Risk factors for lung cancer in Rio de Janeiro, Brazil: a case-control study

Cancer Risk Factors in Southern Brazil: Report of a Comprehensive, Matched Case-Control Study

PURPOSE

To evaluate cancer risk factors among cancer cases and controls from Southern Brazil, to analyze a multigene hereditary panel testing (MGPT, 26 genes) for breast cancer (BC) and colorectal cancer (CCR) cases diagnosed age younger than 50 years and to characterize them for hereditary cancer syndrome (HCS) phenotypes.

METHODS

A case-control (matched by age group and sex) study was conducted on regional cancer. Data on exposure factors and first-/second-degree family history of cancer (1/2FHC) were collected. The MGPT was performed using Illumina next-generation sequencing technology.

RESULTS

A total of 1,007 cases and 1,007 controls were included. The most frequent cancers were BC (n = 311), CCR (n = 147), prostate (n = 132), and lung cancers (n = 89). It was independently associated with cancer, 1/2FHC, tobacco consumption (TC), pesticide exposure (PE), solvent/glue exposure, and BMI <24. BC was associated with 1/2FHC, TC, and hormone replacement therapy use; CCR with 1/2FHC, TC, and BMI <24; prostate cancer with 1/2FHC, TC, and alcohol consumption; and lung cancer with 1/2FHC, TC, PE, and BMI <24. MGPT identified pathogenic/likely pathogenic mutations in 24 (32%) women with BC and in three (18%) women and four (24%) men diagnosed with CCR at under 50 years. Among the tested patients under 50 years with diagnosed BC and CCR, 98.6% and 97% present criteria for HCS, respectively.

CONCLUSION

This study confirmed the association of several factors associated with BC, CCR, prostate, and lung cancers and reinforced the importance of evaluating FHC and genetic testing, especially for patients under 50 years with diagnosed BC or CCR. A better understanding of population-specific cancer risk factors builds on sustainable data for developing prevention strategies. These efforts increase the commitment to early detection and surveillance.

Health effects associated with smoking: a Burden of Proof study

As a leading behavioral risk factor for numerous health outcomes, smoking is a major ongoing public health challenge. Although evidence on the health effects of smoking has been widely reported, few attempts have evaluated the dose-response relationship between smoking and a diverse range of health outcomes systematically and comprehensively. In the present study, we re-estimated the dose-response relationships between current smoking and 36 health outcomes by conducting systematic reviews up to 31 May 2022, employing a meta-analytic method that incorporates between-study heterogeneity into estimates of uncertainty. Among the 36 selected outcomes, 8 had strong-to-very-strong evidence of an association with smoking, 21 had weak-to-moderate evidence of association and 7 had no evidence of association. By overcoming many of the limitations of traditional meta-analyses, our approach provides comprehensive, up-to-date and easy-to-use estimates of the evidence on the health effects of smoking. These estimates provide important information for tobacco control advocates, policy makers, researchers, physicians, smokers and the public.

Using the Negative Exponential Model to Describe Changes in Risk of Smoking-Related Diseases following Changes in Exposure to Tobacco

Recently published analyses for four smoking-related diseases show that the declining excess relative risk by time quit is well fitted by the negative exponential model. These analyses estimated the half-life of this excess, that is, the time after quitting when the excess relative risk reaches half that for continuing smokers. We describe extensions of the simple model. One quantifies the decline following an exposure reduction. We show that this extension satisfactorily predicts results from studies investigating the effect of reducing cigarette consumption. It may also be relevant to exposure reductions following product-switching. Another extension predicts changes in excess relative risk occurring following multiple exposure changes over time. Suitable published epidemiological data are unavailable to test this, and we recommend its validity to be investigated using large studies with data recorded on smoking habits at multiple time points in life. The basic formulae described assume that the excess relative risk for a continuing smoker is linearly related to exposure and that the half-life is invariant of age. We describe model adaptations to allow for nonlinear dose-response and for age-dependence of the half-life. The negative exponential model, though relatively simple, appears to have many potential uses in epidemiological research for summarizing variations in risk with exposure changes.

Meat consumption and risk of lung cancer: evidence from observational studies

BACKGROUND

A number of epidemiological studies have reported inconsistent findings on the association between meat consumption and lung cancer.

