To the Editor:Cadmium is a metal that is widely spread in the environment and human populations are exposed to it through food, mainly grains and vegetables. The tobacco plants accumulate cadmium, and tobacco smokers accumulate the cadmium in tobacco smoke, which is absorbed in the lungs [1]. Occupational exposure to cadmium has been linked to the development of emphysema and impaired lung function [2, 3]. Increased levels of blood cadmium (B-Cd) or urinary cadmium are associated with lower lung function, and it has been suggested that cadmium, in the low-dose interval, is a risk factor for impaired lung function [1,4].The aim of this study was to examine whether cadmium exposure in the low-dose interval was associated with increased prevalence of emphysema and impaired pulmonary function.The study population comprised subjects aged 50-64 years randomly selected from the population in Gothenburg (n=1111) [5]. All subjects answered a questionnaire and performed dynamic spirometry including forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC). From diffusing capacity measurements for carbon monoxide, diffusing capacity (D LCO ) and transfer coefficient (K CO ) of the lung for carbon monoxide were obtained [6]. A Jaeger Master Screen pulmonary function testing (Vyaire Medical, Mettawa, IL, USA) was used for all measurements. Residual volume (RV) and total lung capacity (TLC) were measured using a body box. All procedures were performed after inhalation of 400 µg of salbutamol and according to American Thoracic Society/European Respiratory Society standards, as previously described [5]. Predicted values and lower limits of normal (LLN) were based on published equations [7][8][9][10]. Predicted values (FEV 1 and FVC) were based on recently developed equations from same source population [7]. Cadmium (B-Cd) was analysed in whole blood, as described previously [11]. The pulmonary computed tomography (CT) investigations were performed and assessed according to international guidelines [12]. Chronic airflow limitation according to Global Initiative for Obstructive Lung Disease (CAL GOLD ) was defined as an FEV 1 /FVC ratio <0.7. Chronic airflow limitation (CAL LLN ) was defined as FEV 1 /FVC ratio below the LLN. Emphysema was defined as having at least mild emphysema in any zone of the lungs. Centrilobular emphysema was defined as having centrilobular emphysema in any zone of the lungs. Smoking was categorised as current smoker, former smoker or never-smoker. Pack-years (cumulative tobacco exposure) were calculated for all participants with a history of smoking. Never-smokers were assigned 0 (zero) pack-years. Socioeconomic status was defined according to the highest level of education achieved. Body mass index was defined as measured weight/height 2 (kg•m −2 ). Occupational exposure to vapour, gas, dust or fumes was based on an affirmative answer to the item "Have you ever been exposed to vapour, gas, dust or fumes at your workplace?". B-Cd was classified in quartiles: <0.16 µg•L −1 ; 0.16-<0.23 µg•L ...