Study Design and Sample
infection
STASIS, INFECTION, BLOOD, CHRONIC DISEASE
Twenty-two healthy male and female occasional smokers or Swedish snus users (maximum 10 cigarettes or 10 pouches of snus per month) between 18 and 45 years of age were included in the study. Written informed consent was obtained at inclusion. The study design adhered to the 1975 Helsinki declaration and was approved by the Swedish Ethical Review Authority. The study was performed with a randomised, double-blind crossover design (Fig. 3, supplements). No significant carry-over effects were expected with a wash-out period of one week to allow for elimination of any inhaled nicotine. EC exposures, with and without nicotine, were performed on two occasions separated by a wash-out period of at least one week. Volunteers had to refrain from all sorts of nicotine products, water-pipe, drugs including marijuana, anti-inflammatory medications, and strenuous physical activity one week prior to exposures. Volunteers also had to abstain from caffeine and alcohol 24 h prior to exposure. Exclusion criteria were any chronic disease, infection, pregnancy, or inflammatory symptoms within the last 7 days prior to participation, and BMI below 18 kg/mAll exposures were supervised and performed in a well-ventilated and temperature-controlled room. On each occasion, subjects inhaled one puff of EC aerosol per minute for 30 min. Each puff lasted 2–3 s. A third-generation EC (eVic Primo SE, Joyetech Electronics Co.,Ltd, China) was used, with a proC1-S atomizer with a resistance of 0.25Ω. Exposure settings were standardised (effect 32W, temperature 230 °C). Two commercially available e-liquids were used (Valeo laboratories GmbH, Germany), composed of propylene glycol (49%), glycerine (44%) and ethanol (5%) with no added flavourings; one contained 19 mg/ml of nicotine, the other without nicotine.Venous blood was sampled from the antecubital vein with no or minimal stasis. At inclusion routine blood tests were taken including blood cell count, serum-creatinine, electrolytes and glucose. Blood pressure and pulse were measured at baseline, as well as at 30 and 60 minutes post exposure. Blood pressure equipment was a semi-automatic oscillometric sphygmomanometer (Omron M7, Omron Healthcare Europe B.V., Hoofddorp, NL).