A retrospective cohort study of shift work and risk of cancer-specific mortality in German male chemical workers.

OBJECTIVES: Human evidence of carcinogenicity concerning shift work is inconsistent. In a previous study, we observed no elevated risk of total mortality in shift workers followed up until the end of 2006. The present study aimed to investigate cancer-specific mortality, relative to shift work. METHODS: The cohort consisted of male production workers (14,038 shift work and 17,105 day work), employed at BASF Ludwigshafen for at least 1 year between 1995 and 2005. Vital status was followed from 2000 to 2009. Cause-specific mortality was obtained from death certificates. Exposure to shift work was measured both as a dichotomous and continuous variable. While lifetime job history was not available, job duration in the company was derived from personal data, which was then categorized at the quartiles. Cox proportional hazard model was used to adjust for potential confounders, in which job duration was treated as a time-dependent covariate. RESULTS: Between 2000 and 2009, there were 513 and 549 deaths among rotating shift and day work employees, respectively. Risks of total and cancer-specific mortalities were marginally lower among shift workers when taking age at entry and job level into consideration and were statistically significantly lower when cigarette smoking, alcohol intake, job duration, and chronic disease prevalence at entry to follow-up were included as explanatory factors. With respect to mortality risks in relation to exposure duration, no increased risks were found in any of the exposure groups after full adjustment and there was no apparent trend suggesting an exposure-response relation with duration of shift work. CONCLUSIONS: The present analysis extends and confirms our previous finding of no excess risk of mortality associated with work in the shift system employed at BASF Ludwigshafen. More specifically, there is also no indication of an increased risk of mortality due to cancer.

Urinary creatinine concentrations in an industrial workforce and comparison with reference values of the general population.

PURPOSE: Urinary creatinine is an important parameter for the adjustment of metabolite concentrations in differently diluted urine specimens, as a reference dimension for biological limit or guidance values and as a selection criterion for spot urine samples in human biomonitoring. While the creatinine output of the general population has been well described in environmental surveys, this study focused specifically on creatinine concentrations in a large industrial workforce in order to compare these data with the general population and to provide a database for the calculation of a reasonable conversion factor between volume-related and creatinine-adjusted data and vice versa. METHODS: Urinary creatinine was analysed in 6,438 spot urine samples by a photometric assay in the time period between 1989 and 2009. Basic demographic data (age, sex, body weight, body height) and job category (apprentices, skilled craftsmen, skilled chemical workers, foremen, laboratory staff and executives) were considered in a statistical analysis. RESULTS: The median concentration of urinary creatinine in all urine samples was 1.36 g/L with male employees showing significantly higher values (1.37 g/L, n = 6,148 samples) than female employees (1.00 g/L, n = 290) and concentrations ranging from 0.01 up to 9.76 g/L. Age, body mass index and job category were significant influence factors on urinary creatinine. About 92 % of all samples showed creatinine concentrations between 0.3 and 3.0 g/L, a range recommended by the World Health Organization as a criterion for valid spot urine samples. DISCUSSION: The results of this study correspond well with data from environmental surveys and with recent data from an active workforce in industry with similar sampling strategies. Therefore, a median of 1.4 g creatinine per litre urine seems to be a reasonable value for general calculations and adjustments. The study data also support the validity of the current recommendations by the WHO and several scientific committees and institutions with respect to creatinine limits in spot urine samples for occupational-medical biomonitoring.

Medical program for shift workers--impacts on chronic disease and mortality outcomes.

OBJECTIVE: In 1983, global chemical company BASF SE implemented a supplemental health protection program to help its employees cope with the stressors associated with shift work. The program included comprehensive medical examinations and health promotion activities targeted at shift workers. METHODS: To assess the possible long-term health impacts of the program, cohorts of 14,128 male rotating shift and 17,218 male day wage employees were established via electronic job history searches. Health examination and mortality records were linked to job histories and studied over an 11-year period. RESULTS: Between 1996 and 2006, there were 414 and 463 deaths among rotating shift and day work employees, respectively. Mortality risks were marginally lower among shift working employees when taking age and job level into consideration, and remained so when cigarette smoking, alcohol intake, and existing chronic disease conditions were included as explanatory factors. The incidence of obesity, diabetes, and diseases of the circulatory and digestive system, as diagnosed or reported during health examinations, was higher among shift work employees, possibly as a consequence of enhanced medical surveillance or a direct effect of shift work. CONCLUSION: Incorporation of extensive occupational medical examinations, health seminars, and other intervention programs may help mitigate the long-term health consequences of shift work.

