Occupation and glioma: The Harris County Brain Tumor Study, 2001--2010

The relationship between occupational exposures and glioma has not been adequately assessed due to the lack of studies in current scientific literature. To address this disparity, the Harris County Brain Tumor Study, an ongoing population-based case-control study, began in January 2001. Longest-held occupation for 382 cases and 629 controls were frequency matched on age (within 5 years), sex, and race and placed into 14 predetermined occupational categories. Adjusted odds ratios and 95% confidence intervals were calculated for each category using multiple logistic regression. Potential confounders assessed included sex, age, smoking status, education and income. For all subjects, significantly elevated adjusted odds ratios were found in health-related (aOR=1.66; 95%CI=1.03, 2.68), teaching (aOR=1.84; 95%CI=1.17, 2.88), and protective service (aOR=3.6; 95%CI=1.05, 12.31) occupational categories after controlling for sex and education. A significantly lowered odds ratio was seen in the writers, artists, and entertainers category (aOR=0.14; 95%CI=0.03, 0.58). In the stratified analyses, which controlled for education, males had a significantly elevated odds ratio for protective service workers (aOR=4.83; 95%CI=1.24, 18.83) while a significantly lower odds ratio was found in mechanics and machine operators (aOR=0.33; 95%CI=0.12,0.87). In females, we observed a significantly elevated odds ratio in teachers (aOR=1.99; 95%CI=1.20,3.31) and a significantly lower odds ratio in clerical workers (aOR=0.63; 95%CI=0.45,0.90). These analyses revealed several significant associations and allowed for separate analyses by gender, distinguishing this study from many glioma studies. Further analyses should provide a large enough sample size to stratify by gender as well as histological subtype.^

HPV vaccine coverage in Texas counties: An application of multilevel, small area estimation

Health departments, research institutions, policy-makers, and healthcare providers are often interested in knowing the health status of their clients/constituents. Without the resources, financially or administratively, to go out into the community and conduct health assessments directly, these entities frequently rely on data from population-based surveys to supply the information they need. Unfortunately, these surveys are ill-equipped for the job due to sample size and privacy concerns. Small area estimation (SAE) techniques have excellent potential in such circumstances, but have been underutilized in public health due to lack of awareness and confidence in applying its methods. The goal of this research is to make model-based SAE accessible to a broad readership using clear, example-based learning. Specifically, we applied the principles of multilevel, unit-level SAE to describe the geographic distribution of HPV vaccine coverage among females aged 11-26 in Texas.^ Multilevel (3 level: individual, county, public health region) random-intercept logit models of HPV vaccination (receipt of ≥ 1 dose Gardasil® ) were fit to data from the 2008 Behavioral Risk Factor Surveillance System (outcome and level 1 covariates) and a number of secondary sources (group-level covariates). Sampling weights were scaled (level 1) or constructed (levels 2 & 3), and incorporated at every level. Using the regression coefficients (and standard errors) from the final models, I simulated 10,000 datasets for each regression coefficient from the normal distribution and applied them to the logit model to estimate HPV vaccine coverage in each county and respective demographic subgroup. For simplicity, I only provide coverage estimates (and 95% confidence intervals) for counties.^ County-level coverage among females aged 11-17 varied from 6.8-29.0%. For females aged 18-26, coverage varied from 1.9%-23.8%. Aggregated to the state level, these values translate to indirect state estimates of 15.5% and 11.4%, respectively; both of which fall within the confidence intervals for the direct estimates of HPV vaccine coverage in Texas (Females 11-17: 17.7%, 95% CI: 13.6, 21.9; Females 18-26: 12.0%, 95% CI: 6.2, 17.7).^ Small area estimation has great potential for informing policy, program development and evaluation, and the provision of health services. Harnessing the flexibility of multilevel, unit-level SAE to estimate HPV vaccine coverage among females aged 11-26 in Texas counties, I have provided (1) practical guidance on how to conceptualize and conduct modelbased SAE, (2) a robust framework that can be applied to other health outcomes or geographic levels of aggregation, and (3) HPV vaccine coverage data that may inform the development of health education programs, the provision of health services, the planning of additional research studies, and the creation of local health policies.^

A study of nurses' perceptions of and participation in the resolution of treatment dilemmas for critically ill newborns

