Physical activity and diet pattern do not mitigate C-reactive protein increases associated with oral contraceptive...

Area of Science:

• Public Health
• Biochemistry
• Epidemiology

Background:

• C-reactive protein (CRP) is a key biomarker for systemic inflammation.
• Oral contraceptive (OC) use is widespread, and its potential impact on inflammatory markers requires investigation.
• Understanding factors influencing CRP levels is crucial for assessing overall health and inflammation in diverse populations.

Purpose of the Study:

• To investigate the associations between body mass index (BMI), physical activity (PA) level, dietary inflammatory index (DII), and OC use with C-reactive protein (CRP) levels.
• To determine if elevated CRP in OC users reflects a chronic, systemic inflammatory response.
• To explore the predictive roles of PA, BMI, and DII on CRP levels in both OC users and non-users.

Main Methods:

• Utilized data from four cycles (1999-2006) of the U.S. National Health and Nutrition Examination Survey (NHANES).
• Analyzed a sample of 496 current OC users and 1,583 regularly menstruating non-users.
• Employed general linear models to assess the influence of BMI, PA, OC use, age, and smoking status on log-transformed CRP (lnCRP), testing for interaction effects.

Main Results:

• OC use was positively associated with elevated lnCRP levels (p < 0.0001), indicating higher systemic inflammation.
• Physical activity (PA) was inversely related to lnCRP (p = 0.0019), and BMI was positively associated (p < 0.0001).
• Among OC non-users, PA and BMI predicted lnCRP, and DII was also a predictor in a subset; however, PA and DII did not predict lnCRP in OC users.

Conclusions:

• Elevated CRP levels in oral contraceptive (OC) users appear to represent a chronic, systemic inflammatory response.
• Physical activity and a lower dietary inflammatory index (DII) are associated with reduced CRP in OC non-users.
• These lifestyle factors do not appear to mitigate the CRP elevations observed in current OC users, highlighting a distinct inflammatory profile.