THE EFFECTS OF OCCUPATION-BASED SOCIAL POSITION ON MORTALITY IN A LARGE AMERICAN COHORT

Objectives. Four occupation-based measures were used to derive estimat es of social position's effect on all-cause mortality among men and wo men in a large national cohort. Methods. The National Longitudinal Mor tality Study provided information on principal occupation and 9-year f ollow-up for 229 851 persons aged 25 through 64 years. Cox's proportio nal hazards model was used to estimate the age-adjusted risk of death relative to six ordinal categories of social position. The Slope Index of Inequality described average change in death rates across categori es. Results. Risk of death was consistently elevated among persons at lower positions in the social hierarchy. Estimates comparing lowest wi th highest categories varied within a narrow range (1.47-1.92 for men and 1.23-1.55 for women). However, several discrepancies among analyse s were noted. The analysis by US census groups revealed nonlinear asso ciations, whereas those using other scales found incremental increases in risk. Effect modification by sex was observed for analyses by two of the four measures. Race/ethnicity did not modify the underlying ass ociation between variables. Conclusions. Our analysis complements prev ious findings and sup ports, with few qualifications, the interchangea bility of occupation-based measures of social position in mortality st udies. Explanations for why relative risk estimates were modified by s ex are offered.