Screening for obstructive sleep apnea on the internet: randomized trial.

BACKGROUND: Obstructive sleep apnea is underdiagnosed. We conducted a pilot randomized controlled trial of an online intervention to promote obstructive sleep apnea screening among members of an Internet weight-loss community. METHODS: Members of an Internet weight-loss community who have never been diagnosed with obstructive sleep apnea or discussed the condition with their healthcare provider were randomized to intervention (online risk assessment+feedback) or control. The primary outcome was discussing obstructive sleep apnea with a healthcare provider at 12 weeks. RESULTS: Of 4700 members who were sent e-mail study announcements, 168 (97% were female, age 39.5 years [standard deviation 11.7], body mass index 30.3 [standard deviation 7.8]) were randomized to intervention (n=84) or control (n=84). Of 82 intervention subjects who completed the risk assessment, 50 (61%) were low risk and 32 (39%) were high risk for obstructive sleep apnea. Intervention subjects were more likely than control subjects to discuss obstructive sleep apnea with their healthcare provider within 12 weeks (11% [9/84] vs 2% [2/84]; P=.02; relative risk=4.50; 95% confidence interval, 1.002-20.21). The number needed to treat was 12. High-risk intervention subjects were more likely than control subjects to discuss obstructive sleep apnea with their healthcare provider (19% [6/32] vs 2% [2/84]; P=.004; relative risk=7.88; 95% confidence interval, 1.68-37.02). One high-risk intervention subject started treatment for obstructive sleep apnea. CONCLUSION: An online screening intervention is feasible and likely effective in encouraging members of an Internet weight-loss community to discuss obstructive sleep apnea with their healthcare provider.

Sleep quality and quantity and associated factors among high school students from south Texas

Background. Insufficient and poor quality sleep among adolescents affects not only the cognitive functioning, but overall health of the individual. Existing research suggests that adolescents from varying ethnic groups exhibit differing sleep patterns. However, little research focuses on sleep patterns and associated factors (i.e. tobacco use, mental health indicators) among Hispanic youth. ^ Methods. The study population (n=2,536) included students in grades 9-12 who attended one of the three public high schools along the Texas-Mexico border in 2003. This was a cross sectional study using secondary data collected via a web-based, confidential, self-administered survey. Separate logistic regression models were estimated to identify factors associated with reduced (<9 hours/night) and poor quality sleep on average during weeknights. ^ Results. Of participants, 49.5% reported reduced sleep while 12.8% reported poor quality sleep. Factors significantly (p<0.05) associated with poor quality sleep were: often feeling stressed or anxious (OR=5.49), being born in Mexico (OR=0.65), using a computer/playing video games 15+ hours per week (OR=2.29), working (OR=1.37), being a current smoker (OR=2.16), and being a current alcohol user (OR=1.64). Factors significantly associated with reduced quantity of sleep were: often feeling stressed or anxious (OR=2.74), often having headaches/stomachaches (OR=1.77), being a current marijuana user (OR=1.70), being a current methamphetamine user (OR=4.92), and being a current alcohol user (OR=1.27). ^ Discussion. Previous research suggests that there are several factors that can influence sleep quality and quantity in adolescents. This paper discusses these factors (i.e. work, smoking, alcohol, etc.) found to be associated with poor sleep quality and reduced sleep quantity in the Hispanic adolescent population. A reduced quantity of sleep (81.20% of the participants) and a poor quality of sleep (12.80% of the participants) were also found in high school students from South Texas. ^

Micronutrient intakes and their associations with markers of inflammation, subclinical atherosclerosis, cardiovascular disease, type II diabetes and metabolic syndrome