Health and safety protection for chemical industry employees in a rotating shift system: program design and acute injury and illness experience at work.

OBJECTIVES: To describe a comprehensive health protection program for rotating shift employees and evaluate the program effectiveness in injury and illness prevention. METHODS: For 14,128 shift and 17,218 day wage employees, occupational medical records were linked to job assignment records and studied over an 11-year period. RESULTS: Between 1995 and 2005, initiatives directed to shift employees contributed to their 59% and 100% greater participation in medical examinations and health seminar days, respectively, compared to day wage employees. Injury rates declined over time and with increasing employee age and were not elevated among rotating shift compared to day wage employees. Clinic visit rates for acute illnesses were generally higher for day than shift work employees. CONCLUSION: Coupling of active medical monitoring with additional health and safety initiatives appears to mitigate the expected adverse physiological and psychosocial stresses of shift work.

Pregnancy protection program in a large chemical company: design and initial survey results.

OBJECTIVES: To describe the BASF pregnancy protection program and provide initial results regarding selected pregnancy outcomes. METHODS: Pregnancies (n=1148) occurring between 1997 and 2002 were identified and outcomes were documented by questionnaires administered after the pregnancy announcement, end of pregnancy, and one year later. Potential maternal exposures were assessed via job histories, workplace inspections, and questionnaire. RESULTS: Participation was 90% overall and was consistently high across employee subgroups. Pregnancy losses (11.5%) did not differ significantly by type of work. Among pregnancy symptoms vaginal bleeding was weakly associated with two exposure measures. Preterm births (8.7%) were in agreement with general population norms and did not vary by maternal exposure category. CONCLUSIONS: High participation rates and a structured approach to employee education and documentation of reproductive outcomes may be of value in addressing reproductive health issues in the workplace.

Pregnancy protection program in a large chemical company: infant outcomes.

OBJECTIVES: The purpose of this study was to investigate reproductive outcomes in infants relative to maternal exposures in the chemical industry. METHODS: Via questionnaires administered after the pregnancy announcement, end of pregnancy, and 1 year later, infant outcomes were documented for 1147 live births. Maternal exposure factors were evaluated relative to birth height and weight, sex ratio, Apgar score at 5 minutes, and major malformations. RESULTS: Birth height and weight, sex ratio, and Apgar score did not differ by maternal work area or chemical hazard categories. Major malformations (3.1%) and organ-specific anomalies were consistent with the experience of a regional birth defects registry. Rates of malformation were marginally higher in infants born to women assigned to chemical versus office jobs. CONCLUSIONS: Infant outcomes to date have been consistent with comparable findings from population-based studies. Longer-term observation will be needed to assess trends for low-frequency outcomes and more specific maternal exposures.

Epidemiological and clinical investigations among employees in a former herbicide production process.

OBJECTIVES: To evaluate cancer incidence among employees assigned to a benzothiadiazin herbicide production facility between 1974 and 1984. METHODS: Retrospective cohort study including 185 employees who had worked at least 3 months in the facility. Cancers were identified by review of occupational medical records and interview. Standardized incidence ratios (SIRs) were computed using comparison data provided by the Saarland Cancer Registry. Separately, a medical examination including sonography of the prostate and thyroid and PSA testing was offered to all cohort members including retirees. RESULTS: Between 1975 and 2002, 12 cancers were observed compared with 10.3 expected cases (SIR 1.2; 95% confidence interval 0.6-2.0). Cancer types (including two prostate, two colon and one rectal cancer) were distributed unremarkably with no clustering of rare cancers. Medical screening and subsequent specialist referrals led to detection of three prostate cancers among 117 participants in the screening examination. CONCLUSIONS: Because of the limited study power, a link between former employment in this herbicide production process and the occurrence of cancer cannot be ruled out with confidence, although the observed incidence and distribution of cancers in this small cohort may be consistent with that expected in the general population. Detection of three prostate cancers via the examination program is also consistent with the experience of cancer screening programs that include PSA testing. Enhanced screening for prostate cancer among men over age 50 can lead to detection of cancers at earlier ages than would otherwise be the case. This likelihood needs to be planned for and addressed in communications with the study population prior to undertaking such initiatives.

