Phthalate exposure among US women, NHANES 1999--2002: Relationship to serum gonadotropin levels

Phthalates are industrial chemicals used primarily as plasticizers though they and are found in a myriad of consumer goods such as children's toys, food packaging, dental sealants, cosmetics, pharmaceuticals, perfumes, and building materials. US biomonitoring data show more than 75% of the population have exposure to mono-n-butyl phthalate (MBP), mono-ethyl phthalate (MEP), mono-(2-ethyl) hexyl phthalate (MEHP), and mono-benzyl phthalate (MBZP). Reproductive toxicity from phthalate exposure in animal models has raised concerns about similar effects on fertility in humans. This dissertation research focuses on phthalate exposures in the US population and investigates the plausibility of an exposure-response relationship between phthalates and endocrine hormones essential for ovulation among US women. The objective of this research is to determine the relationship between levels of gonadotropins, follicle stimulating hormone (FSH) and leutinizing hormone (LH), and urinary phthalate monoester metabolites: MBP, MEP, MEHP, MBZP among National Health and Nutrition Examination Survey (NHANES) 1999-2002 women aged 35 to 60 years. Using biomarker data from a one-third sub-sample of NHANES participants, log transformed serum FSH and serum LH, respectively were regressed on phthalates controlling for age, body mass index, smoking, and creatinine taking into consideration the complex survey design (n=385). Models were stratified by reproductive status: reproductive (n=185), menopause transition (n=49) and post-menopausal (n=125). A decrease in FSH associated with increasing MBzP (beta=-0.094, p<0.05) was observed for all participants but no statistical association between log FSH and MBP, MEP, or MEHP was seen. A decrease in LH (beta=-0.125, p<0.05) was also observed with increasing MBzP for all participants though there was no relationship between levels of LH and MBP, MEP, or MEHP. The observed associations between FSH, LH and MBzP did not persist when stratified by reproductive status. Thus, the present study shows a change in endocrine hormones related to ovulation with increasing urinary MBzP among a representative sample of US women from 1999-2002 though this observed exposure-response relationship does not remain after stratification by reproductive status. ^

The School Sealant Program: An evaluation of the oral health education component

Dental caries is a common preventable childhood disease leading to severe physical, mental and economic repercussions for children and their families if left untreated. A needs assessment in Harris County reported that 45.9% of second graders had untreated dental caries. In order to address this growing problem, the School Sealant Program (SSP), a primary preventive initiative, was launched by the Houston Department of Health and Human Services (HDHHS) to provide oral health education, and underutilized dental preventive services to second grade children from participating Local School Districts (LSDs). ^ To determine the effectiveness and efficiency of the SSP, a program evaluation was conducted by the HDHHS between September 2007 and June 2008 for the Oral Health Education (OHE) component of the SSP. The objective of the evaluation was to assess short term changes in oral health knowledge of the participants and determine if these changes, if any, were due to the OHE sessions. An 8-item multiple choice pre/post test was developed for this purpose and administered to the participants before and immediately after the OHE sessions. ^ The present project analyzed pre and post test data of 1,088 second graders from 22 participating schools. Changes in overall and topic-specific knowledge of the program participants before and after the OHE sessions were analyzed using the Wilcoxon's signed rank test. ^ Results. The overall knowledge assessment showed a statistically significant (p <0.001) increase in the dental health knowledge of the participants after the oral health education sessions. Participants in the higher scoring category (7-8 correct responses) increased from 9.5% at baseline to 60.8% after the education sessions. Overall knowledge increased in all school regions with the highest knowledge gains seen in the Central and South regions. Males and females had similar knowledge gains. Significant knowledge differences were also found for each of the topic specific categories (functions of teeth, healthy diet, healthy habits, dental sealants; p<0.001) indicating an increase in topic specific knowledge of the participants post-health education sessions. ^ Conclusions. The OHE sessions were successful in increasing the short term oral health knowledge of the participants. ^

An assessment of differences in pediatric dental services provided for a Medicaid population when compared to a federally subsidized (military) clinic

