title: Income inequality and pregnancy spacing.
abstract: We examined the relationship between county-level income inequality and pregnancy spacing in a welfare-recipient cohort in Washington State. We identified 20,028 welfare-recipient women who had at least one birth between July 1, 1992, and December 31, 1999, and followed this cohort from the date of that first in-study birth until the occurrence of a subsequent pregnancy or the end of the study period. Income inequality was measured as the proportion of total county income earned by the wealthiest 10% of households in that county compared to that earned by the poorest 10%. To measure the relationship between income inequality and the time-dependent risk (hazard) of a subsequent pregnancy, we used Cox proportional hazards methods and adjusted for individual- and county-level covariates. Among women aged 25 and younger at the time of the index birth, the hazard ratio (HR) of subsequent pregnancy associated with income inequality was 1.24 (95% CI: 0.85, 1.80), controlling for individual-level (age, marital status, education at index birth; race, parity) and community-level variables. Among women aged 26 or older at the time of the index birth, the adjusted HR was 2.14 (95% CI: 1.09, 4.18). While income inequality is not the only community-level feature that may affect health, among women aged 26 or older at the index birth it appears to be associated with hazard of a subsequent pregnancy, even after controlling for other factors. These results support previous findings that income inequality may impact health, perhaps by influencing health-related behaviors.
authors.affiliation: Kaiser Permanente, 3800 N Interstate Avenue, Portland, OR 97227-1110, USA. rgold@myuw.net
authors.forename: R
authors.initials: R
authors.lastname: Gold
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Connell
authors.forename: Patrick
authors.initials: P
authors.lastname: Heagerty
authors.forename: Stephen
authors.initials: S
authors.lastname: Bezruchka
authors.forename: Robert
authors.initials: R
authors.lastname: Davis
authors.forename: Mary Lawrence
authors.initials: ML
authors.lastname: Cawthon
mesh_terms: D000293:Adolescent; D000328:Adult; D001721:Birth Intervals; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007182:Income; D011203:Poverty; D011247:Pregnancy; D016016:Proportional Hazards Models; D016019:Survival Analysis; D014861:Washington