We investigated cross-sectional associations between intakes of zinc, magnesium, heme- and non heme iron, beta-carotene, vitamin C and vitamin E and inflammation and subclinical atherosclerosis in the Multi-Ethnic Study of Atherosclerosis (MESA). We also investigated prospective associations between those micronutrients and incident MetS, T2D and CVD. Participants between 45-84 years of age at baseline were followed between 2000 and 2007. Dietary intake was assessed at baseline using a 120-item food frequency questionnaire. Multivariable linear regression and Cox proportional hazard regression models were used to evaluate associations of interest. Dietary intakes of non-heme iron and Mg were inversely associated with tHcy concentrations (geometric means across quintiles: 9.11, 8.86, 8.74, 8.71, and 8.50 µmol/L for non-heme iron, and 9.20, 9.00, 8.65, 8.76, and 8.33 µmol/L for Mg; ptrends <0.001). Mg intake was inversely associated with high CC-IMT; odds ratio (95% CI) for extreme quintiles 0.76 (0.58, 1.01), ptrend: 0.002. Dietary Zn and heme-iron were positively associated with CRP (geometric means: 1.73, 1.75, 1.78, 1.88, and 1.96 mg/L for Zn and 1.72, 1.76, 1.83, 1.86, and 1.94 mg/L for heme-iron). In the prospective analysis, dietary vitamin E intake was inversely associated with incident MetS and with incident CVD (HR [CI] for extreme quintiles - MetS: 0.78 [0.62-0.97] ptrend=0.01; CVD: 0.69 [0.46-1.03]; ptrend =0.04). Intake of heme-iron from red meat and Zn from red meat, but not from other sources, were each positively associated with risk of CVD (HR [CI] - heme-iron from red meat: 1.65 [1.10-2.47] ptrend = 0.01; Zn from red meat: 1.51 [1.02 - 2.24] ptrend =0.01) and MetS (HR [CI] - heme-iron from red meat: 1.25 [0.99-1.56] ptrend =0.03; Zn from red meat: 1.29 [1.03-1.61]; ptrend = 0.04). All associations evaluated were similar across different strata of gender, race-ethnicity and alcohol intake. Most of the micronutrients investigated were not associated with the outcomes of interest in this multi-ethnic cohort. These observations do not provide consistent support for the hypothesized association of individual nutrients with inflammatory markers, MetS, T2D, or CVD. However, nutrients consumed in red meat, or consumption of red meat as a whole, may increase risk of MetS and CVD.^

An evaluation of sleep hypnotic and stimulant effect on human performance using a computerized psychological test battery

This study evaluated the administration-time-dependent effects of a stimulant (Dexedrine 5-mg), a sleep-inducer (Halcion 0.25-mg) and placebo (control) on human performance. The investigation was conducted on 12 diurnally active (0700-2300) male adults (23-38 yrs) using a double-blind, randomized sixway-crossover three-treatment, two-timepoint (0830 vs 2030) design. Performance tests were conducted hourly during sleepless 13-hour studies using a computer generated, controlled and scored multi-task cognitive performance assessment battery (PAB) developed at the Walter Reed Army Institute of Research. Specific tests were Simple and Choice Reaction Time, Serial Addition/Subtraction, Spatial Orientation, Logical Reasoning, Time Estimation, Response Timing and the Stanford Sleepiness Scale. The major index of performance was "Throughput", a combined measure of speed and accuracy.^ For the Placebo condition, Single and Group Cosinor Analysis documented circadian rhythms in cognitive performance for the majority of tests, both for individuals and for the group. Performance was best around 1830-2030 and most variable around 0530-0700 when sleepiness was greatest (0300).^ Morning Dexedrine dosing marginally enhanced performance an average of 3% with reference to the corresponding in time control level. Dexedrine AM also increased alertness by 10% over the AM control. Dexedrine PM failed to improve performance with reference to the corresponding PM control baseline. With regard to AM and PM Dexedrine administrations, AM performance was 6% better with subjects 25% more alert.^ Morning Halcion administration caused a 7% performance decrement and 16% increase in sleepiness and a 13% decrement and 10% increase in sleepiness when administered in the evening compared to corresponding in time control data. Performance was 9% worse and sleepiness 24% greater after evening versus morning Halcion administration.^ These results suggest that for evening Halcion dosing, the overnight sleep deprivation occurring in coincidence with the nadir in performance due to circadian rhythmicity together with the CNS depressant effects combine to produce performance degradation. For Dexedrine, morning administration resulted in only marginal performance enhancement; Dexedrine in the evening was less effective, suggesting the 5-mg dose level may be too low to counteract the partial sleep deprivation and nocturnal nadir in performance. ^

