Women who smoke: are women more susceptible to tobacco-induced lung cancer?

Longitudinal Changes in Smoking Habits in Women and Subsequent Risk of Cancer

INTRODUCTION

This study investigated the association between longitudinal smoking habit changes and cancer risk in a cohort of Korean women.

METHODS

Study population included women aged ≥40 years who underwent 2 biennial cancer screenings (2009-2010 and 2011-2012) and were followed up until 2020. This analysis was conducted in 2021. On the basis of changes in smoking habits, participants were grouped into sustained nonsmokers, sustained quitters, new quitters, relapsers, smoking initiators, and sustained smokers. Outcomes included incident cancer cases, smoking-related cancers, and specific cancer sites.

RESULTS

Of 3,051,946 women, the mean age was 54.8 years, and the median follow-up was 8.9 years. Compared with sustained nonsmokers, other groups had a significantly increased risk of cancer and smoking-related cancers: sustained quitters (adjusted hazard ratio=1.05; 95% CI=1.01, 1.09), new quitters (adjusted hazard ratio=1.12; 95% CI=1.07, 1.17), and sustained smokers (adjusted hazard ratio=1.14; 95% CI=1.09, 1.19). A significantly increased risk of lung, stomach, liver, and pancreas cancers was found in sustained smokers and new quitters. Relapsers/smoking initiators showed a higher risk of liver, lung, and breast cancer than sustained nonsmokers, but the strength of their corresponding adjusted hazard ratio was generally lower than that of sustained smokers. The hazard ratio of cancer risk was 0.92 (95% CI=0.87, 0.97) among sustained quitters and 0.97 (95% CI=0.91, 1.03) among new quitters relative to that among sustained smokers.

CONCLUSIONS

This study found a significant association between changes in smoking behavior and cancer risk. These findings suggest that smoking cessation is critical for cancer prevention in women.

Knowledge for Whom? Inviting Students to Establish an Audience for Knowledge and to Shape Knowledge Construction Activities in a Biology Course

One main obstacle for instructors in inviting students to design knowledge construction is the tension between prioritizing students' ideas and maintaining the scientific validity of the activity. In this study, as a way of supporting students in shaping their own knowledge construction, the establishment of an audience for knowledge was enacted in a knowledge construction activity in a biology course. Applying the multiple case study method, this study aimed to explore whether and how the establishment of an audience for knowledge can support students' shaping of knowledge construction that is both scientifically valid and meaningful to students. The recordings of 26 student discussions and student-produced artifacts were analyzed as the main data sources. Student-created audiences and the epistemic features of knowledge construction processes were identified, and how the establishment of the audience did or did not support students' knowledge construction was inferred. The analysis revealed that the students first explicated their epistemic goals by creating audiences as persons who hold students' uncertainties and then designed processes to resolve these uncertainties. This indicates that the created audiences could explicate the object orientation of student activities, serving as the central axis in the students' subsequent shaping of the process to construct knowledge that is meaningful to themselves. However, the activity had limited value in supporting the students' plans for scientifically valid knowledge construction. The instructional strategies that are needed to support students in maintaining scientifically valid plans in practice are discussed. This study has pedagogical implications for the development of instructional strategies to support students' epistemic agency as they engage in shaping their own knowledge construction.

Lung genotoxicity of benzo(a)pyrene in vivo involves reactivation of LINE-1 retrotransposon and early reprogramming of oncogenic regulatory networks

Several lines of evidence have implicated long interspersed nuclear element-1 (LINE-1) retroelement in the onset and progression of lung cancer. Retrotransposition-dependent mechanisms leading to DNA mobilization give rise to insertion mutations and DNA deletions, whereas retrotransposition-independent mechanisms disrupt epithelial programming and differentiation. Previous work by our group established that tobacco carcinogens such as benzo(a)pyrene (BaP) reactivate LINE-1 in bronchial epithelial cells through displacement of nucleosome remodeling and deacetylase (NuRD) corepressor complexes and interference with retinoblastoma-regulated epigenetic signaling. Whether LINE-1 in coordination with other genes within its regulatory network contributes to the in vivo genotoxic response to BaP remains largely unknown. Evidence is presented here that intratracheal instillation of ORFeus^LSL mice with BaP alone or in combination with adenovirus (adeno)-CRE recombinase is genotoxic to the lung and associated with activation of the human LINE-1 transgene present in these mice. LINE-1 reactivation modulated the expression of genes involved in oncogenic signaling, and these responses were most pronounced in female mice compared with males and synergized by adeno-CRE recombinase. This is the first report linking LINE-1 and genes within its oncogenic regulatory network with early sexually dimorphic responses of the lung in vivo.

Perioperative outcome of lung cancer surgery in women: results from a Spanish nationwide prospective cohort study

Background

To assess possible differences in the perioperative profile between men and women in lung cancer surgery.

Methods

A prospective cohort multicenter study was design, in which consecutive patients undergoing curative intent surgery for lung cancer in 24 Thoracic Services throughout Spain were included. Clinical features, tumor- and surgery-related data, postoperative complications, and mortality were recorded.

