Excessive consumption of cured meat is associated with an increased risk for hospital readmission among patients with chronic obstructive pulmonary disease (COPD), report Jordi de Batlle, BMedBiol, from the Centre for Research in Environmental Epidemiology, Hospital del Mar Research Institute, the CIBER Epidemiología y Salud Pública, and the Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain, and colleagues. Results from their study were scheduled to be published online March 8 in the European Respiratory Journal.
The goal of the Phenotype and Course of COPD Project (PAC-COPD) study was to assess the association between dietary intake of cured meat and risk for COPD readmission among patients with COPD. The researchers calculated the association between cured meat intake and COPD admissions using parametric regression survival-time models.
Researchers demonstrated that higher cured meat consumption was related to a 2-fold increased risk for COPD readmission (adjusted hazard ratio, 2.02; 95% confidence interval [CI], 1.31 - 3.12; P = .001), after adjusting for age, forced expiratory volume in the first second (FEV1), and total calorie intake. In addition, the time to the first COPD readmission was longer in patients with low cured meat intake (P = .028).
COPD researchers have recently turned their sights on the role diet plays in the development of the disease. "Recent studies have shown that a high dietary intake of cured meat increases the risk of COPD development. However, its potential effects on COPD evolution have not been tested," the authors write.
Between January 2004 and March 2006, 274 patients with COPD were recruited from 9 hospitals in Spain during their first COPD hospital admission and were followed-up through December 31, 2007 (median follow-up, 2.6 years). The COPD diagnosis was based on a ratio of postbronchodilator FEV1 to forced vital capacity (FEV1/FVC) equal to 0.70. COPD exacerbations were classified according to the International Classification of Diseases, Ninth Revision, and survival status was obtained for all patients from direct interviews with the patients or their relatives.
Study participants filled out a food frequency questionnaire at the time of enrollment that encompassed dietary habits during the preceding 2 years. Cured meat consumption was defined as the total daily consumption (g/day) of cooked ham, Spanish cured ham, cured and other sausages, and hot dogs.
Using standardized questionnaires, the investigators collected baseline sociodemographic characteristics, respiratory symptoms, drug treatment, and lifestyle information. The team also assessed body mass index (BMI) and fat-free mass index to evaluate participants' nutritional status. In addition, they measured postbronchodilator spirometry (FEV1, FVC, and FEV1/FVC), arterial oxygen and carbon dioxide partial pressures, carbon monoxide diffusing capacity, and serum C-reactive protein.
The mean age of the participants was 68 years, 93% were men, and 42% were current smokers. The mean postbronchodilator FEV1 was 53% predicted, and the median cured meat intake was 23 g/day (equivalent to approximately 1 slice of ham a day).
Most patients had moderate to severe COPD (5% mild, 52% moderate, 37% severe, and 6% very severe); however, median cured meat intake was similar across COPD severity stages. The researchers also noted that a higher daily cured meat intake was positively related to younger age, current working, current smoking, higher levels of regular physical activity, and lower BMI.
The authors hypothesize that cured meats have a deleterious effect on patients with COPD because they contain high level of nitrites. Nitrites used in the preparation of cured meat may lead to an increase in the nitrosative stress burden within the lungs, and lead to the formation of reactive nitrogen species, which results in parenchymal damage and remodeling.
"This study adds new evidence suggesting that in addition to a possible increase in risk of COPD associated with cured meats, these foods may also increase risk of exacerbations, thus supporting the need of considering specific dietary advice to COPD patients," conclude the study authors.
Funding for this study was provided by the Fondo de Investigación Sanitaria, Ministry of Health, Spain; Agéncia d'Avaluació de Tecnologia i Recerca Mèdiques, Catalonia Government; Spanish Society of Pneumology and Thoracic Surgery; Catalan Foundation of Pneumology; Red RESPIRA ; Red RCESP; Fundació La Marató de TV3; DURSI; and an unrestricted educational grant from Novartis Farmacèutica, Spain. CIBERESP and CIBERES are funded by the Instituto de Salud Carlos III, Ministry of Health, Spain. de Batlle has a predoctoral fellowship from the Instituto de Salud Carlos III, and 1 coauthor also has a researcher contract from the Instituto de Salud Carlos III. The other authors have disclosed no relevant financial relationships.
Eur Respir J. Published online March 8, 2012.