Physician and patient determinants of the treatment of sleep difficulties in U.S. outpatient settings

The prevalence of sleep difficulties among the patients seen in the primary care settings is about 30%. This problem increases with age and is more common among females than males. Variations are noticed in prescription choices for different patients with sleep difficulties. Many factors affect a physician's prescription decision while chosen from a wide array of available medications. Both pharmacological and behavioral therapies are available for the treatment of sleep difficulties. It is important to know the impact of use of different types of prescriptions on health outcomes related to sleep difficulties. Thus the knowledge of prescription patterns among different types of patients (e.g. age, gender, race, insurance type etc.) becomes important for determining a clinical guideline. This study is designed to assist in evidence-based policymaking on understanding the variations in physician prescriptions for sleep difficulties and reasons for such variations. ^ A modified version of the model suggested by Eisenberg was used as a theoretical framework for this study to predict the factors influencing treatment of sleep difficulties. Multivariate logistic regression methods were used to analyze the 1996–2001 National Ambulatory Medical Care Survey data. ^ This study found that increased age, female gender, white race, established patients, and mental comorbidity were associated with significantly increased likelihood for prescription of some type of therapy for sleep difficulties in US outpatient settings. Patients with private insurance were associated with lower likelihood of receipt of many therapies. Psychiatrists were more likely to prescribe some kind of treatment as well as more expensive therapies for sleep difficulty as compared to other physician specialties. HMO enrolled patient visits were more likely to be associated with receipt of behavioral therapy. This study also found that 32% of patients with sleep difficulties received no type of therapy during their visits. Only 5% of the patients received behavioral therapy only. Almost three-quarters of the patients receiving some kind of medication prescription were prescribed benzodiazepines. The study results also suggest a need for wider coverage of behavioral therapy by payers in US outpatient settings. ^

Risk factors for metabolic syndrome among overweight and obese Hispanic children attending a pediatric clinic in New Braunfels, Texas

Childhood obesity is a persistent problem in the U.S., especially among Hispanics. Health complications like hypertension, type II diabetes, and metabolic syndrome (Met-S) are being seen at younger ages, and current screening procedures may be inadequate. This study sought to describe the risk factors for Met-S present in a sample of 106 overweight and obese Hispanic children, aged 5-14 years, participating in Nutrition and Exercise Start Today (NEST), a randomized weight management intervention trial at a rural health clinic in New Braunfels, Texas; and to determine associations between these factors and other clinical and socio-demographic characteristics linked to obesity. Baseline data was analyzed for the prevalence of large waist circumference (WC), elevated blood pressure (BP), high fasting serum glucose and serum triglycerides (TG), and low serum HDL cholesterol, in relationship with selected sample characteristics. Main findings included high baseline prevalence rates of large WC (77%), reduced HDL (57%), and elevated BP (30%). WC was significantly associated with BMI percentile and the serum liver function test alanine aminotransferase (ALT) by Fisher's exact test (p<0.001 and p=0.032, respectively), while there were significant relationships between HDL and both female gender and ALT. BMI percentile and ALT were associated with all sets of Met-S diagnostic criteria examined. BMI percentile also had a strong association (p=0.005) with total number of Met-S risk factors, while ALT had a weaker association (p=0.093). WC is a low-cost, simple measure whose use may improve clinic surveillance for childhood obesity and complications like Met-S. WC, BP, HDL and ALT may be used as part of targeted screening for obesity complications like Met-S, particularly in situations where resources are limited.^

Waking Up to Sleep Medicine Education

Background: Sleep disorders are an important cause of morbidity among our population with billions of dollars spent on direct and indirect costs attributed to sleep disorders. In spite of raising prevalence and morbidity, surveys have shown inadequate education in sleep medicine at all levels at medical school. According to national sleep disorders research plan data, in 1990 about 37 % of medical schools did not offer any sleep education and of the schools which offered it, the average time devoted to sleep medicine was about 2 hours. Sleep disorders have found to be uniformly under diagnosed in primary care settings. [See PDF for complete abstract]

