Search

Background: Exposure to second-hand smoke has been shown to be associated with increased cardiovascular mortality in several, but not all, epidemiologic studies. Our aim was to investigate the risk of circulatory death associated with exposure to second-hand smoke in never-smokers in a very large prospective study, the European Prospective Investigation into Cancer and Nutrition. A secondary aim was to use cotinine levels for cross-validating self-reported second-hand smoke exposure., Methods: Cox proportional hazard models were used to investigate the risk of death due to circulatory causes associated with second-hand smoke exposure in 135,233 never-smokers. Exposure to second-hand smoke was assessed through a questionnaire at enrollment and then validated against plasma cotinine measurements in a subsample., Results: Study participants who reported second-hand smoke exposure at home had higher cotinine levels (median plasma cotinine concentration in exposed = 0.82 microg/L; in those unexposed 0.02 microg/L). Second-hand smoke exposure at home was associated with an increased risk of dying from cardiovascular diseases (hazard ratio [HR] = 1.38 [95% confidence interval = 1.01-1.90]), all circulatory diseases (1.28 [0.98-1.69]), and coronary heart disease (1.31 [0.83-2.08]) after adjustment for age, sex, education, physical activity, and body mass index. Dose-response relationships were observed between exposure to second-hand smoke at home and risk of circulatory death (HR per each additional hour/d = 1.25 [1.04-1.50]). Having a partner who smokes more than 30 cigarettes per day considerably increased the risk of a circulatory death (2.94 [1.11-7.78]). Second-hand smoke exposure at home was not associated with total mortality (1.03 [0.93-1.13])., Discussion: Exposure to second-hand smoke at home (as confirmed by plasma cotinine levels) increases the risk of cardiovascular mortality.

The association between intake of N-nitrosodimethylamine (NDMA), the most commonly occurring of the volatile nitrosamines derived from foods, and gastric cancer risk has been investigated using data from a case-control study conducted in Northern Italy between 1985 and 1993, including 746 incident cases of gastric cancer and 2,053 controls admitted to hospital for acute, non-neoplastic and non-digestive tract diseases, not related to long-term modifications of diet. Information was collected on frequency of consumption of 29 food items, including selected sources of NDMA. Compared with subjects in the lowest tertile of NDMA intake, the odds ratios (ORs) were 1.1 in the intermediate and 1.6 in the highest tertile of intake. These estimates were not appreciably modified after allowance for total energy intake, other major dietary and non-dietary correlates of gastric cancer, and estimated intake of nitrite and nitrate: the multivariate OR for the highest NDMA intake tertile was 1.4 (95% CI 1.1-1.7). The association was consistent across strata of sex and age, but somewhat stronger in males and in subjects below age 60 (OR in the highest tertile, 1.8). Limitations of exposure assessment and absence of information on other N-nitrosamines preclude, however, any definite assessment of the possible role of exogenous N-nitrosamines in gastric carcinogenesis.