Results

There were 2,566 men and 741 women. Women were younger than men [mean (SD) age, 61.8 (10.8) vs. 66.5 (9.1) years, P<0.0001] and showed a more favorable preoperative characteristics, with significantly higher percentages of ECOG grade 0 and lower percentages of active smokers (28.4% vs. 33.9%; pack-years 18.8 vs. 26.9) and comorbidities [chronic obstructive pulmonary disease (COPD), diabetes, hypertension, cardiac disorders]. There were significant differences (P<0.001) in histological types and TNM stages with adenocarcinoma (70.1% vs. 46.4%) and IA stage (41.5% vs. 33.6%) more frequent in women. The use of VATS or thoracotomy was similar. The rate of pneumonectomy was higher in men (10.9%) than in women (5.1%) (P<0.001) but the distributions of other procedures were similar. Postoperative complications (pneumonitis, atelectasis, air leak, hemorrhage, fistula, empyema, wound dehiscence, and need of reintubation) were lower in women. Significant differences (P<0.0001) in the severity of postoperative complications (Clavien-Dindo classification) were also found, with higher percentages of grades I (51.6% vs. 43%) and II (37.5% vs. 33%) and lower percentages of grades III and IV among women. The mean length of hospital stay was 7.8 (7.1) days in men versus 6.3 (5.0) days in women, and the 30-day mortality rate 0.3% in women versus 2.9% in men (P<0.0001). The percentage of readmissions within 30 days after surgery was also higher in men (8.6% vs. 2.8%).

Conclusions

This multicenter nationwide study of lung cancer surgery with curative intent shows that the perioperative profile is better in women than in men.

Crosstalk in competing endogenous RNA network reveals the complex molecular mechanism underlying lung cancer

We investigated the transcriptional mechanism underlying lung cancer development. RNA sequencing analysis was performed on blood samples from lung cancer cases and healthy controls. Differentially expressed microRNAs (miRNAs), circular RNAs (circRNAs), mRNAs (genes), and long non-coding RNAs (lncRNA) were identified, followed by pathway enrichment analysis. Based on miRNA target interactions, a competing endogenous network was established and significant nodes were screened. Differentially expressed transcriptional factors were retrieved from the TRRUST database and the transcriptional factor regulatory network was constructed. The expression of 59 miRNAs, 18,306 genes,232 lncRNAs, and 292 circRNAs were greatly altered in patients with lung cancer. miRNAs were closely associated with cancer-related pathways, such as pathways in cancer, colorectal cancer, and transcriptional misregulation in cancer. Two novel pathways, olfactory transduction and neuroactive ligand-receptor interactions, were significantly enriched by differentially expressed genes. The competing endogenous RNA network revealed 5 hub miRNAs. Hsa-miR-582-3p and hsa-miR-582-5p were greatly enriched in the Wnt signaling pathway. Hsa-miR-665 was closely related with the MAPK signaling pathway. Hsa-miR-582-3p and hsa-miR-582-5p were also present in the TF regulatory network. Transcriptional factors of WT1 (wilms tumor 1) and ETV1 (ETS variant 1) were regulated by hsa-miR-657 and hsa-miR-582-5p, respectively, and controlled androgen receptor gene expression. miR-582-5p, miRNA-582-3p, and miR-657 may play critical regulatory roles in lung tumor development. Our work may explore new mechanism of lung cancer and aid the development of novel therapy.

Gender differences in the association of smoking and drinking with the development of cognitive impairment

Modifiable lifestyle-related factors such as smoking and alcohol drinking are associated with cognitive impairment in the elderly population but the relationships have shown various results. To evaluate the relationship of alcohol drinking and smoking in the early 60 s with the risk of developing incident cognitive impairment. In 1999, we evaluated cognitive function, smoking, and drinking status in 3,174 inhabitants aged 60–64 years in a rural area of Korea, with a follow-up assessment of cognitive function 7 years later. A total of 1,810 individuals who did not show cognitive impairment at baseline were included. A stratified analysis was applied to evaluate how smoking and alcohol drinking affected the risk of developing cognitive impairment based on gender. Current smokers showed a higher risk for developing cognitive impairment than did never smokers (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.09–2.15). The OR for female current smokers compared with never smokers was 1.62 (95% CI, 1.05–2.52), and smokers with higher pack-years were more likely to develop cognitive impairment than never smokers, showing a dose–response relationship (P for trend = 0.004). Frequent alcohol consumption increased the risk of developing cognitive impairment (OR, 1.68; 95% CI, 1.01–2.78), and a dose–response relationship was observed among male subjects (P for trend = 0.044). Infrequent drinking in females decreased the odds of developing cognitive impairment (OR, 0.67; 95% CI, 0.42–1.00), whereas frequent drinking tended to increase the odds, although this trend was not significant, suggesting a U-shaped relationship. Although the sample was small for some analyses, especially in female, our data suggest that smoking and drinking in the early 60 s are associated with a risk of developing cognitive impairment, and this relationship is characterized by gender differences.

