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.
case-control studies; lung cancer; sex differences; smoking
The authors examined the relation between occupation and lung cancer in the large, population-based Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study. In 2002–2005 in the Lombardy region of northern Italy, 2,100 incident lung cancer cases and 2,120 randomly selected population controls were enrolled. Lifetime occupational histories (industry and job title) were coded by using standard international classifications and were translated into occupations known (list A) or suspected (list B) to be associated with lung cancer. Smoking-adjusted odds ratios and 95% confidence intervals were calculated with logistic regression. For men, an increased risk was found for list A (177 exposed cases and 100 controls; odds ratio = 1.74, 95% confidence interval: 1.27, 2.38) and most occupations therein. No overall excess was found for list B with the exception of filling station attendants and bus and truck drivers (men) and launderers and dry cleaners (women). The authors estimated that 4.9% (95% confidence interval: 2.0, 7.8) of lung cancers in men were attributable to occupation. Among those in other occupations, risk excesses were found for metal workers, barbers and hairdressers, and other motor vehicle drivers. These results indicate that past exposure to occupational carcinogens remains an important determinant of lung cancer occurrence.
carcinogens; case-control studies; industry; lung neoplasms; occupational health; occupations
Although pneumonia has been suggested as a risk factor for lung cancer, previous studies have not evaluated the influence of number of pneumonia diagnoses in relation to lung cancer risk.
The Environment And Genetics in Lung cancer Etiology (EAGLE) population-based study of 2,100 cases and 2,120 controls collected information on pneumonia more than one year before enrollment from 1,890 cases and 2,078 controls.
After adjusting for study design variables, smoking, and chronic bronchitis, pneumonia was associated with decreased risk of lung cancer (odds ratio (OR), 0.79; 95% confidence interval (CI), 0.64–0.97), especially among individuals with ≥3 diagnoses versus none (OR, 0.35; 95% CI, 0.16–0.75). Adjustment for chronic bronchitis contributed to this inverse association. In comparison, pulmonary tuberculosis was not associated with lung cancer (OR, 0.96; 95% CI, 0.62–1.48).
The apparent protective effect of pneumonia among individuals with multiple pneumonia diagnoses may reflect an underlying difference in immune response and requires further investigation and confirmation.
Careful evaluation of number of pneumonia episodes may shed light on lung cancer etiology.
pneumonia; epidemiology; lung cancer; multiple infections; tuberculosis
Chronic obstructive pulmonary disease (COPD) has been consistently associated with increased risk of lung cancer. However, previous studies have had limited ability to determine whether the association is due to smoking.
The Environment And Genetics in Lung cancer Etiology (EAGLE) population-based case-control study recruited 2100 cases and 2120 controls, of whom 1934 cases and 2108 controls reported about diagnosis of chronic bronchitis, emphysema, COPD (chronic bronchitis and/or emphysema), or asthma more than 1 year before enrollment. We estimated odds ratios (OR) and 95% confidence intervals (CI) using logistic regression. After adjustment for smoking, other previous lung diseases, and study design variables, lung cancer risk was elevated among individuals with a history of chronic bronchitis (OR = 2.0, 95% CI = 1.5–2.5), emphysema (OR = 1.9, 95% CI = 1.4–2.8), or COPD (OR = 2.5, 95% CI = 2.0–3.1). Among current smokers, association between chronic bronchitis and lung cancer was strongest among lighter smokers. Asthma was associated with a decreased risk of lung cancer in males (OR = 0.48, 95% CI = 0.30–0.78).
These results suggest that the associations of personal history of chronic bronchitis, emphysema, and COPD with increased risk of lung cancer are not entirely due to smoking. Inflammatory processes may both contribute to COPD and be important for lung carcinogenesis.
Red and processed meat intake may increase lung cancer risk. However, the epidemiologic evidence is inconsistent and few studies have evaluated the role of meat-mutagens formed during high cooking temperatures. We investigated the association of red meat, processed meat, and meat-mutagen intake with lung cancer risk in Environment And Genetics in Lung cancer Etiology (EAGLE), a population-based case-control study. Primary lung cancer cases (n=2101) were recruited from 13 hospitals within the Lombardy region of Italy examining ~80% of the cases from the area. Non-cancer population controls (n=2120), matched to cases on gender, residence, and age, were randomly selected from the same catchment area. Diet was assessed in 1903 cases and 2073 controls, and used in conjunction with a meat-mutagen database to estimate intake of heterocyclic amines and benzo[a]pyrene. Multivariable odds ratios (ORs) and 95% confidence intervals (CIs) for sex-specific tertiles of intake were calculated using unconditional logistic regression. Red and processed meat were positively associated with lung cancer risk (highest-versus-lowest tertile: OR=1.8; 95% CI=1.5–2.2; p-trend<0.001 and OR=1.7; 95% CI=1.4–2.1; p-trend<0.001, respectively); the risks were strongest among never smokers (OR=2.4, 95% CI=1.4–4.0, p-trend=0.001 and OR=2.5, 95% CI=1.5–4.2, p-trend=0.001, respectively). Heterocyclic amines and benzo[a]pyrene were significantly associated with increased risk of lung cancer. When separated by histology, significant positive associations for both meat groups were restricted to adenocarcinoma and squamous cell carcinoma, but not small cell carcinoma of the lung. In summary, red meat, processed meat, and meat-mutagens were independently associated with increased risk of lung cancer.
