Gastrointestinal cancer and occupational diesel exhaust exposure: a meta-analysis of cohort studies

BACKGROUND

Diesel exhaust exposure and cancer other than the lungs have been limitedly investigated.

AIMS

To conduct a systematic review and meta-analysis on the association between occupational exposure to diesel exhaust and gastrointestinal cancers.

METHODS

Two researchers performed a systematic literature review to identify all cohort studies on occupational exposure to diesel exhaust and risk of cancers other than lung. Of the 30 retained studies, 10 reported risk estimates for oesophageal, 18 on gastric, 15 on colon and 14 on rectal cancer. We performed random-effects meta-analyses to calculate summary relative risks (RRs) and 95% confidence intervals (CIs) for ever-exposure to diesel exhaust.

RESULTS

We calculated summary RR = 1.08 (95% CI 0.97-1.21, P heterogeneity = 0.06) for oesophageal, 1.06 (95% CI 0.99-1.14, P < 0.001) for gastric, 0.98 (95% CI 0.96-1.00, P = 0.453) for colon, and RR = 1.04 (95% CI 0.97-1.11, P = 0.013) for rectal cancer. Drivers showed an association with oesophageal (RR = 1.26, 95% CI 0.99-1.62), gastric (RR = 1.20, 95% CI 0.91-1.59) and rectal cancer (RR = 1.41, 95% CI 1.13-1.75); machine operators with oesophageal (RR = 1.09, 95% CI 1.00-1.20) and gastric (RR = 1.15, 95% CI 1.10-1.20) and handlers with oesophageal cancer (RR = 1.95, 95% CI 1.23-3.09). Studies from Europe revealed an association with gastric cancer while those from North America did not (P < 0.05). No difference was found by quality score except for gastric cancer, where high-quality studies but not low-quality ones showed increased risk (P heterogeneity = 0.04). There was no evidence of publication bias.

CONCLUSIONS

An increased but insignificant risk of oesophageal, gastric and rectal, but not colon cancer, was suggested in workers exposed to diesel exhaust. Residual confounding cannot be excluded.

Occupational exposure to diesel exhaust and head and neck cancer: a systematic review and meta-analysis of cohort studies

Exposure to diesel exhaust (DE) and other fossil fuels in the workplace can cause several health effects including cancer. We conducted a systematic review and meta-analysis of cohort studies examining the association between occupational DE exposure and the risk of head and neck cancer (HNC), including cancer of the oral cavity, pharynx and larynx. We included cohort studies mentioned in the Monograph of the International Agency for Research on Cancer, 2014, on DE. Forest plots of relative risk (RR) were constructed for HNC overall and its anatomical subtypes. A random-effects model was used to address heterogeneity between studies. Fifteen articles were included after removing duplicates and irrelevant reports. The summary RR for DE exposure was 1.08 [95% confidence interval (CI) = 1.01-1.17, P heterogeneity = <0.001] for HNC overall, 0.98 (95% CI = 0.87-1.11) for oral cavity, 1.05 (95% CI = 0.77-1.43) for pharyngeal, 1.15 (95% CI = 0.96-1.38) for oral cavity and pharyngeal combined, and 1.13 (95% CI = 1.03-1.24) for laryngeal cancer. There were elevated RRs for incidence studies of HNC (RR = 1.13; 95% CI = 1.05-1.22, P  = 0.001), European studies (RR = 1.13; 95% CI = 1.05-1.23, P  = 0.001), and female studies (RR = 1.77; 95% CI = 1.31-2.39, P  = 0.003). Our study suggested an association between occupational DE exposure and the risk of HNC, particularly laryngeal cancer. Although residual confounding cannot be ruled out, our results support the importance of controlling occupational DE exposure.

Occupational-related exposure to diesel exhaust and risk of leukemia: systematic review and meta-analysis of cohort studies

PURPOSE

Diesel exhaust (DE) is an established lung carcinogen. The association with leukemia is not well established. We conducted a systematic review and meta-analysis of cohort studies to determine the association between occupational DE exposure and risk of leukemia.

METHODS

A systematic literature review was performed to identify all cohort studies on occupational exposure to DE and associated risk of leukemia. STROBE guidelines and PECOS criteria were followed. Meta-analyses with fixed effects (and random-effects model in cases of high heterogeneity) were performed to calculate summary relative risks (RR) and 95% confidence intervals (CI), including subgroup analyses by outcome (mortality or incidence), sex, geographic region, industry type, and study quality. Study quality was assessed using the the Joanna Briggs Institute (JBI) critical appraisal checklist for cohort studies.

