Mortality among Boston firefighters, 1915--1975

Non-cancer health risks in firefighters: a systematic review

osFirefighters are occupationally exposed to hazardous factors that may increase their risk of disease. However, non-cancer disease risk in firefighters has not been systematically examined. This systematic review aimed to identify non-cancer disease risk in firefighters and determine whether the risk differs according to job characteristics. We searched the Cochrane Library, Embase, PubMed, and KoreaMed databases using relevant keywords from their inception to April 30, 2021. The Risk of Bias Assessment Tool for Non-randomized Studies version 2.0 was used to assess the quality of evidence. Due to study heterogeneity, a narrative synthesis was presented. The systematic literature search yielded 2,491 studies, of which 66 met the selection and quality criteria. We confirmed that the healthy worker effect is strong in firefighters as compared to the general population. We also identified a significant increase in the incidence of lumbar disc herniation, lower back pain, angina pectoris, acute myocardial infarction, and post-traumatic stress disorder (PTSD) in firefighters compared to other occupational groups. Contradictory results for the risk of PTSD and anxiety disorders related to rank were reported. Sufficient evidence for increased risk of lumbar disc herniation, lower back pain, angina pectoris, acute myocardial infarction, and PTSD was available. The risk of non-cancer diseases varied depending on job type, years of service, and rank. However, caution should be exercised when interpreting the results because the classification criteria for firefighters' jobs and ranks differ by country.

Cancer Incidence and Mortality among Firefighters: An Overview of Epidemiologic Systematic Reviews

Firefighters are exposed to carcinogens that may increase their risk of developing many types of occupational cancer. Many systematic reviews (SRs) have been produced with sometimes conflicting conclusions. In this overview of reviews, we aim to assess the conclusion consistency across the available systematic reviews on the cancer risk in firefighters. Literature searches were conducted in several indexed databases and grey literature to retrieve systematic reviews aiming to evaluate cancer incidence or cancer mortality in firefighters. Results from included SRs were analyzed according to the tumour site. Out of 1054 records identified by the search in the databases, a total of 11 SRs were ultimately included. The original studies (n = 104) analyzed in the SRs were published between 1959 and 2018. The results consistently reported a significant increase in the incidence of rectal, prostate, bladder and testicular cancers as well as mesothelioma and malignant melanoma in firefighters compared to the general population. The SRs also indicate that death rates from rectal cancer and non-Hodgkin's lymphoma are higher among firefighters. Consistent SR results suggest that several types of cancer may be more frequent in firefighters than in the general population.

Suicide Among the Emergency Medical Systems Occupation in the United States

Introduction

Suicide claimed 47,173 lives in 2017 and is the second leading cause of death for individuals 15–34 years old. In 2017, rates of suicide in the United States (US) were double the rates of homicide. Despite significant research funding toward suicide prevention, rates of suicide have increased 38% from 2009 to 2017. Recent data suggests that emergency medical services (EMS) workers are at a higher risk of suicidal ideation and suicide attempts compared to the general public. The objective of this study was to determine the proportionate mortality ratio (PMR) of suicide among firefighters and emergency medical technicians (EMT) compared to the general US working population.

Methods

We analyzed over five million adult decedent death records from the National Occupational Mortality Surveillance database for 26 states over a 10-year non-consecutive period including 1999, 2003–2004, and 2007–2013. Categorizing firefighters and EMTs by census industry and occupation code lists, we used the underlying cause of death to calculate the PMRs compared to the general US decedent population with a recorded occupation.

Results

Overall, 298 firefighter and 84 EMT suicides were identified in our study. Firefighters died in significantly greater proportion from suicide compared to the US.working population with a PMR of 172 (95% confidence interval [CI], 153–193, P<0.01). EMTs also died from suicide in greater proportion with an elevated PMR of 124 (95% CI, 99–153), but this did not reach statistical significance. Among all subgroups, firefighters ages 65–90 were found to have the highest PMR of 234 (95% CI, 186–290), P<0.01) while the highest among EMTs was in the age group 18–64 with a PMR of 126 (95% CI, 100–156, P<0.05).

Conclusion

In this multi-state study, we found that firefighters and EMTs had significantly higher proportionate mortality ratios for suicide compared to the general US working population. Firefighters ages 65–90 had a PMR more than double that of the general working population. Development of a more robust database is needed to identify EMS workers at greatest risk of suicide during their career and lifetime.

