Purpose
This study investigated the relationship between chronic obstructive pulmonary disease (COPD) and metabolic syndrome (MetS), focusing on gender differences and using large-scale data on the Korean general population.

Methods
The total sample included 9,079 eligible participants aged ≥ 40 years who participated in the fifth Korea National Health and Nutrition Examination Survey, conducted between 2010 and 2012. Complex sampling methods, including strata sampling, clustering, and sample weighting were used to allow generalization of the findings to the Korean population. For the bivariate analysis, chi-square tests were conducted to compare differences in general/behavioral characteristics, individual MetS components, the prevalence of COPD, and the number of MetS components according to the presence or absence of COPD and gender. Finally, a multiple logistic regression analysis adjusted for variables was conducted.

Results
The prevalence rates of COPD and MetS were 13.6% and 26.0%, respectively. The prevalence rate of MetS in the COPD group was 23.0% for the total sample, 18.5% for men, and 38.5% for women. After sample weighting and adjusting for covariates, there were no significant relationships among COPD, MetS, and the individual MetS components.

Conclusion
Although MetS components were not significantly associated with COPD, the results indicate that health care professionals should recognize that two conditions, respiratory symptoms and MetS, may coexist in patients, women in particular, or healthy general populations encountered even if a patient has a normal body mass index and does not drink or smoke at all.