RESULTS

Of the 30 studies retained, 20 (8 from North America, 12 from Europe) reported a total of 33 estimates of the risk of leukemia. Overall, the relative risk (RR) of leukemia was 1.01 (95% CI = 0.97-1.05, I2 = 21.2%, n = 33); corresponding results for leukemia incidence and mortality were RR = 1.02 (95% CI = 0.98-1.06, I2 = 27.9%, n = 19) and RR = 0.91 (95% CI = 0.81-1.02, I2 = 0.0%, n = 15), respectively. The main results were confirmed in analyses by sex and geographic area. A statistically significant association was detected for miners (RR = 1.58, 95% CI = 1.15-2.15, I2 = 77.0%, n = 2) but not for other occupational groups. Publication bias was not detected (p = 0.7).

CONCLUSION

Our results did not indicate an association between occupational DE exposure and leukemia, with the possible exception of miners. Residual confounding cannot be excluded.

Occupational exposure to diesel exhausts and liver and pancreatic cancers: a systematic review and meta-analysis

BACKGROUND

Diesel exhaust (DE) is human carcinogen with sufficient evidence only for lung cancer. Systematic evidence on other cancer types is scarce, thus we aimed to systematically review current literature on the association between occupational DE exposure and risk of liver and pancreatic cancers.

METHODS

We performed a systematic literature review to identify cohort studies on occupational DE exposure and risk of cancers other than lung. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) for liver and pancreatic cancers using DerSimonian and Laird random-effects model.

RESULTS

Fifteen studies reporting results on pancreatic cancer and fourteen on liver cancer were included. We found a weakly increased risk of pancreatic cancer in workers exposed to DE (RR: 1.07, 95% CI: 1.00, 1.14), mainly driven by results on incidence (RR: 1.11, 95% CI: 1.02, 1.22). As for liver cancer, results were suggestive of a positive association (RR: 1.09; 95% CI: 0.99, 1.19), although a significant estimate was present in studies published before 2000 (RR: 1.41; 95% CI: 1.09, 1.82). We found no compelling evidence of publication bias.

CONCLUSIONS

Our findings suggest an association between occupational DE exposure and liver and pancreatic cancer. Further studies with detailed exposure assessment, environmental monitoring data, and appropriate control for confounders are warranted.

Diesel exhaust exposure and risk of non-Hodgkin lymphoma: a meta-analysis

OBJECTIVE

We aimed at carrying out a systematic review and meta-analysis of epidemiological studies on the association between occupational and non-occupational exposures to diesel exhaust and risk of non-Hodgkin lymphoma.

METHODS

We conducted a systematic search of the literature and identified 16 cohort studies and 7 case-control studies that analyzed non-Hodgkin lymphoma alone or combined with Hodgkin lymphoma or multiple myeloma, from which we extracted 29 independent risk estimates. We performed random-effects meta-analyses for ever-exposure to diesel exhaust, overall and after stratification for outcome and study design.

RESULTS

The meta-relative risk of non-Hodgkin lymphoma was 0.97 (95% confidence interval, 0.93-1.01; P -heterogeneity = 0.43). The meta-relative risk of results of cohort studies was 0.97 (95% confidence interval, 0.94-1.01) that of case-control studies was 1.00 (95% confidence interval, 0.84-1.17). Similar results were obtained when the meta-analysis was restricted to studies that analyzed only non-Hodgkin lymphoma. There was no indication of publication bias.

CONCLUSION

Our meta-analysis provided no overall evidence of an increased risk of non-Hodgkin lymphoma in subjects exposed to diesel exhausted.

Truck Drivers' Cigarette Smoking and Preferred Smoking Cessation Methods

Introduction:

Some studies show that truck drivers use tobacco and other stimulants to stay awake as they drive. Despite their increased risks for many of tobacco-related health disparities, there is limited engagement of truck drivers in smoking cessation programs. The objective of this study was to describe smoking characteristics and identify their preferred smoking cessation methods among truck drivers.

Methods:

This was a cross-sectional mixed methods study. Participants were truck drivers recruited at trucking companies in Utah in 2019. Participants were either individually interviewed (n = 4), or filled out a survey (n = 33). We conducted qualitative data analysis of the interviews followed by descriptive statistics of smoking and cessation characteristics from the survey.

Results:

Reasons for smoking included, staying awake, stress reduction, or something to do while driving. Of the drivers surveyed, 68.8% were daily smokers while 97% had smoked at least 100 cigarettes in their life time. The mean number of cigarettes per day (cpd) was 15.7, and 25 among those who had 10 or more cpd. Sixty-one percent had made at least a quit attempt. In addition to counseling or brief advice, 68% reported interest in using Nicotine Replacement Therapy (NRT) either as gum or patch to help them quit. 21% reported interest in telephone text messaging to engage them in treatment.

Conclusion:

Cigarette smoking is a public health problem among truck drivers. Our findings suggest that truck drivers are interested in quitting smoking. Evidence based interventions tailored to this population are needed to help them quit and reduce their smoking-related morbidity.