Cancer risks of firefighters: a systematic review and meta-analysis of secular trends and region-specific differences

PURPOSE

The objective of this study was to conduct a systematic review and meta-analysis to evaluate the cancer risks among firefighters in the time course and from different geographical areas.

METHOD

A PubMed search was performed to identify cohort studies about cancer risk and firefighting presented with standardized incidence ratios (SIRs) or standardized mortality ratios (SMRs). Using random-effect models, meta-relative risk estimates (mSIRs, mSMRs) and 95% confidence intervals (CI) were assessed. Cohort studies with employment starting before 1950 were classified as "old", studies starting between 1950 and 1970 as "medium", and later studies as "new".

RESULTS

The general cancer risk of firefighters was similar to the general population, but mSMR decreased over time (new studies: mSMR = 0.81, 95% CI 0.70-0.92). We observed an increase of mSIR for melanoma of the skin and prostate cancer as well as a decrease of mSIR for stomach cancer with later employment onset. For those cancer sites, we did not observe a secular trend of mSMRs. Regional differences between relative cancer risks were particularly observed for bladder cancer.

CONCLUSIONS

Among other things, innovative firefighting techniques and better personal protective equipment have provided a safer and healthier working environment for firefighters over time leading to a reduction of overall cancer incidence and mortality ratios. Increased general preventive medical checkups and possible additional screenings for firefighters might have led to more findings of malignant melanoma of the skin and prostate cancer in the recent past.

Cancer Incidence and Mortality in Firefighters: A State-of-the-Art Review and Meta-َAnalysis

Objective:

A systematic literature review and meta-analysis was conducted on the association between firefighting and cancer.

Methods:

A comprehensive literature search of databases including Medline, EMBASE, Biosis, NIOSHTIC2, Web of Science, Cancerlit, and HealthStar, for the period between 1966 to January 2007, was conducted. We also retrieved additional studies by manual searching.

Results:

A total of 49 studies were included in the meta-analysis. We found statistically significant associations between firefighting and cancers of bladder, brain and CNS, and colorectal cancers, consistent with several previous risk estimates. We also found statistically significant associations of firefighting with non-Hodgkin’s lymphoma, skin melanoma, prostate, and testicular cancer. For kidney, Hodgkin’s lymphoma, leukemia, lymphosarcoma and reticulosarcoma, multiple myeloma, and pancreatic cancer, we found some statistically significant but less consistent results. For all other cancers evaluated (esophageal, laryngeal, oral and pharyngeal, liver and gallbladder, lung, lymphatic and hematopoietic, non-melanoma skin cancer, stomach, and urinary cancer) we did not find any statistically significant associations.

Conclusions:

Although our meta-analysis showed statistically significant increased risks of either cancer incidence or mortality of certain cancers in association with firefighting, a number of important limitations of the underlying studies exist, which, precluded our ability to arrive at definitive conclusions regarding causation.

Mortality due to malignant and non-malignant diseases in Korean professional emergency responders

OBJECTIVE

This study was conducted to estimate the cause-specific mortality in male emergency responders (ER), compare with that of Korean men. Mortality was also compared between more experienced firefighters (i.e., firefighters employed ≥ 20 years and firefighters employed ≥ 10 to < 20 years) and less experienced firefighters and non-firefighters (i.e., firefighters employed < 10 years and non-firefighters) to investigate associations between mortality and exposure to occupational hazards.

METHODS

The cohort was comprised of 33,442 males who were employed as ERs between 1980 and 2007 and not deceased as of 1991. Work history was merged with the death registry from the National Statistical Office of Korea to follow-up on mortality between 1992 and 2007. Standardized mortality ratios (SMR) for ERs were calculated in reference to the Korean male population. Adjusted relative risks (ARRs) of mortalities for firefighters employed ≥ 20 years and ≥ 10 years to < 20 years were calculated in reference to non-firefighters and firefighters employed < 10 years.

RESULTS

Overall (SMR = 0.43, 95%CI = 0.39-0.47) and some kinds of cause-specific mortalities were significantly lower among ERs compared with the Korean male population. No significant increase in mortality was observed across the major ICD-10 classifications among ERs. Mortality due to exposure to smoke, fire, and flames (SMR = 3.11, 95% CI = 1.87-4.85), however, was significantly increased among ERs. All-cause mortality (ARR = 1.46, 95% CI=1.13-1.89), overall cancer mortality (ARR = 1.54, 95% CI = 1.02-2.31) and mortality of external injury, poisoning and external causes (ARR = 3.13, 95% CI = 1.80-5.46) were significantly increased among firefighters employed ≥ 20 years compared to those of non-firefighters and firefighters employed < 10 years.

