Francesco Barone-Adesi

Cancer risk after cessation of asbestos exposure: a cohort study of Italian asbestos cement workers.

Objectives: We aimed to study mortality for asbestos related diseases and the incidence of mesothelioma in a cohort of Italian asbestos cement workers after cessation of asbestos exposure. Methods: The Eternit factory operated from 1907 to 1986. The cohort included 3434 subjects active in 1950 or hired in 1950–86, ascertained from company records, without selections. Local reference rates were used for both mortality and mesothelioma incidence. Results: Mortality was increased in both sexes for all causes (overall 1809 observed (obs) vs 1312.3 expected (exp); p<0.01), pleural (135 obs vs 3.6 exp; p<0.01) and peritoneal (52 vs 1.9; p<0.01) malignancies and lung cancer (249 vs 103.1; p<0.01). In women, ovarian (9 vs 4.0; p<0.05) and uterine (15 vs 5.8; p<0.01) malignancies were also in excess. No statistically significant increase was found for laryngeal cancer (16 obs vs 12.2 exp). In Poisson regression analyses, the RR of death from pleural neoplasm linearly increased with duration of exposure, while it showed a curvilinear increase with latency and time since cessation of exposure. RR for peritoneal neoplasm continued to increase by latency, duration and time since cessation of exposure. RR for lung cancer showed a reduction after 15 years since cessation of exposure and levelled off after 40 years of latency. Conclusion: This study of a cohort of asbestos exposed workers with very long follow-up confirmed the reduction in risk of death from lung cancer after the end of exposure. It also suggested a reduction in risk for pleural mesothelioma with over 40 years of latency, while risk for peritoneal mesothelioma showed a continuing increase.

Atrazine and Cancer Incidence Among Pesticide Applicators in the Agricultural Health Study (1994–2007)

Background: Atrazine is a triazine herbicide used widely in the United States. Although it is an animal carcinogen, the mechanism in rodents does not appear to operate in humans. Few epidemiologic studies have provided evidence for an association. Methods: The Agricultural Health Study (AHS) is a prospective cohort that includes 57,310 licensed pesticide applicators. In this report, we extend a previous AHS analysis of cancer risk associated with self-reported atrazine use with six additional years of follow-up and more than twice as many cancer cases. Using Poisson regression, we calculated relative risk estimates and 95% confidence intervals for lifetime use of atrazine and intensity-weighted lifetime days, which accounts for factors that impact exposure. Results: Overall, 36,357 (68%) of applicators reported using atrazine, among whom there were 3,146 cancer cases. There was no increase among atrazine users in overall cancer risk or at most cancer sites in the higher exposure categories compared with the lowest. Based on 29 exposed cases of thyroid cancer, there was a statistically significant risk in the second and fourth quartiles of intensity-weighted lifetime days. There was a similar pattern for lifetime days, but neither the risk estimates nor the trend were statistically significant and for neither metric was the trend monotonic. Conclusions: Overall, there was no consistent evidence of an association between atrazine use and any cancer site. There was a suggestion of increased risk of thyroid cancer, but these results are based on relatively small numbers and minimal supporting evidence.

Risk of lung cancer associated with domestic use of coal in Xuanwei, China: retrospective cohort study

Objective To estimate the risk of lung cancer associated with the use of different types of coal for household cooking and heating. Setting Xuanwei County, Yunnan Province, China. Design Retrospective cohort study (follow-up 1976-96) comparing mortality from lung cancer between lifelong users of “smoky coal” (bituminous) and “smokeless coal” (anthracite). Participants 27 310 individuals using smoky coal and 9962 individuals using smokeless coal during their entire life. Main outcome measures Primary outcomes were absolute and relative risk of death from lung cancer among users of different types of coal. Unadjusted survival analysis was used to estimate the absolute risk of lung cancer, while Cox regression models compared mortality hazards for lung cancer between smoky and smokeless coal users. Results Lung cancer mortality was substantially higher among users of smoky coal than users of smokeless coal. The absolute risks of lung cancer death before 70 years of age for men and women using smoky coal were 18% and 20%, respectively, compared with less than 0.5% among smokeless coal users of both sexes. Lung cancer alone accounted for about 40% of all deaths before age 60 among individuals using smoky coal. Compared with smokeless coal, use of smoky coal was associated with an increased risk of lung cancer death (for men, hazard ratio 36 (95% confidence interval 20 to 65); for women, 99 (37 to 266)). Conclusions In Xuanwei, the domestic use of smoky coal is associated with a substantial increase in the absolute lifetime risk of developing lung cancer and is likely to represent one of the strongest effects of environmental pollution reported for cancer risk. Use of less carcinogenic types of coal could translate to a substantial reduction of lung cancer risk.

