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

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.

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.

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.

[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]

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]

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.

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.

[Analysis of survival of patients with end-stage renal disease in 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.