Loud noise exposure and acoustic neuroma.

The results from studies of loud noise exposure and acoustic neuroma are conflicting. A population-based case-control study of 451 acoustic neuroma patients and 710 age-, sex-, and region-matched controls was conducted in Sweden between 2002 and 2007. Occupational exposure was based on historical measurements of occupational noise (321 job titles summarized by a job exposure matrix) and compared with self-reported occupational noise exposure. We also evaluated self-reported noise exposure during leisure activity. Conditional logistic regression was used to estimate odds ratios. There was no statistically significant association between acoustic neuroma and persistent occupational noise exposure, either with or without hearing protection. Exposure to loud noise from leisure activity without hearing protection was more common among acoustic neuroma cases (odds ratio = 1.47, 95% confidence interval: 1.06, 2.03). Statistically significant odds ratios were found for specific leisure activities including attending concerts/clubs/sporting events (odds ratio = 1.82, 95% confidence interval: 1.09, 3.04) and participating in workouts accompanied by loud music (odds ratio = 2.84, 95% confidence interval: 1.37, 5.89). Our findings do not support an association between occupational exposure to loud noise and acoustic neuroma. Although we report statistically significant associations between leisure-time exposures to loud noise without hearing protection and acoustic neuroma, especially among women, we cannot rule out recall bias as an alternative explanation.

Comorbid conditions associated with glioblastoma.

To inform clinical management of glioblastoma patients, we estimated the relative prevalence (present at glioblastoma diagnosis) and incidence (newly diagnosed) of comorbid conditions among these patients and their matched controls. We identified 2,424 glioblastoma patients registered in the Swedish National Cancer Registry between 1993 and 2006. Next, 12,120 randomly sampled population-based controls were individually matched to cases on age, sex and calendar year of diagnosis. We then evaluated patient discharge data for selected potential comorbid conditions. Seizures (odds ratio (OR) 31.6, 95% confidence interval (CI) 24.7-40.3) and cerebral edema (OR 25.0, 95% CI 5.5-114) were the most prevalent conditions at diagnosis. Beginning 30 days after diagnosis, increased risks of incident deep vein thrombosis (hazard ratio (HR) 119.7, 95% CI 60.8-211.0) and pulmonary embolism (HR 92.4, 95% CI 48.3-176.6) were observed. Risks of incident cardiovascular diseases including heart failure (HR 4.0, 95% CI 2.6-6.1), coronary artery disease (HR 2.3, 95% CI 1.7-3.2), and myocardial infarction (HR 1.9, 95% CI 1.1-3.4) were also elevated among glioblastoma patients. In this first population-based study of both prevalent and incident comorbid conditions among glioblastoma patients, we have quantified risk of those conditions related to the tumor and its treatment-based on nationwide registry data. However, for incident conditions we cannot distinguish between the effects of the tumor and the effects of treatment. A novel finding was the elevated risk of cardiovascular disease among glioblastoma patients; glioblastoma patients should be monitored for signs of cardiovascular disease.

Role of tobacco use in the etiology of acoustic neuroma.

Two previous studies suggest that cigarette smoking reduces acoustic neuroma risk; however, an association between use of snuff tobacco and acoustic neuroma has not been investigated previously. The authors conducted a case-control study in Sweden from 2002 to 2007, in which 451 cases and 710 population-based controls completed questionnaires. Cases and controls were matched on gender, region, and age within 5 years. The authors estimated odds ratios using conditional logistic regression analyses, adjusted for education and tobacco use (snuff use in the smoking analysis and smoking in the snuff analysis). The risk of acoustic neuroma was greatly reduced in male current smokers (odds ratio (OR) = 0.41, 95% confidence interval (CI): 0.23, 0.74) and moderately reduced in female current smokers (OR = 0.70, 95% CI: 0.40, 1.23). In contrast, current snuff use among males was not associated with risk of acoustic neuroma (OR = 0.94, 95% CI: 0.57, 1.55). The authors' findings are consistent with previous reports of lower acoustic neuroma risk among current cigarette smokers than among never smokers. The absence of an association between snuff use and acoustic neuroma suggests that some constituent of tobacco smoke other than nicotine may confer protection against acoustic neuroma.