteriological/psychosocial caries screening model significantly increased its diagnostic values (Se+Sp: 160.6, AUC: 0.846). In conclusion, as a proof of concept, the results of this study indicate that measuring the ability of dental plaque and saliva to metabolize urea together with the ability to generate acid from sugars may have a promising role in caries screening either independently, or as part of a multidimensional biological test.

Urease activity as a risk factor for caries development in children during a three-year study period: a survival analysis approach.

UNLABELLED: Recent cross-sectional studies suggest that reduced ability to generate alkali via the urease pathway in dental plaque may be an important caries risk factor, but it has not been assessed prospectively. OBJECTIVE: To evaluate the effect of plaque and saliva urease activity on the risk for developing new caries over a three-year period in children. METHODS: A panel of 80 children, three to six years of age at recruitment, was followed prospectively for three years. Plaque urease activity, saliva urease activity and dental caries were measured every six months. Survival analysis methodology was used to evaluate the effect of urease on caries development during the study period adjusted for gender, age, baseline caries levels, sugar consumption, amount of plaque, and mutans streptococci levels. RESULTS: The risk for developing new caries increased in a dose-responsive manner with increasing levels of urease activity in saliva (adjusted HR(Q4 vs. Q1): 4.98; 95% CI: 1.33, 18.69) and with decreasing urease activity in plaque (adjusted HR(Q4 vs. Q1): 0.29; 95% CI: 0.11, 0.76). Multiple measurements of urease activity were conducted to overcome the variability of urease activity in this study. Baseline caries and mutans streptococci in saliva were also important predictors of caries risk. CONCLUSIONS: Increased urease activity in saliva can be an indicator of increased caries risk in children, whilst increased urease activity in plaque may be associated with reduced caries risk. The reproducibility of urease measurements must be improved before these findings can be further tested and clinically applied.

Urease activity in dental plaque and saliva of children during a three-year study period and its relationship with other caries risk factors.

UNLABELLED: Bacterial urease activity in dental plaque and in saliva generates ammonia, which can increase the plaque pH and can protect acid-sensitive oral bacteria. Recent cross-sectional studies suggest that reduced ability to generate ammonia from urea in dental plaque can be an important caries risk factor. In spite of this proposed important clinical role, there is currently no information available regarding important clinical aspects of oral ureolysis in children. OBJECTIVE: The objective of this study was to evaluate the distribution and pattern of urease activity in the dental plaque and in the saliva of children during a three-year period, and to examine the relationship of urease with some important caries risk factors. METHODS: A longitudinal study was conducted with repeated measures over a three-year period on a panel of 80 children, aged 3-6 years at recruitment. The dynamics of change in urease activity were described and associated with clinical, biological, and behavioural caries risk factors. RESULTS: Urease activity in plaque showed a trend to remain stable during the study period and was negatively associated with sugar consumption (P<0.05). Urease activity in unstimulated saliva increased with age, and it was positively associated with the levels of mutans streptococci in saliva and with the educational level of the parents (P<0.05). CONCLUSIONS: The results of this study reveal interesting and complex interactions between oral urease activity and some important caries risk factors. Urease activity in saliva could be an indicator of mutans infection in children.

The effect of sucrose on plaque and saliva urease levels in vivo.

OBJECTIVE: Dietary sugar exposures induce an immediate drop of the plaque pH. Based on in vitro observations, it was hypothesized that oral bacteria may rapidly respond to this environmental change by increasing the activity or expression of alkali-generating pathways, such as the urease pathway. The objective of this exploratory in vivo study was to determine the short-term effect of a brief sucrose exposure on plaque and saliva urease activity and expression, and to relate this effect to caries experience. METHODS: Urease activity levels were measured in plaque and saliva samples collected from 20 children during fasting conditions and 30 min after rinsing with a sucrose solution. Streptococcus salivarius ureC-specific mRNA in saliva was quantified using real-time RT-PCR. The impact of host-related factors, such as age, gender, sugar consumption, salivary mutans streptococci levels and caries status on urease activity was evaluated. RESULTS: Plaque urease activity under fasting conditions was higher in subjects with low caries and mutans streptococci levels. This difference was not observed after the sucrose exposure. The response of urease to sucrose in vivo did not depend on caries experience or salivary mutans levels. Significant increase in urease activity of plaque and saliva after exposure to sucrose was observed only in the subjects who had low urease levels at baseline. CONCLUSIONS: The findings of this exploratory study suggest that plaque urease activity may have an important long-term influence in caries development but not during a cariogenic challenge.

