A study of mortality among 14,730 male workers in 12 Norwegian ferroalloy plants: cohort characteristics and the main causes of death.

Abstract

Objectives-Concern about the health hazards of exposure to workers in the ferroalloy industry has initiated this historical cohort study. (SMR 1.47) were found among employees with at least three years of employment. Mortality from accidents, poisonings, and violence was increased among all employees (SMR 1*28). Excess deaths from this cause were however only found for the time after the end of employment in this industry and not during employment (SMR 0.90). Conclusions-The increased mortality from cancer and sudden death could be related to work exposures, at least in subgroups, and these results warrant further studies. The excess deaths from accidents, poisonings, and violence were probably not related to work exposures. The mortality results for short term workers and other information indicate that systematic errors contribute to the increased overall mortality. (Occup Environ Med 1996;53:540-546)

Mortality from nonmalignant respiratory diseases among male workers in Norwegian ferroalloy plants

“…The data were analyzed for mortality in time-related categories of employment status (active and inactive person-time) (20,21). Active persontime was defined as all person-time from the start of follow-up until the end of the last employment period added by 0.1 year (17). Inactive person-time was defined as person-time passing after this point, Induction time analyses (ie, exposure window analyses) were also performed (21).…”

“…We have recently presented the main causes of death from a study among 14 730 male workers in 12 Norwegian ferroalloy plants, 8 plants producing ferrosilicon/ silicon-metal (FeSiISi-met) and 4 producing FeMnISiMn (17). The cohort included workers from the FeMnISiMn plant where the aforementioned epidemic of lobar pneumonia had previously occurred in the surrounding community, and workers from the aforementioned plant producing ferrosilicon and ferrochsomium.…”

“…Only an indirect evaluation of the influence of individual smoking on mortality could be performed, as only 18.5% of the deceased (from all causes) could be categorized into ever or never smokers (17). However, recent smoking status information was available for 1989-1990 for over 90% of the men employed in some of the plants.…”

“…According to results from a previous Norwegian study a RR, of 8 was used for deaths from bronchitis, emphysema and asthma combined (25). Further details about the cohort and the applied methods of analyses have been presented elsewhere (17,18).…”

“…The main strengths of our study are the large size of the cohort (14 730 employees), the long-term follow-up (median 20.7 years) (17), the low proportion lost to follow-up (3%) (17), the ahnost complete information about the cause of death (17), and the ability to study mortality in relation to work in separate departments.…”