Issues and findings in the evaluation of occupational risk among women high nickel alloys workers

Background:

We present the mortality experience for a cohort of women (n=2,877) from a large epidemiologic study of production and fabrication high nickel alloys workers (n=31,165).  All the plants were located within the United States and cohort eligibility required some work experience within the period of the late 1940s through the mid 1960s.

Methods:

Cause specific mortality was evaluated by comparing cohort mortality to the general US female population and to local populations in geographic proximity to the plants.  Relative risk estimates were determined for 62 causes of death using the Standardized Mortality Ratio and were adjusted for age, race, gender and calendar time by the indirect method using a modified life table technique.

Results:

Relative risks for all causes (0.98), all cancers (0.90), lung cancer (1.34) and breast cancer (0.96) were nonsignifcant when mortality was compared to the US female population.  No relationship between mortality and length of time employed in the industry or work area was identified.

Conclusions:

Although there were some difficulties in tracing women due to name changes, comprehensive follow-up was obtained when using multiple sources of information. Our strategy resulted in resolving vital status for over 95% of the women which is comparable to that of the male cohort.

The type of jobs and work activities differed between the genders.  Females were employed predominantly in two work areas (allocated services, 87%;  and, grinding, 46%), whereas males were employed in several work areas (allocated services, 76%; grinding, 27%; hot working, 20%; and, cold working, 17%).  Considerable variation was noted
among the study plants with respect to the percent of female production workers in the workforce.

Generally, the patterns of relative risks derived for the total cohort and various subgroups are similar across the different comparison populations.  Estimated elevated risks are usually lower when cohort mortality is compared to that of local populations.  No increased risk was identified for any site-specific cancers or nonmalignant causes of death.