Cigarette smoking and cancer risk: modeling total exposure and intensity

A recent analysis showed that the excess odds ratio (EOR) for lung cancer due to smoking can be modeled by a function which is linear in total pack-years and exponential in the logarithm of smoking intensity and its square. Below 15-20 cigarettes per day, the EOR/pack-year increased with intensity (direct exposure rate or enhanced potency effect), suggesting greater risk for a total exposure delivered at higher intensity (for a shorter duration) than for an equivalent exposure delivered at lower intensity. Above 20 cigarettes per day, the EOR/pack-year decreased with increasing intensity (inverse exposure rate or reduced potency effect), suggesting greater risk for a total exposure delivered at lower intensity (for a longer duration) than for an equivalent exposure delivered at higher intensity. The authors applied this model to data from 10 case-control studies of cancer, including cancers of the lung, bladder, oral cavity, pancreas, and esophagus. At lower intensities, there was enhanced potency for several cancer sites, but narrow ranges for pack-years increased uncertainty, precluding definitive conclusions. At higher intensities, there was a consistent reduced potency effect across studies. The intensity effects were statistically homogeneous, indicating that after accounting for risk from total pack-years, intensity patterns were comparable across the diverse cancer sites.     

Smoking habits of Greek preschool children's parents

Background  

Smoking is Greece's largest public health threat. Greece has the highest adult smoking prevalence among all E.U countries, which in turn possibly predisposes Greek children and adolescents to smoke. The purpose of our study was to research into the smoking habits of preschool children's parents since children of that age could be vulnerable to parental negative role modeling and to investigate into the necessity of conducting a public health awareness programme aimed at the general population.     

Ivabradine: a selective If current inhibitor in the treatment of stable angina

The role of heart rate reduction in the management of myocardial ischemia and chronic stable angina is pivotal. However, broad use and appropriate dosing of commonly used rate-slowing drugs is limited by their poor tolerability. Ivabradine is a selective inhibitor of the If currents of the sinoatrial node cells. If currents activity determines the slope of the depolarization curve towards the threshold level controlling heart rate in patients with sinus rhythm. Ivabradine, a compound of the benzocyclobutane (S 16257), exhibits a unique specificity for the If current and has a more favorable profile of adverse reactions compared to other If inhibitors. Accordingly, ivabradine has been used in the treatment of stable angina, where it presented anti-anginal and anti-ischemic effects equivalent to the effects of atenolol and amlodipine. Clinical studies proved the efficacy of ivabradine in patients with stable angina, while clinical data are awaited to verify its probable value in the treatment of atrial tachyarrhythmias and tachycardia due to ventricular dysfunction. Thus, the clinical value of ivabradine, which has completed clinical development for stable angina, is expected to exceed its role in the treatment of myocardial ischemia. In this context, ivabradine, promising efficacious and safe pharmacological management of heart rate, is a huge step in cardiovascular therapeutics.     

Employment status and use of respiratory protection among metalworkers, solderers and welders

Objectives

Reported associations of self‐employment with occupational injury and cerebrovascular disease suggest that worker safety and health precautions may vary by occupational status. The authors assessed the extent to which use of respiratory protection and ventilation equipment is associated with self‐employed versus employee status among adults in an international study.

Methods

The European Community Respiratory Health Survey II (ECRHS II) is a follow‐up study conducted in a population‐based random sample of adult ECRHS I participants. Men and women enrolled in the ECRHS II completed interviewer‐administered questionnaires to provide information about their occupational status and job history during the 9‐year ECRHS follow‐up period. Respondents in selected occupational groups completed supplemental questionnaires about their jobs and use of respiratory protection and ventilation equipment on‐the‐job. The authors assessed self‐reported use of respiratory and ventilation equipment among 72 self‐employed and 371 employed adults in metalworking, soldering and welding occupations.

Results

Local exhaust ventilation (fixed extraction: OR 0.37, 95% CI 0.17 to 0.80; mobile extraction: OR 0.23, 95% CI 0.09 to 0.60; on‐tool extraction: OR 0.39, 95% CI 0.18 to 0.88) was reported less frequently among self‐employed respondents than among employed respondents. The magnitude of the negative association between self‐employment status and any of the three types of local exhaust ventilation was not attenuated by adjustment for duration of work per day or week or asthma and/or wheezing symptoms. Respiratory protection was not associated with employment status in these data.

