PRETERM BIRTH AND OCCUPATIONAL PHYSICAL ACTIVITY: A CASE-CONTROL STUDY OF THE RELATIONSHIP BETWEEN LENGTH OF GESTATION AND THE PHYSICAL DEMAND OF U.S. ARMY MILITARY OCCUPATIONAL SPECIALTIES (UNITED STATES)

A case-control study has been conducted examining the relationship between preterm birth and occupational physical activity among U.S. Army enlisted gravidas from 1981 to 1984. The study includes 604 cases (37 or less weeks gestation) and 6,070 controls (greater than 37 weeks gestation) treated at U.S. Army medical treatment facilities worldwide. Occupational physical activity was measured using existing physical demand ratings of military occupational specialties.^ A statistically significant trend of preterm birth with increasing physical demand level was found (p = 0.0056). The relative risk point estimates for the two highest physical demand categories were statistically significant, RR's = 1.69 (p = 0.02) and 1.75 (p = 0.01), respectively. Six of eleven additional variables were also statistically significant predictors of preterm birth: age (less than 20), race (non-white), marital status (single, never married), paygrade (E1 - E3), length of military service (less than 2 years), and aptitude score (less than 100).^ Multivariate analyses using the logistic model resulted in three statistically significant risk factors for preterm birth: occupational physical demand; lower paygrade; and non-white race. Controlling for race and paygrade, the two highest physical demand categories were again statistically significant with relative risk point estimates of 1.56 and 1.70, respectively. The population attributable risk for military occupational physical demand was 26%, adjusted for paygrade and race; 17.5% of the preterm births were attributable to the two highest physical demand categories. ^

AN EPIDEMIOLOGIC DESCRIPTION AND ANALYSIS OF LOST WORKDAY OCCUPATIONAL BURN INJURIES

Background research consisted of a hospital case series of all adult burn patients (n = 162) admitted to John Sealy Hospital's burn unit from January 1978 to June 1979. Comparisons between occupationally and nonoccupationally burned adults demonstrated that occupationally burned adults were significantly more likely to have been active in the burn injury event and to have changed jobs during the prior year. They were significantly less likely to have physical or mental problems which contributed to sustaining the burn injury. Comparisons between occupational and nonoccupational burn injury events concluded that occupational burn injury events were significantly more likely to involve multiple sources of energy, sparks as the source of ignition and gases as the source of combustion. Other salient characteristics of occupational burn injuries indicated that subsequent research should focus upon lost workday occupational burns and other injuries sustained by blue-collar petrochemical workers employed in Galveston County, Texas.^ Subsequent research consisted of a historical cohort study of occupational injuries sustained in 1979 by a cohort of blue-collar petrochemical workers (n = 1771) who belonged to O.C.A.W. Local 4-449 in Texas City, Texas. Specific cohort injury rates included 15.08 occupational injuries per 100 person work-years, 11.98 lost workday occupational injuries per 100 person work-years, and 1.64 lost workday occupational burn injuries per 100 person work-years. Salient results from this study indicate that burn injuries are a very important type (in terms of both frequency and severity) of occupational injury sustained by blue-collar petrochemical workers, pipefitters are at greatest risk of lost workday injuries and lost workday burn injuries, company-specific experiences are comparable for lost workday occupational injuries, differences among company-specific nonlost workday occupational injury experiences may not be "safety-related", and minimal job-specific experience may not place employees at greater risk of lost workday burn injuries.^

OCCUPATIONAL CAUSES OF LUNG CANCER IN NEW MEXICO'S ANGLOS AND HISPANICS

Although, elevated risk for lung cancer has been associated with certain industries and occupations in previous studies, the lack of cigarette smoking information in many of these investigations resulted in estimates that could not be adjusted for the effects of smoking. To determine lung cancer risk due to occupation and smoking, for New Mexico's Anglos and Hispanics, a population-based case-control study was conducted. Incident cases diagnosed 1980-1982, and controls from the general population, were interviewed for lifetime occupational and smoking histories. Specific high risk industries and occupations were identified in advance and linked with industrial and occupational codes for hypotheses-testings. Significantly elevated risks were found for welders (RR = 3.5) and underground miners (RR = 2.0) with adjustment for smoking. Because shipbuilding was the industry of employment for only five of the 18 cases who were welders, exposures other than asbestos could be causal agents. Among the underground for only five of the 18 cases who were welders, exposures other than asbestos could be causal agents. Among the underground miners, uranium, copper, lead and zinc, coal, and potash mining industries were represented. Low prevalence of employment in some of the industries and occupations of interest resulted in inconclusive results. ^