The relationship between dental caries status and dental plaque urease activity.

INTRODUCTION: Ammonia production from the metabolism of urea by urease enzymes of oral bacteria moderates plaque acidification and may inhibit dental caries, as suggested by in vitro studies and indirect clinical observations. The objective of this study was to examine the relationship of urease activity with dental caries at the clinical level. METHODS: Urease activity was measured in dental plaque and saliva samples from 25 caries-free subjects (CF) and in eight subjects with six or more open caries lesions (CA). Plaque and saliva collection was repeated for each subject 1 week later using identical procedures. RESULTS: Urease-specific activity in the dental plaque of CF subjects was significantly higher compared to that in the subjects with caries. The association of low plaque urease levels with increased caries was further supported by odds ratio analysis using different plaque urease cut-off points. Using a receiver operating characteristic curve it was estimated that there was an approximately 85% probability of correctly classifying the subjects as CA or CF based on the relative ordering of their plaque urease activity levels. No statistically significant differences were observed in salivary urease activity. CONCLUSION: This study suggests that loss of alkali-generating potential of tooth biofilms via the urease pathway has a positive relationship to dental caries.

Prevalence of chronic hepatitis C virus genotypes among patients between 21 to 65 years old in Puerto Rico

OBJECTIVES: This is the first study done in Puerto Rico to estimate the prevalence of hepatitis C virus (HCV) genotype distribution in patients with chronic infection and to determine the statistical association between the genotype and variables such as age, sex, HCV risk factors, and viral load. METHODS: Chronic HCV infected patients diagnosed with ELISA, RIBA or PCR from 1990 to 2002 who were under follow up with members of the Puerto Rico Gastroenterological Association were asked to participate. Eligible patients were those without evidence of HIV or other viral hepatic infection; had no previous antiviral treatment or if previously treated, therapy ended at least six months prior to their participation in the study; had no history of organ transplant and were willing to participate. All study subjects completed a study questionnaire and had blood samples taken to determine HCV genotype and viral load. RESULTS: 500 patients were recruited. Most of the study subjects were males (68%); 70% were 45 to 65 years old. The principal reported risk factors were: surgeries (75.5%), drug use (46.8%), sexual relationships with intravenous/intranasal drug users (30.3%), blood transfusions (30.2%), multiple sex partners (28.9%), tattoos (22.0%), needle accidents (12.7%), and sexual relationships with an HCV infected partner (9.0%). Most patients had multiple risks factors for infection, only 3.4% (17/500) reported a single risk factor whereas 2.0% (10/500) reported none. 33% of the patients were previously treated (non-responders or relapsers) while 67% were naive. In general, 82% of the HCV patients had genotype 1, while 18% had non-1 genotypes. Among genotype 1 subtypes, genotype la (39.8 %) was more common than 1b (27%). The most common non-1 genotype was genotype 2 of which 2b represented 9.8% of the study population. Similar distribution was observed within the categories of the HCV risk factors, with the exception of those who reported sex with an infected partn...

Trends in diabetes mellitus mortality in Puerto Rico: 1980-1997.