Metabolism of the environmental toxicant benzo(a)pyrene by subcellular fractions of human ovary

Knowledge of the ability of the female reproductive system to metabolize environmental chemicals is critical not only from the standpoint of toxicity but also from infertility risk assessment. Benzo(a)pyrene (BaP) is a toxicant that is released into the environment from automobile exhausts, cigarette smoke, burning of refuse, industrial emissions, and hazardous waste sites. In exposed animals, BaP becomes activated to reactive metabolites that interfere with target organ function and as a consequence cause toxicity. Studies on animal models conducted in our laboratories and those of others have shown that BaP possess endocrine disrupting properties. Thus, this chemical has the potential to cause infertility and cancers in the female genital tract. An understanding of BaP metabolism in the female reproductive system will be of importance in the diagnosis and management of female fertility as well as cancers in the reproductive tissues. Therefore, the objective of our study was to examine the metabolism of BaP by human ovarian subcellular fractions. Human ovary samples (eight individuals) were obtained from postoperative tissue removed from subjects with uterine tumors. Subcellular fractions (nuclear, cytosolic, mitochondrial, and microsomal) were prepared by differential centrifugation. BaP (1 μM and 3 μM) was individually incubated with individual subcellular fractions for 15 min and the products were analyzed by high-performance liquid chromatography. Among the different fractions tested, microsomal BaP metabolism was higher than the rest of the fractions. The BaP metabolites identified were as follows: BaP-9,10-diol, BaP-4,5-diol, BaP-7,8-diol, 9(OH) BaP, 3(OH) BaP, BaP-1,6-dione, BaP-3,6-dione, and BaP-6,12-dione. Of interest was the presence of DNA-reactive metabolites such as BaP-3,6-dione, BaP-6,12-dione, and BaP 7,8-diol, which have been implicated in the causation of infertility and cancer. Our results indicate that women who are exposed to BaP via cigarette smoke, occupational settings, and diet are more likely at a larger risk of this toxicant-induced infertility and cancer than others.

Are women who smoke at higher risk for lung cancer than men who smoke?

Worldwide lung cancer incidence is decreasing or leveling off among men, but rising among women. Sex differences in associations of tobacco carcinogens with lung cancer risk have been hypothesized, but the epidemiologic evidence is conflicting. We tested sex-smoking interaction in association with lung cancer risk within a population-based case-control study, the Environment and Genetics in Lung Cancer Etiology (EAGLE) Study (Lombardy, Italy, 2002-2005). Detailed lifetime smoking histories were collected by personal interview in 2,100 cases with incident lung cancer and 2,120 controls. Odds ratios and 95% confidence intervals for pack-years of cigarette smoking were estimated by logistic regression, adjusted for age, residence area, and time since quitting smoking. To assess sex-smoking interaction, we compared the slopes of odds ratios for logarithm of pack-years in a model for men and women combined. Overall, the slope for pack-years was steeper in men (odds ratio for female-smoking interaction = 0.39, 95% confidence interval: 0.24, 0.62; P < 0.0001); after restriction to ever smokers, the difference in slopes was much smaller (odds ratio for interaction = 0.63, 95% confidence interval: 0.29, 1.37; P = 0.24). Similar results were found by histological type. Results were unchanged when additional confounders were evaluated (e.g., tobacco type, inhalation depth, Fagerström-assessed nicotine dependence). These findings do not support a higher female susceptibility to tobacco-related lung cancer.

Sex differences in susceptibility to PAHs is an intrinsic property of human lung adenocarcinoma cells

Recent epidemiological studies have disputed whether females are at increased risk of lung cancer compared to males. However, several molecular studies are in support of an increased susceptibility to tobacco smoke carcinogens among females. Our earlier findings suggest that women display higher levels of smoking-induced bulky/hydrophobic DNA adducts which may be related to an increased expression of CYP1A1 in their lungs, compared to men. In this in vitro study, 11 lung adenocarcinoma cell lines, 6 of male and 5 of female origin, were exposed to benzo[a]pyrene, cigarette smoke condensate (CSC), or vehicle control. Subsequent expression analysis of genes in the polycyclic aromatic hydrocarbon bioactivation pathway was conducted with Real-Time RT-PCR. DNA adducts were measured in benzo[a]pyrene-exposed cells by ³²P-postlabelling analysis, and CYP1 activity was measured by EROD assay. Analysis of benzo[a]pyrene-DNA adducts showed higher levels of adducts in cell lines from women compared to cell lines from men (p=0.03). The results also revealed significant sex differences in CYP1A1 gene expression, both in untreated cells (p=0.03), and in cells exposed to benzo[a]pyrene (p=0.017) and cigarette smoke condensate (p=0.0043). In CSC-exposed cells, significantly higher levels of CYP1 activity was found in cell lines of female origin (p=0.049). These results are in support of the previously published in vivo data, providing evidence for a higher susceptibility to PAH of women's lungs.

Gender-related differences in response to mutagens and carcinogens

The incidences of many cancers can be very different in men and women. Besides differences in exposures to putative causative agents, it is plausible that both genetic and epigenetic effects play roles in these differences. In addition, gender-specific lifestyle and behavioural factors may modulate the effects of exposure to genotoxins. This commentary focuses on several aspects of gender-related differences in responses to mutagens and carcinogens, including sensitivity to chromosome damage, the contribution of genotypic variation and the role of DNA methylation. It is concluded that the reasons for gender differences in cancer susceptibility remain largely unknown in many cases, and the subject deserves more attention and study.

Relationships between hand-rolled cigarettes and primary lung cancer: a Norwegian experience

INTRODUCTION

Detailed smoking history of patients developing lung cancer is rarely known, especially not for users of hand-rolled cigarettes. In Norway, smoking hand-rolled tobacco is still popular, accounting for one-third of the total tobacco consume.

METHODS

A questionnaire-based study revealing detailed information about tobacco consume with consecutive inclusion of all persons developing lung cancer in Southern Norway 2002-2005.