Conclusions

More limited use of local exhaust ventilation among self‐employed workers compared to employees suggests the need to promote occupational safety among self‐employed workers.Information about the working conditions of employees may not reflect the experiences of self‐employed individuals working in the same fields. Self‐employed people who work independently or operate their own businesses may take advantage of the increased autonomy often associated with self‐employment to organise their work schedules and practices to more closely suit their professional preferences. In many industries, self‐employed workers have the opportunity to select their own hours, work settings, clients and equipment. Workers with this degree of flexibility may develop their own occupational health and safety practices, but existing information describing the working conditions of self‐employed individuals is insufficient to indicate how practices differ from those of employees, or how these differences affect health and safety.Recent research provides evidence that health and safety precautions and job training vary between workers in self‐employed and employed work situations.¹ Results from a 2005 survey conducted in the EU indicate that self‐employed workers experienced greater autonomy and less violence, harassment and/or discrimination on the job and had fewer days of health‐related absence over the past year compared to employed respondents. In contrast, the self‐employed respondents more frequently reported that they considered their health and safety to be at risk because of work and a slightly smaller percentage reported wearing personal protective clothing or equipment at work (self‐employed 29% vs employed 35%).¹ Although the survey did not include industry‐ or job‐specific estimates or health outcomes related to the use of personal protective equipment, overall these responses reveal some of the reasons individuals may seek self‐employment situations, and raise the possibility that self‐employed work arrangements may result in important health and safety risks.Previous research has shown differences in the rates of work‐related mortality among the self‐employed and privately‐employed populations.^2,3 For example, using data reported through a medical examiner''s surveillance system, notably higher fatal occupational injury rates were observed among self‐employed workers in the agricultural sector and in retail and transportation industries.² The surveillance‐based study found lower rates among self‐employed workers in the construction industry, suggesting differences in the occupational health and safety practices of self‐employed and employed individuals.² Such variations in the rates of occupational injury may reflect differences in work‐related tasks, settings, use of protective equipment or differences in the age and/or levels of work experience between the two populations. In contrast, lower rates of cerebrovascular disease have been reported among self‐employed men than among employed men. Although the differences were not observed for overall mortality or other circulatory disorders, the investigators concluded that the effect of self‐employment status was independent of those associated with other lifestyle and medical factors and thus may be considered an additional determinant of health.⁴ Differences in mortality rates between self‐employed and employed populations led the investigators to suggest considering employment status as a proxy for differences in working practices, including the physical work environment.Despite these observed differences in occupational practices, mortality and cardiovascular morbidity, occupational health and safety practices of self‐employed workers remain largely unreported in the public health literature. For this analysis, we investigated a hypothesis for which there is little epidemiological evidence—that is, whether employment status is associated with use of respiratory protection and/or ventilation equipment. We used data from the European Community Respiratory Health Survey (ECRHS), a population‐based cohort of adult men and women, to examine self‐reported use of respiratory protection and ventilation equipment among self‐employed and employed respondents.     

Considerations of circadian impact for defining 'shift work' in cancer studies: IARC Working Group Report

Based on the idea that electric light at night might account for a portion of the high and rising risk of breast cancer worldwide, it was predicted long ago that women working a non-day shift would be at higher risk compared with day-working women. This hypothesis has been extended more recently to prostate cancer. On the basis of limited human evidence and sufficient evidence in experimental animals, in 2007 the International Agency for Research on Cancer (IARC) classified 'shift work that involves circadian disruption' as a probable human carcinogen, group 2A. A limitation of the epidemiological studies carried out to date is in the definition of 'shift work.' IARC convened a workshop in April 2009 to consider how 'shift work' should be assessed and what domains of occupational history need to be quantified for more valid studies of shift work and cancer in the future. The working group identified several major domains of non-day shifts and shift schedules that should be captured in future studies: (1) shift system (start time of shift, number of hours per day, rotating or permanent, speed and direction of a rotating system, regular or irregular); (2) years on a particular non-day shift schedule (and cumulative exposure to the shift system over the subject's working life); and (3) shift intensity (time off between successive work days on the shift schedule). The group also recognised that for further domains to be identified, more research needs to be conducted on the impact of various shift schedules and routines on physiological and circadian rhythms of workers in real-world environments.     

Mediterranean diet adherence during pregnancy and fetal growth: INMA (Spain) and RHEA (Greece) mother-child cohort studies

Dietary intake of specific nutrients or food groups during pregnancy could influence fetal growth, but scant evidence is available on effects of dietary patterns. The aim of this study was to evaluate the impact of Mediterranean diet (MD) adherence during pregnancy on fetal growth in two population-based mother-child cohorts in Spain and Greece. We studied 2461 mother-newborn pairs from the Spanish multi-centre 'INMA' study (Atlantic area: INMA-Atlantic; Mediterranean area: INMA-Mediterranean), and 889 pairs from the 'RHEA' study in Crete, Greece. Maternal diet during pregnancy was assessed by FFQ and MD adherence was evaluated through an a priori score. Fetal growth restriction was based on a customised model, and multivariate log-binomial and linear regression models were used to adjust for several confounders. MD scores differ significantly between the cohorts with women in INMA-Atlantic reporting higher intakes of fish and dairy products, while women in the Mediterranean area reported higher intakes of cereals, vegetables and fruits. Women with high MD adherence had a significantly lower risk of delivering a fetal growth-restricted infant for weight (risk ratios: 0·5; 95?% CI 0·3, 0·9) in the INMA-Mediterranean cohort. Stratified analysis by smoking revealed that higher MD adherence increased birth weight and birth length in smoking mothers, whereas this effect was not apparent in non-smoking mothers. The results of the present study show that several types of MD exist across European Mediterranean regions. High MD adherence may modify the detrimental effect of smoking on birth size, but overall effects of diet were not universal for the studies in this analysis.     

