1259Sleep and Preterm Birth-Blair et al. INTRODUCTIONIn the United States, preterm birth affects 11.5% of deliveries and is the underlying cause of more than one third of infant deaths.1 A high proportion of surviving preterm infants suffer from severe physical and cognitive consequences, potentially requiring intensive medical and/or educational support throughout the lifespan.2 The morbidity and mortality associated with preterm birth pose significant drains on the financial and emotional resources of afflicted families, and on the nation as a whole, costing more than $26 billion annually in the United States. 3Inflammation is a causal mechanism in the initiation of preterm as well as term labor. 4 Inflammatory mediators can initiate contractions, encourage cervical ripening, and cause rupture of the membranes.4,5 Via these mechanisms, inflammation induced by infection or psychological stress may trigger early parturition. 6,7Importantly, poor sleep promotes inflammation.8 For example, in a population-based cohort of more than 5,000 adults, shorter sleep duration was associated with elevations in Study Objectives: Poor sleep promotes inflammation. In turn, inflammation is a causal mechanism in term as well as preterm parturition. In the United States, a persistent racial disparity in preterm birth exists, with African Americans showing ~1.5 times greater risk. This study examined associations among sleep quality, serum proinflammatory cytokines, and length of gestation in a racially diverse sample of 138 pregnant women. Design: Observational. Measurements: Women completed the Pittsburgh Sleep Quality Index (PSQI) and other psychosocial and behavioral measures during midpregnancy. Serum levels of interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor (TNF)-α were determined by high-sensitivity assays. Birth outcomes were determined via medical record review. Results: Among African American women (n = 79), shorter gestation was predicted by poorer overall sleep (r s = −0.35, P = 0.002) as well the following PSQI subscales: subjective sleep quality (r s = −0.34, P = 0.002), sleep latency (r s = −0.27, P = 0.02), and sleep efficiency (r s = −0.27, P = 0.02). African American women with poor sleep quality (PSQI > 5) had 10.2 times the odds of preterm birth compared to those with good sleep quality. In contrast, among European American women (n = 53), gestational length was not significantly predicted by sleep quality (Ps > 0.12). Bootstrapping analyses showed that, among African Americans, IL-8 significantly mediated the association between sleep quality and length of gestation (indirect effect estimate −0.029; 95% confidence interval −0.06, −0.002). Conclusions:The data provide novel evidence that African American women exhibit greater inflammation in response to sleep disturbance than European American women and these effects correspond with length of gestation. Racial differences in susceptibility to sleep induced immune dysregulation may contribute to marked racial disparities in preterm birth.

Soft X-ray absorption spectroscopy coupled with nano-scale microscopy has been widely used in material science, environmental science, and physical sciences. In this work, the advantages of soft X-ray absorption spectromicroscopy for plant biopolymer research were demonstrated by determining the chemical sensitivity of the technique to identify common plant biopolymers and to map the distributions of biopolymers in plant samples. The chemical sensitivity of soft X-ray spectroscopy to study biopolymers was determined by recording the spectra of common plant biopolymers using soft X-ray and Fourier Transform mid Infrared (FT-IR) spectroscopy techniques. The soft X-ray spectra of lignin, cellulose, and polygalacturonic acid have distinct spectral features. However, there were no distinct differences between cellulose and hemicellulose spectra. Mid infrared spectra of all biopolymers were unique and there were differences between the spectra of water soluble and insoluble xylans. The advantage of nano-scale spatial resolution exploited using soft X-ray spectromicroscopy for plant biopolymer research was demonstrated by mapping plant cell wall biopolymers in a lentil stem section and compared with the FT-IR spectromicroscopy data from the same sample. The soft X-ray spectromicroscopy enables mapping of biopolymers at the sub-cellular (~30 nm) resolution whereas, the limited spatial resolution in the micron scale range in the FT-IR spectromicroscopy made it difficult to identify the localized distribution of biopolymers. The advantages and limitations of soft X-ray and FT-IR spectromicroscopy techniques for biopolymer research are also discussed.

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Mechanistic pathways linking maternal polyunsaturated fatty acid (PUFA) status with gestational length are poorly delineated. This study examined whether inflammation and sleep quality serve as mediators, focusing on the antiinflammatory ω-3 docosahexaenoic acid (DHA; 22:6n3) and proinflammatory ω-6 arachidonic acid (AA; 20:4n6). Pregnant women (n = 135) provided a blood sample and completed the Pittsburgh Sleep Quality Index (PSQI) at 20–27 weeks gestation. Red blood cell (RBC) fatty acid levels were determined by gas chromatography and serum inflammatory markers [interleukin (IL)-6, IL-8, tumor necrosis factor-α, IL-1β, and C-reactive protein] by electrochemiluminescence using high sensitivity kits. Both higher serum IL-8 (95% CI = 0.10,3.84) and poor sleep (95% CI = 0.03,0.28) served as significant mediators linking lower DHA:AA ratios with shorter gestation. Further, a serial mediation model moving from the DHA:AA ratio → sleep → IL-8 → length of gestation was statistically significant (95% CI = 0.02, 0.79). These relationships remained after adjusting for depressive symptoms, age, BMI, income, race, and smoking. No interactions with race were observed in relation to length of gestation as a continuous variable. However, a significant interaction between race and the DHA:AA ratio in predicting preterm birth was observed (p = 0.049); among African Americans only, odds of preterm birth decreased as DHA:AA increased (p = 0.048). These data support a role for both inflammatory pathways and sleep quality in linking less optimal RBC PUFA status with shorter gestation in African American and European American women and suggest that African-Americans have greater risk for preterm birth in the context of a low DHA:AA ratio.