CHARACTERIZING A NOVEL GENETIC LOCUS ASSOCIATED WITH FAMILIAL CO-OCCURRENCE OF THORACIC AORTIC ANEURYSMS AND INTRACRANIAL ANEURYSMS

The Mendelian inheritance of genetic mutations can lead to adult-onset cardiovascular disease. Several genetic loci have been mapped for the familial form of Thoracic Aortic Aneurysms (TAA), and many causal mutations have been identified for this disease. Intracranial Aneurysms (ICA) also show linkage heterogeneity, but no mutations have been identified causing familial ICA alone. Here, we characterized a large family (TAA288) with an autosomal dominant pattern of inherited aneurysms. It is intriguing that female patients predominantly present with ICA and male patients predominantly with TAA in this family. To identify a causal mutation in this family, a genome-wide linkage analysis was previously performed on nine members of this family using the 50k GenChips Hind array from Affymetrix. This analysis eventually identified a single disease-segregating locus, on chromosome 5p15. We build upon this previous analysis in this study, hypothesizing that a genetic mutation inherited in this locus leads to the sex-specific phenotype of TAA and ICA in this family First we refined the boundaries of the 5p15 disease linked locus down to the genomic coordinates 5p15: 3,424,465- 6,312,925 (GRCh37/hg19 Assembly). This locus was named the TAA288 critical interval. Next, we sequenced candidate genes within the TAA288 critical interval. The selection of genes was simplified by the relatively small number of well-characterized genetic elements within the region. Seeking novel or rare disease-segregating variants, we initially observed a single point alteration in the metalloproteinase gene ADAMTS16 fulfilling this criteria. This variant was later classified as a low-frequency population polymorphism (rs72647757), but we continued to explore the potential role of the ADAMTS16 as the cause of disease in TAA288. We observed that fibroblasts cultured from TAA288 patients consistently upregulated the expression of this gene more strongly compared to matched control fibroblasts when treated with the cytokine TGF-β1, though there was some variation in the exact nature of this expression. We also observed evidence that this protein is expressed at elevated levels in aortic aneurysm tissue from patients with mutations in the gene TGFBR2 and Marfan syndrome, shown by immunohistochemical detection of this protein.

The genetic basis of thoracic aortic aneurysms and dissections: Genetic heterogeneity and mapping of TAAD1 and TAAD2 loci

Thoracic aortic aneurysms leading to aortic dissections (TAAD) are a major cause of morbidity and mortality in the United States. TAAD is a complication of some known genetic disorders, such as Marfan syndrome and Turner syndrome, but the majority of familial cases are not due to a known genetic syndrome. Previous studies by our group have established that nonsyndromic, familial TAAD is inherited in an autosomal dominant manner with decreased penetrance and variable expression. Using one large family with multiple members with TAAD for the genome wide scan, a major locus for familial TAAD was mapped to 5q13–14 (TAAD1). Nine out of 15 families studied were linked to this locus, establishing that TAAD1 was a major locus, and that there was genetic heterogeneity for the condition. Mapping of TAAD2 locus was accomplished using a single large family with multiple members with TAAD not linked to known loci of aneurysm formation. This established a second novel locus for familial TAAD on 3p24–25 (LOD score of 4.3), termed the TAAD2 locus. Two putative loci with suggestive LOD scores were mapped on 4q and 12q through a genome scan carried out using three families. TAAD phenotype in 12 families did not segregate with known loci, indicating further genetic heterogeneity. An STS-tagged BAC based contig was constructed for 7.8Mb and 25Mb critical interval of TAAD1 and TAAD2 respectively and characterized to identify the defective gene. The hypothesis that the defective genes responsible for the TAAD1 and TAAD2 encoded extracellular matrix (ECM) proteins, the major components of the elastic fiber system in the aortic media was tested. Four genes encoding ECM proteins, versican, thrombospondin-3, CRTL1, on TAAD1 and FBLN2 at TAAD2 were sequenced, but no disease-causing mutations were identified. Studies to identify the defective gene are initiated through the positional candidate gene approach using combination of bioinformatics and expression studies. The identification of the TAAD susceptibility genes will allow for presymptomatic diagnosis of individuals at risk for this life threatening disease. The identification of the molecular defects that contribute to TAAD will also further our understanding of the proteins that provide structural integrity to the aortic wall. ^

