PURPOSE: While both diabetes (DM) and proinflammatory states may identify persons at greater likelihood of reduced pulmonary function, whether increased levels of inflammation may increase such risks further in persons with metabolic syndrome (MetS) or DM is unknown. We examined the potential additive value of C-reactive protein (CRP) in persons with MetS and DM in relation to decreased forced vital capacity (FVC).
METHODS: We examined in 4,272 (projected to 43.2 million) U.S. adults aged 18–79 in the Third National Health and Nutrition Examination Survey, non-smokers and without known obstructive lung disease, the association of MetS (without DM) and DM with CRP (low <3 mg/L, high >3 mg/L) in relation to percent of predicted FVC. Multiple logistic regression examined the odds ratio (OR) (with 95% confidence interval [CI]) of FVC <80% in relation to CRP stratified by the presence of MetS/DM adjusted for age, sex, ethnicity, total cholesterol, and body mass index.
RESULTS: In multivariable analysis, mean FVC in persons with MetS with high-CRP (94.3%) and DM with high-CRP (92.5%) was lower when compared to those without MetS/DM with low-CRP (101.7%) (p<0.01). MetS, DM, and no MetS/DM with high-CRP had lower FVC than MetS, DM, and no MetS/DM with low-CRP (p<0.05). The OR's of FVC <80% were highest among persons with MetS and high-CRP (OR=4.35 [2.12–8.96], p<0.01) when compared to persons with no disease and low CRP. DM with either low or high CRP had significantly higher OR's of FVC <80% (3.53 [1.29–64], 3.01 [1.23–7.37], respectively, p<0.05).
CONCLUSION: Elevated CRP levels appear to modestly contribute to an increased likelihood of lower FVC in persons with MetS and DM; however, MetS and DM are associated with lower FVC than those without these conditions regardless of the presence of elevated CRP. Prospective investigations are needed to confirm the prognostic significance of these observations.
CLINICAL IMPLICATIONS: A proinflammatory state (e.g. from elevated CRP levels) in persons with MetS or DM may identify patients at greater likelihood of showing reduced FVC.
DISCLOSURE: Hwa Lee, No Financial Disclosure Information; No Product/Research Disclosure Information