This study was an exploratory investigation of variables which are associated with neonatal intensive care nurses' perceptions of and participation in life-sustaining treatment decisions for critically ill newborns. The primary purpose of the research was to examine the extent to which assessment of infants' physical and mental prognoses, parents' preferences regarding treatment, and legal consequences of non-treatment influence nurses' recommendations about life-saving treatment decisions for handicapped newborns. Secondly, the research explored the extent and nature of nurses' reported participation in the resolution of treatment dilemmas for these critically ill newborns. The framework of the study draws upon the work of Crane (1977), Blum (1980), and Pearlman (1982) who have explored the sociological context of decision-making with critical care patients.^ Participants in the study were a volunteer sample of eighty-three registered nurses who were currently working in neonatal intensive care units in five large urban hospitals in Texas. Data were collected through the use of intensive interviews and case study questionnaires. Results from the study indicate that physical and mental prognoses as well as parent preferences and concerns about legal liability are related to nurses' treatment recommendations, but their levels of significance vary according to the type of handicapping condition and whether the treatment questions are posed in terms of initiating aggressive therapy or withdrawing aggressive therapy.^ The majority of nurses reported that the extent of their participation in formal decision-making regarding handicapped newborns was fairly minimal although they provide much of the definitive data used to make decisions by physicians and parents. There was substantial evidence that nurse respondents perceive their primary role as advocates for critically ill newborns, and believe that their involvement in the resolution of treatment dilemmas should be increased. ^

Incidence of fatal gunshot injuries occurring to Galveston County residents between 1979--1981

Fatal gunshot injury deaths and their characteristics were ascertained for the population of Galveston County, Texas, for 1979-81. A total of 147 gunshot deaths occurring to residents of Galveston County were enumerated from death certificates, police and hospital records. Residents accounted for 96.1% of all gunshot deaths occurring in the county. The overall firearms death rate was 25 per 100,000 population. This ranked gunshot mortality as the third leading cause of injury death and the sixth leading cause of death from all causes. Gunshot deaths accounted for 10% of all years of life lost due to premature mortality.^ Firearms accounted for 73% of all homicide deaths. The median age of gunshot homicide victims was 27 years. Gunshot homicide mortality was highest among black males with a rate of 61 per 100,000. Rates of 23 per 100,000 and 12 per 100,000 were observed for Hispanic males and black females respectively. Gunshot homicide cases were characterized by use of "low quality" handguns (76.1%), circumstances involving a "relationship breakup" (38.1%), and alcohol consumption (79.6%). The place of occurrence of gunshot homicide was a residence in over half of all cases. The occupation most frequently associated was fishing and farming. Homicide was the primary motivation for 84% of the cases.^ The descriptive epidemiology of gunshot suicide differed from that of gunshot homicide. Firearms accounted for 64% of all suicide deaths. The median age of gunshot suicide victims was 41 years. Gunshot suicide mortality was highest among white males with a rate of 24 per 100,000. Rates of 14 per 100,000 and 9 per 100,000 were observed for black males and Hispanic females respectively. Gunshot suicide cases were characterized by use of "low quality" handguns (69.4%), circumstances involving a "relationship breakup" (39.1%) and alcohol consumption (63%). The place of occurrence was a residence in 80% of the cases. The occupation most frequently associated was police or security guard.^ Strategies for primary prevention are recommended. The research strategy, based on Haddon's model, is suggested for further investigations. ^

Assessment of cancer incidence in Titus County, Texas, 1977--1984

The purpose of this study was to determine the incidence of cancer in Titus County, Texas, through the identification of all cases of cancer that occurred in residents of the county during the period from 1977 to 1984. Data gathered from Texas Cancer Registry, hospital records, and death certificates were analyzed with regard to anatomic site, race, sex, age, city of residence, and place of birth. Adjustment of incidence rates by sex and race allowed comparisons with U.S. rates provided by the Surveillance, Epidemiology, and End Results Program (SEER).^ Seven hundred sixty-six (766) cancer cases were identified for the eight year period during 171,536 person-years of observation. In whites, statistically significant standardized incidence ratios (SIR) were found for leukemia (males SIR = 2.70 and females SIR = 2.26), melanoma (males SIR = 1.90 and females SIR = 2.25), lung (males SIR = 1.45) and for multiple myeloma (both sexes combined SIR = 1.86). In blacks, significant excess numbers of cases were found for Hodgkin's disease (males SIR = 8.33 and females SIR = 13.3) and for esophagus and bone considering both sexes together (SIR = 2.68 and 12.54, respectively). Rates for blacks were based on a small population and therefore unstable. A statistically significant excess number of cases for all sites combined was found in Mount Pleasant residents (age-adjusted incidence rate = 563.6 per 100,000 per year).^ A review of possible environmental risk factors in the area: hazardous waste disposal site, lignite deposits, and petrochemical and poultry industries are presented. A need for further epidemiological and environmental studies to identify etiological factors that could be responsible for the excess number of leukemia cases are recommended. For melanoma, a public health educational program to teach the population methods of protection from sun exposure is also suggested. ^