DESIGN

We therefore conducted a systematic review and meta-analysis to investigate the relationship between meat consumption and lung cancer risk in epidemiological studies.

RESULTS

Twenty-three case-control and 11 cohort studies were included. All studies adjusted for smoking or conducted in never smokers. The summary relative risks (RRs) of lung cancer for the highest versus lowest intake categories were 1.35 (95% confidence interval (CI) 1.08-1.69) for total meat, 1.34 (95% CI 1.18-1.52) for red meat, and 1.06 (95% CI 0.90-1.25) for processed meat. An inverse association was found between poultry intake and lung cancer (RR = 0.91, 95% CI 0.85-0.97), but not for total white meat (RR = 1.06, 95% CI 0.82-1.37) or fish (RR = 1.01, 95% CI 0.96-1.07).

CONCLUSIONS

The relationship between meat intake and lung cancer risk appears to depend on the types of meat consumed. A high intake of red meat may increase the risk of lung cancer by about 35%, while a high intake of poultry decreases the risk by about 10%. More well-designed cohort studies on meat mutagens or heme iron, meat cooking preferences, and doneness level are needed to fully characterize this meat-lung cancer association.

The Brazil SimSmoke policy simulation model: the effect of strong tobacco control policies on smoking prevalence and smoking-attributable deaths in a middle income nation

BACKGROUND

Brazil has reduced its smoking rate by about 50% in the last 20 y. During that time period, strong tobacco control policies were implemented. This paper estimates the effect of these stricter policies on smoking prevalence and associated premature mortality, and the effect that additional policies may have.

METHODS AND FINDINGS

The model was developed using the SimSmoke tobacco control policy model. Using policy, population, and smoking data for Brazil, the model assesses the effect on premature deaths of cigarette taxes, smoke-free air laws, mass media campaigns, marketing restrictions, packaging requirements, cessation treatment programs, and youth access restrictions. We estimate the effect of past policies relative to a counterfactual of policies kept to 1989 levels, and the effect of stricter future policies. Male and female smoking prevalence in Brazil have fallen by about half since 1989, which represents a 46% (lower and upper bounds: 28%-66%) relative reduction compared to the 2010 prevalence under the counterfactual scenario of policies held to 1989 levels. Almost half of that 46% reduction is explained by price increases, 14% by smoke-free air laws, 14% by marketing restrictions, 8% by health warnings, 6% by mass media campaigns, and 10% by cessation treatment programs. As a result of the past policies, a total of almost 420,000 (260,000-715,000) deaths had been averted by 2010, increasing to almost 7 million (4.5 million-10.3 million) deaths projected by 2050. Comparing future implementation of a set of stricter policies to a scenario with 2010 policies held constant, smoking prevalence by 2050 could be reduced by another 39% (29%-54%), and 1.3 million (0.9 million-2.0 million) out of 9 million future premature deaths could be averted.

CONCLUSIONS

Brazil provides one of the outstanding public health success stories in reducing deaths due to smoking, and serves as a model for other low and middle income nations. However, a set of stricter policies could further reduce smoking and save many additional lives. Please see later in the article for the Editors' Summary.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Socioeconomic differences in lung cancer incidence: a systematic review and meta-analysis

OBJECTIVE

To investigate the associations between various socioeconomic indicators and lung cancer incidence.

METHODS

We searched PubMed and EMBASE databases for studies on socioeconomic position (SEP) and lung cancer incidence published through October 2007. Random-effect model was used to pool the risk estimates from the individual studies. We stratified the analysis by adjustment strategy to investigate the influence of smoking on socioeconomic gradient in lung cancer incidence.

RESULTS

Out of 3,288 citations, we identified 64 studies eligible for inclusion. Compared to the highest SEP level, we observed an overall increased risk in lung cancer incidence among people with low educational SEP (61%), low occupational SEP (48%), and low income-based SEP (37%). The negative social gradient for lung cancer incidence remained for most of the possible sets of pooled estimates obtained in subgroup analyses for occupational and educational SEP with less consistency for SEP based on income in studies adjusted and unadjusted for smoking. No evidence of publication bias was apparent.

CONCLUSION

Lung cancer incidence was associated with low educational, occupational, and income-based SEP. The association, adjusted or unadjusted for smoking, points out the importance of social position to be addressed in all discussions on cancer preventive measures.