RESULTS

In this unselected population with 479 patients with newly diagnosed lung cancer, 95% had a smoking history and 88% of ever-smokers had smoked primarily hand-rolled cigarettes. The hand-rolled cigarette smokers had smoked fewer cigarettes daily (15) and less pack-years of tobacco (34) than fabricated cigarette smokers (20, P < 0.0001 and 42, P = 0.021, respectively). Smoking hand-rolled cigarettes was considerably more frequent than expected from official sales statistics. Hand-rolled cigarette smoking revealed an odds ratio of 13 for developing lung cancer compared with smoking fabricated cigarettes.

CONCLUSION

In this unselected population with newly diagnosed lung cancer, nine out of 10 ever-smokers had smoked primarily hand-rolled cigarettes. Patients smoking hand-rolled cigarettes had a smoking history of fewer daily cigarettes and less pack-years tobacco consumed than fabricated cigarette smokers. In this study, hand-rolled cigarettes are more frequently used than shown in national statistics. Smokers of hand-rolled cigarettes may have a greatly increased risk for lung cancer compared with smokers of fabricated cigarettes.

Sex-based differences in premature first myocardial infarction caused by smoking: twice as many years lost by women as by men

BACKGROUND

It has been debated whether smoking increases the risk of heart disease relatively more in women than in men. It is not known whether there are sex differences with regard to how many years prematurely smoking causes acute myocardial infarction (AMI) to occur. We aimed to determine how smoking affects the age of onset of first myocardial infarction in both the sexes.

DESIGN

Clinical data were consecutively entered into a database and were analysed with a multivariate regression technique.

METHODS

In the years 1998-2005, data on 1784 consecutive patients (38.3% women) who were discharged from or died in a district general hospital with a diagnosis of first myocardial infarction were included in the study. Age at first AMI was analysed.

RESULTS

Unadjusted mean ages were 76.2 years for women and 69.8 years for men, a difference of 6.4 years (P<0.001). Mean age within the various groups was: women nonsmokers 80.7 years, women smokers 66.2 years, difference 14.4 years (P<0.001); men nonsmokers 72.2 years, men smokers 63.9 years, difference 8.3 years (P<0.001). After adjustment for risk factors (hypertension, cholesterol levels, diabetes) and patient characteristics (history of angina, history of stroke) 13.7 years of the age difference in women were attributed to smoking; the corresponding figure in men was 6.2 years (P<0.001).

CONCLUSION

First AMI occurred significantly more prematurely in women than in men smokers, implying that twice as many years were lost by women as by men smokers.

Occupation, gender, race, and lung cancer

OBJECTIVE

To examine associations between occupation and lung cancer by gender and race.

METHODS

We used data from the Maryland Lung Cancer Study of nonsmall cell lung carcinoma (NSCLC), a multicenter case control study, to estimate odds ratios (ORs) of NSCLC in different occupations.

RESULTS

After adjusting for smoking, environmental tobacco smoke, and other covariates, NSCLC ORs among women but not men were elevated in clerical-sales, service, and transportation-material handling occupations; ORs were significantly increased in all three categories (OR [95% confidence interval]: 4.07 [1.44 to 11.48]; 5.15 [1.62 to 16.34]; 7.82 [1.08 to 56.25], respectively), among black women, but only in transportation-material handling occupations (OR [95% confidence interval[: 3.43 [1.02 to 11.50]) among white women.

CONCLUSIONS

Women, especially black women, in certain occupations had increased NSCLC ORs.

Combination therapeutic effect of cisplatin along with Solanum trilobatum on benzo(a)pyrene induced experimental lung carcinogenesis

Lung cancer is one of the leading causes of cancer death in the world and is notoriously difficult to treat effectively. In the present study, male Swiss albino mice were divided into five groups of six animals each: group I animals received corn oil orally and served as a control; group II cancer-induced animals received benzo(a)pyrene (B[a]P) (50 mg kg(-1) bodyweight dissolved in corn oil, orally) twice weekly for four successive weeks; group III cancer-bearing animals (after 12 weeks of induction) were treated with cisplatin (6 mg kg(-1) bodyweight, i.p.) once weekly for 4 weeks; group IV cancer-bearing animals were treated with cisplatin along with Solanum trilobatum (300 mg kg(-1) bodyweight) orally once weekly for 4 weeks; and group V animals constituted the drug control treated with cisplatin along with S. trilobatum. The serum, lung and liver were investigated biochemically for aryl hydrocarbon hydroxylase, gamma-glutamyl transpeptidase, 5'-nucleotidase, lactate dehydrogenase (LDH) and protein-bound carbohydrate components (hexose, hexosamine and sialic acid). These enzyme activities were increased significantly in cancer-bearing animals compared with control animals. The elevation of these in cancer-bearing animals was indicative of the persistent deteriorating effect of B[a]P in cancer-bearing animals. Our data suggest that cisplatin, administered with S. trilobatum, may extend its chemotherapeutic effect through modulating protein-bound carbohydrate levels and marker enzymes, as they are indicators of cancer. The combination of cisplatin with S. trilobatum could effectively treat the B[a]P-induced lung cancer in mice by offering protection from reactive oxygen species damage and also by suppressing cell proliferation.

Serum cotinine level as predictor of lung cancer risk

BACKGROUND

No prospective studies are available on serum cotinine level as a marker of lung cancer risk.