Bladder cancer and exposure to water disinfection by-products through ingestion, bathing, showering, and swimming in pools

Bladder cancer has been associated with exposure to chlorination by-products in drinking water, and experimental evidence suggests that exposure also occurs through inhalation and dermal absorption. The authors examined whether bladder cancer risk was associated with exposure to trihalomethanes (THMs) through ingestion of water and through inhalation and dermal absorption during showering, bathing, and swimming in pools. Lifetime personal information on water consumption and water-related habits was collected for 1,219 cases and 1,271 controls in a 1998-2001 case-control study in Spain and was linked with THM levels in geographic study areas. Long-term THM exposure was associated with a twofold bladder cancer risk, with an odds ratio of 2.10 (95% confidence interval: 1.09, 4.02) for average household THM levels of >49 versus < or =8 micro g/liter. Compared with subjects not drinking chlorinated water, subjects with THM exposure of >35 micro g/day through ingestion had an odds ratio of 1.35 (95% confidence interval: 0.92, 1.99). The odds ratio for duration of shower or bath weighted by residential THM level was 1.83 (95% confidence interval: 1.17, 2.87) for the highest compared with the lowest quartile. Swimming in pools was associated with an odds ratio of 1.57 (95% confidence interval: 1.18, 2.09). Bladder cancer risk was associated with long-term exposure to THMs in chlorinated water at levels regularly occurring in industrialized countries.     

Three-dimensional treatment planning for lung cancer

The experience of four institutions involved in a three-dimensional treatment planning contract (NCI) for lung cancer is described. It was found that three-dimensional treatment planning has a significant potential for optimization of treatment plans for radiotherapy of lung cancer both for tumor coverage and sparing of critical normal tissues within the complex anatomy of the human thorax. Evaluation tools, such as dose-volume histograms, and three-dimensional isodose displays, such as multiple plane views, surface dose displays, etc., were found to be extremely valuable in evaluation and comparison of these complex plans. It is anticipated that with further developments in three-dimensional simulation and treatment delivery systems, major progress towards uncomplicated local regional control of lung cancer may be forthcoming.     

Clinical significance of ultrasonographically detected coincidental gallstones

The clinical profiles of 139 patients with gallstones found coincidentally during ultrasonography were reviewed and the patients followed prospectively for five years. Indications for ultrasonography included follow-up of abdominal malignancy (33%), evaluation of abdominal aortic aneurysm or other arteriosclerotic vascular disease (22%), renal insufficiency (12%), and lower abdominal pain (7%). At the time of gallstone detection, 14 patients (10%) had symptoms attributable to cholelithiasis. Over the next five years, only 15 patients (11%) developed episodes resembling biliary pain. Nine patients underwent cholecystectomy during this period. Three of the cholecystectomies were incidental to other abdominal procedures. Two cholecystectomies were performed as emergencies for gallstone complications with no perioperative mortality. Interestingly, 54 patients (40%) with coincidental gallstones died during the follow-up period. All the deaths were unrelated to gallstones. These data indicate that Ultrasonographically detected coincidental gallstones rarely have clinical significance, lending strong support to the expectant management of most patients with purely coincidental gallstones.     

Three-dimensional photon treatment planning for Hodgkin's disease

A multi-institutional study was undertaken using computerized planning systems to develop three-dimensional (3-D) radiotherapy plans for Hodgkin's disease (H.D.). Two patients, the first afflicted with bulky stage II disease and another one with early stage I H.D., were studied. Three main categories of plan were produced for each patient: a) a traditional plan which modelled a conventional mantle treatment on the 3-D system, b) a 3-D standard plan where anterior and posterior fields were designed to cover 3-D target volumes, and c) a 3-D unconstrained plan where innovational techniques were employed. Three-dimensional planning provides information about the dose distribution throughout the large volume irradiated in patients with H.D. that is not available with conventional mantle planning. The use of 3-D techniques resulted in improved tumor coverage, but by allowing for uncertainties such as motion, the doses to normal tissues tended to be higher. The use of unorthodox beam arrangements introduced added complexities, and further increased the lung doses. The most even dose distributions were obtained by incorporating compensating filters into anterior fields. Clinicians showed wide variations in their assessment of the plans, possible reasons for which are addressed in this paper. In addition, calculated probabilities from models of tumor control and normal tissue damage are also presented.