Factors related to employment among chronically mentally ill patients

A descriptive study of demographic and psychosocial factors believed to be associated with employment was carried out through face-to-face interviews with 417 chronically mentally-ill patients. Subjects had been hospitalized a minimum of two times for psychiatric treatment, had been discharged from at least one of these hospitalizations in the two years prior to the study, and were currently residing within a specific community mental health center catchment area in Texas. The study group ranged in age from 16 to 68 years and over one-half had chart diagnoses of schizophrenia.^ A structured interview was developed which addressed current employment status, length of current employment, job title of current or last job, and detailed work history for the prior five years. Four measures of social support were included in the interview. Each subject was asked to identify one recent work and one recent non-work situation which had been stressful or very demanding. A coping questionnaire was verbally administered to measure the ways in which subjects had coped with these specific stressful situations.^ Analysis of results revealed that 27 percent of the sample was gainfully employed at time of interview. Differences between the employed and unemployed groups were analyzed by t-test an chi square. The employed demonstrated significantly more weeks of employment in the prior five years than the unemployed. The current jobs of the employed required a significantly higher relationship to "things" or inanimate objects than the last jobs of the unemployed. Subjects diagnosed as schizophrenic were significantly less likely to be employed than subjects with other diagnoses.^ Employed subjects scored significantly higher on three of four measures of social support than unemployed subjects, including reported frequency of social group attendance and/or meetings with mental health professionals. Problem-focused coping was used significantly more by the employed than by the unemployed to deal with stressful situations in the work, but not the non-work, context. ^

Procedure for the identification of population characteristics for targeting intervention services on the basis of outcome-goal priorities: Case management services for the chronic mentally ill

Although the processes involved in rational patient targeting may be obvious for certain services, for others, both the appropriate sub-populations to receive services and the procedures to be used for their identification may be unclear. This project was designed to address several research questions which arise in the attempt to deliver appropriate services to specific populations. The related difficulties are particularly evident for those interventions about which findings regarding effectiveness are conflicting. When an intervention clearly is not beneficial (or is dangerous) to a large, diverse population, consensus regarding withholding the intervention from dissemination can easily be reached. When findings are ambiguous, however, conclusions may be impossible.^ When characteristics of patients likely to benefit from an intervention are not obvious, and when the intervention is not significantly invasive or dangerous, the strategy proposed herein may be used to identify specific characteristics of sub-populations which may benefit from the intervention. The identification of these populations may be used both in further informing decisions regarding distribution of the intervention and for purposes of planning implementation of the intervention by identifying specific target populations for service delivery.^ This project explores a method for identifying such sub-populations through the use of related datasets generated from clinical trials conducted to test the effectiveness of an intervention. The method is specified in detail and tested using the example intervention of case management for outpatient treatment of populations with chronic mental illness. These analyses were applied in order to identify any characteristics which distinguish specific sub-populations who are more likely to benefit from case management service, despite conflicting findings regarding its effectiveness for the aggregate population, as reported in the body of related research. However, in addition to a limited set of characteristics associated with benefit, the findings generated, a larger set of characteristics of patients likely to experience greater improvement without intervention. ^

