Table 3

Association of prevalence of airflow obstruction (%FEV1/FVC<LLN), spirometric restriction (% FVC <LLN) with mean pack years smoked and GNI/capita ($US PPP) in 22 BOLD sites

β95% CIp Valueβ95% CIp Value
Airflow obstruction
 Mean pack years0.400.15 to 0.640.0030.670.24 to 1.100.004
 GNI (per US$1000 PPP)0.02−0.10 to 0.130.780.12−0.01 to 0.250.063
Spirometric restriction
 Mean pack years−1.07−2.24 to 0.100.071−2.32−4.25 to −0.400.021
 1/GNI (per US$1000 PPP)140101 to 179<0.001168115 to 221<0.001
  • BOLD, Burden of Obstructive Lung Disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; GNI, gross national income; LLN, lower limit of normal; PPP, purchasing power parity.