Illness experience before and after an initiative to identify, treat, and prevent Helicobacter pylori-related diseases in the workplace.

Objective outcome measures are needed to confirm the merits of large-scale health initiatives in the workplace. We used aggregate medical claims data to evaluate the illness experience of 5160 employees during the 2 years after versus the 2 years before an intervention intended to identify, treat, and prevent Helicobacter pylori-related illnesses. Across all participants, a 2.1-fold reduction (95% confidence interval 1.4-3.1) in ulcer-related illness episodes and a marginal 1.1-fold reduction (95% confidence interval 0.9-1.4) in episodes due to other stomach and duodenal diseases were achieved. Improvement in claims experience was most notable among 250 employees with ulcer findings on the screening examination. This H. pylori health initiative appears to have contributed to a cost-effective reduction in subsequent illness episodes due to ulcer and possibly due to other stomach and duodenal disease.

[Dyspepsia and Helicobacter pylori infection in employees of a large industry. Results of a prospective BASF Helicobacter pylori prevention campaign]. / Dyspepsie und Helicobacter-pylori-Infektion bei Beschäftigten eines grossen Industrieunternehmens. Ergebnisse der prospektiven BASF-Helicobacter-pylori-Vorsorgeaktion.

BACKGROUND: The role of Helicobacter pylori (H. pylori) infection in dyspepsia is controversial. In the course of a health initiative within a large industrial corporation, we investigated the prevalence of both dyspepsia and positive H. pylori serology and the outcome of eradication therapy in symptomatic H. pylori positive employees. TEST PERSONS AND METHODS: H. pylori serology (IgG ELISA) was determined in 6,143 employees of BASF AG Ludwigshafen/Germany who were also asked to complete a standardized health history administered by a physician. Peptic ulcer disease (PUD) and dyspepsia subgroups were defined based on past medical history and symptom profiles using the criteria of Heading. Upper GI endoscopy, abdominal ultrasound and eradication therapy (Italian Triple Therapy) was recommended for symptomatic H. pylori positive individuals. The prognostic value of antibodies against CagA and VacA was evaluated in 37 and 39 employees with PUD and non-ulcer dyspepsia (NUD) confirmed by endoscopy, respectively. RESULTS: Of 6,143 employees, 1,255 (20.4%) were classified as dyspeptic, 492 (39.2%) of whom were H. pylori positive. The seroprevalence of H. pylori in asymptomatic employees was 35.8%. There were no significant differences in H. pylori seroprevalence among dyspepsia subgroups (reflux only, dysmotility only, reflux/dysmotility, ulcer-like and non-specific). However, individuals reporting severe dyspeptic symptoms were significantly more likely to be H. pylori positive (OR 2.09, CI 1.43-3.05). The seroprevalence of CagA and VacA was not significantly different among employees with NUD compared to referents or among employees with NUD compared to those with PUD. 330 (72%) of 458 employees with dyspepsia received eradication therapy, 128 persons refused therapy. Based on a 12-month follow-up of 402 individuals (300 of whom had received therapy), eradication success was 81.5% as judged by serology. Of the successfully treated employees, 33.2% reported a total absence and 42.8% reported a decrease in symptoms. Among the employees who refused therapy, the corresponding percentages were 37.3% and 16.7%, respectively. An increase in reflux complaints was not observed among treated employees. CONCLUSION: In a large active employee population, at most a very weak association was observed between the prevalence of H. pylori seropositivity and dyspepsia. Frequent and severe dyspeptic symptoms were associated with an increased rate of H. pylori seropositivity. The analysis of the virulence factors is not particularly helpful in discriminating PUD or NUD. Eradication of H. pylori infection leads to a decrease in dyspeptic symptoms after 12 months, but not more often to their complete absence compared to untreated individuals.