REGRESSION ANALYSIS FOR STANDARDIZED MORTALITY RATIOS WITH APPLICATION TO OCCUPATIONAL FOLLOW-UP STUDIES

Traditional comparison of standardized mortality ratios (SMRs) can be misleading if the age-specific mortality ratios are not homogeneous. For this reason, a regression model has been developed which incorporates the mortality ratio as a function of age. This model is then applied to mortality data from an occupational cohort study. The nature of the occupational data necessitates the investigation of mortality ratios which increase with age. These occupational data are used primarily to illustrate and develop the statistical methodology.^ The age-specific mortality ratio (MR) for the covariates of interest can be written as MR(,ij...m) = ((mu)(,ij...m)/(theta)(,ij...m)) = r(.)exp (Z('')(,ij...m)(beta)) where (mu)(,ij...m) and (theta)(,ij...m) denote the force of mortality in the study and chosen standard populations in the ij...m('th) stratum, respectively, r is the intercept, Z(,ij...m) is the vector of covariables associated with the i('th) age interval, and (beta) is a vector of regression coefficients associated with these covariables. A Newton-Raphson iterative procedure has been used for determining the maximum likelihood estimates of the regression coefficients.^ This model provides a statistical method for a logical and easily interpretable explanation of an occupational cohort mortality experience. Since it gives a reasonable fit to the mortality data, it can also be concluded that the model is fairly realistic. The traditional statistical method for the analysis of occupational cohort mortality data is to present a summary index such as the SMR under the assumption of constant (homogeneous) age-specific mortality ratios. Since the mortality ratios for occupational groups usually increase with age, the homogeneity assumption of the age-specific mortality ratios is often untenable. The traditional method of comparing SMRs under the homogeneity assumption is a special case of this model, without age as a covariate.^ This model also provides a statistical technique to evaluate the relative risk between two SMRs or a dose-response relationship among several SMRs. The model presented has application in the medical, demographic and epidemiologic areas. The methods developed in this thesis are suitable for future analyses of mortality or morbidity data when the age-specific mortality/morbidity experience is a function of age or when there is an interaction effect between confounding variables needs to be evaluated. ^

Occupational injuries among day laborers in Houston

Research has indicated that day laborers engage in higher risk occupations and suffer a high number of occupationally related fatal and non-fatal injuries. Although there have been some studies focusing on immigrant workers and their occupational injuries, none to our knowledge has studied Houston’s day laborers. An exploratory study of Houston’s day laborer population was conducted in 2008 by Dr. Fernández-Esquer from the University of Texas. ^ The aims of the current study are to analyze secondary data from this parent study and describe the prevalence of the self reported occupational injuries among Houston immigrant day laborers seeking work during the months of October through December 2008. The study also aims to determine if the reported injuries varied by age group, education level, length of time living in the U.S. and length of time working as day laborers and describe if injuries were more common by the number of different job types or job conditions reported or the use of personal protective equipment used (PPE). ^ This study analyzed 325 questionnaires that included job-related information from the parent study. One hundred and nine workers (35 %) reported an occupational injury or illness in the year before the interview. The most frequent injuries or illnesses reported were falls (26.7 %), cuts and lacerations (23.3 %) and being struck by an object (18.3 %). Over half of the workers (57 %) reported working 4 to 6 different jobs in the year before the interview, followed by 22.5 % reporting 1 to 3 different jobs. A combined 79 % of day laborers in Houston reported exposure to 7 or more of the job conditions listed and 69 % of those workers also reported an injury or illness. PPE use varied from 44 % of workers reporting using 4 to 6 PPE items to 6.8 % reporting not using any type of PPE. Thirty two percent of workers reporting not using any PPE also reported an injury or illness. ^ Injuries were found not to have varied significantly by age group, time living in the US, time working as a day laborer, numbers of different job types and the number of PPE used. Injuries did vary significantly by education level of the participants and the number of different job conditions reported (education, X2 (4, N = 315) = 12.651, p =0.013; and job conditions, X2 (3, N = 319) = 14.698, p = 0.002). ^ Although this first study of Houston’s day laborers was successful at engaging the population and getting background information regarding the occupational health of these workers, more studies are needed to further characterize the day laborers occupational experiences and injuries along with determining what specific job types and job conditions were present when injuries occurred and what kind of PPE was being used at the time. It is also clear that these workers need better safety training programs regarding working in potentially dangerous jobs and job conditions. They would also benefit from programs that would help empower them to negotiate for safer conditions.^

