Interleukin-6 promoter −174 polymorphism and spontaneous preterm birth

Objective We assessed the relationship between interleukin-6 (IL-6) promoter −174 polymorphism and spontaneous preterm birth (sPTB) less than 34 weeks and the relationship of polymorphism status with race. Study design Polymerase chain reaction was used to evaluate DNA from 156 controls who delivered after spontaneous labor at term and 51 subjects who had sPTB less than 34 weeks. Results Among the 156 controls, the C/C variant was present in 30 (19.2%). Among the 51 subjects, the C/C variant was present in 2 (6.3%) (odds ratio 0.17, 95% CI 0.04-0.74). Among white women, the C/C variant was present in 30 (27.2%) controls but only 2 (5.2%) cases. No African American women carried the C/C variant. The racial disparity was statistically significant. (P<.001) Conclusion The IL-6 promoter −174 allelic variant C/C is significantly less frequent among women with sPTB less than 34 weeks. There is a dramatic racial disparity in the distribution of allelic variants of this polymorphism.