Blood pressure and dietary factors in Mexican-Americans of Starr County, Texas

This study examined the cross-sectional associations between blood pressure, hypertension and dietary factors among 580 Mexican-American adults residing in Starr County, Texas. The data were collected as part of Gallbladder Disease Study between April, 1985 and December, 1986.^ Dietary intake was assessed for the month previous to the interview by means of a 38 food item quantified frequency questionnaire representing foods and mixed dishes commonly consumed in the community. From the dietary information intake of calcium, cholesterol, total kilocalories, and percent of kilocalories contributed by total fat, saturated fat, monounsaturated fatty acids, polyunsaturated fatty acids, protein, carbohydrates were calculated. The effect of other factors associated with blood pressure, such as age, body mass index, body fat distribution, smoking, and drinking were controlled.^ Age was the most important predictor of both systolic and diastolic blood pressure and hypertension. For both males and females, systolic and diastolic blood pressure levels were consistently positively associated with body mass index but were not associated with waist hip ratio. However, a strong positive relationship between hypertension and waist hip ratio but not body mass index was observed.^ After controlling for age and body mass index it was noted that for males there were no significant associations between the dietary variables and systolic blood pressure. For diastolic blood pressure there were significant associations with percent fat, percent monounsaturated fatty acids, percent protein and percent carbohydrates.^ For females, there were significant associations between systolic blood pressure and percent protein, percent carbohydrates and cholesterol. There were no significant associations between dietary variables and diastolic blood pressure.^ After controlling for age and waist hip ratio significant associations between hypertension and percent fat, percent saturated fat, percent monounsaturated fatty acids, percent carbohydrate and percent protein were observed in males. Significant associations between hypertension and percent polyunsaturated fatty acids and percent protein were noted in females. ^

A categorical data analysis approach to estimation of demographic characteristics for Texas county populations

The need for timely population data for health planning and Indicators of need has Increased the demand for population estimates. The data required to produce estimates is difficult to obtain and the process is time consuming. Estimation methods that require less effort and fewer data are needed. The structure preserving estimator (SPREE) is a promising technique not previously used to estimate county population characteristics. This study first uses traditional regression estimation techniques to produce estimates of county population totals. Then the structure preserving estimator, using the results produced in the first phase as constraints, is evaluated.^ Regression methods are among the most frequently used demographic methods for estimating populations. These methods use symptomatic indicators to predict population change. This research evaluates three regression methods to determine which will produce the best estimates based on the 1970 to 1980 indicators of population change. Strategies for stratifying data to improve the ability of the methods to predict change were tested. Difference-correlation using PMSA strata produced the equation which fit the data the best. Regression diagnostics were used to evaluate the residuals.^ The second phase of this study is to evaluate use of the structure preserving estimator in making estimates of population characteristics. The SPREE estimation approach uses existing data (the association structure) to establish the relationship between the variable of interest and the associated variable(s) at the county level. Marginals at the state level (the allocation structure) supply the current relationship between the variables. The full allocation structure model uses current estimates of county population totals to limit the magnitude of county estimates. The limited full allocation structure model has no constraints on county size. The 1970 county census age - gender population provides the association structure, the allocation structure is the 1980 state age - gender distribution.^ The full allocation model produces good estimates of the 1980 county age - gender populations. An unanticipated finding of this research is that the limited full allocation model produces estimates of county population totals that are superior to those produced by the regression methods. The full allocation model is used to produce estimates of 1986 county population characteristics. ^

Prevalence and trends of substance abuse in Harris County, Texas, 1989 to 1991

In the late 1980s, Harris County, Texas began experiencing an escalation of drug-related activities. Various indicators used in this analysis tracked drug-related trends from 1989 to 1991 to determine patterns for comparison of local (Houston/Harris County, Texas) to national levels.^ An important indicator of the drug scenario was drug-related activities among youths, which increased during the period of this study. The Harris County Juvenile Probation Department showed that among arrests for drug-related activities, felonies increased from 25% in 1988 to 53% in 1991. With the rise in drug-related crimes, and substance abuse among the student body, school districts were forced to institute drug education programs in an effort to curtail such activities.^ Law enforcement agencies in the county saw increased demands for their services as a result of drug activities. Harris County Sheriffs Department reported a 32% plus increase in drug-related charges between 1986 and 1991. Houston Police Department reported an increase of 109% for the same period.^ Data from the Harris County Medical Examiner, the National Institute of Justice's Drug Use Forecasting System (Houston), and drug treatment facilities around Houston/Harris County, Texas indicated similar drug usage trends. Over a four-year period (1988-91), the drugs most frequently detected during blood and urine analyses were cocaine, followed by marijuana, heroin, LSD, and methamphetamines.^ From 1988 to 1991, most drug rehabilitation organizations experienced increased demands for their services by approximately 35%. Several other organizations experienced as much as a 70 percent increase. Males accounted for roughly 70% and females about 30% of persons seeking treatment. However, the number of females pursuing treatment increased, thereby reducing the gender gap.^ Blacks in Houston/Harris County were at higher risk for drug usage among the general population, but sought treatment more readily than other ethnic groups. Whites sought treatment in similar numbers as Blacks, but overall the risk appeared smaller because they made up a larger portion of the Houston/Harris County population.^ This analysis concluded that drug trends for the Houston/Harris County, Texas did not follow national trends, but showed patterns of its own. It was recommended that other communities carry out similar studies to determine drug use trends particular to their local. ^