An assessment of the relative influence of a vapor recovery system in reducing occupational exposure to volatile organic compounds in high performance liquid chromatography

Occupational exposures to organic solvents, specifically acetonitrile and methanol, have the potential to cause serious long-term health effects. In the laboratory, these solvents are used extensively in protocols involving the use of high performance liquid chromatography (HPLC). Operators of HPLC equipment may be potentially exposed to these organic solvents when local exhaust ventilation is not employed properly or is not available, which can be the case in many settings. The objective of this research was to characterize the various sites of vapor release in the HPLC process and then to determine the relative influence of a novel vapor recovery system on the overall exposure to laboratory personnel. The effectiveness of steps to reduce environmental solvent vapor concentrations was assessed by measuring exposure levels of acetonitrile and methanol before and after installation of the vapor recovery system. With respect to acetonitrile, the concentration was not statistically significant with p=0.938; moreover, exposure after the intervention was actually higher than prior to intervention. With respect to methanol, the concentration was not statistically significant with p=0.278. This indicates that the exposure to methanol after the intervention was not statistically significantly higher or lower than prior to intervention. Thus, installation of the vapor recovery device did not result in statistically significant reduction in exposures in the settings encountered, and acetonitrile actually increased significantly.^

Survey analysis on dental infection control & occupational safety from India---1999 & 2010

The objective was to study knowledge, attitudes, practice (KAP) and needs regarding infection control measures using two cross-sectional surveys from 1999 and 2010 conducted in India. Both data collection instruments had only about 35 comparable variables in common. In 1999, there were 456 respondents (dentists) who completed a self-administered survey instrument compared to 272 respondents in 2010. Both the 1999 and 2010 samples were mutually independent with no overlap, had regional differences, and therefore, were not completely comparable for changes in KAP over time. While almost all respondents from both surveys felt that education in dental safety was needed and wanted mandatory dental safety curriculum in dental schools, severe inadequacies in dental safety knowledge, protection against immunizable diseases, and practice of universal precaution were noted. Data from the study demonstrated that there is a substantial opportunity to improve the knowledge, attitude and practice of dental infection control and occupational safety in India. Few respondents (27%) reported that the infectious disease status of a patient is always known and a significant number reported that they had the right to refuse care for patients of known infectious disease status. This indicates that Stigma in treating HIV/AIDS patients remains a concern, which in turn suggests that a stronger focus on educating dentists about dental safety and on stigma and infectious disease is needed. Information obtained from this study could be utilized for developing policies oriented towards increasing dental safety educational efforts, in both dental schools as curriculum, and for practicing dentists through professional updates or continuing dental education.^

Prevalence of symptoms of neurotoxicity and potential occupational pesticide and solvent exposures among high school students in Starr County, Texas: A pilot study

