A 56-year mortality follow-up of Texas petroleum refinery and chemical employees, 1948-2003.

OBJECTIVE: To further investigate the mortality risk of employees who worked in the petroleum refinery industry, we updated an earlier investigation by extending the mortality follow-up by an additional 14 years through 2003. METHODS: The cohort consisted of 10,621 employees with an average follow-up of 34 years. We used the standardized mortality ratio (SMR) adjusted for age, race, and calendar years as a measure of risk. RESULTS: Overall mortality (SMR=0.77, 95% confidence interval [CI], 0.74-0.79), all cancer mortality (SMR=0.87, 95% CI=0.82-0.93), and most cause-specific mortalities for the total study population were lower than or similar to that of the population of Harris County, Texas. This study did not show a significant increase in leukemia in the total population or in any of the subgroups. The only statistically significant excess of mortality found in this study was an increase in mesothelioma among maintenance employees; the SMR was 4.78 (95% CI=2.54-8.17) among employees who worked for a minimum of one year and was 7.51 (95% CI=3.75-13.45) among those with 10 or more years of employment and 20 or more years of latency. CONCLUSIONS: After more than half a century of follow-up, employees at this facility continue to show more favorable mortality outcomes than the general local population. Overall, no statistically significant increase of leukemia or of any of the specific cell types was found. The increased mesothelioma is likely related to past exposure to asbestos.

Illness absence patterns among employees in a petrochemical facility: impact of selected health risk factors.

BACKGROUND: Illness absence in a working population is a complex phenomenon and can be influenced by many factors, such as age, gender, and personal health risk factors. The current study used prospectively collected employee health risk and morbidity data to examine illness absence patterns for a working population and to quantify the impact of selected health risk factors on employee illness absence. METHODS: The study population consisted of 2550 regular employees working at a Texas petrochemical facility. Morbidity data were extracted from the company's Health Surveillance System, and records of absences were derived from personnel and payroll systems. The morbidity frequency rate and average duration of absence per employee per year were calculated by age, gender, and selected health risk factors, including smoking, body mass index, cholesterol, triglycerides, hypertension, and fasting glucose. RESULTS: Morbidity frequency rates and average duration of absence increased with age and with the presence of health risk factors. The absence frequency rate increased with an increase in the number of risk factors present from no risk factors (11.8 per 100 employees) to four or more risk factors (32.3 per 100 employees). The number of workdays lost also increased with the number of risk factors present, with the least number of workdays lost by employees with zero risk factors (4.1 day), followed by one (6.4 days), two (8.8 days), three (9.3 days), and four or more risk factors (12.6 days). CONCLUSIONS: The impact of employee health risk factors has been shown in this study to be associated with absence frequency and duration of absence. Reduction in employee health risk factors can be an effective means of improving employees' health and increasing a company's productivity.