CONCLUSIONS

An increase in mortality due to all cancer and external injury, poisoning, and external causes in firefighters employed ≥ 20 years compared with non-firefighters and firefighters employed < 10 years suggests occupational exposure.

Mortality and life expectancy of professional fire fighters in Hamburg, Germany: a cohort study 1950-2000

BACKGROUND

The healthy worker effect may hide adverse health effects in hazardous jobs, especially those where physical fitness is required. Fire fighters may serve as a good example because they sometimes are severely exposed to hazardous substances while on the other hand their physical fitness and their strong health surveillance by far exceeds that of comparable persons from the general population.

METHODS

To study this effect a historic cohort study was conducted to assess mortality and life expectancy of professional fire fighters of the City of Hamburg, Germany. Fire departments and trade unions questioned the validity of existing studies from outside Germany because of specific differences in the professional career. No mortality study had been conducted so far in Germany and only few in Europe. Information on all active and retired fire fighters was extracted from personnel records. To assure completeness of data the cohort was restricted to all fire fighters being active on January 1, 1950 or later. Follow up of the cohort ended on June 30th 2000. Vital status was assessed by personnel records, pension fund records and the German residence registries. Mortality of fire fighters was compared to mortality of the Hamburg and German male population by means of standardized mortality ratios. Life expectancy was calculated using life table analysis. Multivariate proportional hazard models were used to assess the effect of seniority, time from first employment, and other occupational characteristics on mortality.

RESULTS

The cohort consists of 4640 fire fighters accumulating 111,796 person years. Vital status could be determined for 98.2% of the cohort. By the end of follow up 1052 person were deceased. Standardized Mortality Ratio (SMR) for the total cohort was 0.79 (95% CI, 0.74-0.84) compared to Hamburg reference data and 0.78 (95% CI, 0.74-0.83) compared to National German reference data. Conditional life expectancy of a 30 year old fire fighter was 45.3 years as compared to 42.9 year of a German male in normal population. Job tasks, rank status and early retirement negatively influenced mortality. For fire fighters with comparably short duration of employment the mortality advantage diminished with longer time since first employment. SMR of persons who retired early was 1.25 (95% CI, 1.13-1.60) in reference to the general German population and the SMR of 1.71 (1.18-2.50) in the multivariate regression model.

CONCLUSION

A strong healthy worker effect was observed for the cohort, which diminished with longer time since first employment for fire fighters with shorter duration of employment, as expected. The negative effects on mortality of job tasks, rank status and in particular early retirement indicate the presence of undetermined and specific risks related to occupational hazards of fire fighters.

Work and mental health

BACKGROUND

Studies investigating the psychological correlates of types of occupation have focused on such disorders as stress, depression, suicide and substance abuse. There have also been some models proposed to allow understanding of factors common to different types of occupations. We sought to provide an overview of research related to work and mental health and consider future research directions.

METHODS

A literature search was conducted using the Medline, PsycInfo, Embase and PubMed databases. The key words "occupation" or "work" were searched in combination with the key words "mental health", "risk factors", "disorders", "depression", "suicide", "trauma", "stress" or "substance use".

RESULTS

Studies of "stress" tend to be more applicable to specific workplace issues. While some of the studies relating to onset of depression, suicide, substance abuse and trauma pertain to specific occupational issues and results are often not generalizable, they have progressed our understanding of risk factors to those disorders. There are workplace factors involving exposure to danger and crisis that lead to posttraumatic stress disorder (PTSD), substance abuse (including stimulants) and depersonalization. Workplace risk factors for depression involve situations promoting lack of autonomy, and involving "caring" for others as part of the work role, particularly where there is dependence on others for their livelihood. Risk factors for alcohol abuse include workplaces with access to alcohol and where use of alcohol is sanctioned. There appears to be a bi-directional relationship between personality and work, so that people are drawn to particular occupations, but the occupations then have an effect on them. An interactional model is proposed to consider this.

CONCLUSION

The research questions pertaining to mental health are varied and will determine what mental health issues are of interest and the models of work applicable. There need to be more longitudinal studies and consideration of factors which the worker brings to the workplace (psychosocial issues, personality traits), as well as interpersonal issues and consideration of systemic, organizational, political and economic factors, including leadership styles.