Numerous harmful occupational exposures affect working teens in the United States. Teens working in agriculture and other heavy-labor industries may be at risk for occupational exposures to pesticides and solvents. The neurotoxicity of pesticides and solvents at high doses is well-known; however, the long term effects of these substances at low doses on occupationally exposed adolescents have not been well-studied. To address this research gap, a secondary analysis of cross-sectional data was completed in order to estimate the prevalence of self-reported symptoms of neurotoxicity among a cohort of high school students from Starr County, Texas, a rural area along the Texas-Mexico border. Multivariable linear regression was used to estimate the association between work status (i.e., no work, farm work, and non-farm work) and symptoms of neurotoxicity, while controlling for age, gender, Spanish speaking preference, inhalant use, tobacco use, and alcohol use. The sample included 1,208 students. Of these, the majority (85.84%) did not report having worked during the prior nine months compared to 4.80% who did only farm work, 6.21% who did only non-farm work, and 3.15% who did both types of work. On average, students reported 3.26 symptoms with a range from 0-16. The most commonly endorsed items across work status were those related to memory impairment. Adolescents employed in non-farm work jobs reported more neurotoxicity symptoms than those who reported that they did not work (Mean 4.31; SD 3.97). In the adjusted multivariable regression model, adolescents reporting non-farm work status reported an average of 0.77 more neurotoxicity symptoms on the Q16 than those who did not work (P = 0.031). The confounding variables included in the final model were all found to be factors significantly associated with report of neurotoxicity symptoms. Future research should examine the relationship between these variables and self-report of symptoms of neurotoxicity.^

Use of a modified delphi process for establishing occupational exposure limits in support of health surveillance for space travelers

On-orbit exposures can come from numerous factors related to the space environment as evidenced by almost 50 years of environmental samples collected for water analysis, air analysis, radiation analysis, and physiologic parameters. For astronauts and spaceflight participants the occupational exposures can be very different from those experienced by workers performing similar tasks in workplaces on Earth, because the duration of the exposure could be continuous for very long orbital, and eventually interplanetary, missions. The establishment of long-term exposure standards is vital to controlling the quality of the spacecraft environment over long periods. NASA often needs to update and revise its prior exposure standards (Spacecrafts Maximum Allowable Concentrations (SMACs)). Traditional standards-setting processes are often lengthy, so a more rapid method to review and establish standards would be a substantial advancement in this area. This project investigates use of the Delphi method for this purpose. ^ In order to achieve the objectives of this study a modified Delphi methodology was tested in three trials executed by doctoral students and a panel of experts in disciplines related to occupational safety and health. During each test/trial modifications were made to the methodology. Prior to submission of the Delphi Questionnaire to the panel of experts a pilot study/trial was conducted using five doctoral students with the goals of testing and adjusting the Delphi questionnaire to improve comprehension, work out any procedural issues and evaluate the effectiveness of the questionnaire in drawing the desired responses. The remainder of the study consisted of two trials of the Modified Delphi process using 6 chemicals that currently have the potential of causing occupational exposures to NASA astronauts or spaceflight participants. To assist in setting Occupational Exposure Limits (OEL), the expert panel was established consisting of experts from academia, government and industry. Evidence was collected and used to create close-ended questionnaires which were submitted to the Delphi panel of experts for the establishment of OEL values for three chemicals from the list of six originally selected (trial 1). Once the first Delphi trial was completed, adjustments were made to the Delphi questionnaires and the process above was repeated with the remaining 3 chemicals (trial 2). ^ Results indicate that experience in occupational safety and health and with OEL methodologies can have a positive effect in minimizing the time experts take in completing this process. Based on the results of the questionnaires and comparison of the results with the SMAC already established by NASA, we conclude that use of the Delphi methodology is appropriate for use in the decision-making process for the selection of OELs.^

Occupational health and safety among commercial sex workers in Ghana

The topic of occupational health and safety (OHS) has been investigated for many years and continues to be a concept often researched today. Generally speaking OHS research has been centered around food safety, construction safety, transportation safety, fire safety, drug and alcohol testing, health and medical management, and industrial hygiene to name a few. However, the concept of OHS concerning female commercial sex workers (FCSWs) has rarely been investigated, often neglected, seldom discussed and is lacking in sound research. Although regarded as the "oldest profession", commercial sex work (CSW) has consistently been ignored, disregarded and under-researched due to the illegality and stigmatization of prostitution. This paper reviews occupational safety and health issues faced by FCSWs in Tema and Accra, Ghana, through in-depth interviews, visits to women's homes, field work, informal conversations and participant observations with FCSWs over a period of two months. Facets of OHS that emerged among FCSWs included sexually transmissible infections, risks associated with harassment and violence from police and clients, alcohol and drug use, irregular hospital visits and/or lack of hospital visits, immigration issues, legal and policing risks. We argue that CSW be viewed as an occupation in great need of interventions to reduce workplace risks and improve the health and safety of FCSWs^