Effects of Italian Smoking Regulation on Rates of Hospital Admission for Acute Coronary Events: A Country-Wide Study

Background Several studies have reported a reduction in acute coronary events (ACEs) in the general population after the enforcement of smoking regulations, although there is uncertainty concerning the magnitude of the effect of such interventions. We conducted a country-wide evaluation of the health effects of the introduction of a smoking ban in public places, using data on hospital admissions for ACEs from the Italian population after the implementation of a national smoking regulation in January 2005. Methods and Findings Rates of admission for ACEs in the 20 Italian regions from January 2002 to November 2006 were analysed using mixed-effect regression models that allowed for long-term trends and seasonality. Standard methods for interrupted time-series were adopted to assess the immediate and gradual effects of the smoking ban. Effect modification by age was investigated, with the assumption that exposure to passive smoking in public places would be greater among young people. In total, 936,519 hospital admissions for ACEs occurred in the Italian population during the study period. A 4% reduction in hospital admissions for ACEs among persons aged less than 70 years was evident after the introduction of the ban (Rate Ratio [RR], 0.96; 95% Confidence Interval [CI], 0.95–0.98). No effect was found among persons aged at least 70 years (RR 1.00; 95% CI 0.99–1.02). Effect modification by age was further suggested by analyses using narrower age categories. Conclusions Smoke-free policies can constitute a simple and inexpensive intervention for the prevention of cardiovascular diseases and thus should be included in prevention programmes.

Cardiovascular benefits of smoking regulations: The effect of decreased exposure to passive smoking

OBJECTIVES Decreases in population rates of acute myocardial infarction (AMI) have been repeatedly seen in the first months after the introduction of regulations banning smoking in public places. By decreasing the exposure to passive smoking and its acute cardiovascular effects, smoking regulations may cause an immediate drop in AMI incidence, beginning from the initial days after their introduction. Using simulations, we quantified this expected decrease. METHODS Expected AMI decreases were estimated using several parameters, including prevalence of exposure to passive and active smoking, relative risks of AMI associated with active and passive smoking, decrease in exposure to passive smoking after the introduction of the regulation, and level of susceptibility of active smokers to exposure to passive smoking. RESULTS After evaluating several possible combinations of these parameters, we found that AMI reductions of 5-15% seem likely. For example, a scenario with a population average of 5 hours per week of overall exposure to passive smoking, a 50% reduction in this exposure after the introduction of the regulation, an acute relative risk (RR) of AMI of 4.5 in the first hour after passive smoking exposure, and similar susceptibility to passive smoking among both active and passive smokers translates into a 8.6% decrease in AMI. CONCLUSIONS Smoking regulations can cause immediate and relevant decreases in AMI through the prevention of exposure to passive smoking.

It is just a game: lack of association between watching football matches and the risk of acute cardiovascular events

BACKGROUND The role of trigger factors in acute cardiovascular events has been much studied in the past few years. A recent study analysed changes in the rates of cardiac emergencies in Bavaria (Germany) during the last Football World Cup. The authors reported a 2.7-fold increase in the incidence of cardiac emergencies in the 12 h before and after football matches involving the German team, which sparked the debate on the necessity of the introduction of ad hoc cardiovascular preventive measures. METHODS We studied 25,159 hospital admissions for acute myocardial infarction (AMI) among the Italian population during three international football competitions: the World Cup 2002, the European Championship 2004 and the World Cup 2006. Poisson regression was used to estimate the relative risk of hospital admission for AMI on the days when football matches involving the Italian team were disputed, compared with the other days of the three competitions. Furthermore, we reviewed the available published studies regarding the association between football matches and the risk of cardiovascular events. RESULTS We did not find an increase in the rates of admission for AMI on the days of football matches involving Italy in either the single competitions or the three competitions combined (relative risk 1.01; 95% confidence interval 0.98-1.05). We identified 10 studies published on this topic. With the exception of the recently published German study and two small Swiss studies, all relative risk estimates were between 0.7 and 1.3. CONCLUSIONS The cardiovascular effects of watching football matches are likely to be, if anything, very small.