OBJECTIVE: To determine the characteristics and trends of diabetes mortality among the Puerto Rican population from 1980 through 1997. METHODS: Death certificates for Puerto Rican residents whose underlying cause of death was diabetes mellitus (ICD-9-250.0) were reviewed, and sociodemographic information was abstracted. The proportion mortality ratio (PMR) and 95% confidence intervals were calculated by gender, age group, educational level and period of time. Trend analysis in mortality was performed using a Poisson regression model. RESULTS: A total of 26,193 deaths (5.8%) were primarily attributed to diabetes mellitus in the study period. Females accounted for 55.8% of all diabetes related deaths. Diabetes accounted for a higher proportion of deaths among persons aged 60-64 years (8.14%), persons aged 65-74 (8.12%), females (7.73%) and those with 1-6 years of education (7.08%). The PMR steadily increased from 4.55% in the 1980-85 period to 6.91% in the 1992-97 period. There was a higher mortality in male diabetic subjects aged < or = 64 than in females during the 18 year period. Between 1980 and 1991, females aged 65-74 had a higher mortality than males, however, mortality increased in males of the same age group during 1992-97. When the oldest age group (> or = 75) was examined, males had a higher mortality between 1986 and 1997, whereas females had a slightly higher rate between 1980 and 1985. CONCLUSIONS: Our results indicate that diabetes mortality has been markedly increasing in the Puerto Rican population, primarily in persons aged 65 years or more. Further analysis is needed to evaluate the determinants of mortality in diabetes.

Knowledge and beliefs of breast cancer among elderly women in Puerto Rico.

This is the first national study of breast-cancer knowledge, beliefs, and early detection practices among elderly women (65+) in Puerto Rico. Cancer breast examination (CBE) was the most common early detection practice, followed by the mammogram, with breast self exam (BSE) a distant third. The primary reasons most often cited for never having a mammogram related to both personal and external factors: not having symptoms, negligence or forgetfulness, and not having a physician's referral. No statistically significant difference (p < 0.05) was found between knowledge and early detection practices. Conversely, beliefs had an impact on preventive behavior. Those who had less misconceptions were most likely to have had a CBE or a mammogram. Bivariate analysis demonstrated that age was associated with performing a BSE once or twice monthly, ever having a mammogram, and having a mammogram in the past two years. A higher socioeconomic status was associated to performing BSE and ever having had a mammogram. Education correlated positively to ever having a mammogram or having a mammogram in the two years prior to the interview. Factors that explained compliance with a mammogram in the last two years included referral from a physician, owning a car, and receiving information after menopause on breast cancer from a health care provider. A gynecological visit increased the probability of having had a mammogram during the last two years. Logistic regression determined that a referral from a physician was the most important factor for mammogram compliance when a combination of variables were considered.

The epidemiology of tuberculosis in patients with AIDS in Puerto Rico: morbidity and survival, 1981-1998.

SETTING: Puerto Rico. OBJECTIVE: To describe the characteristics and survival experience of AIDS patients with tuberculosis (TB) from 1981 through 1998. DESIGN: A population based study using the AIDS Surveillance System, including survival analysis. RESULTS: During the period studied, 1000 AIDS cases were reported with TB, representing 4.3% of total cases. Of these, males accounted for 82.1%, and 84% were diagnosed with pulmonary TB. Approximately 71% of the cases were reported as having died. AIDS cases who were intravenous drug users (IDU) accounted for 63.7% of the cases. The median survival of AIDS/TB cases was 21.4 months, and did not differ by sex or TB site (P > 0.05). IDUs with TB had a longer survival than IDUs with other AIDS-defining conditions; however, AIDS/TB cases with a CD4 count < 200/mm3 had a poorer survival (23.4 months) than those with a count of > or = 200/mm3 (47.9 months). CONCLUSIONS: The overall prevalence of TB in AIDS patients in Puerto Rico is low compared with other countries. As in other studies, the variable that explained poorer survival among AIDS/TB cases was the CD4+ lymphocyte count. Further prospective studies regarding survival in the Hispanic population are needed to confirm these findings.