Reimbursement for dental services performed for children receiving Medicaid is reimbursed per service while dental treatment for military dependents provided at a military installation is neither directly reimbursable to those providing the care nor billed to those receiving the care. The purpose of this study was to compare pediatric dental services provided for a Medicaid population to a federally subsidized military facility to compare treatment choices and subsequent costs of care. It was hypothesized that differences in dental procedures for Medicaid and military dependent children would exist based upon treatment philosophy and payment method. A total of 240 records were reviewed for this study, consisting of 120 Medicaid patients at the University of Texas Health Science Center at San Antonio (UTHSCSA) and 120 military dependents at Wilford Hall Medical Center (WHMC), Lackland Air Force Base, San Antonio. Demographic data and treatment information were abstracted for children receiving dental treatment under general anesthesia between 2002 and 2006. Data was analyzed using the Wilcoxon rank sum test, Kruskal-Wallis test, and Fisher's exact test. The Medicaid recipients treated at UTHSCSA were younger than patients at WHMC (40.2 vs. 49.8 months, p<.001). The university also treated significantly more Hispanic children than WHMC (78.3% vs. 30.0%, p<.001). Children at UTHSCSA had a mean of 9.5 decayed teeth and were treated with 2.3 composite fillings, 0 amalgam fillings, 5.6 stainless steel crowns, 1.1 pulp therapies, 1.6 extractions, and 1.0 sealant. Children at WHMC had a mean of 8.7 decayed teeth and were treated with 1.4 composite fillings, 0.9 amalgam fillings, 5.6 stainless steel crowns, 1.7 pulp therapies, 0.9 extractions, and 2.1 sealants. The means of decayed teeth, total fillings, and stainless steel crowns were not statistically different. UTHSCSA provided more composite fillings (p<.001), fewer amalgam fillings (p<.001), fewer pulp therapies (p <.001), more extractions (p=.01), and fewer sealants (p<.001) when compared to WHMC. Age and gender did not effect decay rates, but those of Hispanic ethnicity did experience more decay than non-Hispanics (9.5 vs. 8.6, p=.02). Based upon Texas Medicaid reimbursement rates from 2006, the cost for dental treatment at both sites was approximately $650 per child. The results of this study do not support the hypothesis that Medicaid providers provide less conservative therapies, which would be more costly, care when compared to a military treatment center. ^

Findings of the University of Texas Health Science Center at San Antonio's Dental School pilot mobile van program in Laredo, Texas

Lack of access to oral health care frequently affects those of lower socio-economic level; individuals in this group experience more dental decay, and the caries experience is more likely to be untreated. Inadequate dental care access may be attributed to exclusion that is due to income, geography, age, race or ethnicity. Objective: The present study aims were to: (1) determine how oral disease prevalence and access to dental services in four US-Mexico Border unincorporated low socioeconomic settlements identified as colonias compare to each other and Laredo, Texas, and (2) determine if insurance status affects dental care access and/or disease prevalence. Methods: A secondary analysis of data from a retrospective chart review of 672 patients attending a Mobile Dental Van Program in the Webb County colonias. Demographic information, (ethnicity, age, gender, insurance coverage and colonia site), dental visits within past year, insurance status, presence of dental sealants, prevalence of untreated dental decay (caries), and presence of gum disease (gingivitis and periodontitis) were extracted. Pearson's chi-square tests (χ2) were computed to compare the prevalence of these outcomes between colonias and Laredo and their potential association with insurance status. Results: For 6 - 11 year olds, dental visits in the past year were lower for colonias (39%), than Laredo (58.5%) (p<0.002). Caries prevalence was higher for colonias (56.6%), than Laredo (37.1%) (p<0.001). Gum disease prevalence was higher in colonias (73%), than in Laredo (21.4%) (p<0.001). No significant differences were noted for caries (χ2=1.73; p<0.188) and gum disease (χ2=0.0098; p<0.921) by patient's insurance status. For adults 36 - 64 years of age, dental visits in the past year were lower in colonias (22.4%), than Laredo (36.3%) (p<0.001). Caries prevalence was higher for colonias (78.3%), than Laredo (54.0%) (p<0.001). Gum disease prevalence was also higher among colonias (91.3%) than Laredo (61.3%) (p<0.001). No significant differences were noted for caries (χ2=0.0010; p<0.975) and gum disease (χ2=0.0607; p<0.805) by patient's insurance status. Conclusion: Colonia residents seeking dental care at a Mobile Dental Van Program in Webb County have significantly higher prevalence of oral disease regardless of insurance status.^

U.S. school based sealant programs: Review of their most common characteristics

In the United States, dental caries is the most common chronic illness in children, occurring five to eight times as frequently as asthma. 11 Dental caries is an unmet health need, disproportionately affecting minority groups and individuals with low socio-economic status.15,34,36 School-Based Sealant Programs were developed to target children at risk, to provide dental services in a closer geographic area, to offer low cost preventive dental services, and to educate families about oral health and prevention.1 There is scientific, evidence based literature that shows the effectiveness of dental sealants preventing dental decay. 13^ Currently, there is no central source for cataloging School-Based Sealant Programs (SBSPs). Information is scattered around publications and documents. For instance, the National Health and Nutrition Examination Survey (NHANES) does not have information about all the existing SBSPs. ^ This literature review determined which are the most common characteristics of SBSPs in the U.S. and determined the extent to which these programs provide sealants to children of low socio-economic status. The method utilized was an electronic database search. Pubmed and EBESCO host databases were searched with Mesh terms like “dental school sealant programs”, “community dentistry”, “school based sealant programs” and “oral preventive programs”. Results were organized in terms of location, population served, providers, funding source and data shared. ^ The searches produced 77 studies, from which 40 were included in this work. Only 18 U.S. states were represented in the results; however these findings are very consistent with the Best Practice Approach – School Based Sealant Programs3. Most of the SBSPs provide their services to children from low income families, and utilized the lower labor cost providers permitted by their state regulations. The author intends that this thesis work will become an aide in the development of future programs, and as evidence for the sustainability of these programs.^