red meat; processed meat; meat-mutagens; cooking methods; lung cancer
Background Exposure to occupational carcinogens is an important preventable cause of lung cancer. Most of the previous studies were in highly exposed industrial cohorts. Our aim was to quantify lung cancer burden attributable to occupational carcinogens in a general population.
Methods We applied a new job–exposure matrix (JEM) to translate lifetime work histories, collected by personal interview and coded into standard job titles, into never, low and high exposure levels for six known/suspected occupational lung carcinogens in the Environment and Genetics in Lung cancer Etiology (EAGLE) population-based case–control study, conducted in Lombardy region, Italy, in 2002–05. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in men (1537 cases and 1617 controls), by logistic regression adjusted for potential confounders, including smoking and co-exposure to JEM carcinogens. The population attributable fraction (PAF) was estimated as impact measure.
Results Men showed an increased lung cancer risk even at low exposure to asbestos (OR: 1.76; 95% CI: 1.42–2.18), crystalline silica (OR: 1.31; 95% CI: 1.00–1.71) and nickel–chromium (OR: 1.18; 95% CI: 0.90–1.53); risk increased with exposure level. For polycyclic aromatic hydrocarbons, an increased risk (OR: 1.64; 95% CI: 0.99–2.70) was found only for high exposures. The PAFs for any exposure to asbestos, silica and nickel–chromium were 18.1, 5.7 and 7.0%, respectively, equivalent to an overall PAF of 22.5% (95% CI: 14.1–30.0). This corresponds to about 1016 (95% CI: 637–1355) male lung cancer cases/year in Lombardy.
Conclusions These findings support the substantial role of selected occupational carcinogens on lung cancer burden, even at low exposures, in a general population.
lung neoplasms; case–control study; carcinogens; occupational health
Mood disorders may affect lung cancer risk. We evaluated this hypothesis in two large studies.
We examined 1,939 lung cancer cases and 2,102 controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study conducted in Italy (2002–2005), and 82,945 inpatients with a lung cancer diagnosis and 3,586,299 person-years without a lung cancer diagnosis in the U.S. Veterans Affairs Inpatient Cohort (VA study), composed of veterans with a VA hospital admission (1969–1996). In EAGLE, we calculated odds ratios (ORs) and 95% confidence intervals (CI), with extensive adjustment for tobacco smoking and multiple lifestyle factors. In the VA study, we estimated lung cancer relative risks (RRs) and 95% CIs with time-dependent Poisson regression, adjusting for attained age, calendar year, hospital visits, time within the study, and related previous medical diagnoses. In EAGLE, we found decreased lung cancer risk in subjects with a personal history of mood disorders (OR: 0.59, 95% CI: 0.44–0.79, based on 121 lung cancer incident cases and 192 controls) and family history of mood disorders (OR: 0.62, 95% CI: 0.50–0.77, based on 223 lung cancer cases and 345 controls). The VA study analyses yielded similar results (RR: 0.74, 95% CI: 0.71–0.77, based on 2,304 incident lung cancer cases and 177,267 non-cancer person-years) in men with discharge diagnoses for mood disorders. History of mood disorders was associated with nicotine dependence, alcohol and substance use and psychometric scales of depressive and anxiety symptoms in controls for these studies.
The consistent finding of a relationship between mood disorders and lung cancer risk across two large studies calls for further research into the complex interplay of risk factors associated with these two widespread and debilitating diseases. Although we adjusted for smoking effects in EAGLE, residual confounding of the results by smoking cannot be ruled out.
