中国心力衰竭流行病学调查及其患病率

目的　了解我国成年人慢性心力衰竭 (心衰 )的患病率和分布特征。方法　中国心血管健康多中心合作研究应用四阶段整群随机抽样方法 ,在全国 1 0个省市 (南方和北方各 5个省市 )抽取具有代表性的样本 ,年龄在 35～ 74岁之间 ,城市和农村各半 ,男、女人数均衡。统计不同年龄组、不同性别和不同地区人群的心衰患病率。结果　共抽样调查 35～ 74岁城乡居民 1 5 51 8人 ,心衰患病率为0 9% ;其中男性为 0 7% ,女性为 1 0 % ,女性患病率高于男性 (P <0 0 5)。 35～ 44岁、45～ 54岁、55～64岁、65～ 74岁年龄组的心衰患病率分别为 0 4%、1 0 %、1 3 %和 1 3 % ;随着年龄增高 ,心衰的患病率显著上升 (P <0 0 1 )。我国北方地区心衰患病率为 1 4% ,南方地区心衰患病率为 0 5 % ,北方明显高于南方 (P <0 0 1 ) ;城市人群心衰患病率为 1 1 % ,农村人群心衰患病率为 0 8% ,城市人群心衰患病率高于农村。结论　心衰正在成为我国心血管病领域的重要公共卫生问题     

Detection of lung nodules on digital chest radiographs: potential usefulness of a new contralateral subtraction technique

PURPOSE: To evaluate the potential usefulness of a contralateral subtraction technique developed for radiologists' performance in the detection of subtle lung nodules on chest radiographs. MATERIALS AND METHODS: Fifty chest radiographs (25 normal and 25 abnormal with a subtle lung nodule) that were digitized with a 0.175-mm pixel size and 4,096 gray levels were used. Twelve radiologists (10 attending and two residents) participated in observer tests and read both original and contralateral subtraction images with a sequential testing method. Radiologists' performance was evaluated by means of receiver operating characteristic analysis with use of a continuous rating scale. The beneficial and detrimental effects of the contralateral subtraction technique on the radiologists' performance were also evaluated. RESULTS: The area under the receiver operating characteristic curve values obtained without and with contralateral subtraction images were 0.926 and 0.962, respectively. Results indicated that the contralateral subtraction images significantly (P <.05) improved diagnostic accuracy, particularly for radiologists with limited experience. CONCLUSION: The contralateral subtraction technique can assist radiologists in the correct identification of subtle lung nodules on chest radiographs.     

Oral contraceptive use: association with frequency of hospitalization and chronic disease risk indicators.

A questionnaire was mailed to 97,364 married women, aged 26--50, resident in Greater Boston in 1970, requesting information on lifetime oral contraceptive (OC) use, reproductive history, education, and hospitalization experience in 1969; 65,843 women responded. In 1973 a second questionnaire was mailed to 37,292 of these women, including all OC users and an equal number of non-users matched on age, parity, education, and town of residence. This questionnaire related to use of OCs, other female hormones, and the menopause. OC use was most strongly related to age, with a sixfold increase in use from the oldest women (of whom 10 per cent had used OCs at some time) to the youngest. Use was directly related to education and mobility and inversely related to parity. Reasons for beginning and ceasing use differed for women of different ages and educational attainment. Thus, use of OCs varies with social and reproductive characteristics that are risk indicators for many diseases. OC use was associated with increased risk of hospitalization for thromboembolic disease (risk ratio = 1.5, 95 per cent confidence limits 1.2, 3.2) and for mental illness, hyperthyroidism, hypertension, and cancer of the cervix. OC users were hospitalized for many non-life threatening conditions 20 to 40 per cent more frequently than were non-users.     

Age at first birth and breast cancer risk

An international collaborative study of breast cancer and reproductive experience has been carried out in 7 areas of the world. In all areas studied, a striking relation between age at first birth and breast cancer risk was observed. It is estimated that women having their first child when aged under 18 years have only about one-third the breast cancer risk of those whose first birth is delayed until the age of 35 years or more. Births after the first, even if they occur at an early age, have no, or very little, protective effect. The reduced risk of breast cancer in women having their first child at an early age explains the previously observed inverse relationship between total parity and breast cancer risk, since women having their first birth early tend to become ultimately of high parity. The association with age at first birth requires different kinds of etiological hypotheses from those that have been invoked in the past to explain the association between breast cancer risk and reproductive experience.     

Evaluation of semiautomated measurements of mesothelioma tumor thickness on CT scans

RATIONALE AND OBJECTIVES: To evaluate the clinical acceptability of semiautomated methods for the measurement of mesothelioma tumor thickness in computed tomography (CT) scans. MATERIALS AND METHODS: A computer interface was developed to allow the acquisition of semiautomated mesothelioma tumor thickness measurements, which require the manual selection of a point along the outer margin of the tumor in a CT section. After application of an automated lung segmentation method, the computer automatically identifies a corresponding point along the inner margin of the tumor (as represented by the lung boundary), constructs a line segment between the manually selected outer tumor margin point and the computer-determined inner tumor margin point, and computes tumor thickness as the length of this line segment. Three radiologists and oncologists independently reviewed line segments representing the semiautomated measurements generated by three different algorithms at 134 measurement sites in the CT scans of 22 mesothelioma patients. The observers either accepted a measurement line segment or modified it through the interface. Differences between the initial semiautomated measurements and the measurements as modified by the observers were analyzed. RESULTS: The frequency with which observers accepted the semiautomated measurements without modification was as high as 86%. Of all measurements across all observers and methods (1,206 measurements), 89% were changed by 2 mm or less. CONCLUSION: We have developed semiautomated methods to measure mesothelioma tumor thickness. The potential of these methods has been demonstrated through an observer study. We expect these methods to become important tools for the efficient quantification of tumor extent.