Hispanic incorporation and access to health care in Houston and Harris County, Texas: Adopting an Hispanic perspective to the Aday and Andersen model

This study examines Hispanic levels of incorporation and access to health care. Applying the Aday and Andersen framework for the study of access, the study examined the relationship between two levels of Hispanic incorporation into U.S. society, i.e., mainstream versus ethnic, and potential and realized measures of access to health care. Data for the study were drawn from a 1992 telephone survey of 600 randomly selected Hispanics in Houston and Harris County.^ The hypotheses tested were: (1) Hispanics who are incorporated into mainstream society are more likely to have better potential and realized access to health care than those who are incorporated into ethnic-group enclaves regardless of their socioeconomic status (SES), health status and health needs, and (2) there is no interaction between the levels of incorporation (mainstream or ethnic) and SES, health status, and health needs in predicting potential and realized access.^ The data analysis supported Hypothesis One for the two measures of potential access. The results of bivariate and multiple logistic regression analyses indicated that for Hispanics in Houston and Harris County, being in the "mainstream" incorporation category increased their potential access to care, having "health insurance" and a "regular place of care". For the selected measure of realized access, having a "regular check-up", the analysis did not demonstrate statistically significant differences in having a regular check-up among Hispanics incorporated in the ethnic or mainstream incorporation categories.^ Hypothesis Two, that there is no interaction between the levels of incorporation and socioeconomic characteristics, health status, and health needs in predicting potential and realized access among Hispanics was supported by the data. The results of the logistic regression analysis showed that, after adjusting for socioeconomic status, health status, and health needs, the association between "level of incorporation" and the two measures of potential access ("health insurance" and having a "usual place of care") was not modified by the control variables nor by their interaction with level of incorporation. That is, the effect of incorporation on Hispanics' health insurance coverage, and having a usual place of care, was homogenous across Hispanics with different SES and health status.^ The main research implication of this dissertation is the employment of a theoretical framework for the assessment of cultural factors essential to research on migrating heterogeneous subpopulations. It also provided strategies to solve practical and methodological difficulties in the secondary analyses of data on these populations. ^

The use of invasive myocardial revascularization procedures following myocardial infarction and the effectiveness of these procedures in the biethnic community of Nueces County, Texas, 1988--1991

High levels of poverty and unemployment, and low levels of health insurance coverage may pose barriers to obtaining cardiac care by Mexican Americans. We undertook this study to investigate differences in the use of invasive myocardial revascularization procedures received within the 4-month period following hospitalization for a myocardial infarction (MI) between Mexican Americans and non-Hispanic whites in the Corpus Christi Heart Project (CCHP). The CCHP is a population-based surveillance program for hospitalized MI, percutaneous transluminal coronary angioplasty (PTCA), and aortocoronary bypass surgery (ACBS). Medical record data were available for 1706 patients identified over a three-year period. Mexican Americans had significantly lower rates of receiving a PTCA following MI than non-Hispanic Whites (RR: 0.56, 95% CI: 0.44-0.70). No meaningful ethnic difference was seen in the rates of ACBS use. History of PTCA use appeared to interact with ethnicity. Among patients without a history of PTCA use, Mexican Americans were less likely to receive a PTCA than non-Hispanic whites (RR: 0.59; 95% CI: 0.46-0.76). Among patients with a history of PTCA use, however, Mexican Americans were more likely to receive a PTCA than non-Hispanic whites (RR: 1.47; 95% CI: 0.75-2.87).^ Differences in the effectiveness of a first-time PTCA and first-time ACBS between Mexican Americans and non-Hispanic whites in the CCHP were also investigated. Mexican Americans were more likely to receive a 2nd PTCA (RR: 1.56, 95% CI: 1.11-2.17) and suffer a subsequent MI (RR: 1.42, 95% CI: 1.03-1.96) following a first-time PTCA than non-Hispanic whites. No meaningful ethnic differences were found in the rates of death and rates of ACBS following a first-time PTCA. Also, no significant ethnic differences were found in the rates of any of the events following a first-time ACBS. After adjusting for potential demographic, socioeconomic, clinical and angiographic confounders using Cox regression analysis, Mexican Americans were still more likely to receive a 2nd PTCA (HR: 1.38; 95% CI: 0.99-1.93) following a first-time PTCA than non-Hispanic whites. A significant difference in the rates of a subsequent MI following a first-time PTCA persisted (HR: 1.39, 95% CI: 1.01-1.93). (Abstract shortened by UMI.) ^

