Dietary supplementation by Japanese patients with chronic obstructive pulmonary disease

Objectives: To investigate the prevalence and type of dietary supplements taken by Japanese patients with chronic obstructive pulmonary disease (COPD) and factors affecting their use. Design: Cross-sectional study by face-to-face interviews. Setting: Six hospitals in central Japan. Participants: Of the 300 referred COPD patients aged between 50 and 75 years, 278 eligible participants (244 men and 34 women) with complete data were available for analysis. Main outcome measures: Prevalence of supplement use, dietary supplement categories (multivitamin, beta-carotene, vitamin C, vitamin E, and miscellaneous). Results: Overall, 42% of participants were dietary supplement users taking at least one category of supplements weekly; the prevalence being higher for female (47%) than mate patients (41%). The most common supplements consumed were energy drink for men (11.1%), and multivitamin (11.8%) and vinegar (11.8%) for women. Dietary supplementation was found to be affected by age (p = 0.04), COPD severity (p = 0.03) and presence of co-morbidity (p = 0.03). Older patients over 60 years were more likely to take dietary supplements (odds ratio (OR) 2.44, 95% Cl 1.03-5.80), whereas severe COPD patients (OR 0.41, 95% Cl 0.18-0.95) and those with a co-morbidity (OR 0.54, 95% Cl 0.32-0.94) tended not to use. Conclusions: Dietary supplements are popular for patients with COPD especially among older patients. The findings are important to clinical trials and experimental interventions advocating nutritional supplementation therapy for pulmonary rehabilitation. (C) 2008 Elsevier Ltd. All rights reserved.