Large fractions of the human population do not express GSTM1 and GSTT1 (GSTM1/T1) enzymes because of deletions in these genes. These variations affect xenobiotic metabolism and have been evaluated in relation to lung cancer risk, mostly based on null/present gene models. We measured GSTM1/T1 heterozygous deletions, not tested in genome-wide association studies, in 2120 controls and 2100 cases from the Environment And Genetics in Lung cancer Etiology (EAGLE) study. We evaluated their effect on mRNA expression on lung tissue and peripheral blood samples and their association with lung cancer risk overall and by histology types. We tested the null/present, dominant and additive models using logistic regression. Cigarette smoking and gender were studied as possible modifiers. Gene expression from blood and lung tissue cells was strongly down-regulated in subjects carrying GSTM1/T1 deletions by both trend and dominant models (p<0.001). In contrast to the null/present model, analyses distinguishing subjects with 0, 1 or 2 GSTM1/T1 deletions revealed several associations. There was a decreased lung cancer risk in never-smokers (OR=0.44;95%CI=0.23–0.82; p=0.01) and women (OR=0.50;95%CI=0.28–0.90; p=0.02) carrying 1 or 2 GSTM1 deletions. Analogously, male smokers had an increased risk (OR=1.13;95%CI=1.0–1.28; p=0.05) and women a decreased risk (OR=0.78;95%CI=0.63–0.97; p=0.02) for increasing GSTT1 deletions. The corresponding gene-smoking and gene-gender interactions were significant (p<0.05). Our results suggest that decreased activity of GSTM1/T1 enzymes elevates lung cancer risk in male smokers, likely due to impaired carcinogens’ detoxification. A protective effect of the same mutations may be operative in never-smokers and women, possibly because of reduced activity of other genotoxic chemicals.
GST; copy numbers; gene expression; lung cancer; smoking and gender differences
Family history (FH) of lung cancer is an established risk factor for lung cancer, but the modifying effect of smoking in relatives has been rarely examined. Also, the role of FH of non-malignant lung diseases on lung cancer risk is not well known. We examined the role of FH of cancer and FH of non-malignant lung diseases in lung cancer risk, overall, and by personal smoking, FH of smoking, and histology in 1,946 cases and 2,116 population-based controls within the Environment And Genetics in Lung cancer Etiology (EAGLE) study. Odds ratios (ORs) and 95% CI from logistic regression were calculated adjusting for age, gender, residence, education, and cigarette smoking. FH of lung cancer in any family member was associated with increased lung cancer risk (OR = 1.57, 95% CI = 1.25–1.98). The odds associated with fathers’, mothers’ and siblings’ history of lung cancer were 1.41, 2.14, and 1.53, respectively. The associations were generally stronger in never smokers, younger subjects, and for the adenocarcinoma and squamous cell carcinoma subtypes. FH of chronic bronchitis and pneumonia were associated with increased (OR =1.49, 95% CI = 1.23–1.80) and decreased (OR = 0.73, 95% CI = 0.61–0.87) lung cancer risk, respectively. FH of lung cancer and FH of non-malignant lung diseases affected lung cancer risk independently, and did not appear to be modified by FH of smoking.
family history; lung cancer; smoking; chronic bronchitis; pneumonia
Polymorphisms in genes coding for enzymes that activate tobacco lung carcinogens may generate inter-individual differences in lung cancer risk. Previous studies had limited sample sizes, poor exposure characterization, and a few single nucleotide polymorphisms (SNPs) tested in candidate genes. We analyzed 25 SNPs (some previously untested) in 2101 primary lung cancer cases and 2120 population controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) study from six phase I metabolic genes, including cytochrome P450s, microsomal epoxide hydrolase, and myeloperoxidase. We evaluated the main genotype effects and genotype-smoking interactions in lung cancer risk overall and in the major histology subtypes. We tested the combined effect of multiple SNPs on lung cancer risk and on gene expression. Findings were prioritized based on significance thresholds and consistency across different analyses, and accounted for multiple testing and prior knowledge. Two haplotypes in EPHX1 were significantly associated with lung cancer risk in the overall population. In addition, CYP1B1 and CYP2A6 polymorphisms were inversely associated with adenocarcinoma and squamous cell carcinoma risk, respectively. Moreover, the association between CYP1A1 rs2606345 genotype and lung cancer was significantly modified by intensity of cigarette smoking, suggesting an underling dose-response mechanism. Finally, increasing number of variants at CYP1A1/A2 genes revealed significant protection in never smokers and risk in ever smokers. Results were supported by differential gene expression in non-tumor lung tissue samples with down-regulation of CYP1A1 in never smokers and up-regulation in smokers from CYP1A1/A2 SNPs. The significant haplotype associations emphasize that the effect of multiple SNPs may be important despite null single SNP-associations, and warrants consideration in genome-wide association studies (GWAS). Our findings emphasize the necessity of post-GWAS fine mapping and SNP functional assessment to further elucidate cancer risk associations.