Bridging the Gaps in Health Service Delivery for Truck Drivers of India Through Mobile Medical Units

Background:

Truck drivers in India suffer from many lifestyle-related health problems. Providing primary health care services to truck drivers is essential to improve their overall health and well-being. This paper reports the findings of a community-based mobile medical unit program providing nonemergency and basic primary care services to truck drivers along the major highways of India. Piramal Swasthya Management and Research Institute launched this community-based mobile medical unit program, in partnership with Shriram Transport Finance Corporation Limited (STFCL).

Materials and Methods:

The paper describes the program model, its coverage, the sociodemographic profile, and common health morbidities of the truck drivers availing the program services. 2-year routine program data (April 2017 to March 2019) were accessed and analyzed.

Results:

A total of 1,167,210 number of unique truck drivers availed the program services during the reference period, of which 61,331 had complete data. The majority of truck drivers were male (99.1%) and just a few women (0.88%) and transgender (0.003%). The mean age was 45.5 years ± 10.91 and nearly half (49%) were in the productive age group (31–45 years). Noncommunicable and other chronic diseases (34.74%), musculoskeletal problems (24.17%), communicable diseases (14.52%), oral cavity-related problems (1.23%), and other minor ailments (17.77%) were the major consultation categories.

Conclusion:

Truck drivers in India have significant health morbidities. Providing primary health care services to truck drivers through mobile medical units is a step toward achieving universal health coverage.

Psychosocial Factors and Tobacco Use Among Commercial Truck Drivers

OBJECTIVES

To explore the relationships between tobacco, social support, job satisfaction, and depression among truck drivers.

METHODS

Cross-sectional data were collected from 797 truck drivers in six US states. Data collected included self-reported medical history and biological samples. Modified Zung depression scale and Work Apgar scores were used to measure depression and social support. Adjusted logistic regression models were used to calculate odds ratios (OR).

RESULTS

24.0% of tobacco users were in the least depressed category and 18.2% were most depressed. 22.8% of the tobacco users had the most social support compared with 27.9% of the non-users. Drivers in the two most depressed categories were significantly less likely to use tobacco (OR = 0.62, 95% confidence interval [CI] = 0.39-0.96, and OR = 0.64, 95% CI = 0.41-0.99).

CONCLUSIONS

Drivers with low social support or low levels of depression are more likely to be tobacco users.

The Work Organization of Long-Haul Truck Drivers and the Association With Body Mass Index

OBJECTIVE

The aim of this study was to examine relationships between work organization features of work hours, work schedules, and job stress with body mass indexes (BMIs) of long-haul truck drivers.

METHODS

Face-to-face survey data were collected first, followed by collection of anthropometric measures including height and weight (n = 260). Logistic regression (backward stepwise model) was used to identify significant predictors of BMI and to analyze odds ratios.

RESULTS

Mean BMI was 33.40 kg/m(2), with 64.2% obese (BMI > 30 kg/m(2)) and 18.4% extreme/morbidly obese (BMI > 40 kg/m(2)). Working more than 11 daily hours was associated with statistically significant increased odds for being extreme obese.

CONCLUSION

Findings suggest that longer work hours (>11 hours daily) have a major influence on odds for obesity among this population. The results align with recent NIOSH calls for integrated approaches to worker health.

National Survey of US Long-Haul Truck Driver Health and Injury: health behaviors

OBJECTIVE

To compare selected health behaviors and body mass index (modifiable risk factors) of US long-haul truck drivers to the US working population by sex.

METHODS

The National Survey of US Long-Haul Truck Driver Health and Injury interviewed a nationally representative sample of long-haul truck drivers (n = 1265) at truck stops. Age-adjusted results were compared with national health surveys.

RESULTS

Compared with US workers, drivers had significantly higher body mass index, current cigarette use, and pack-years of smoking; lower prevalence of annual influenza vaccination; and generally lower alcohol consumption. Physical activity level was low for most drivers, and 25% had never had their cholesterol levels tested.

CONCLUSIONS

Working conditions common to long-haul trucking may create significant barriers to certain healthy behaviors; thus, transportation and health professionals should address the unique work environment when developing interventions for long-haul drivers.

Impact of air quality on lung health: myth or reality?

The respiratory system is a primary target of the harmful effects of key air pollutants of health concern. Several air pollutants have been implicated including particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). It is well known that episodes of exposure to high concentrations of outdoor air pollutants can cause acute respiratory exacerbations. However, there is now increasing evidence suggesting that significant exposure to outdoor air pollutants may be also associated with development of lung cancer and with incident cases of chronic obstructive pulmonary disease (COPD) and respiratory allergies. Here we provide a critical appraisal of the impact of air pollution on respiratory diseases and discuss strategies for preventing excessive exposure to harmful air pollutants. However, the evidence that significant exposure to air pollutants is causing COPD, lung cancer or respiratory allergies is not conclusive and therefore regulators must be aware that execution of clean air policies may not be that cost-effective and may lead to unintended consequences. Addressing the lung health effects of air pollution must be considered work in progress.