Prevalencia de asma y utilización de servicios médicos en asegurados de una compañía de servicios de salud en Puerto Rico, 1996-1997 / The prevalence of asthma and the utilization of medical services among those insured by a health-services company in Puerto Rico, 1996-1997

OBJECTIVE: To describe the prevalence and pattern of utilization of medical services in insured of SSS with a diagnosis of asthma during 1996 and 1997. METHODS: The medical claims of SSS insured whose main diagnosis was asthma (ICD-9 9 493-493.9) were selected for analysis. The prevalence and medical service utilization (medical visits, emergency and hospital admissions) were estimated. Differences in health service utilization by age group were analyzed by the Poisson model. RESULTS: The asthma prevalence was 14.5, being larger in patients younger than 18 years of age and in females. 54.3 of the asthmatic patients visited medical offices and the larger proportion of users was observed in the younger group (< 18 years). However, the larger proportion of users of the emergency room was observed in the 18-44 age group, while the hospital admissions was larger in the 45-64 age group. More than half (56) of the cost per service was attributed to hospital admissions while 31 was for pharmacy services. 65.9 of the insurers with asthma had prescriptions for short relief beta-antagonist. CONCLUSIONS: The prevalence of asthma in this study was high and similar to rates of the disease reported in Puerto Ricans residing in the U. S. and in other areas of the island. Similarly, the prevalence differed by age in the utilization of medical services as well as the high cost of hospital admissions. Prevalence studies using other sources as well as a standard definition of the condition may be helpful to confirm these results

[Basic components in the development of research proposals in health sciences]. / Componentes básicos para el desarrollo de propuestas de investigación en las ciencias de la salud.

Any investigation in the health sciences should have a plan or proposal to answer a specific research question. This document, designed for persons preparing for or already pursuing a research project, describes the conceptual framework related with a research proposal, from the study design until its implementation. The objective of this document is to summarize different theoretical aspects that should be considered in a research project, including pertinent references that might be used to deepen the discussion. First, a series of definitions related to the scientific method are presented and then the processes to carry out a research proposal including common epidemiologic designs are illustrated. In addition, a series of research questions that can serve as a guide to perform a critical analysis of published papers are included. Finally, an interdisciplinary group integrated by health professionals with the clinical expertise and health professionals with the necessary skills in biostatistics and epidemiology to undertake a sound scientific research is recommended.

[The prevalence of asthma and the utilization of medical services among those insured by a health-services company in Puerto Rico, 1996-1997]. / Prevalencia de asma y utilización de servicios médicos en asegurados de una compañía de servicios de salud en Puerto Rico, 1996-1997.

OBJECTIVE: To describe the prevalence and pattern of utilization of medical services in insured of SSS with a diagnosis of asthma during 1996 and 1997. METHODS: The medical claims of SSS insured whose main diagnosis was asthma (ICD-9 9 493-493.9) were selected for analysis. The prevalence and medical service utilization (medical visits, emergency and hospital admissions) were estimated. Differences in health service utilization by age group were analyzed by the Poisson model. RESULTS: The asthma prevalence was 14.5%, being larger in patients younger than 18 years of age and in females. 54.3% of the asthmatic patients visited medical offices and the larger proportion of users was observed in the younger group (< 18 years). However, the larger proportion of users of the emergency room was observed in the 18-44 age group, while the hospital admissions was larger in the 45-64 age group. More than half (56%) of the cost per service was attributed to hospital admissions while 31% was for pharmacy services. 65.9% of the insurers with asthma had prescriptions for short relief beta-antagonist. CONCLUSIONS: The prevalence of asthma in this study was high and similar to rates of the disease reported in Puerto Ricans residing in the U. S. and in other areas of the island. Similarly, the prevalence differed by age in the utilization of medical services as well as the high cost of hospital admissions. Prevalence studies using other sources as well as a standard definition of the condition may be helpful to confirm these results.