METHODS

We analyzed serum cotinine level among 1,741 individuals enrolled since the 1970s in a prospective study of Norwegian volunteers who developed lung cancer during the follow-up and 1,741 matched controls free from lung cancer. Serum cotinine was measured with a competitive immunoassay. Regression dilution was corrected for based on repeated measures on samples from 747 subjects.

RESULTS

Mean serum cotinine level was higher in cases than in controls. Compared with subjects with a cotinine level of < or = 5 ng/mL, the odds ratio of lung cancer was increasing linearly, reaching 55.1 (95% confidence interval, 35.7-85.0) among individuals with a serum cotinine level of > 378 ng/mL. There was no clear suggestion of a plateau in risk at high exposure levels. Odds ratios were very similar in men and women. We found no association between serum cotinine level (range, 0.1-9.9 ng/mL) and lung cancer risk among self-reported nonsmokers and long-term quitters (79 cases and 350 controls).

DISCUSSION

The association between tobacco smoking and lung cancer risk might be stronger than is estimated from questionnaire-based studies. Serum cotinine level is a predictor of risk of lung cancer among smokers. The reported plateau in risk at high doses is likely due mainly to artifacts. There is no difference between men and women in the carcinogenicity of tobacco smoking.

Sex differences in risk of lung cancer: Expression of genes in the PAH bioactivation pathway in relation to smoking and bulky DNA adducts

It is controversial whether women have a higher lung cancer susceptibility compared to men. We previously reported higher levels of smoking-related bulky DNA adducts in female lungs. In a pilot study (27 cases), we also found a higher level of female lung cytochrome P4501A1 (CYP1A1) gene expression. In the present extended study we report on the pulmonary expression of several genes involved in polycyclic aromatic hydrocarbon bioactivation in relation to sex, smoking and DNA adducts. CYP1A1, CYP1B1, aryl hydrocarbon receptor and microsomal epoxide hydrolase gene expression was measured by quantitative real-time reverse transcriptase-PCR in 121 normal lung tissue samples. The expression of CYP1A1 and CYP1B1 was significantly higher among current smokers compared to ex-smokers and never-smokers. Among current smokers, females had a 3.9-fold higher median level of CYP1A1 compared to males (p = 0.011). CYP1B1 expression was not related to sex. Lung DNA adducts (measured by 32P-postlabeling) were highly significantly related to CYP1A1 (p < 0.0001) irrespective of smoking-status. Our results are consistent with the hypothesis that CYP1A1 plays a significant role in lung DNA adduct formation and support a higher susceptibility to lung cancer among females.

Chemotherapeutic efficacy of paclitaxel in combination with Withania somnifera on benzo(a)pyrene-induced experimental lung cancer

Lung cancer is one of the leading causes of cancer death in the world and is notoriously difficult to treat effectively. In the present study, male Swiss albino mice were divided into five groups of six animals each: group I animals received corn oil orally and served as a control; group II cancer-induced animals received benzo(a)pyrene (50 mg/kg bodyweight dissolved in corn oil, orally) twice weekly for four successive weeks; group III cancer-bearing animals (after 12 weeks of induction) were treated with paclitaxel (33 mg/kg bodyweight, i.p.) once weekly for 4 weeks; group IV cancer-bearing animals were treated with paclitaxel along with Withania somnifera (400 mg/kg bodyweight) orally once weekly for 4 weeks; and group V animals constituted the drug control treated with paclitaxel along with W. somnifera. The serum, lung and liver were investigated biochemically for aryl hydrocarbon hydroxylase, gamma-glutamyl transpeptidase, 5'-nucleotidase, lactate dehydrogenase and protein-bound carbohydrate components (hexose, hexosamine and sialic acid). These enzyme activities were increased significantly in cancer-bearing animals compared with control animals. The elevation of these in cancer-bearing animals was indicative of the persistent deteriorating effect of benzo(a)pyrene in cancer-bearing animals. Our data suggest that paclitaxel, administered with W. somnifera, may extend its chemotherapeutic effect through modulating protein-bound carbohydrate levels and marker enzymes, as they are indicators of cancer. The combination of paclitaxel with W. somnifera could effectively treat the benzo(a)pyrene-induced lung cancer in mice by offering protection from reactive oxygen species damage and also by suppressing cell proliferation.

A pooled analysis of bladder cancer case-control studies evaluating smoking in men and women

OBJECTIVE

A recent study suggested that risk of bladder cancer may be higher in women than in men who smoked comparable amounts of cigarettes. We pooled primary data from 14 case-control studies of bladder cancer from Europe and North America and evaluated differences in risk of smoking by gender.

METHODS

The pooled analysis included 8316 cases (21% women) and 17,406 controls (28% women) aged 30-79 years. Odds ratios (ORs) and 95% confidence intervals (95% CI) for smoking were adjusted for age and study. Exposure-response was evaluated in a stratified analysis by gender and by generalized additive models.

RESULTS

The odds ratios for current smokers compared to nonsmokers were 3.9 (95% CI 3.5-4.3) for males and 3.6 (3.1-4.1) for females. In 11 out of 14 studies, ORs were slightly higher in men. ORs for current smoking were similar for men (OR = 3.4) and women (OR = 3.7) in North America, while in Europe men (OR = 5.3) had higher ORs than women (OR = 3.9). ORs increased with duration and intensity in both genders and the exposure-response patterns were remarkably similar between genders.

CONCLUSION

These results do not support the hypothesis that women have a higher relative risk of smoking-related bladder cancer than men.

