Effects of cigarette smoke exposure on pulmonary physiology, muscle strength and exercise capacity in a retrospective cohort with 30,000 subjects.

BACKGROUND: The effects of long-term cigarette smoke exposure on pulmonary physiology and how those effects lead to reduced exercise capacity are not well established. METHODS: We retrospectively analyzed the spirometry, single-breath gas transfer (DLCO), peripheral muscle strength, and maximum exercise capacity data in patients referred to McMaster University Medical Centre for cardiopulmonary exercise testing between 2000 and 2012. RESULTS: 29,441 subjects underwent CPET and had a recorded smoking history [58% male, mean age 51.1 years (S.D.±19.6), BMI 27.4 kg/m2(±5.8)]. 7081 (24%) were current or former smokers and were divided into 4 categories by packs years (mean ±S.D.): <10 (5.8±3.3), 10-20 (17.1±2.9), 20-30 (27.1±2.8), 30-40 (37.3±2.8), and >40 (53.9±12.8). Patients with greater cigarette smoke exposure had lower expiratory flow rates (FEV1, FEF50, FEF75, PEFR), DLCO, and maximum power output (MPO) during exercise. There was no association between smoke exposure and muscle strength. Modeling MPO (kpm/min) output as a function of demographic and physiologic variables showed that the data are well explained by muscle strength (kg), FEV1 (L), and DLCO (mmHg/min/mL) in similar magnitude (MPO = 42.7*Quads0.34*FEV10.34 * DLCO0.43; r = 0.84). CONCLUSIONS: Long-term cigarette smoke exposure is associated with small airway narrowing and impaired diffusion capacity but not with peripheral muscle weakness. The effects of smoking, age, and gender on maximum power output are mediated by reductions in FEV1, muscle strength and DLCO. Exercise capacity in smokers may benefit from therapies targeting all 3 variables.

Primary female urethral carcinoma. A retrospective comparison of different treatment techniques.

Between July 1951 and January 1984, 14 female patients (11 black and three white; average age, 58 years) were treated for primary urethral carcinoma. Five patients had radical surgery, six received preoperative radiotherapy (2000 cGy in five fractions) followed by anterior exenteration, and three had definitive radiotherapy (external beam 4000 to 5000 cGy plus 2800 to 3000 cGy interstitial implant). The mean follow-up times were 5.6, 3.9, and 2 years, respectively. In the first two groups, two of 11 patients (18%) are alive and well with no evidence of disease. The rest died of local as well as distant disease. In the third group, two of three patients (67%) are alive and well with no evidence of disease. The third patient died of papillary adenocarcinoma of the uterus 30 months later with no evidence of the primary tumor.