Objectives We investigated the contributions of cigarette smoking to the age-related patterns of preterm (<37 weeks) birth (PTB) rates among African-American and White women within the context of lifelong neighborhood income. Methods Stratified and multilevel logistic regression analyses were performed on an Illinois transgenerational dataset of non-Hispanic White and African-American infants (1989-1991) and their mothers (1956-1976) with appended US census income information.
Results: Among non-smoking African-American women (n = 20,107) with a lifelong residence in lower income neighborhoods, PTB rates decreased from 18.5 % for teens to 15.0 % for 30-35 year-olds, p < 0.0001. The opposite pattern occurred among African-American women smokers (n = 5936) with a lifelong residence in lower income neighborhoods, p < 0.01. Among upwardly mobile African-American women smokers (n = 756), PTB rates increased from 11.1 % for teens to 24.9 % for 30-35 year-olds, p < 0.05. Cigarette smoking was not associated with an age-related increase in PTB rates among African-American women with a lifelong residence in upper income neighborhoods. No subgroup of White women, even cigarette smokers with a lifelong residence in lower income neighborhoods, exhibited weathering with regard to PTB. Conclusions A weathering pattern of rising PTB rates with advancing age occurs only among African-American women cigarette smokers with an early-life or lifelong residence in lower income neighborhoods, underscoring the public health policy importance of targeted smoking cessation programs in eliminating the racial disparity in the age-related patterns of PTB rates.
Keywords: Cigarette smoking; Maternal age; Neighborhood income; Preterm birth; Racial disparity; Weathering.