Sex Differences of Risk Factors for Acute Myocardial Infarction in Japanese Patients

BACKGROUND

Acute myocardial infarction (AMI) is prevalent and has serious consequences including re-infarction and death. Although the risk factors for AMI have been extensively studied in Western countries, they are less well documented in Japan. To determine the risk factors for AMI, we performed a case-control study in unselected patients with AMI.

METHODS AND RESULTS

Risk factors were assessed in 1,925 consecutive patients with a first AMI (age, 28-103 years old; men, 1,353; women, 572), who were admitted to one of the major institutes in Japan, and in 2,279 age-and sex-matched population-based controls. Hypertension (odds ratio (OR), 4.80; 95% confidence interval (CI), 3.80 to 5.95; p < 0.01), diabetes (OR, 3.44; 95% CI, 2.50 to 4.75; p < 0.01), current smoking (OR, 3.39; 95% CI, 2.78 to 4.18; p < 0.01), family history (OR, 1.84; 95% CI, 1.30 to 2.62; p < 0.01), and hypercholesterolemia (OR, 1.28; 95% CI, 1.00 to 1.62; p < 0.05) were all independent risk factors for AMI. However, obesity (OR, 1.13; 95% CI, 0.92 to 1.50; NS) was not. Hypertension (OR, 4.80; 95% CI, 3.80 to 6.02; p < 0.01), current smoking (OR, 4.00; 95% CI, 3.02 to 5.00; p < 0.01), and diabetes (OR, 2.9; 95% CI, 2.00 to 4.04; p < 0.01) were all independent risk factors for AMI in men. In contrast, only current smoking (OR, 8.22; 95% CI, 3.98 to 18.88; p < 0.01), diabetes (OR, 6.12; 95% CI, 3.78 to 12.02; p < 0.01), and hypertension (OR, 5.04; 95% CI, 2.92 to 7.52; p < 0.01) were independent risk factors for AMI in women. Hypercholesterolemia was an independent risk factor for AMI in men (OR, 1.52; 95% CI, 1.00 to 1.98; p < 0.05), but not in women.

CONCLUSIONS

Hypertension, diabetes, current smoking, family history and hypercholesterolemia are associated with AMI in Japanese patients, and the importance of the risk factors for AMI differs between men and women. Hypertension, current smoking, diabetes and family history are the most important risk factors in men, whereas current smoking, diabetes, hypertension and family history are the most important risk factors in women. Hypercholesterolemia is an independent risk factor for AMI in men, but not in women. To the best of our knowledge, this is the first clinical study to define the relative importance of risk factors for AMI in Japanese patients.

Second-hand smoke-induced cardiac fibrosis is related to the Fas death receptor apoptotic pathway without mitochondria-dependent pathway involvement in rats

Exposure to environmental tobacco smoke has been epidemiologically linked to heart disease among nonsmokers. However, the molecular mechanism behind the pathogenesis of cardiac disease is unknown. In this study, we found that Wistar rats, exposed to tobacco cigarette smoke at doses of 5, 10, or 15 cigarettes for 30 min twice a day for 1 month, had a dose-dependently reduced heart weight to body weight ratio and enhanced interstitial fibrosis as identified by histopathologic analysis. The mRNA and activity of matrix metalloprotease-2 (MMP-2), representing the progress of cardiac remodeling, were also elevated in the heart. In addition, we used reverse-transcriptase polymerase chain reaction and Western blotting to demonstrate significantly increased levels of the apoptotic effecter caspase-3 in treated animal hearts. Dose-dependently elevated mRNA and protein levels of Fas, and promoted apoptotic initiator caspase-8 (active form), a molecule of a death-receptor-dependent pathway, coupled with unaltered or decreased levels of cytosolic cytochrome c and the apoptotic initiator caspase-9 (active form), molecules of mitochondria-dependent pathways, may be indicative of cardiac apoptosis, which is Fas death-receptor apoptotic-signaling dependent, but not mitochondria pathway dependent in rats exposed to second-hand smoke (SHS). With regard to the regulation of survival pathway, using dot blotting, we found cardiac insulin-like growth factor-1 (IGF-1) and IGF-1 receptor mRNA levels to be significantly increased, indicating that compensative effects of IGF-1 survival signaling could occur. In conclusion, we found that the effects of SHS on cardiomyocyte are mediated by the Fas death-receptor-dependent apoptotic pathway and might be related to the epidemiologic incidence of cardiac disease of SHS-exposed nonsmokers.

DNA adducts as markers of exposure and risk

Many carcinogens exert their biological effects through the formation of DNA adducts by metabolically activated intermediates. Detecting the presence of DNA adducts in human tissues is, therefore, a tool for molecular epidemiological studies of cancer. A large body of evidence demonstrates that DNA adducts are useful markers of carcinogen exposure, providing an integrated measurement of carcinogen intake, metabolic activation, and delivery to the target macromolecule in target tissues. Monitoring accessible surrogate tissues, such as white blood cells, also provides a means of investigating occupational or environmental exposure in healthy individuals. Such exposure to carcinogens, e.g. to polycyclic aromatic hydrocarbons, has been demonstrated in several industries and in defined populations, respectively, by the detection of higher levels of adducts. Adducts detected in many tissues of smokers are at levels significantly higher than in non-smokers, although the magnitude of the elevation does not predict the magnitude of the risk. While such associations do not demonstrate causality, they do, importantly, lend plausibility to observed associations between smoking and cancer. However, there is still resistance to the notion that such monitoring can inform, rather than merely confirm, epidemiological investigations of cancer causation. Interestingly, smoking was recently causally linked to cervical cancer after years of being considered a confounding factor; yet smoking-related adducts have been known to be present in cervical epithelium for some time. In the few prospective studies thus far, elevated adduct levels have been found in individuals who subsequently developed cancer compared with individuals who did not. The potential for biomarker measurements, such as DNA adducts, to provide answers to the origin of many cases of human cancer for which an environmental cause is suspected, needs to be exploited more fully in future epidemiological studies.

