Racial differences in work trajectories and their effects on racial disparities in LBW

Background: With the increased number of women who continue to work during pregnancy, occupational characteristics have been advanced as a potential contributor to adverse pregnancy outcomes. We sought to investigate racial disparities in work trajectories and their effect on LBW. Methods: Work characteristics from the O*NET were imputed to job data from the National Longitudinal Study of Youth (NLSY79). We examined whether racial differences in low substantive complexity (SC) of work were significant contributors to racial disparities in LBW. Longitudinal analysis of SC trajectories produced an ordered 5-class solution. Using age as a time scale, Cox regression was performed in SPSS v.18 to evaluate the temporal relationship between race and LBW. Results: Classes with lower work trajectories were significantly associated with LBW. Minorities were working in low SC jobs at higher rates than white women (p= 0.000). Contrasted with whites, hazard ratio for LBW was 3 times greater for black mothers (HR=3.10; 95% CI=2.48-3.87), twice that of Hispanic mothers (HR=1.50; 95% CI=1.11-2.03). Adjustment for education and SC trajectory obviated increased risk for Hispanics; while high risks for blacks persisted (HR=2.8; 95% CI = 2.21-3.48). As maternal age increased, the gap between blacks and whites continued to widen. Discussion: Improved occupational trajectories appear to ameliorate educational associations with LBW outcomes between Hispanic and white women. Differentials in trajectories of work SC may play a role in racial/ethnic disparities in birth outcomes and warrant continued investigation.