Macular edema in Hispanics with non-insulin dependent diabetes mellitus in Starr County, Texas: Prevalence, incidence and risk factors

This project is based on secondary analyses of data collected in Starr County, Texas from 1981 till 1991 to determine the prevalence, incidence and risk factors for macular edema in Hispanics with non-insulin-dependent diabetes in Starr County, Texas. Two studies were conducted. The first study examined the prevalence of macular edema in this population. Of the 310 diabetics that were included in the study 22 had macular edema. Of these 22 individuals 9 had clinically significant macular edema. Fasting blood glucose was found to be significantly associated with macular edema. For each 10 mg/dl increase in fasting blood glucose there was a 1.07 probability of an increase in the risk of having macular edema. Individuals with fasting blood glucose $\ge$200 mg/dl were found to be more than three times at risk of having macular edema compared to those with fasting blood glucose $<$200 mg/dl.^ In the second study the incidence and the risk factors that could cause macular edema in this Hispanic population were examined. 240 Hispanics with non-insulin-dependent diabetes mellitus and without macular edema were followed for 1223 person-years. During the follow-up period 27 individuals developed macular edema (2.21/100 person-years). High fasting blood glucose and glycosylated hemoglobin were found to be strong and independent risk factors for macular edema. Participants taking insulin were 3.9 times more at risk of developing macular edema compared to those not taking insulin. Systolic blood pressure was significantly related to macular edema, where each 10 mmHg increase in systolic blood pressure was associated with a 1.3 increase in the risk of macular edema.^ In summary, this study suggests that hyperglycemia is the main underlying factor for retinal pathological changes in this diabetic population, and that macular edema probably is not the result of sudden change in the blood glucose level. It also determined that changes in blood pressure, particularly systolic blood pressure, could trigger the development of macular edema.^ Based on the prevalence reported in this study, it is estimated that 35,500 Hispanic diabetics in the US have macular edema. This imposes a major public health challenge particularly in areas with high concentration of Mexican Americans. It also highlights the importance of public health measures directed to Mexican Americans such as health education, improved access to medical care, and periodic and careful ophthalmologic examination by ophthalmologists knowledgeable and experienced in the management of diabetic macular edema. ^

A GENETIC MARKER STUDY OF NON - INSULIN DEPENDENT DIABETICS IN THE MEXICAN-AMERICAN COMMUNITY FROM STARR COUNTY, TEXAS (PLASMA GLUCOSE, HEMOGLOBIN ANALYSIS)

Diabetes mellitus occurs in two forms, insulin-dependent (IDDM, formerly called juvenile type) and non-insulin dependent (NIDDM, formerly called adult type). Prevalence figures from around the world for NIDDM, show that all societies and all races are affected; although uncommon in some populations (.4%), it is common (10%) or very common (40%) in others (Tables 1 and 2).^ In Mexican-Americans in particular, the prevalence rates (7-10%) are intermediate to those in Caucasians (1-2%) and Amerindians (35%). Information about the distribution of the disease and identification of high risk groups for developing glucose intolerance or its vascular manifestations by the study of genetic markers will help to clarify and solve some of the problems from the public health and the genetic point of view.^ This research was designed to examine two general areas in relation to NIDDM. The first aims to determine the prevalence of polymorphic genetic markers in two groups distinguished by the presence or absence of diabetes and to observe if there are any genetic marker-disease association (univariate analysis using two by two tables and logistic regression to study the individual and joint effects of the different variables). The second deals with the effect of genetic differences on the variation in fasting plasma glucose and percent glycosylated hemoglobin (HbAl) (analysis of Covariance for each marker, using age and sex as covariates).^ The results from the first analysis were not statistically significant at the corrected p value of 0.003 given the number of tests that were performed. From the analysis of covariance of all the markers studied, only Duffy and Phosphoglucomutase were statistically significant but poor predictors, given that the amount they explain in terms of variation in glycosylated hemoglobin is very small.^ Trying to determine the polygenic component of chronic disease is not an easy task. This study confirms the fact that a larger and random or representative sample is needed to be able to detect differences in the prevalence of a marker for association studies and in the genetic contribution to the variation in glucose and glycosylated hemoglobin. The importance that ethnic homogeneity in the groups studied and standardization in the methodology will have on the results has been stressed. ^