Risk factors in arteriosclerosis and cardiovascular disease with special emphasis on cigarette smoking

Survival among Chinese women with lung cancer in Singapore: a comparison by stage, histology and smoking status

Lung cancer generally carries a poor prognosis and the determinants of survival have been of interest. However, survival estimates in Asian populations are scarce. This study describes survival rates and their determinants in Singapore Chinese women, a primarily non-smoking population. Three hundred and twenty-six Chinese women, diagnosed with primary lung carcinoma in three major hospitals in Singapore between April 1996 and December 1998, were followed up till 31 December 2000. The Kaplan-Meier method was used for survival analysis. Two hundred and eighty (85.7%) died from the disease during follow-up. The median survival time was 0.7 years and the three-year survival was 15.8%. These survival rates are similar to those of Western populations, and they provide a basis for examining trends over time. Age at diagnosis was an independent prognostic factor [adjusted hazard ratio (relative risk) 1.4, 95% confidence intervals (CI) 1.1-1.9 for women above 65 years relative to younger women]. Most (70.5%) tumours were stage III/IV at diagnosis. Three-year survival ranged from 72% among patients with stage I tumours to 7% for stage IV tumours. Overall, there was no survival difference among different histological types in all stages combined. When limited to stages I and II cancers, adenocarcinomas were associated with a better outcome relative to other histological subtypes combined (adjusted relative risk 0.4, 95% CI 0.1-1.0). Smoking was an independent risk factor (adjusted relative risk 1.3, 95% CI 1.0-1.8). Nevertheless, non-smokers comprised 57.4% of this series, highlighting the importance of increased awareness among health professionals and the public that lung cancer is not only a disease of smokers. The high proportion of late-stage tumours in this study and the impact of disease stage on outcome underline the importance of early detection in improving survival of lung cancer.

Cigarette smoking as a risk for cardiovascular disease V: Biochemical parameters with increased and decreased nicotine content cigarettes

Cigarette smokers were assessed for customary smoking behavior and then were assigned a cigarette which was 0.4 mg higher or lower in nicotine and after 4 weeks, were returned to their customary brand. Biochemical indices of smoking behavior including blood carboxyhemoglobin (COHb), plasma nicotine, cotinine and thiocyanate (-SCN) were measured every 2 weeks. When nicotine availability was increased, smokers received an increased nicotine bolus per puff as determined by plasma nicotine and did not alter smoking topography or cigarettes per day. Over the 4 weeks, plasma cotinine increased without corresponding increases in COHb and -SCN. The return to standard brand resulted in declining cotinine levels but increasing COHb and -SCN, suggesting altered inhalation patterns. In smokers switched to a low yield cigarette, there was a decrease in the nicotine obtained per cigarette followed by a steady rise in plasma cotinine, -SCN and blood COHb over the 4-week period. A positive correlation was observed between cotinine and the gas phase constituents during the change to lower yield and back to standard brand cigarettes. These results indicate that cigarette smokers compensate for decreased nicotine yield with concomitant increases in gas phase components. In addition, increased nicotine availability results in an increased body burden of nicotine and "tar," but not gas phase constituents. The relative risks of cardiovascular disease under these two situations, which increase exposure to nicotine or gas phase components, deserve careful consideration.