Self-reported intake of fruit and vegetables and risk of chronic obstructive pulmonary disease: A nation-wide twin study.

BACKGROUND

Although smoking is the major risk factor for chronic obstructive pulmonary disease (COPD) many patients with obstructive lung function suggesting COPD are never-smokers. Therefore, other lifestyle factors have been suggested as risk factors.

AIMS

i) To examine the association between self-reported intake of fruit and vegetables and risk of COPD and ii) to examine whether the association between these traits are due to underlying genetic factors.

METHODS

12,449 twins, aged 40-80, from the Danish Twin Registry were recruited. The participants completed a questionnaire on medical history and lifestyle factors and participated in clinical examination. COPD was defined according to ATS/ERS recommendations. Multivariate logistic regressions were used to estimate the risk of COPD in individuals with a low intake of fruit and vegetables. Co-twin control analyses were performed to examine whether the association between fruit and vegetables and COPD is explained by genetic factors. Self-reported physician-diagnosed asthmatic individuals were excluded.

RESULTS

Of the 11,458 individuals were included in the analyses, 48% of the participants were males. Mean age was 58.9 (years)±SD 9.6, mean BMI (kg/m)26.6 ± SD 4.4. A multivariate logistic regression, including sex, age and BMI showed that both smoking, no and heavy drinking and physical inactivity were independent predictors of COPD. There was a significant frequency-pendent association between intake of fruit and vegetables and increased risk of COPD. Conditional logistic regression analyses showed that the association might be controlled by genetic factors.

CONCLUSIONS

This study shows that low intake of fruit and vegetables is associated with an increased risk of COPD and the association might be under influence of genetic factors.