In areas where the practise of betel quid chewing is widespread and the chewers also often smoke and drink alcohol, the relation between oral precancerous lesion and condition to the three habits is probably complex. To explore such association and their attributable effect on oral leukoplakia (OL) and oral submucous fibrosis (OSF), a gender–age-matched case–control study was conducted at Kaohsiung, southern Taiwan. This study included 219 patients with newly diagnosed and histologically confirmed OL or OSF, and 876 randomly selected community controls. All information was collected by a structured questionnaire through in-person interviews. A preponderance of younger patients had OSF, while a predominance of older patients had OL. Betel quid chewing was strongly associated with both these oral diseases, the attributable fraction of OL being 73.2% and of OSF 85.4%. While the heterogeneity in risk for areca nut chewing across the two diseases was not apparent, betel quid chewing patients with OSF experienced a higher risk at each exposure level of chewing duration, quantity and cumulative measure than those who had OL. Alcohol intake did not appear to be a risk factor. However, cigarette smoking had a significant contribution to the risk of OL, and modified the effect of chewing based on an additive interaction model. For the two oral premalignant diseases combined, 86.5% was attributable to chewing and smoking. Our results suggested that, although betel quid chewing was a major cause for both OL and OSF, its effect might be difference between the two diseases. Cigarette smoking has a modifying effect in the development of oral leukoplakia.

In this study the recently developed technique of thermal desorption electrospray ionization/mass spectrometry (TD-ESI/MS) was applied to the rapid analysis of multiple controlled substances. With the reallocation of mass spectral resources [from a standard ESI source coupled with liquid chromatography (LC) to an ambient TD-ESI source], this direct-analysis technique allows the identification of a wider range of illicit drugs through a dual-working mode (pretreatment-free qualitative screening/conventional quantitative confirmation). Through 60-MRM (multiple reaction monitoring) analysis-in which the MS/MS process was programmed to sequentially scan 60 precursor ion/product ion transitions and, thereby, identify 30 compounds (two precursor/product ion transitions per compound)-of a four-component (drug) standard, the signal intensity ratios of each drug transition were comparable with those obtained through 8-MRM analysis, demonstrating the selectivity of TD-ESI/MS for the detection of multiple drugs. The consecutive analyses of tablets containing different active components occurred with no cross-contamination or interference from sample to sample, demonstrating the reliability of the TD-ESI/MS technique for rapid sampling (two samples min-1). The active ingredients in seized drug materials could be detected even when they represented less than 2 mg g-1 of the total sample weight, demonstrating the sensitivity of TD-ESI/MS. Combining the ability to rapidly identify multiple drugs with the "plug-and-play" design of the interchangeable ion source, TD-ESI/MS has great potential for use as a pretreatment-free qualitative screening tool for laboratories currently using LC-MS/MS techniques to analyze illicit drugs.