Early and Late Preterm Birth Rates Among US-Born Urban Women: The Effect of Men's Lifelong Class Status.

Abstract

To ascertain the relation of men's lifelong class status (as measured by neighborhood income) to the rates of early (< 34weeks) and late (34-36weeks) preterm birth (PTB). Stratified and multilevel, multivariable binomial regression analyses were computed on the Illinois transgenerational birth-file of infants (born 1989-1991) and their parents (born 1956-1976) with appended U.S. census income information. The median family income of men's census tract residence at two-time periods were utilized to assess lifelong class status (defined by residence in either the lower or upper half of neighborhood income distribution). In Cook County Illinois, the preterm rate for births (n = 8115) to men with a lifelong lower class status was twice that of births (n = 10,330) to men with a lifelong upper class status: 13% versus 6.0%, RR = 2.2 (2.0, 2.4). This differential was greatest in early PTB rates: 3.9% versus 1.4%, RR = 3.0 (2.5, 3.7). The relation of men's lifelong class status to both PTB components persisted among non-teens, married, college-educated, and non-Latina White women, respectively. The adjusted (controlling for maternal demographic characteristics) RR of early and late PTB for men with a lifelong lower (versus upper) class status were 1.4 (1.1, 1.9) and 1.2 (1.0, 1.4), respectively. The population attributable risk of early PTB for men's lifelong lower class status equaled 16%. Men's lifelong lower (versus upper) class status is a novel risk factor for early preterm birth regardless of maternal demographic characteristics. This intriguing finding has public health relevance.