We aimed to examine the effect of alcohol consumption on lung cancer risk stratified by smoking, and to explore whether the impact of alcohol was modified by familial susceptibility to cancer. We recruited 1208 male lung cancer incident cases and 1069 community referents during 2004–2006 and collected their lifetime history of alcohol consumption, cigarette smoking, and family cancer history. Unconditional multivariate logistic regression analysis was performed to estimate the adjusted odds ratio (OR). We tested multiplicative-scale interaction between exposures of interest and examined the additive-scale interaction using synergy index. A moderate association between frequent alcohol consumption and lung cancer was observed among men who had family cancer history (OR = 4.22, 95%CI: 2.46–7.23) after adjustment of smoking and other confounders, while the alcohol effect among men without family history was weak (OR = 1.24, 95%CI: 0.95–1.63) and it became no excess in the never smokers. We observed a consistent synergistic effect between alcohol drinking and family cancer history for all lung cancers and the adenocarcinoma, while there was no multiplicative-scale interaction between the exposures of interest (likelihood ratio test for interaction, p>0.05). Our study revealed a possible synergistic effect between alcohol consumption and familial susceptibility for lung cancer risk; however, this observed possible association needs to be confirmed by future larger analytic studies with more never smoking cases.
Epidemiological and mechanistic evidence on the association of quercetin-rich food intake with lung cancer risk and carcinogenesis are inconclusive. We investigated the role of dietary quercetin and the interaction between quercetin and P450 and glutathione S-transferase (GST) polymorphisms on lung cancer risk in 1822 incident lung cancer cases and 1991 frequency-matched controls from the Environment And Genetics in Lung cancer Etiology study. In non-tumor lung tissue from 38 adenocarcinoma patients, we assessed the correlation between quercetin intake and messenger RNA expression of the same P450 and GST metabolic genes. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) for sex-specific quintiles of intake were calculated using unconditional logistic regression adjusting for putative risk factors. Frequent intake of quercetin-rich foods was inversely associated with lung cancer risk (OR = 0.49; 95% CI: 0.37–0.67; P-trend < 0.001) and did not differ by P450 or GST genotypes, gender or histological subtypes. The association was stronger in subjects who smoked >20 cigarettes per day (OR = 0.35; 95% CI: 0.19–0.66; P-trend = 0.003). Based on a two-sample t-test, we compared gene expression and high versus low consumption of quercetin-rich foods and observed an overall upregulation of GSTM1, GSTM2, GSTT2, and GSTP1 as well as a downregulation of specific P450 genes (P-values < 0.05, adjusted for age and smoking status). In conclusion, we observed an inverse association of quercetin-rich food with lung cancer risk and identified a possible mechanism of quercetin-related changes in the expression of genes involved in the metabolism of tobacco carcinogens in humans. Our findings suggest an interplay between quercetin intake, tobacco smoking, and lung cancer risk. Further research on this relationship is warranted.
Despite extensive investigation of the association between alcohol consumption and breast cancer risk, effect of low-to-moderate alcohol intake on breast cancer incidence has been inconsistent.
A case–control study was conducted in China, 2004–2005 to examine the association by menopausal status, oestrogen (ER) and progesterone receptor (PR) status of the tumour. There were 1009 incident cases with histologically confirmed breast cancer and 1009 age-matched controls recruited. We assessed alcohol consumption by face-to-face interview using a validated questionnaire and obtained tumour ER and PR status from pathology reports.
Low-to-moderate alcohol consumption was inversely associated with breast cancer risk. Compared with nondrinkers, the adjusted odds ratios (ORs) for alcohol <5 g per day were 0.41 (95% confidence interval 0.27–0.62) and 0.62 (0.48–0.79) in postmenopausal and premenopausal women, respectively. The inverse association was consistent for alcohol <15 g per day across hormone receptor status groups with ORs of 0.36–0.56 in postmenopausal women and 0.57–0.64 in premenopausal women. An exception was that alcohol ⩾15 g per day appeared to increase the risk of breast cancers with discordant receptor status in postmenopausal women, that is, ER+/PR− or ER−/PR+ (4.27, 1.57–11.65).