Epidemiology of pediatric AIDS in Puerto Rico: 1981-1998.

The objective of this study was to describe the AIDS-defining conditions (ADC) and survival experience of pediatric AIDS cases (< 13 years age) reported in Puerto Rico. A descriptive analysis of the data gathered by the Puerto Rico AIDS Surveillance System was performed. Data for the 377 pediatric AIDS cases reported from January 1981 through June 1998 were reviewed. Survival curves following AIDS diagnosis were estimated using the Kaplan--Meier method and differences between curves were assessed by the Wilcoxon test. The majority (61%) of the cases were diagnosed before 2 years of age, and nearly 94% of them acquired the infection through perinatal transmission. The most common ADC were Pneumocystis carinii pneumonia (PCP) (23%), wasting syndrome (19.4%), and esophageal candidiasis (19.1%). The overall median survival time during the study period was 53.5 (95% CI: 38.0-106.2) months. Children < 1 year of age had a significantly shorter median survival time compared with older ages (p < 0.05). The survival experience in children diagnosed with PCP, pulmonary candidiasis, cytomegalovirus, and lymphocytic interstitial pneumonia (LIP) was significantly different (p < 0.05) to those children not diagnosed with these conditions. Although patients diagnosed after 1990 showed a median survival time longer than those diagnosed prior to 1990, the difference did not reach statistical significance (p > 0.05). The frequency of several ADC and median survival time of Puerto Rican children differed from those reported in the United States. This may reflect differences in diagnostic procedures or reporting practices.

[Description of health status and functional capacity of the 65-year-old and older population residing in the University Region of Health of Puerto Rico]. / Descripción del estado de salud y la capacidad funcional de la población de 65 años o más residente en la Región Universitaria de Salud de Puerto Rico.

This study intended to describe the health and functional status of the population 65 years and over resident in the Puerto Rico University Health Region (municipalities of Canóvanas, Loiza, Carolina and Trujillo Alto, Puerto Rico). Four ninety one hundred elderly subjects selected from a random sample of households, were interviewed. A questionnaire was designed to gather data of the following variables: health conditions, functional capacity, health services utilization, social support and preventive measures. Descriptive measures and chi-square were utilized for the statistical analysis. Findings revealed a population composed mostly of women with a higher prevalence of health conditions than their male counterparts. More than half of the sample report visual problems, arthritis or hypertension. Almost a quarter had diabetes mellitus. The prevalence of these conditions was higher in the age group over 75, with the exception of diabetes. Thirty percent of the sample was classified as functionally dependent, condition that increased with the subject's age. Findings evidence the need of an early assessment in this population in order to intervene with potentially modifiable factors to prevent future disability and improve quality of life of the aged.

[Health status and functional limitations in the elderly population of the University Region of Health of Puerto Rico: methodologic aspects and prevalence estimates]. / Condiciones de salud y limitaciones funcionales en la población de edad avanzada de la Región Universitaria de Salud de Puerto Rico: aspectos metodológicos y estimación de prevalencias.

In order to plan the health services for the elderly population, it is necessary to quantify their health status and their functional capacity. In Puerto Rico, few epidemiological studies have been conducted regarding functional capacity and chronic diseases in the elderly population. One of the difficulties to undertake these studies is the high cost and risks to move this population for clinical exams, in addition to the methodology limitation of self-report in the elderly population. This study shows the use of logistic regression to estimate the prevalence of chronic diseases and functional capacity, when the observed data are not consisted with the planed sampling scheme. Four hundred and eighty-seven elderly persons (65 yr. and over) were interviewed in the municipalities of Canóvanas, Carolina, Loíza and Trujillo Alto in Puerto Rico, using a cross-sectional design. More than half of the elderly had visual problems (IC 95%: 54.8%, 63.8%), arthritis (IC 95%: 52.7%, 61.5%) and hypertension (IC 95%: 47.3%, 56.3%). In the case of hypertension, significant differences (p < 0.05) by sex were observed, where women reported a higher prevalence than men. One of the higher prevalences in the functional capacity status was with urine accidents. More than one-third of the population is estimated to have this problem (IC 95%: 34.7%, 43.4%). One-fourth of the population had limitations with going out for shopping (IC 95%: 23.9%, 31.9%) and using public and private transportation (IC 95%: 19.5%, 26.9%). We conclude that the applied methodology was consistent with the estimation presented in the literature and statistics from the Puerto Rico Health Department. However, it is necessary to continue assessing the design and analytical methodology, in order to undertake consistent and periodic evaluations of the elderly population.

