James F. Bena

Lung Cancer Risk and Workplace Exposure to Environmental Tobacco Smoke

OBJECTIVES We sought to quantitatively evaluate the association between work-place environmental tobacco smoke exposure and lung cancer. METHODS We performed a meta-analysis in 2003 of data from 22 studies from multiple locations worldwide of workplace environmental tobacco smoke exposure and lung cancer risk. Estimates of relative risk from these studies were analyzed by fitting the data to fixed and mixed effects models. Analyses of highly exposed workers and of the relationship between duration of exposure and lung cancer were also performed. RESULTS The meta-analysis indicated a 24% increase in lung cancer risk (relative risk [RR]=1.24; 95% confidence interval [CI]=1.18, 1.29) among workers exposed to environmental tobacco smoke. A 2-fold increased risk (RR=2.01; 95% CI=1.33, 2.60) was observed for workers classified as being highly exposed to environmental tobacco smoke. A strong relationship was observed between lung cancer and duration of exposure to environmental tobacco smoke. CONCLUSIONS The findings from this investigation provide the strongest evidence to date that exposure to environmental tobacco smoke in the workplace is associated with an increased risk of lung cancer.

Fatal occupational injury rates in southern and non-southern states, by race and Hispanic ethnicity

OBJECTIVES We investigated fatal occupational injury rates in the United States by race and Hispanic ethnicity during the period 1990-1996. METHODS Fatalities were identified by means of the national traumatic occupational fatalities surveillance system. Fatal occupational injury rates were calculated by race/ethnicity and region using US-census-based workforce estimates. RESULTS Non-Hispanic Black men in the South had the highest fatal occupational injury rate (8.5 per 100000 worker-years), followed by Hispanic men in the South (7.9 per 100000 worker-years). Fatal injury rates for Hispanic men increased over the study period, exceeding rates for non-Hispanic Black men in the latter years of observation. CONCLUSIONS These data suggest a change in the demographics of fatal occupational injuries in the United States. Hispanic men in the South appear to be emerging as the group with the nations highest unintentional fatal occupational injury rate.

Deindustrialisation and the long term decline in fatal occupational injuries

Aims: To examine the extent to which deindustrialisation accounts for long term trends in occupational injury risk in the United States. Methods: Rates of fatal unintentional occupational injury were computed using data from death certificates and the population census. Trends were estimated using Poisson regression. Standardisation and regression methods were used to adjust for the potential effect of structural change in the labour market. Results: The fatal occupational injury rate for all industries declined 45% from 1980 to 1996 (RR (rate ratio) 0.55, 95% CI 0.52 to 0.57). Adjustment for structural changes in the workforce shifted the RR to 0.62 (95% CI 0.60 to 0.65). Expanding industries enjoyed more rapid reduction in risk (−3.43% per year, 95% CI −3.62 to −3.24) than those that contracted (−2.65% per year, 95% CI −2.88 to −2.42). Conclusions: Deindustrialisation contributed to the decline of fatal occupational injury rates in the United States, but explained only 10–15% of the total change.

Incorporating uncertainty and variability in the assessment of occupational hazards

Uncertainty reflects ignorance associated with population traits (e.g. average exposure levels to a contaminant), with models used to predict risk (e.g. which statistical model is correct), and with a host of other considerations. Variability reflects an intrinsic property of a system (e.g. body mass indices possess a distribution across a population). The incorporation of uncertainty and variability in the assessment of occupational hazards is an important objective. General issues of uncertainty and variability in occupational risk estimation are discussed. This is followed by three illustrations where: firstly, the impact of variability in an exposure assessment and sampling variability in a regression model on risk estimates is considered; secondly, the impact of uncertainty in the size of a workforce on rate modelling is considered; and thirdly, the impact of using different models to predict risk is considered.

A Graphical Analysis of Mortality Rates and Years of Potential Life Lost

One challenge in assessing occupational fatal injuries is choosing a summary measure of the impact of these injuries. Each metric emphasizes different aspects of health risk, and fatal injury reports often focus on only one summary measure at a time. Deaths from the National Traumatic Occupational Fatality database were combined into external cause of death (e-code) groups. Graphs comparing average years of potential life lost (YPLL), mortality rate, and their product, “YPLL-rate”, are presented for e-code groups overall, industries and occupations, and e-code groups within selected industries and occupations. This integrated analysis of fatal injury characteristics allows identification of the portion of the workforce at highest risk. Homicides and electrocutions (e-code groups) had high mortality rates, average YPLL, and YPLL-rates, both overall, and within several of the industries and occupations examined. The industry and occupation of Agriculture, Forestry, and Fishing experienced a very high mortality rate and the lowest average YPLL for both industries and occupations. Laborer was the most hazardous occupation for young workers with an average YPLL near 40, and a mortality rate greater than 15 deaths per 100,000 worker-years.