We found that low-to-moderate alcohol intake was not associated with increased risk of breast cancer in pre- or postmenopausal Chinese women. Future studies are required to understand differences in effect of alcohol on breast cancers by tumour hormone receptor status.
alcohol consumption; breast cancer; Chinese women; hormone receptor
The mechanism for the observed association of alcohol consumption breast cancer risk is not known; understanding that mechanism could improve understanding of breast carcinogenesis and optimize prevention strategies. Alcohol may impact breast malignancies or tumor progression by altering DNA methylation. We examined promoter methylation of three genes, the E- cadherin, p16, and RAR-β2 genes in archived breast tumor tissues from participants in a population-based case-control study. Real time methylation-specific PCR was performed on 803 paraffin-embedded samples; and lifetime alcohol consumption was queried. Unordered polytomous and unconditional logistic regression were used to derive adjusted odds ratios (OR) and 95% confidence intervals (CI). RAR-β2 methylation was not associated with drinking. Among premenopausal women, alcohol consumption was also not associated with promoter methylation for E- cadherin and p16 genes. In case-case comparisons of postmenopausal breast cancer, compared to lifetime never drinkers, promoter methylation likelihood was increased for higher alcohol intake for E - cadherin (OR = 2.39, 95% CI, 1.15–4.96), in particular for those with ER-negative tumors (OR = 4.13, 95% CI, 1.16–14.72), and decreased for p16 (OR = 0.52, 95% CI, 0.29-0.92). There were indications that the association with p16 was stronger for drinking at younger ages. Methylation was also associated with drinking intensity independent of total consumption for both genes. We found alcohol consumption was associated with DNA methylation in postmenopausal breast tumors, suggesting that the association of alcohol and breast cancer may be related, at least in part, to altered methylation, and may differ by drinking pattern.
alcohol consumption; breast cancer; epidemiology; epigenetics; promoter methylation
MicroRNAs (miRs) have an important role in lung carcinogenesis and progression. Single-nucleotide polymorphisms (SNPs) in genes involved in miR biogenesis may affect miR expression in lung tissue and be associated with lung carcinogenesis and progression.
We analysed 12 SNPs in POLR2A, RNASEN and DICER1 genes in 1984 cases and 2073 controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) study. We investigated miR expression profiles in 165 lung adenocarcinoma (AD) and 125 squamous cell carcinoma tissue samples from the same population. We used logistic and Cox regression models to examine the association of individual genotypes and haplotypes with lung cancer risk and with lung cancer-specific survival, respectively. SNPs-miR expression associations in cases were assessed using two-sample t-tests and global permutation tests.
A haplotype in RNASEN (Drosha) was significantly associated with shorter lung cancer survival (hazard ratio=1.86, 95% CI=1.19–2.92, P=0.007). In AD cases, a SNP within the same haplotype was associated with reduced RNASEN mRNA expression (P=0.013) and with miR expression changes (global P=0.007) of miRs known to be associated with cancer (e.g., let-7 family, miR-21, miR-25, miR-126 and miR15a).
Inherited variation in the miR-processing machinery can affect miR expression levels and lung cancer-specific survival.
microRNA biogenesis; polymorphism; lung cancer; survival
Background: Few epidemiological studies have examined the effect of wine on the risk of lung cancer. A study was therefore undertaken to estimate the effect of wine consumption, both overall and by type of wine, on the risk of developing lung cancer.
Methods: A hospital based case-control study was conducted on 319 subjects (132 cases, 187 controls) in 1999–2000. All subjects were interviewed about their lifestyles with particular reference to alcohol consumption and tobacco use. The results were analysed using non-parametric logistic regression. The main outcome measure was the risk of lung cancer associated with consumption of wine and its individual types.
Results: A very slight but significant association was observed between the risk of lung cancer and white wine consumption (odds ratio (OR) 1.20 for each daily glass). Red wine consumption, on the other hand, had an OR of 0.43 (95% CI 0.19 to 0.96), with each daily glass of red wine having an inverse association with the development of lung cancer (OR 0.87 (95% CI 0.77 to 0.99)). There was no apparent association between lung cancer and consumption of beer or spirits.
Conclusions: These results suggest that the consumption of red wine is negatively associated with the development of lung cancer. Further studies are needed to test this finding in cancer induced laboratory animals.