[Analysis of survival of patients with end-stage renal disease in Puerto Rico, 1970-1994]. / Análisis de sobrevivencia de pacientes con enfermedad renal permanente en Puerto Rico 1970-1994.

To assess the survival probabilities of patients with end stage renal disease in Puerto Rico, the data from the United States Renal Data System from 1970 through 1994 was analyzed. The Kaplan Meier method was used to determine the survival rate for the following variables: diagnosis, gender, age groups, treatment modality and health regions. The analysis included 7,527 patients reported to the United States Renal Disease System of which 4,295 (57%) patients were reported dead. The median time of survival rate (50%) was 47.7 months. There was significantly lower survival rate (p = 0.0001) for diabetics compared with all the other diagnosis. Age was also a strong predictor of survival (p = 0.0001) and modality treatment (p = 0.0001). We concluded that diabetes, the elderly and the hemodialysis modality, had the lower survival rate in the puerto rican population.

Knowledge and beliefs of breast cancer among elderly Puerto Rican women: validation process of scales.

This paper presents the results of the validation process to determine the concepts for knowledge and beliefs about breast cancer early detection practices among Puerto Rican elderly women. An initial questionnaire was designed based on the scientific literature review and focus group experiences. To determine its reliability and validity, 50 elderly women, stratified by type of profession and place of residence, were interviewed twice. Consistency of the questionnaire was analyzed using binomial test, matched t-test, Pearson correlation coefficient, and Cronbach's coefficient effect. Factor analysis (FA) was the statistical technique used to analyze the grouping of the knowledge and beliefs statements. FA indicated that three scales for knowledge and one for beliefs can be constructed. The purpose of the scales was to identify differences among groups, according to breast cancer early detection practices. Construct validity was performed to determine the number of statistical associations between the scales and these practices. The results showed that beliefs scales was associated with practice of mammogram (p < 0.05), and visit to the gynecologist (p < 0.05) while the knowledge scale for early-detection was associated with the clinical breast examination (p < 0.05). The beliefs scale had better consistency than the knowledge scale. The Cronbach's alpha was 0.75 for the beliefs' scale and 0.30, 0.41 and 0.43 for each defined knowledge scale, respectively.

[Permanent renal disease in Puerto Rico, morbidity and mortality trends 1970-1994]. / Enfermedad renal permanente en Puerto Rico, tendencias de morbilidad y mortalidad 1970-1994.

To describe the characteristics and trends of the incidence and mortality of End-Stage Renal Diseases (ESRD) in Puerto Rico, a descriptive analysis of the data of all patients treated with dialysis between 1970 through 1994 was conducted. A total of 7,256 patients received dialysis treatment for ESRD in Puerto Rico. Of these, 61% were males and 39% were females. Diabetes (41.7%) and glomerulonephritis (18.3) accounted for the largest number of cases followed by circulatory problems (8.3%). Hemodialysis was the predominant treatment modality (76%). The incidence trend was significant for the predictor variable period of time after adjusting by age and gender (Poisson). The mortality trend was significant for the predictor variables, period of time, gender and age (Poisson). A substantial increment in the incidence and mortality of persons receiving dialysis was found, particularly in the diabetics, males and elderly persons. The casual explanations of these findings requires further study.