Familial multiple primary lung cancers: a population-based analysis from Sweden

Multiple primary cancers arise because of inherited or acquired deficiencies, and their causes may depend on the first primary cancer, or they may be entirely independent. We used a nation-wide family dataset to search for evidence for a genetic predisposition to lung cancer. The Swedish Family-Cancer Database includes all Swedes born in 1932 and later with their parents, totalling over 10.2 million individuals. Cancer cases were retrieved from the Swedish Cancer Registry up to year 2000. Standardized incidence ratios (SIR) and 95% confidence limits (CI) were calculated for first and second primary lung cancers by a family history. The incidence of second primary lung cancer was nine times higher among cases with familial lung cancer compare to that of first primary lung cancer. The proportion of multiple primary lung cancer patients with family history for lung cancer was 4.7% (9/190) for men and 6.5% (5/77) for women. Lung cancer patients with a family history of lung cancer were at a significantly increased risk for subsequent primary lung cancer among both men (SIR=9.89, 95%CI 4.48-18.66) and women (SIR=17.86, 95%CI 5.63-42.00). The corresponding SIRs in patients without a family history were 2.04 (95%CI 1.75-2.36) and 5.10 (95%CI 3.99-6.43) for men and women, respectively. The present study suggests that the development from the first primary lung cancer to the second primary lung cancer may be more strongly affected by genetic factor than the first primary lung cancer.

Lung cancer in women

Lung cancer is the leading cause of cancer death in the United States and is responsible for 20,000 more deaths yearly in US women than breast cancer. Cigarette smoking is the major cause of lung cancer, and unfortunately, approximately 22 million US women smoke. Mounting evidence suggests that there are significant differences in lung cancer between the sexes. There is a difference in the histologic distribution of lung cancer, with glandular differentiation being more common in women. Genetic variation may account for differences in susceptibility, and hormonal and biologic factors may play a role in carcinogenesis. Lung cancer patients have few therapeutic options. A more thorough understanding of the heterogeneity of lung cancer across populations may lead to innovations in treatment and prevention strategies.

TP53 Mutation Spectrum in Lung Cancer Is Not Different in Women and Men

Whether women are more susceptible to lung cancer than men has been controversial. Several case-control studies suggested that women have greater risk of lung cancer compared with men at similar levels of cigarette smoking, whereas some large cohort studies failed to observe this association. Other studies indicated that lung cancer may have biological characteristics and mechanisms of carcinogenesis that are gender specific. Therefore, we hypothesized that women are more susceptible to the carcinogenic effects of tobacco smoke exposure, as evidenced by a higher frequency of G:C-to-T:A somatic mutations in tumors from women in comparison with men at similar levels of tobacco smoke exposure. To investigate our hypothesis, we examined the TP53 mutational spectrum in a case-only (102 women and 201 men) series study where complete smoking information was available. A similar frequency and type of somatic TP53 mutations were observed in women and men. In conclusion, our study indicates that the TP53 mutation spectrum is similar in women and men. Our results are consistent with a recent large cohort study and summary of previous cohort studies, suggesting that women likely have equivalent susceptibility to lung cancer as men.

Influence of Sex on Toxicity and Treatment Outcome in Small-Cell Lung Cancer

Purpose

Female sex has been shown consistently to be a favorable prognostic factor in small-cell lung cancer (SCLC). Studies have shown that women with other tumor types experience greater treatment toxicity, but there have been few studies of sex-related toxicity in SCLC.

Patients and Methods

This was a sex-based retrospective analysis of four SCLC trials conducted by the National Cancer Institute of Canada Clinical Trials Group between 1987 and 1999. The 1,006 patients (648 males and 358 females) received similar chemotherapy consisting of cyclophosphamide-doxorubicin-vincristine and etoposide-cisplatin. Toxicities examined included myelosuppression, stomatitis, vomiting, and infection. Other end points included dose reductions and omissions, response, and survival.

Results

Women experienced significantly more hematologic toxicity than men (grade 3 and 4 anemia, 16.3% v 7.6%, respectively, P < .001; grade 3 and 4 leukopenia, 80.4% v 69.2%, respectively, P = .0001). However, toxic death rates were similar for men and women (1.5% v 1.1%, respectively, P = .58). Women also had significantly more stomatitis and vomiting of all grades. Despite increased toxicity, 76% of females versus 73.4% of males received all six treatment cycles (P = .38), but 52% of females versus 43.4% of males had treatment delayed for 2 weeks or more (P = .022). Only 31.8% of females and 28.2% of males had at least one cycle of chemotherapy dose reduction (P = .23). The overall response rate was 80.3% for females and 66.9% for males (P < .0001), and the median survival time was 1.31 years for females compared with only 0.91 year for males (P < .0001).

Conclusion

Women experience more chemotherapy-related toxicity in the treatment of SCLC, but they also have increased response rates and survival.

