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. 2010 Jul 2;5(7):e11431.
doi: 10.1371/journal.pone.0011431.

Systemic Inflammation in Young Adults Is Associated With Abnormal Lung Function in Middle Age

Free PMC article

Systemic Inflammation in Young Adults Is Associated With Abnormal Lung Function in Middle Age

Ravi Kalhan et al. PLoS One. .
Free PMC article

Erratum in

  • PLoS One. 2010;5(8). doi 10.1371/annotation/ed92662b-c566-488d-b090-6c80046d3499.


Background: Systemic inflammation is associated with reduced lung function in both healthy individuals and those with chronic obstructive pulmonary disease (COPD). Whether systemic inflammation in healthy young adults is associated with future impairment in lung health is uncertain.

Methodology/principal findings: We evaluated the association between plasma fibrinogen and C-reactive protein (CRP) in young adults and lung function in the Coronary Artery Risk Development in Young Adults cohort study. Higher year 7 fibrinogen was associated with greater loss of forced vital capacity (FVC) between years 5 and 20 (439 mL in quartile 4 vs. 398 mL in quartile 1, P<0.001) and forced expiratory volume in 1 second (FEV(1)) (487 mL in quartile 4 vs. 446 mL in quartile 1, P<0.001) independent of cigarette smoking, body habitus, baseline lung function and demographic factors. Higher year 7 CRP was also associated with both greater loss of FVC (455 mL in quartile 4 vs. 390 mL in quartile 1, P<0.001) and FEV(1) (491 mL in quartile 4 vs. 442 mL in quartile 1, P = 0.001). Higher year 7 fibrinogen and CRP were associated with abnormal FVC at year 20 (odds ratio (OR) per standard deviation 1.51 (95% confidence interval (CI): 1.30-1.75) for fibrinogen and 1.35 (95% CI: 1.14-1.59) for CRP). Higher year 5 fibrinogen was additionally associated with abnormal FEV(1). A positive interaction was observed between pack-years cigarette smoking and year 7 CRP for the COPD endpoint, and among participants with greater than 10 pack-years of cigarette exposure, year 7 CRP was associated with greater odds of COPD at year 20 (OR per standard deviation 1.53 (95% CI: 1.08-2.16).

Conclusion/significance: Systemic inflammation in young adults is associated with abnormal lung function in middle age. In particular, elevated CRP may identify vulnerability to COPD among individuals who smoke.

Trial registration: NCT00005130.

Conflict of interest statement

Competing Interests: Ravi Kalhan has served as a paid consultant to Boehringer-Ingelheim, Dey Pharmaceuticals, and AstraZeneca, and has received honoraria for speaking on behalf of GlaxoSmithKline, Boehringer-Ingelheim, Pfizer, and AstraZeneca, and is the recipient of research grant support from GlaxoSmithKline. No other authors have competing interests to disclose.


Figure 1
Figure 1. Summary of the population from CARDIA included in the present analysis.
Figure 2
Figure 2. Relationship between age, lung function and quartile of fibrinogen or CRP (measured at year 7).
Spirometry exams performed at CARDIA visits at years 5, 10, and 20 were used to determine a mean lung function for each 2 year age group across year 7 CRP or fibrinogen quartiles, and slopes compared between the highest and lowest quartile groups. For both fibrinogen and CRP, the age-related decline in FVC was significantly different between quartiles 1 and 4. There were no significant differences in the FEV1 across CRP or fibrinogen quartiles.Covariates in the model include race-sex group, exam year, pack-years of cigarette exposure, and time-dependent age, time-dependent height and height-squared, and year 5 waist circumference and time-dependent change in waist circumference.

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