Carcinoma of the lower uterine segment: A newly described association with Lynch Syndrome

Purpose. We performed a case-comparison study to describe the characteristics of LUS tumors and their association with risk factors for endometrial cancer. ^ Patients and Methods. From January 1996 through October 2007, 3,892 women were identified with a diagnosis of primary endometrial carcinoma or primary cervical adenocarcinoma. Pathology records from the 1,009 women who had a hysterectomy were reviewed. Subjects were included in the LUS group only if the tumor was clearly originating from the area between the lower corpus and upper cervix in the hysterectomy specimen. The LUS group was compared to all patients with endometrial corpus carcinoma who underwent hysterectomy at our institution in a 12-month period randomly selected from the study period. Risk factors for endometrial carcinoma such as body mass index (BMI) and Lynch Syndrome were assessed. Expression of estrogen receptor (ER), vimentin, carcinoembryonic antigen (CEA), p16, and human papilloma virus DNA (HPV DNA) was assessed; this panel is known to be effective in distinguishing adenocarcinomas of endometrial versus endocervical origin. Fisher's Exact, Chi-square, Mann-Whitney, and Student's t-tests were utilized for statistical analysis. ^ Results. Thirty-five of 1,009 women had endometrial carcinoma of the LUS (3.5%; 95% CI: 2–4%). Compared to patients with corpus tumors, LUS patients were younger (54.2 vs. 62.9 years, P = .001), had higher stage (P < .001), and more invasive tumors (P = .001). Preoperative diagnosis of the LUS tumors more frequently included the possibility of endocervical adenocarcinoma ( P < .001), leading to preoperative radiation therapy in 4 patients. Median BMI was similar in the LUS and corpus groups. Seventy-three percent of the available LUS tumors had a similar immunohistochemical expression pattern to conventional endometrioid adenocarcinoma. Because of the young median age for the LUS group, we performed immunohistochemistry for Lynch syndrome-associated DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. Microsatellite instability testing (MSI) and MLH1 promoter hypermethylation were performed when indicated. Thirty-six percent of the LUS tumors were MSI-high. Ten of thirty-five (29%) women with LUS tumors were either confirmed to have Lynch Syndrome or were strongly suspected to have Lynch Syndrome based on tissue-based molecular assays (95% CI, 16 to 45%). ^ Conclusions. Endometrial carcinoma arising in the LUS is a clinical and pathologic entity which can be diagnostically confused with cervical adenocarcinoma. In general, LUS tumors can be correctly identified as being endometrial carcinoma using the immunohistochemical panel noted above. The prevalence of Lynch Syndrome in patients with LUS tumors is much greater than that of the general endometrial cancer population (1.8%) or in endometrial cancer patients younger than 50 years of age (8–9%). Based on our results, the possibility of Lynch Syndrome should be considered in women with LUS tumors. ^

