Carter R, Nicotra B, Huber G
Departments of Medicine and Physiology, University of Texas Health Center at Tyler 75710.
Chest. 1994 Dec;106(6):1730-9. doi: 10.1378/chest.106.6.1730.
Although the natural history of COPD is thought to be well known, studies assessing differences in the onset and course of the disease by gender are surprisingly lacking. This study is a cross-sectional analysis using progressive cycle ergometry exercise testing to assess male and female patients at specific levels of airway obstruction to see if they differ in their exercise capacity and decline in functional capacity.
The study group included 417 patients with COPD, 55 to 85 years of age, who were compared with 29 controls of similar age; all patients had COPD (FEV1/FVC < 75% predicted) without restrictive disease. Exercise testing in groups based on the level of pulmonary dysfunction defined by FEV1/FVC ratios (mild, 60.5 to 69.5%; moderate, 50.5 to 60.5%; severe < 50.5%) was analyzed. Data were evaluated using the Statistical Analysis System, analyzing gender and degree of airway obstruction and adjusting for any difference in age and peak exercise heart rate (covariate analysis of variance).
Men demonstrated progressive reductions of body weight, exercise ability (assessed by the VO2), oxygen pulse (O2P, an indicator of stroke volume), and maximum exercise ventilation (VEmax) even with mild pulmonary dysfunction. Women did not lose weight, and maintained usual exercise ability (VO2, VEmax) and O2P until moderate or severe disease was present. Additional confirmation of a decrease in cardiac function for men with mild airway obstruction (p < 0.0001, controls), but not for women with mild airway disease, was obtained by estimation of cardiac output. Further, women presented with COPD at lower levels of tobacco smoke exposure than men for the entire group (43.8 vs 63.0 pack-years, p < 0.0001) and for each subgroup of disease severity. There were proportionally more life-time female nonsmokers than male nonsmokers with COPD (16 vs 5, p < 0.001).
Male and female patients with COPD differed in their decline of functional aerobic capacity even at equivalent levels of pulmonary dysfunction. One reason for this appeared to be a decrease in the O2P occurring early in the natural history of the disease in the men and not in the women. Although general body de-conditioning may be the cause, heart disease may also be a contributing aspect. The relative delay in the loss of exercise capacity and body mass by the women may relate to predisease differences in physical activity. Women manifested significant lung disease with less cigarette smoking than men. This may be attributable to a different susceptibility to cigarette smoke between the sexes. These results suggest that there appear to be differences in the natural history of COPD in men and women.
尽管慢性阻塞性肺疾病（COPD）的自然病程被认为已为人熟知，但令人惊讶的是，缺乏评估该疾病发病和病程中性别差异的研究。本研究是一项横断面分析，采用渐进式循环测力计运动测试，以评估处于特定气道阻塞水平的男性和女性患者，看他们在运动能力和功能能力下降方面是否存在差异。
研究组包括417例年龄在55至85岁之间的COPD患者，并与29例年龄相仿的对照组进行比较；所有患者均患有COPD（第一秒用力呼气容积/用力肺活量[FEV1/FVC]<预测值的75%）且无限制性疾病。根据FEV1/FVC比值定义的肺功能障碍水平（轻度，60.5%至69.5%；中度，50.5%至60.5%；重度<50.5%）对各小组的运动测试进行分析。使用统计分析系统对数据进行评估，分析性别和气道阻塞程度，并对年龄和运动峰值心率的任何差异进行校正（协方差分析）。
即使存在轻度肺功能障碍，男性的体重、运动能力（通过摄氧量评估）、氧脉搏（O2P，每搏输出量的指标）和最大运动通气量（VEmax）也呈逐渐下降趋势。女性在中度或重度疾病出现之前体重未减轻，且保持正常运动能力（VO2、VEmax）和O2P。通过心输出量估计进一步证实，轻度气道阻塞男性的心脏功能下降（p<0.0001，与对照组相比），而轻度气道疾病女性则无此情况。此外，在整个研究组中，女性出现COPD时的烟草烟雾暴露水平低于男性（43.8对63.0包年，p<0.0001），且在疾病严重程度的每个亚组中均如此。患有COPD的终身女性非吸烟者比例高于男性非吸烟者（16对5，p<0.001）。
即使在肺功能障碍程度相当的情况下，男性和女性COPD患者在有氧功能能力下降方面仍存在差异。其中一个原因似乎是，在疾病自然病程早期，男性的O2P下降，而女性则没有。虽然全身机能失调可能是原因，但心脏病也可能是一个因素。女性运动能力和体重丧失的相对延迟可能与疾病前的身体活动差异有关。女性在吸烟较少的情况下出现明显的肺部疾病。这可能归因于两性对香烟烟雾的易感性不同。这些结果表明，COPD的自然病程在男性和女性中似乎存在差异。
