Abstract
BACKGROUND: Sex differences in levels of C-reactive protein (CRP) are well established in adulthood, but little is known about when and why they emerge. Here, we tested longitudinal models of CRP levels from ages 9 to 21, when marked physical and behavioral changes could contribute to growing sex disparities in CRP. METHODS: Data from the community-based prospective-longitudinal Great Smoky Mountains Study (N=1420) were used. Participants were 9-13 years old at intake and were followed through age 21. High-sensitivity C-reactive protein (CRP) was assayed from up to nine bloodspot collections per person. BMI, physical/sexual maturation, substance use, and control variables were assessed during yearly interviews to age 16, and at ages 19 and 21. RESULTS: Multilevel models revealed that the development of CRP in females was best described by a quadratic trend: after slow increases in CRP until age 15, the rate of increase accelerated thereafter. Changes in CRP in males were best described by a smaller, linear increase. After sex-differentiated associations with BMI, physical/sexual maturation, and substance use variables had been accounted for, increases in CRP after age 15 no longer differed by sex. CONCLUSION: Physical/sexual maturation and behavioral changes during adolescence could initiate life-long sex disparities in CRP.