Prevalence and Contributors to Low-grade Inflammation in Three U.S. Populations of Reproductive Age Women.

BACKGROUND: Inflammation, measured by high-sensitivity C-reactive protein (hsCRP), is linked to adverse reproductive outcomes. However, prevalence and predictors of low-grade inflammation are poorly understood among reproductive age women. Therefore, the current aim was to characterize: (i) the prevalence of elevated hsCRP and (ii) whether the association of various demographic, anthropometric, life style, and metabolic characteristics with higher hsCRP varies across populations of reproductive age women with varying risk profiles for adverse reproductive outcomes.

METHODS: Bivariate analysis of characteristics among women ages 18-40 having hsCRP <2.0 vs. ≥2.0 mg/L in the BioCycle Study (N = 259), the Effects of Aspirin in Gestation and Reproduction Trial (EAGeR) (N = 1228), and the National Health and Nutrition Examination Survey (NHANES; N = 2173) were conducted. Multivariable regression analysis estimated the association of all characteristics to hsCRP within each cohort.

RESULTS: Prevalence of hsCRP≥2 mg/L ranged from 20 to 40%. Age, BMI, waist circumference, blood pressure, lipids, glucose, and insulin were frequently higher in women with hsCRP ≥2 mg/L. In multivariable models, however, only adiposity (BMI, waist circumference) was independently associated with hsCRP within all three cohorts. Some variables showed cohort-specific associations with higher hsCRP: white race (EAGeR), higher fasting glucose (BioCycle), and lesser education and employment (NHANES). The total characteristics explained 28-46% of the variation in hsCRP across the three cohorts.

CONCLUSIONS: Low-grade inflammation was common, including among predominantly non-obese women, affecting from 20 to 40% of reproductive age women. Given the potential to reduce inflammation through inexpensive, widely available therapies, examination of the impact of chronic inflammation on reproductive and pregnancy outcomes, as well as preventive interventions, are now needed.