Delays in diagnosis and referral and treatment for hematologic malignancies

The purpose of this thesis project was to identify factors that may contribute to a delay in the diagnosis, referral or treatment of the hematologic malignancies. This thesis is a secondary data analysis of both qualitative and quantitative data collected during a pilot study for a parent CDC study to determine factors related to time to diagnosis, referral, and treatment of chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), multiple myeloma (MM), and myelodisplastic syndrome (MDS). To identify patterns for referral, as well as explore referral, treatment, and follow-up patterns, MDACC performed a pathways analysis, and conducted semi-structured interviews with hematologic cancer patients to help identify factors related to delays. Interviews were also conducted with primary care physicians and community hematologists/oncologists to help identify factors associated with optimal and sub-optimal patterns of diagnosis and referral. The results of these analyses suggest a set of factors that may be related to a fairly smooth and rapid trajectory to treatment, and factors that may be related to a slower, more disrupted trajectory. Factors that may be especially important to facilitating rapid treatment include the presence of cues to seek diagnosis in the patient's environment and the patient recognizing and acting upon these cues to seek immediate medical attention. Furthermore, providers who perform behaviors including recognizing cues as indicators of hematologic malignancies and conducting appropriate diagnostic testing effectively and efficiently indicate that these behaviors may also contribute to shorter times to diagnosis. In regards to referrals, direct and effective communication between providers and patients, as well between providers themselves helped facilitate speedier referrals. A patient's insurance status as well as the presence or absence of social support in his environment served as factors that may increase or decrease time to diagnosis, referral, and treatment for a hematologic malignancy. Further research is needed to define delay to diagnosis, referral and treatment in order to improve early diagnosis, referral, and treatment of hematologic malignancies.^

SEVERITY OF IRON DEFICIENCY ANEMIA AND ITS RELATIONSHIP TO GROWTH AND MORBIDITY IN A POPULATION OF PRE-SCHOOLERS IN RURAL GUATEMALA (IRON DEFICIENCY, MORBIDITY, GROWTH)

The objectives of this study were to determine the nature of the relationship between severity of iron deficiency anemia, response to iron treatment, respiratory and gastrointestinal illness and weight change. Seventy-five pre-school children from rural Guatemala received daily oral iron therapy for an eleven week period, and were classified into one of three groups having different degrees of iron deficiency anemia. Anthropometric and biochemical data were collected prior and after iron treatment; morbidity data were collected throughout the period of treatment. The outcome variables were percentage weight change, percentage of total days ill with any type of symptom, percentage of total days ill with gastrointestinal symptoms, percentage of total days ill with respiratory symptoms, percentage of total days ill with combination syndrome symptoms. Age, sex and socio-economic status, were independent of any of the independent or outcome variables used. On the other hand, the level of hemoglobin covaried with the height of the children, the smallest children were the most severely anemic. The relationships between hemoglobin levels and weight change, frequency of morbidity (gastrointestinal, respiratory and combination syndrome) and total number of days ill with any symptomatology were investigated. No statistical significance was found in these analyses except when contrasting children with normal hemoglobin levels to iron deficient children, where the findings indicated the normal children experienced more gastrointestinal morbidity. The same relationship were again analyzed but including delta hemoglobin as covariate in the analysis, this latter one was found to be significant at 7% when the percentage of days ill from gastrointestinal morbidity was tested against the hemoglobin groups. The relationship found indicates that, all other covariates accounted for, the percentage of days ill from gastrointestinal morbidity will decrease approximately 1% for each 1% increase in delta of hemoglobin. ^

Ozone and fine particulate matter association with CVD and COPD emergency room visits in Harris County, Texas: Spatiotemporal analysis