Fatores associados ao índice de cessação do hábito de fumar em duas diferentes populações adultas (Projetos Bambuí e Belo Horizonte)

O objetivo deste trabalho foi verificar o índice de cessação do tabagismo e os fatores associados ao mesmo. O estudo foi conduzido na Região Metropolitana de Belo Horizonte e na cidade de Bambuí, em Minas Gerais, Brasil. Participaram, respectivamente, 13.261 e 1.018 adultos (> 20 anos) selecionados aleatoriamente entre os residentes das áreas de estudo. O índice de cessação do tabagismo foi igual a 40,6% (IC95%: 39,1-42,3) na Região Metropolitana de Belo Horizonte e 38,8% (IC95%: 34,4-43,1) em Bambuí. Na Região Metropolitana de Belo Horizonte, associações independentes e positivas com esse índice foram observadas para idade (> 40 anos), escolaridade (4-7 e > 8 anos de estudo), número de condições crônicas (> 2) e número de consultas médicas no último ano (1-3 e > 4); associação negativa foi observada para estado civil (não casados). Em Bambuí, foi observada associação independente e positiva com idade (> 40 anos) e negativa com número de hospitalizações no último ano (> 2). A heterogeneidade dos fatores associados à interrupção do tabagismo dificulta a identificação de grupos vulneráveis, visando estratégias de prevenção. São necessários novos estudos para um melhor entendimento dessa heterogeneidade.

Fruit and vegetables in cancer prevention

Our aim was to review the epidemiological literature on possible cancer-preventive effects of the consumption of fruits and vegetables in humans, to quantify the effect of high versus low consumption of fruits and vegetables, and to give an overall assessment of the existing evidence. We based our work on an expert meeting conducted by the International Agency for Research on Cancer in 2003. A qualitative reading and evaluation of relevant articles on the cancer-preventive effect of the consumption of fruits and vegetables was made followed by the calculation of the mean relative risk and range for cohort and case-control studies separately. The possible population-preventable fraction for modifying diet in relation to fruit and vegetable consumption was calculated as well as an overall statement about the degree of evidence for the cancer-preventive effect of fruit and vegetable consumption for each cancer site. There is limited evidence for a cancer-preventive effect of the consumption of fruits and vegetables for cancer of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary (vegetables only), bladder (fruit only), and kidney. There is inadequate evidence for a cancer-preventive effect of the consumption of fruits and vegetables for all other sites. Applying this range of risk difference to the range of prevalence of low intake, the preventable fraction for low fruit and vegetable intake would fall into the range of 5-12%. It is important to recognize that this is only a crude range of estimates and that the proportion of cancers that might be preventable by increasing fruit and vegetable intake may vary beyond this range for specific cancer sites and across different regions of the world.

Elevated lung cancer risk shortly after smoking cessation: is it due to a reduction of endotoxin exposure?

Several reports indicate that the risk of lung cancer increases slightly for a short period of time after cessation of smoking while the risk of adverse cardiovascular events drops immediately. Recent studies on subjects occupationally exposed to organic dust-containing endotoxin have revealed lower than expected rates of lung cancer. There is experimental evidence that stimulation of the immune system by endotoxin has a protective effect against cancer. Tobacco smoke has been shown to contain high levels of endotoxin. We therefore postulate that cessation of smoking eliminates the protective effect of endotoxin. Any benefit conferred by endotoxin does not, however, justify smoking. As the inverse relationship between exposure to endotoxin and the risk of lung cancer is a strong one, endotoxin-like substances could form the basis of vaccination strategies.

Epidemiologic evidence of the protective effect of fruit and vegetables on cancer risk

BACKGROUND

Diets rich in fruit and vegetables have been recommended for preventing cancer. The evidence supporting this recommendation is based on observational studies, although results of several prospective studies have cast some doubts on whether fruit and vegetables are associated with cancer risk reduction.

OBJECTIVE

We sought to summarize evidence from case-control and prospective studies on fruit and vegetable intake and cancer risk with a meta-analytic approach.

DESIGN

Published case-control and cohort studies that reported on total vegetable and fruit intake and risk of cancer of several sites were included. Relative risks were estimated by using linear logistic regression models.