Affordable early screening in subjects with high risk of lung cancer has great potential to improve survival from this deadly disease. We measured gene expression from lung tissue and peripheral whole blood (PWB) from adenocarcinoma cases and controls to identify dysregulated lung cancer genes that could be tested in blood to improve identification of at-risk patients in the future. Genome-wide mRNA expression analysis was conducted in 153 subjects (73 adenocarcinoma cases, 80 controls) from the Environment And Genetics in Lung cancer Etiology (EAGLE) study using PWB and paired snap-frozen tumor and non-involved lung tissue samples. Analyses were conducted using unpaired t-tests, linear mixed effects and ANOVA models. The area under the receiver operating characteristic curve (AUC) was computed to assess the predictive accuracy of the identified biomarkers. We identified 50 dysregulated genes in stage I adenocarcinoma versus control PWB samples (False Discovery Rate ≤0.1, fold change ≥1.5 or ≤0.66). Among them, eight (TGFBR3, RUNX3, TRGC2, TRGV9, TARP, ACP1, VCAN, and TSTA3) differentiated paired tumor versus non-involved lung tissue samples in stage I cases, suggesting a similar pattern of lung cancer-related changes in PWB and lung tissue. These results were confirmed in two independent gene expression analyses in a blood-based case-control study (n=212) and a tumor-non tumor paired tissue study (n=54). The eight genes discriminated patients with lung cancer from healthy controls with high accuracy (AUC=0.81, 95% CI=0.74–0.87). Our finding suggests the use of gene expression from PWB for the identification of early detection markers of lung cancer in the future.
microarray gene expression; peripheral blood; lung cancer; stage I
Evidence about the role for reproductive and hormonal factors in the etiology of lung cancer in women is conflicting. To clarify this question, we examined 407 female cases and 499 female controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) population-based case-control study. Subjects were interviewed in person using a computer-assisted personal interview to assess demographics, education, smoking history, medical history, occupational history, reproductive and hormonal factors. Associations of interest were investigated using logistic regression models, adjusted for catchment area and age (matching variables), cigarette smoking (status, pack-years, and time since quitting). Additional confounding variables were investigated but did not substantially affect the results. We observed a reduced risk of lung cancer among women with later age at first live birth (≥31 years: OR=0.57, 95%CI=0.31–1.06, p-trend=0.05), later age at menopause (≥51 years: OR=0.49, 95%CI=0.31–0.79, p-trend=0.003), and longer reproductive periods (≥41 years: OR=0.44, 95%CI=0.25–0.79, p-trend=0.01). A reduced risk was also observed for Hormone Replacement Therapy (OR=0.63, 95%CI=0.42–0.95, p=0.03) and oral contraceptive use (OR=0.67, 95%CI=0.45–1.00, p=0.05), but no trend with duration of use was detected. Menopausal status (both natural and induced) was associated with an augmented risk. No additional associations were identified for other reproductive variables. This study suggests that women who continue to produce estrogens have a lower lung cancer risk. Large studies with great number of never smoking women, biomarkers of estrogen and molecular classification of lung cancer are needed for a more comprehensive view of the association between reproductive factors and lung cancer risk.
case-control study; lung cancer; reproductive factors
Protective effect of garlic on the development of cancer has been reported in vitro and in vivo experimental studies, however, few human epidemiological studies have evaluated the relationship. A population-based case-control study has been conducted in a Chinese population from 2003 to 2010, with the aim to explore the association between raw garlic consumption and lung cancer. Epidemiological data were collected by face-to-face interviews using a standard questionnaire among 1,424 lung cancer cases and 4,543 healthy controls. Unconditional logistic regression was employed to estimate adjusted odds ratios (OR) and their 95% confidence intervals (CIs), and to evaluate ratio of odds ratios (ROR) for multiplicative interactions between raw garlic consumption and other risk factors. After adjusting for potential confounding factors, raw garlic consumption of ≥ 2 times per week is inversely associated with lung cancer (OR = 0.56, 95% CI = 0.44-0.72) with a monotonic dose-response relationship (p for trend <0.001). Furthermore, strong interactions at either additive and/or multiplicative scales were observed between raw garlic consumption and tobacco smoking (Synergy Index (SI) = 0.70, 95% CI = 0.57-0.85; and ROR = 0.78, 95% CI = 0.67-0.90), as well as high-temperature cooking oil fume (ROR = 0.77, 95% CI = 0.59-1.00). In conclusion, protective association between intake of raw garlic and lung cancer has been observed with a dose-response pattern, suggesting that garlic may potentially serve as a chemopreventive agent for lung cancer. Effective components in garlic in lung cancer chemoprevention warrant further in-depth investigation.