This study represents a secondary analysis of the merging of emergency room visits and daily ozone and PM2.5. Although the adverse health effects of ozone and fine particulate matter have been documented in the literature, evidence regarding the health risks of these two pollutants in Harris County, Texas, is limited. Harris County (Houston) has sufficiently unique characteristics that analysis of these relationships in this setting and with the ozone and industry issues in Houston is informative. The objective of this study was to investigate the association between the joint exposure to ozone and fine particulate matter, and emergency room diagnoses of chronic obstructive pulmonary disease and cardiovascular disease in Harris County, Texas, from 2004 to 2009, with zero and one day lags. ^ The study variables were daily emergency room visits for Harris County, Texas, from 2004 to 2009, temperature, relative humidity, east wind component, north wind component, ozone, and fine particulate matter. Information about each patient's age, race, and gender was also included. The two dichotomous outcomes were emergency room visits diagnoses for chronic obstructive pulmonary disease and cardiovascular disease. Estimates of ozone and PM2.5 were interpolated using kriging, in which estimates of the two pollutants were predicted from monitoring data for every case residence zip code for every day of the six years, over 3 million estimates (one of each pollutant for each case in the database). ^ Logistic regressions were conducted to estimate odds ratios of the two outcomes. Three analyses were conducted: one for all records, another for visits during the four months of April and September of 2005 and 2009, and a third one for visits from zip codes that are close to PM2.5 monitoring stations (east area of Harris County). The last two analyses were designed to investigate special temporal and spatial characteristics of the associations. ^ The dataset included all ER visits surveyed by Safety Net from 2004 to 2009, exceeding 3 million visits for all causes. There were 95,765 COPD and 96,596 CVD cases during this six year period. A 1-μg/m3 increase in PM2.5 on the same day was associated with a 1.0% increase in the odds of chronic obstructive pulmonary disease emergency room diagnoses, a 0.4% increase in the odds of cardiovascular disease emergency room diagnoses, and a 0.2% increase in the odds of cardiovascular disease emergency room diagnoses on the following day. A 1-ppb increase in ozone was associated with a 0.1% increase in the odds of chronic obstructive pulmonary disease emergency room diagnoses on the same day. These four percentages add up to 1.7% of ER visits. That is, over the period of six years, one unit increase for both ozone and PM2.5 (joint increase), resulted in about 55,286 (3,252,102 * 0.017) extra ER visits for CVD or COPD, or 9,214 extra ER visits per year. ^ After adjustment for age, race, gender, day of the week, temperature, relative humidity, east wind component, north wind component, and wind speed, there were statistically significant associations between emergency room chronic obstructive pulmonary disease diagnosis in Harris County, Texas, with joint exposure to ozone and fine particulate matter for the same day; and between emergency room cardiovascular disease diagnosis and exposure to PM2.5 of the same day and the previous day. ^ Despite the small association between the two air pollutants and the health outcomes, this study points to important findings. Namely, the need to identify reasons for the increase of CVD and COPD ER visits over the course of the project, the statistical association between humidity (or whatever other variables for which it may serve as a surrogate) and CVD and COPD cases, and the confirmatory finding that males and blacks have higher odds for the two outcomes, as consistent with other studies. ^ An important finding of this research suggests that the number and distribution of PM2.5 monitors in Harris County - although not evenly spaced geographically—are adequate to detect significant association between exposure and the two outcomes. In addition, this study points to other potential factors that contribute to the rising incidence rates of CVD and COPD ER visits in Harris County such as population increases, patient history, life style, and other pollutants. Finally, results of validation, using a subset of the data demonstrate the robustness of the models.^

The association between parity and selected structural birth defects

BACKGROUND: Parity is a risk factor in neonatal morbidity and mortality. This dissertation examined the association between first births and selected birth defects. The first aim was to assess the risk of 66 birth defects among first births and third or greater births. The second aim was to determine if maternal race, maternal age, infant sex or infant birth weight modify the association between first births and selected birth defects. METHODS: The Texas Birth Defects Registry provided data for 1999-2009. For the first aim, odds ratios were calculated for each birth defect. For the second aim, analysis was restricted to the ten birth defects significantly associated with first births. Stratified analyses were conducted and interaction terms were added to logistic regression models to assess whether differences in the odds ratios for the effect of first birth were statistically significant across strata. RESULTS: Findings for the first aim showed that first births had significantly increased odds of having an infant with 24 of the 66 birth defects. Third or greater births had significantly increased odds of having four of the 66 birth defects. For the second aim, a number of significant effect modifiers were observed. For patent ductus arteriosis, obstructive urinary defects and gastroschisis, the effect of first births was significantly modified by black or U.S.-born Hispanic mothers. The effect of first birth was also significantly modified among mothers ≥30 years for mitral valve insufficiency, atrial septal defect and congenital hip dislocation. The effect of first births was significantly modified among infants with low birth weight for hypospadias, congenital hip dislocation and gastroschisis. CONCLUSIONS: First births were associated with an elevated risk of 24 categories of birth defects. For some of the birth defects studied, the effect of first birth is modified by maternal age, maternal race and low birth weight. Knowledge of the increased risk for birth defects among women having their first birth allows physicians and midwives to provide better patient care and spur further research into the etiology of associated birth defects. This knowledge may bring about interventions prior to conception in populations most likely to conceive.^