Epidemiological evidence on tooth loss and lung cancer risk remains limited, especially for smoking-specific associations. To investigate the association between tooth loss and lung cancer risk by smoking status, we first analyzed data from the Shanghai Men’s Health Study (n = 49,868) and the Shanghai Women’s Health Study (n = 44,309). Cox regression models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer risk in relation to tooth loss. We also conducted a meta-analysis to summarize epidemiologic findings to date, incorporating results from the current study and six previously published studies. For 7.3 median follow-up years, 973 incident lung cancer cases (613 men and 360 women) were ascertained. After adjustment for major covariates, tooth loss was associated with an increased risk of lung cancer among men (HR [95% CI] for >10 teeth vs. none = 1.59 [1.21–2.11]) but not among women (0.86 [0.50–1.46]). The positive association was stronger among male current smokers (1.75 [1.26–2.45], p-interaction by smoking status = 0.04). In a meta-analysis incorporating 4052 lung cancer cases and 248,126 non-cases, tooth loss was associated with a 1.64-fold increased risk of developing lung cancer (relative risk [RR, 95% CI] for the uppermost with the lowest category = 1.64 [1.44–1.86]). The positive association was more evident among current smokers (1.86 [1.41–2.46]), but no significant associations were found among never or former smokers. Our findings suggest that tooth loss may be associated with an increased risk of lung cancer, and the association could be modified by smoking status.
The association between benzene exposure and non-Hodgkin lymphoma (NHL) has been the subject of debate, and an IARC working group recently concluded for the first time that there is now limited evidence to support this association in humans. We evaluated the relationship between occupational benzene exposure and NHL risk among 73 087 women in a population-based cohort study of women in Shanghai.
Method
Benzene exposure estimates were derived using a previously developed exposure assessment framework that combined ordinal job-exposure matrix intensity ratings with quantitative benzene exposure measurements from an inspection database of Shanghai factories collected between 1954–2000. Associations between benzene exposure metrics and NHL (n = 102) were assessed using Cox proportional hazard models, with study follow-up occurring from 1997–2009.
Results
Women ever exposed to benzene had a significantly elevated risk of NHL (Hazard Ratio (HR) = 1.87, 95% CI = 1.19–2.96). Compared to unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (ptrend = 0.009) and increasing cumulative exposure levels (ptrend = 0.01), with women in the highest duration and cumulative exposure tertiles having a significantly elevated association with NHL (HR = 2.07, 95% CI = 1.07–4.01 and HR = 2.16, 95% CI = 1.17–3.98, respectively).
Conclusions
Our study is the first to our knowledge to evaluate this association in the context of a population-based prospective cohort of all women with diverse occupational histories. Our findings add to the evidence that benzene is associated with risk of NHL.
Abstract Carbon black (CB) is a material produced by the combustion of hydrocarbon gases or liquids and widely used in various industrial settings. The International Agency for Research on Cancer has classified CB as possibly carcinogenic to humans. Previous studies suggest that CB might induce lung inflammation and injury and it is well known that inflammation can play an important role in tumor development. However, the relationship between CB exposure and peripheral white blood cell counts is still not clear. To address this issue, we conducted a cross-sectional molecular epidemiology study of 106 CB-exposed male workers responsible for packing CB in a CB manufacturing facility that produced very high purity CB and 112 unexposed male control workers from the same geographic region who were frequency-matched to the exposed workers by age. The average number of years worked in the factory for the exposed workers was 12.5 years. Peripheral blood samples were collected and a complete blood cell count (CBC) and lymphocyte subset analysis were conducted. There was a borderline significant increase in eosinophil count, and a significant decrease in total lymphocyte and NK cell counts, among the exposed vs. control workers. Among non-smokers (35 exposed and 29 controls), CB exposure was associated with a borderline significant increase in total white blood cell and neutrophil counts, a significant increase in eosinophil counts, and a significant decrease in total lymphocyte, CD3+ T cell, CD8+ T cell and NK cell counts. There were no significant differences between exposed and control workers for any white blood cell measure among smokers. Also, there was some evidence of an interaction between carbon black exposure and smoking status for neutrophil, total lymphocyte, CD3+ T cell, and CD8+ T cell counts. Our results suggest that CB exposure may be associated with altered levels of cells that play an important role in the inflammatory process among non-smokers. Also, there was evidence for an interaction between CB exposure and tobacco use. These findings may provide new insights into particulate-associated disease. Citation Format: Yufei Dai, Rong Zhang, Yong Niu, Huawei Duan, Tao Meng, Meng Ye, Meili Shen, Ping Bin, Shanfa Yu, Roel Vermeulen, Nathaniel Rothman, Qing Lan, Yuxin Zheng. Effects of occupational exposure to carbon black on peripheral white blood cell counts. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 839. doi:10.1158/1538-7445.AM2015-839
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