Home kitchen ventilation, cooking fuels, and lung cancer risk in a prospective cohort of never smoking women in Shanghai, China

Indoor air pollution (IAP) caused by cooking has been associated with lung cancer risk in retrospective case–control studies in developing and rural countries. We report the association of cooking conditions, fuel use, oil use, and risk of lung cancer in a developed urban population in a prospective cohort of women in Shanghai. A total of 71,320 never smoking women were followed from 1996 through 2009 and 429 incident lung cancer cases were identified. Questionnaires collected information on household living and cooking practices for the three most recent residences and utilization of cooking fuel and oil, and ventilation conditions. Cox proportional hazards regression estimated the association for kitchen ventilation conditions, cooking fuels, and use of cooking oils for the risk of lung cancer by hazard ratios (HR) with 95% confidence intervals (95% CI). Ever poor kitchen ventilation was associated with a 49% increase in lung cancer risk (HR: 1.49; 95% CI: 1.15–1.95) compared to never poor ventilation. Ever use of coal was not significantly associated. However, ever coal use with poor ventilation (HR: 1.69; 95% CI: 1.22–2.35) and 20 or more years of using coal with poor ventilation (HR: 2.03; 95% CI: 1.35–3.05) was significantly associated compared to no exposure to coal or poor ventilation. Cooking oil use was not significantly associated. These results demonstrate that IAP from poor ventilation of coal combustion increases the risk of lung cancer and is an important public health issue in cities across China where people may have lived in homes with inadequate kitchen ventilation.

Incidence of solid tumours among pesticide applicators exposed to the organophosphate insecticide diazinon in the Agricultural Health Study: an updated analysis

Objective Diazinon, a common organophosphate insecticide with genotoxic properties, was previously associated with lung cancer in the Agricultural Health Study (AHS) cohort, but few other epidemiological studies have examined diazinon-associated cancer risk. We used updated diazinon exposure and cancer incidence information to evaluate solid tumour risk in the AHS. Methods Male pesticide applicators in Iowa and North Carolina reported lifetime diazinon use at enrolment (1993–1997) and follow-up (1998–2005); cancer incidence was assessed through 2010(North Carolina)/2011(Iowa). Among applicators with usage information sufficient to evaluate exposure-response patterns, we used Poisson regression to estimate adjusted rate ratios (RRs) and 95% CI for cancer sites with ≥10 exposed cases for both lifetime (LT) exposure days and intensity-weighted (IW) lifetime exposure days (accounting for factors impacting exposure). Results We observed elevated lung cancer risks (N=283) among applicators with the greatest number of LT (RR=1.60; 95% CI 1.11 to 2.31; Ptrend=0.02) and IW days of diazinon use (RR=1.41; 95% CI 0.98 to 2.04; Ptrend=0.08). Kidney cancer (N=94) risks were non-significantly elevated (RRLT days=1.77; 95% CI 0.90 to 3.51; Ptrend=0.09; RRIW days 1.37; 95% CI 0.64 to 2.92; Ptrend=0.50), as were risks for aggressive prostate cancer (N=656). Conclusions Our updated evaluation of diazinon provides additional evidence of an association with lung cancer risk. Newly identified links to kidney cancer and associations with aggressive prostate cancer require further evaluation.

Using directed acyclic graphs to consider adjustment for socioeconomic status in occupational cancer studies

There is an ongoing debate on whether analyses of occupational studies should be adjusted for socioeconomic status (SES). In this paper directed acyclic graphs (DAGs) were used to evaluate common scenarios in occupational cancer studies with the aim of clarifying this issue. It was assumed that the occupational exposure of interest is associated with SES and different scenarios were evaluated in which (a) SES is not a cause of the cancer under study, (b) SES is not a cause of the cancer under study, but is associated with other occupational factors that are causes of the cancer, (c) SES causes the cancer under study and is associated with other causal occupational factors. These examples illustrate that a unique answer to the issue of adjustment for SES in occupational cancer studies is not possible, as in some circumstances the adjustment introduces bias, in some it is appropriate and in others both the adjusted and the crude estimates are biased. These examples also illustrate the benefits of using DAGs in discussions of whether or not to adjust for SES and other potential confounders.

Population attributable risk for occupational cancer in Italy.

Abstract Population studies estimating the proportion of cancer attributable to occupation (PAR) in different geographical areas in Italy are reviewed. Studies using lists of industrial activities. and occupations which are known or suspectedto entail exposure to lung carcinogens gave lung cancer PARs between 5% and 36%. Those using job-exposure matrices estimated PARs of 3%–53%, with most of the values ranging between 17 and 33%. For bladder cancer, PARs ranged between 4% and 24%. The uses and limitations of calculating population attribultable risk are discussed.