A cohort study on the mortality of firefighters

This study was set up to investigate the effect of exposure to combustion effluents on the chronic health of firefighters. A cohort of firefighters was followed up through 10 years with regard to cause specific mortality. Comparisons were made with another cohort of civil servants and salaried employees in physically demanding jobs. After a latency of five years, an excess mortality from cancer was seen for persons aged 30 to 74 (standardised mortality ratio (SMR) 173, 95% confidence interval (95% CI) 104-270). A significant increase in lung cancer was seen in the group aged 60 to 74 (SMR 317, 95% CI 117-691), whereas non-pulmonary cancer was significantly increased in the group aged 30 to 49 (SMR 575, 95% CI 187-1341). It is concluded that inhalation of carcinogenic and toxic compounds during firefighting may constitute an occupational cancer risk. An extended use of respiratory protective equipment is advocated.

Respiratory mortality among firefighters

Although firefighters have been shown in some studies to suffer chronic respiratory morbidity from their occupational exposures, an increased risk for dying from non-malignant respiratory diseases has not been documented in any previous retrospective cohort mortality study. In order to assess the possibility that an unusually strong "healthy worker effect" among firefighters might mask this increased risk, a mortality analysis of firefighters was carried out in three cities in relation to the United States population and also to a comparison cohort of police officers. The firefighters were employed between 1945 and 1980 and experienced 886 deaths by 1 January 1984; compared with the United States population they had a significantly reduced risk of dying from all causes (SMR = 82, 95% confidence interval, 77-87), and from non-malignant circulatory diseases (SMR = 81, 95% confidence interval 73-89), but no significant difference in risk of non-malignant respiratory diseases (SMR = 88, 95% confidence interval 66-117). Compared with police, the firefighters experienced a trend toward improved mortality outcomes for all causes investigated (SMR = 82), but they had an excess of deaths from non-malignant respiratory diseases (SMR = 141). The results indicate that firefighters are probably at increased risk for dying from non-malignant respiratory diseases; this increased risk may have been missed in previous studies because of the limitations of using a general reference population.

Ischemic heart disease mortality of firemen and policemen

Ischemic heart disease (IHD) mortality of Connecticut firemen and policemen is studied for the years 1960-78, using death certificate data. The mortality of these two occupations is expected to be greater than that of other workers. Standardized Mortality Odds Ratios for firemen and policemen are greater than 1.00. Although some increased IHD risk for firemen and policemen is suggested, the exact role of occupational risk factors remains to be determined.

Pulmonary function of London firemen

In a longitudinal study of a sample of firemen in London 1006 firemen were interviewed and examined in 1976 and 895 were seen a second time 12 months later. On each occasion a Medical Research Council respiratory questionnaire was administered and forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were measured. The average levels of FEV1, FVC, and FEV1/FVC in both years compared favourably with conventional predicted values. Separate multiple regression analysis for the two years indicated that the FEV1 and FVC fell more rapidly in those aged over 40, and that cigarette smoking had a strong harmful effect on these measures of function. Only among men with over 20 years' service was there possibly any evidence (not statistically significant) of an effect from duration of employment. The comparatively large fall in FEV1 and FVC from 1976 to 1977 was due mainly to instrumental variation. The prevalence of respiratory symptoms was higher in smokers than non-smokers and increased with the number of cigarettes smoked.

Mortality of fire fighters in Western Australia

All except 17 (1.7%) of 990 fire fighters employed by the Western Australian Fire Brigade between 1 October 1939 and 31 December 1978 were successfully followed up to 31 December 1978. Mortality from all causes was less than expected (SMR 0.80 with 95% confidence interval 0.67 to 0.96). There was evidence of the healthy worker effect but none that mortality increased with increasing duration of employment. A small proportional excess of deaths from road traffic accidents ( SPMR 1.66) appeared to be unrelated to fire service. Deaths from other accidents, poisonings, and violence were significantly less than expected (SMR 0.35 with 95% confidence interval 0.10 to 0.90) and may indicate an effect of training and experience on accident proneness. There was no evidence of increased mortality from cardiovascular or respiratory disease, or from any other cause.

Healthy worker effect in the total Finnish population

The selection due to the "healthy worker effect" was estimated from a random sample of the total Finnish population. The sample of 20 000 people was followed for changes in occupations from 1960 to 1970 and for deaths in 1971-5. Those entering the active work force had a standard mortality ratio of 70, indicating a healthy population selection effect. Those staying in the same occupational category from 1960 to 1970 had a 20% lower mortality than those who did not. This survivor population effect was due to changes to another occupational group and to early retirement. These factors had an inverse effect on the survival history of an occupational group.