RESULTS

Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables; breast cancer is associated with vegetables but not with fruit; and bladder cancer is associated with fruit but not with vegetables. The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit.

CONCLUSIONS

Prospective studies provide weaker evidence than do case-control studies of the association of fruit and vegetable consumption with reduced cancer risk. The discrepancies may be related to recall and selection biases in case-control studies. In contrast, the association may have been underestimated in prospective studies because of the combined effects of imprecise dietary measurements and limited variability of dietary intakes within each cohort.

[Association between smoking and paracoccidioidomycosis: a case-control study in the State of Espírito Santo, Brazil]

Paracoccidioidomycosis, the main systemic mycosis in Brazil, requires long-term, high-cost treatment and leaves serious sequelae in the lungs, the organ most frequently affected and further subject to aggressive external risk factors like smoking. The influence of tobacco and alcohol consumption on chronic paracoccidioidomycosis was investigated using a case-control study. Data on occupation, place of residence, and living habits were obtained from 70 cases and 180 controls residing in the same geographic areas. The risk of becoming ill was 14 times greater among smokers and 3.6 times greater among individuals with an alcohol intake of more than 50 g/day. Logistic regression showed as significant variables: tobacco consumption for more than 20 years (OR = 10.1), smoking manufactured (not hand-rolled) cigarettes (OR = 4.8), and alcohol intake > 50 g/day (OR = 2.9). Cases who smoked 20 or more cigarettes/day became ill on average eight years before others (p = 0.002). Alcohol intake > 50 g/day had no statistically significant impact on age at onset of illness (p = 0.78). The study concludes that smoking stands as an important risk factor for the development of chronic paracoccidioidomycosis. As for alcoholism, there is evidence that it acts as a co-factor, together with smoking.

Familial cancer aggregation and the risk of lung cancer

CONTEXT

Around 90% of lung cancer worldwide is attributable to cigarette smoking, although less than 20% of cigarette smokers develop lung cancer. Other factors such as diet, chronic lung diseases, occupation and possibly environmental agents also contribute to this cancer. Genetic factors seem to play a role in lung cancer, but the precise characteristics influencing lung cancer susceptibility are not known, since genetic factors are easily obscured by the strong environmental determinants of lung cancer, particularly smoking.

OBJECTIVE

To estimate the effect that cancer occurrence among first-degree relatives has on the risk of lung cancer.

DESIGN

Hospital-based case-control study.

SETTING

The metropolitan region of São Paulo, Brazil.

PARTICIPANTS

334 incident lung cancer cases and 578 controls matched by hospitals.

MAIN MEASUREMENTS

By means of a structured questionnaire, cases and controls were interviewed about cancer occurrence in first-degree relatives, tobacco smoking, exposure to passive smoking, occupation, migration and socioeconomic status. Non-conditional logistic regression was used to calculate the risk of familial cancer aggregation, the effect of cancer in first-degree relatives and smoking in conjunction, and for controlling confounders.

RESULTS

The adjusted odds ratio (OR) revealed a slight, but not statistically significant, excess risk of lung cancer for subjects with a history of lung cancer in relatives (OR 1.21; 95% confidence interval [CI] 0.50 - 2.92). The same was found among those with a history of other tobacco-related cancers in relatives (OR 1.36; 95% CI 0.87 - 2.14). A step gradient effect was observed regarding lung cancer risk, in accordance with increases in the number of pack-years of cigarette consumption. An interaction between familial cancer aggregation and tobacco smoking was detected.

CONCLUSIONS

A mildly elevated risk of lung cancer among persons with a positive history of lung and other tobacco-related cancers was observed. The finding of an interaction between the variables of familial cancer aggregation and smoking suggests that familial cancer aggregation could be considered as a marker of susceptibility, increasing the risk of lung cancer among smokers. These results improve our knowledge of lung carcinogenesis and can guide future cancer genetic studies.

