Longitudinal influence of BMI and grey spaces on COPD in a general population sample

<bold>Introduction:</bold> Chronic obstructive pulmonary disease (COPD) is a global public health problem and it is therefore important to understand its risk factors. <bold>Objects:</bold> To assess the influence of BMI and grey spaces on the risk of developing COPD. <bold>Methods:</bold> 1145 subjects (females: 54.1%; mean age: 42 yr) living in Pisa and its suburb Cascina, Italy, were investigated in 1991-93 (PI baseline - PIb) and 2009-2011 (PI follow-up - PIfu) through a questionnaire on health status and risk factors. Incidence of COPD was assessed as presence of diagnosis of COPD at PIfu in subjects without COPD diagnosis at PIb (n=1086). The associations of incidence of COPD with body mass index (BMI) (obesity/overweight: BMI >25 kg/m², normal weight/underweight: BMI < 25 kg/m²) and grey space exposure within 1 km from home address (high/low = >/<76.5%) at baseline were assessed through the use of logistic regression model adjusted for sex, age, education, smoking habits and active lifestyle (>2 hours a day outdoors) at PIb. <bold>Results:</bold> At PIb, overweight and obese individuals had a prevalence of 37,1% and 11,5%, respectively. Mean grey space was 53,05% (±20,88). Cumulative COPD incidence at PIfu was 9%. Obese/overweight subjects with high exposure to grey space at PIb had a significant association with the incidence of COPD (OR 2.63; IC 95% 1.27-5.47). Obese/overweight subjects with low exposure to grey space also showed a significant association with COPD incidence (OR 2.19; IC 95% 1.23-3.89). <bold>Conclusions:</bold> Obesity and overweight show an important influence on the incidence of COPD, particularly when combined with a high exposure to grey spaces.