lung cancer; garlic consumption; case-control study; China
It has been hypothesized that effects of alcohol consumption on one-carbon metabolism may explain, in part, the association of alcohol consumption with breast cancer risk. The methylenetetrahydrofolate reductase (MTHFR) and 5-methyltetrahydrofolate-homocysteine methyltransferease (MTR) genes express key enzymes in this pathway. We investigated the association of polymorphisms in MTHFR (rs1801133 and rs1801131) and MTR (rs1805087) with breast cancer risk and their interaction with alcohol consumption in a case-control study, the Western New York Exposures and Breast Cancer (WEB) study. Cases (n=1063) were women with primary, incident breast cancer and controls (n= 1890) were frequency matched to cases on age and race. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression. We found no association of MTHFR or MTR genotype with risk of breast cancer. In the original case control study, there was a nonsignificant increased odds of breast cancer among women with higher lifetime drinking. In the current study, there was no evidence of an interaction of genotype and alcohol in premenopausal women. However, among postmenopausal women there was an increase in breast cancer risk for women who were homozygote TT for MTHFR C677T and had high lifetime alcohol intake (≥1161.84 ounces) (OR=1.92, CI=1.13–3.28) and for those who had a high number of drinks per drinking day (> 1.91 drinks/day) (OR=1.80, CI=1.03–3.28) compared to nondrinkers who were homozygote CC. Our findings indicate that among postmenopausal women, increased breast cancer risk with alcohol consumption may be as a result of effects on one-carbon metabolism.
breast cancer epidemiology; one carbon metabolism genes; alcohol
Alcohol consumption is postulated to be a risk factor for pancreatic cancer (PCA), but clarification of degree of risk related to consumption characteristics is lacking. We examined the association between alcohol consumption and PCA in a population-based case–control study (532 cases, 1,701 controls) in the San Francisco Bay Area. Population-based controls were frequency-matched by sex, age within 5-year categories and county of residence to cases identified by the cancer registry’s rapid case ascertainment. Detailed alcohol consumption data, including binge drinking (≥5 drinks/day), were collected during in-person interviews. Odds ratios (OR) and 95% confidence intervals (95% CI) were computed using adjusted unconditional logistic regression. Depending on dose, duration, and pattern of drinking, ORs were increased 1.5- to 6-fold among men but not women. In men, ORs increased with increasing overall alcohol consumption (22–35 drinks/week OR = 2.2, 95% CI = 1.1–4.0; ≥35 drinks/week OR = 2.6, 95% CI = 1.3–5.1, p-trend = 0.04). Most notable were effects with a history of binge drinking (OR = 3.5, 95% CI = 1.6–7.5) including increased number of drinks per day (p-trend = 0.002), and increased years of binge drinking (p-trend = 0.0006). In fully adjusted models that included smoking and other confounders, ORs for binge drinking in men were somewhat higher than in age-adjusted models. Results from our detailed analyses provide support for heavy alcohol consumption (including binge drinking) as a risk factor for PCA in men.
Pancreatic neoplasms; Alcohol-related disorders; Case–control studies; Risk; Epidemiology; Alcohol drinking; Alcoholic beverages
The authors used data collected from 1995 to 1999, from an on-going cancer case–control study in greater Johannesburg, to estimate the importance of tobacco and alcohol consumption and other suspected risk factors with respect to cancer of the oesophagus (267 men and 138 women), lung (105 men and 41 women), oral cavity (87 men and 37 women), and larynx (51 men). Cancers not associated with tobacco or alcohol consumption were used as controls (804 men and 1370 women). Tobacco smoking was found to be the major risk factor for all of these cancers with odds ratios ranging from 2.6 (95% CI 1.5–4.5) for oesophageal cancer in female ex-smokers to 50.9 (95% CI 12.6–204.6) for lung cancer in women, and 23.9 (95% CI 9.5–60.3) for lung cancer and 23.6 (95% CI 4.6–121.2) for laryngeal cancer in men who smoked 15 or more grams of tobacco a day. This is the first time an association between smoking and oral and laryngeal cancers has been shown in sub-Saharan Africa. Long-term residence in the Transkei region in the southeast of the country continues to be a risk factor for oesophageal cancer, especially in women (odds ratio=14.7, 95% CI 4.7–46.0), possibly due to nutritional factors. There was a slight increase in lung cancer (odds ratio=2.9, 95% CI 1.1–7.5) in men working in ‘potentially noxious’ industries. ‘Frequent’ alcohol consumption, on its own, caused a marginally elevated risk for oesophageal cancer (odds ratio=1.7, 95% CI 1.0–2.9, for women and odds ratio=1.8, 95% CI 1.2–2.8, for men). The risks for oesophageal cancer in relation to alcohol consumption increased significantly in male and female smokers (odds ratio=4.7, 95% CI=2.8–7.9 in males and odds ratio=4.8, 95% CI 3.2–6.1 in females). The above results are broadly in line with international findings.