Molecular epidemiology of lung cancer in female passive smokers

To clarify etiology of lung cancer in nonsmoker females, various studies have been done. Particularly, host factors and environmental tobacco smoking (ETS) of females have been emphasized. However, traditional epidemiological data showed controversial results of sex or gender differences in lung cancer susceptibility and suggest presence of some confounders. One of them is that most of epidemiology studies are based on self-reports for ETS. To prevent misestimate effects of ETS via the self-report, exposure monitoring of ETS is required. On the other hand, focusing on genetic polymorphisms in metabolic enzymes and DNA repair, molecular epidemiological studies have been done in nonsmoker females. Therefore, this review considered: 1. gender differences in lung cancer; 2. effects of passive smoking on lung cancer; 3. exposure monitoring of ETS including genetic risks of lung cancer to clarify etiology of lung cancer in the nonsmoker females with molecular epidemiological discussion.

Time trends of lung cancer incidence by histologic types and smoking prevalence in Hong Kong 1983-2000

The gender difference in epidemiology of lung cancer has been postulated to be due to the higher susceptibility of women to risk factors especially tobacco smoking. Alternatively, such difference may also be explained by some unknown gender-specific etiological factors, which can have been masked if both the female and male prevalence of smoking are high. Hong Kong has a low female smoking prevalence rate and therefore the trend of the female incidence of lung cancer is particularly interesting because it can reflect the effects of the non-smoking related risk factors more clearly. The present study examined the trends of incidence rates for the major histologic types and smoking prevalence from 1983 to 2000 in Hong Kong with respect to gender. The prevalence of daily smokers decreased from 39.7% in 1982 to 22% in 2000 in males and from 5.6 to 3.5% in females. The time trends of the lung cancer incidence (overall or with respect to age and histology) were similar for both genders. The overall incidence decreased progressively throughout the study period, attributable to the decrease in squamous cell, small cell and large cell carcinoma. The decline occurred in all age groups but to a greater extent in the younger age groups. The incidence of adenocarcinoma increased until 1988-1990 and then stabilized. The initial increase was restricted to the older age groups. These temporal patterns suggested that the same etiological factors affected both genders to a different extent but manifested as similar changes in the direction of incidence over time. To confirm this hypothesis, further studies were needed to clarify the nature of these etiological factors for the non-smoking related lung cancer cases.

Gender and lung cancer

Accumulating data suggest that the risks for development of lung cancer are different in women compared with men. An increased susceptibility in women to the adverse effects of tobacco may be due to higher levels of DNA adducts, decreased DNA repair capacity, increased frequency of mutations in tumor suppressor genes, and hormonal differences. There are many sex and gender differences in lung cancer presentation, including a greater proportion of adenocarcinoma among women, a greater representation of women in cohorts of younger patients who have lung cancer, and women who do not smoke are more likely to be diagnosed with lung cancer than men. When guidelines for screening, preventive therapies, and treatment options for lung cancer are outlined these differences should be considered.

Urinary 1-hydroxypyrene and mutagenicity in bus drivers and mail carriers exposed to urban air pollution in Denmark

BACKGROUND

Previous studies in Denmark have shown that bus drivers and tramway employees were at an increased risk for developing several types of cancer and that bus drives from central Copenhagen have high levels of biomarkers of DNA damage.

AIMS

The present study evaluates 1-hydroxypyrene concentrations and mutagenic activity in urine as biomarkers of exposure in non-smoking bus drivers in city and rural areas on a work day and a day off and in non-smoking mail carriers working outdoors (in the streets) and indoors (in the office).

METHODS

Twenty-four hour urine samples were collected on a working day and a day off from 60 non-smoking bus drivers in city and rural areas and from 88 non-smoking mail carriers working outdoors (in the streets) and indoors (in the office). The concentration of 1-hydroxypyrene was measured by means of HPLC and the mutagenic activity was assessed by the Ames assay with Salmonella tester strain YG1021 and S9 mix. The N-acetyltransferase (NAT2) phenotype was used as a biomarker for susceptibility to mutagenic/carcinogenic compounds.

RESULTS

Bus drivers excreted more 1-hydroxypyrene in urine than did mail carriers. The differences were slightly smaller when NAT2 phenotype, cooking at home, exposure to vehicle exhaust, and performing physical exercise after work were included. The NAT2 slow acetylators had 29% (1.29 [CI: 1.15-1.98]) higher 1-hydroxypyrene concentrations in urine than the fast acetylators. Male bus drivers had 0.92 revertants/mol creatinine [CI: 0.37-1.47] and female bus drivers 1.90 revertants/mol creatinine [CI: 1.01-2.79] higher mutagenic activity in urine than mail carriers.

CONCLUSION

The present study indicates that bus drivers are more exposed to polycyclic aromatic hydrocarbons (PAH) and mutagens than mail carriers. Mail carriers who worked outdoors had higher urinary concentration of 1-hydroxypyrene, a marker of exposure to PAH, than those working indoors. The individual levels of urinary mutagenic activity were not correlated to excretion of 1-hydroxypyrene. This might be due to the fact that the most potent mutagenic compounds in diesel exhaust are not PAH but dinitro-pyrenes. Among bus drivers, fast NAT2 acetylators had higher mutagenic activity in urine than slow NAT2 acetylators and female bus drivers had higher mutagenic activity than male bus drivers.