The primary risk factor for bladder cancer is cigarette smoking. Using a combined analysis of 11 case‐control studies, we have accurately measured the relationship between cigarette smoking and bladder cancer in men. Available smoking information on 2,600 male bladder cancer cases and 5,524 male controls included duration of smoking habit, number of cigarettes smoked per day and time since cessation of smoking habit for ex‐smokers. There was a linear increasing risk of bladder cancer with increasing duration of smoking, ranging from an odds ratio (OR) of 1.96 after 20 years of smoking (95% confidence interval [CI] 1.48–2.61) to 5.57 after 60 years (CI 4.18–7.44). A dose relationship was observed between number of cigarettes smoked per day and bladder cancer up to a threshold limit of 15–20 cigarettes per day, OR = 4.50 (CI 3.81–5.33), after which no increased risk was observed. An immediate decrease in risk of bladder cancer was observed for those who gave up smoking. This decrease was over 30% after 1–4 years, OR = 0.65 (0.53–0.79), and was over 60% after 25 years of cessation, OR = 0.37 (0.30–0.45). However, even after 25 years, the decrease in risk did not reach the level of the never‐smokers, OR = 0.20. (0.17–0.24). The proportion of bladder cancer cases attributable to ever‐smoking was 0.66 (0.61–0.70) for all men and 0.73 (0.66–0.79) for men younger than 60. These estimates are higher than previously calculated. Int. J. Cancer 86:289–294, 2000. © 2000 Wiley‐Liss, Inc.

The aim of the present analysis was to examine the association of a medical history of asthma, hay fever, eczema, or epilepsy with the risk of glioma and meningioma. Data of a German population-based case-control study included 381 meningioma cases, 366 glioma cases, and 1,494 controls. Participants' histories of asthma, hay fever, eczema, and epilepsy and the respective ages at onset were asked during a personal interview. A small inverse association between allergic condition and both glioma (odds ratio: 0.92; 95% CI: 0.70-1.22) and meningioma (odd ratio: 0.87; 95% CI: 0.66-1.14) was found. For glioma, this inverse association was more pronounced in persons reporting to have asthma compared to other allergic conditions. The positive association between epilepsy and particularly glioma suggests that epilepsy is an early symptom of the disease. As the association was seen also for epilepsies occurring more than a decade before the diagnosis of glioma, this might indicate either an aetiological role of epilepsy, or a relatively long preclinical phase. In conclusion our study confirms previous findings of case control studies but not those from cohort studies. However, possible selection bias in case control studies might not explain the different results in its entirety.

Several diseases and medical treatments are discussed as risk factors for the development of brain tumors. A population‐based case‐control study in the Rhein‐Neckar‐Odenwald area (containing 1.3 million inhabitants) of Germany was established to investigate this question. A total of 226 patients (cases) with primary brain tumors (International Classification of Diseases, ninth edition, classes 191, 191.1, and 192.0) and 418 control subjects (controls) were interviewed using a standardized questionnaire over a period of 2 years. No association was seen for head injuries, hereditary diseases, family history, and radiographic examination of the head and teeth. However, more cases than controls had had meningitis (relative risk [RR], 2.7; 95% confidence interval [CI], 0.9 to 8.6) or epilepsy (RR, 2.6; 95% CI, 0.6 to 11.7). The RR was decreased for those who had allergic diseases (RR, 0.7; 95% CI, 0.5 to 1.0), diabetes (RR, 0.7; 95% CI, 0.3 to 1.8), and infections and colds (RR, 0.3; 95% CI, 0.1 to 0.8).