Occupational exposures and lung cancer in Buenos Aires, Argentina

The main objective of this study was to analyze the risks associated with occupational exposures in an industrializing country where lung cancer is the primary neoplastic cause of death in men. A full occupational history was collected through interviewing 199 men with lung cancer and 393 control subjects. Exposure to arsenic, asbestos, chromium, dust, nickel, and polynuclear aromatic hydrocarbons was assessed by means of a job-exposure matrix. Elevated odds ratios were observed for employment in the alcoholic beverages industry (5.2; 95% confidence interval [CI], 1.1 to 23.1), sawmills and wood mills (4.8; 95% CI, 1.2 to 19.0), water transport (3.3; 95% CI, 1.1 to 12.1), and chemicals/plastics manufacturers (1.9; 95% CI, 1.1 to 3.3). A small, non-significant increased risk was observed after long-term exposure to arsenic and chromium, with a dose-response for chromium. Although some of the present results may result from chance, most are consistent with those of previous investigations in other countries.

Environmental and occupational cancer in Argentina: a case-control lung cancer study

The main objective of this study was to analyze the risks for lung cancer associated with occupational exposures in a developing country where lung cancer is the first cause of mortality from cancer in men. The study involved 200 men with lung cancer and 397 hospital controls. The OR for current smokers was 8.5, whereas former smokers displayed an OR of 5.3. The fraction attributable to smoking was 85%. Statistically significant high ORs were observed for employment in the alcoholic beverages (4.5, 95% CI: 1.02-20.2), sawmills and wood mills (4.6, 95% CI:1.1-18.4), chemicals/plastics (1. 8, 95% CI:1.04-3.2), and pottery, glass, or mineral manufactures (3.4, 95% CI:1.1-10.6). Other high (but not statistically significant) risks were observed for employment in leather shoe industry and repair (2.1, 95% CI:0.8-5.4), rubber industries (3.4, 95% CI:0.9-12.4), metal workers, including welders (1.9, 95% CI:0.8-4.4), motor vehicle mechanics (2.0, 95% CI:0.9-4.2), workers in cleaning services (1.9, 95% CI: 0.8-4.5), and for workers in agriculture (2.4, 95% CI:0.9-6.0). Although some of the present results may be due to chance, most are consistent with those of previous investigations in other countries.

Air pollution, temperature, and regional differences in lung cancer mortality in Japan

In this study, the authors investigated regional differences in lung cancer mortality in Japan, and, based on data acquired between 1970 and 1990 for 47 Japanese prefectures, estimated the relationship between regional lung cancer mortality and air pollution and/or temperature. Investigators used data for nitrogen dioxide, sulfur dioxide, motor vehicle density, tobacco expenditure, and temperature as independent variables for age-adjusted lung cancer death rates. The age-adjusted lung cancer death rates were higher in the southern geographical block of Japan (i.e., approximately 1.2-fold in males and 1.1-fold in females) and in the northern block (approximately 1.2-fold in males) than in the central block. The regional differences in the age-adjusted lung cancer death rates were explained by nitrogen dioxide and temperature. Temperature caused a greater effect (regression coefficients) of nitrogen dioxide on the age-adjusted lung cancer death rates than did nitrogen dioxide alone in the southern block (i.e., approximately 1.3-fold in males and 1.2-fold in females). These results provide the first evidence of a possible synergistic interaction between air pollution and high temperature on lung cancer mortality.

Diet and lung cancer 20+ years later: more questions than answers?

A critical review of epidemiological studies on diet and lung cancer over the last 20+ years has not provided overwhelming evidence that higher consumption of vegetables, fruit, low-fat/low-cholesterol foods or such micronutrients as carotenoids, selenium and vitamins A, C or E is associated with reduced lung cancer risk. Results from case-control studies have been more positive, with about one half showing fruit and vegetables or their associated micronutrients to be associated with reduced risk. However, most results from cohort and serum micronutrient studies, which avoid the problems of inaccurate accounting of diet and recall bias, were statistically insignificant. Moreover, although most studies were conducted on white male smokers in North America and Europe, the few studies which found significant contrary trends were among subjects of different backgrounds, i.e., black American males and Chinese women in China. Since male smokers vs. nonsmokers in Europe, North America and Japan have been shown in other studies to be lower consumers of fruit/vegetables, and less likely to pursue "perceived healthier lifestyles," the possibility that some of the epidemiological findings on diet and lung cancer are artifactually due to inadequate adjustment for behavioral correlates of smoking and health seekers in a particular society must be considered. This is especially true with recent chemoprevention trials showing higher lung cancer incidence and deaths among consumers of beta-carotene supplements vs. placebo.