British Journal of Cancer (2002) 86, 1751–1756. doi:10.1038/sj.bjc.6600338 www.bjcancer.com
© 2002 Cancer Research UK
epidemiology; case–control; oesophagus; lung; oral; larynx
Alcohol consumption is increasing worldwide and is associated with numerous cancers. This systematic review examined the role of alcohol in the incidence of cancer in the Chinese population.
Medline/PubMed, EMBASE, CNKI and VIP were searched to identify relevant studies. Cohort and case-control studies on the effect of alcohol use on cancers in Chinese were included. Study quality was evaluated using the Newcastle-Ottawa Scale. Data were independently abstracted by two reviewers. Odds ratios (OR) or relative risks (RR) were pooled using RevMan 5.0. Heterogeneity was evaluated using the Q test and I-squared statistic. P<.01 was considered statistically significant.
Pooled results from cohort studies indicated that alcohol consumption was not associated with gastric cancer, esophageal cancers (EC) or lung cancer. Meta-analysis of case-control studies showed that alcohol consumption was a significant risk factor for five cancers; the pooled ORs were 1.79 (99% CI, 1.47–2.17) EC, 1.40 (99% CI, 1.19–1.64) gastric cancer, 1.56 (99% CI, 1.16–2.09) hepatocellular carcinoma, 1.21 (99% CI, 1.00–1.46) nasopharyngeal cancer and 1.71 (99% CI, 1.20–2.44) oral cancer. Pooled ORs of the case-control studies showed that alcohol consumption was protective for female breast cancer and gallbladder cancer: OR 0.76 (99% CI, 0.60–0.97) and 0.70 (99% CI, 0.49–1.00) respectively. There was no significant correlation between alcohol consumption and lung cancer, colorectal cancer, pancreatic cancer, cancer of the ampulla of Vater, prostate cancer or extrahepatic cholangiocarcinoma. Combined results of case-control and cohort studies showed that alcohol consumption was associated with 1.78- and 1.40-fold higher risks of EC and gastric cancer but was not significantly associated with lung cancer.
Health programs focused on limiting alcohol intake may be important for cancer control in China. Further studies are needed to examine the interaction between alcohol consumption and other risk factors for cancers in Chinese and other populations.
Although alcohol is a recognized teratogen, evidence is limited on alcohol intake and oral cleft risk. The authors examined the association between maternal alcohol consumption and oral clefts in a national, population-based case-control study of infants born in 1996–2001 in Norway. Participants were 377 infants with cleft lip with or without cleft palate, 196 with cleft palate only, and 763 controls. Mothers reported first-trimester alcohol consumption in self-administered questionnaires completed within a few months after delivery. Logistic regression was used to calculate odds ratios and 95% confidence intervals, adjusting for confounders. Compared with nondrinkers, women who reported binge-level drinking (≥5 drinks per sitting) were more likely to have an infant with cleft lip with or without cleft palate (odds ratio = 2.2, 95% confidence interval: 1.1, 4.2) and cleft palate only (odds ratio = 2.6, 95% confidence interval: 1.2, 5.6). Odds ratios were higher among women who binged on three or more occasions: odds ratio = 3.2 for cleft lip with or without cleft palate (95% confidence interval: 1.0, 10.2) and odds ratio = 3.0 for cleft palate only (95% confidence interval: 0.7, 13.0). Maternal binge-level drinking may increase the risk of infant clefts.
alcohol drinking; cleft lip; cleft palate
Epidemiological studies of lung cancer among nonsmoking men are few. This case–control study was conducted among lifetime nonsmoking men between 1990 and 1996 in Germany to examine lung cancer risk in relation to occupation, environmental tobacco smoke, residential radon, family history of cancer and previous lung disease. A total of 58 male cases with confirmed primary lung cancer and 803 male population controls who had never smoked more than 400 cigarettes in their lifetime were personally interviewed by a standardized questionnaire. In addition, 1-year radon measurements in the living and bedroom of the subjects' last dwelling were carried out. Unconditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Having ever worked in a job with known lung carcinogens was associated with a two-fold significantly increased lung cancer risk (OR = 2.2; Cl = 1.0–5.0), adjusted for age and region. The linear trend test for lung-cancer risk associated with radon exposure was close to statistical significance, demonstrating an excess relative risk for an increase in exposure of 100 Bq m−3 of 0.43 (P = 0.052). Nonsignificantly elevated effects of exposure to environmental tobacco smoke in public transportation and in social settings were observed. No associations with a family history of cancer or previous lung diseases were found. Our results indicate that occupational carcinogens and indoor radon may play a role in some lung cancers in nonsmoking men. © 2001 Cancer Research Campaign http://www.bjcancer.com
lung cancer; case-control study; radon; nonsmokers