Table 2 Summary of key findings based on health outcome and measurement period
From: Health risks and mitigation strategies from occupational exposure to wildland fire: a scoping review
Health Outcome | Key Findings: cross-shift | Key Findings: cross-season | Key Findings:Â other |
|---|---|---|---|
Respiratory Health | • Significant decrease in FEV1 and FVC [17, 26,27,28] • No significant change in FEF75, PEF, and FEV/FVC [27] • Respiratory symptoms were observed in some studies to increase post-shift [26, 29], but in other studies, no significant change was observed [17] • Post-shift exposure declines in PEF (lesser extent FEV1 and FVC) [30] | • Significant decrease in spirometry scores FEV1 [18, 31, 32], FEF25 [17], FEF50 [17], MEF [17], FVC [31, 32], FEF25–75 [32] • No significant change in spirometry values [17, 26], respiratory symptoms [17], or sputum levels [26] • Significant increase in respiratory symptom scores [26, 31] | • No significant associations: previous exposure and lung functioning [24, 34], and smoker vs. non-smoker lung function [28] • Significant associations: upper and lower respiratory tract symptoms and FEV1 values [26], lung functioning and allergies [27], levoglucosan concentration and FEV1 values [36], and firefighting and overall decreased lung function [33] |
Cardiovascular Health | • None reported | • Significant increase in LDL, cholesterol, and globulin [38] | • Significant associations: experience in wildland firefighting and hypertension [106], firefighting and risk of lung cancer and cardiovascular disease mortality [19], levoglucosan, particulate matter exposure, and oxidative stress leading to arterial stiffness [37] • No significant associations: between FEV1/FVC % and oxidative stress or levoglucosan concentrations [37], wood smoke exposure and vascular vasomotor or fibrinolytic function [39] |
Mental Health (PTSD) | • None reported | • None reported | • PTSD symptoms remained long-term after disaster [41, 42], the most common psychological impairment among firefighters [43] • Significant curvilinear relationship between post-traumatic symptoms’ severity and post-traumatic growth [44] • Permanent positions associated with lower risk of PTSD [45] • Increased fear of death and insomnia associated with increased PTSD [45] • Coping mechanisms of minimization and blame were associated with increased PTSD [107] |
Mental Health (Other) | • None reported | • None reported | • Intensity of disaster distress is positively associated to the level of psychological impairment [43], the losses sustained in disaster and severity of exposure to disaster were not major determinant of post-traumatic morbidity in firefighters [43, 46] • Association between fatigue, depression, and cytokines [47] • Wildland firefighters have higher levels of suicide risk when compared to non-wildland firefighters [48] • Increased prevalence of ADHD in wildland firefighters compared to general population [53] |
Hydration | • Ad libitum drinking and prescribed drinking did not adequately hydrate firefighters throughout shift [22, 23] • Not euhydrated at all times during shift with ad libitum drinking [55] but ad libitum drinking is sufficient for maintaining hydration status pre to post shift [55] and for rehydration [22, 23] • Decreased body weight and total body water pre- to post-shift [56] | • None reported | • Prescribed drinking associated with temporarily lower core temperatures than ad libitum drinking [23] • Wildland firefighters experienced increased core temperature without euhydration [55] • Building fireline increases rate of sweating [59], firefighting is associated with rapid dehydration [59] • Urinary protein excretion associated with intensity of work [57] • Firefighters doubled their fluid consumption in a simulated environment with hot conditions and recorded significantly lower urine specific gravity values (estimating hydration) relative to the lower temperature group (though both groups fell within the ‘hydrated’ range) [110] • Hydration in hot conditions not significantly impaired by restricted sleep [58] |
Fatigue and Sleep | • Wildland firefighters reported significantly higher levels of fatigue and decreased alertness with increasing days on deployment and these levels did not improve following a three-day rest period [60] • Wildland firefighters sleep quantity on fire days was significantly less than non-fire days [61] • No differences in sleep efficiency, sleep latency and subjective reports of times woken or sleep quality between non-fire and fire days for wildland firefighters [61] • Self-reported levels of pre- and post-sleep fatigue by wildland firefighters was greater on fire days compared to non-fire days [61] • Decreased sleep quantity and quality associated with high intensity initial attack fire deployment and base work periods [63] • No significant differences between sleep measurements on burn/non-burn days [64], burn day sleep measurements had no association with work shift start time and total sleep time [64] | • None reported | • Decreased gastrointestinal damage, subjective fatigue and perceived exertion associated with glutamine supplementation [22] • Firefighters not under additional thermal strain when working while sleep restricted [58] • Sleep environment, shift duration, and shift start times were associated with reduced sleep time [61] • Sleep measurements decreased and sleep efficiency increased with restricted sleep, slow wave sleep did not change significantly with restricted sleep [62] • No significant association between sleep and hot daytime temperatures [62] |
Acute Injuries | • None reported | • None reported | • Injuries more likely to be severe during peak/late season in comparison to early season [65] • Most common causes of injuries: slips/trips/falls [65,66,67], • Most common injuries sprains/strains [65,66,67], injuries of lower back/knee/foot/ankle [67] • 20% of firefighters thought their injury was preventable [67] • Majority of injuries occur in rocky, mountainside terrain [67] and are classified as minor [68] • Significant relationship between peak incident management level, person-days of exposure, and resistance of fire to control and odds of at least one injury [69] • Significant associations: an increase in fire complexity and a decrease in incident rate [69], likelihood of injury and increased age, increased neuroticism, decreased openness, and history of injury [70], experience and decreased likelihood of injury [70], reduction in entrapment rates and safety culture shift [71] • Significant predictor of injury is high job stress [70] • Transportation is high-risk [72] • Engine/chainsaw operations had highest incident rates [72] |
Fatalities | • None reported | • None reported | • Significant association with death and aviation, vehicles, medical events, and entrapments/burn overs [74] • Leading cause of aircraft crashes resulting in death include aircraft failure, loss of control, failure to clear terrain/water/objects and hazardous weather [75] Yearly Reports: • Four+ deaths of state/federal (USA) wildland management agency personnel on average at fires each year [76, 77] • Deaths by burns [76, 78,79,80,81,82,83], inhalation [76, 78], cardiac events [76, 81, 85,86,87], heat stroke [76], vehicle strike [76], strike tree/boulder [76, 78, 80,81,82, 83, 86,87,88], equipment failure [79], aircraft crashes [77, 79, 83,84,85, 87, 89], vehicle crashes [77, 80,81,82,83,84,85,86, 88, 89], parachute failure [80], fatal fall [87], chainsaw [81] • 23% of fire ground deaths at wildland fires [70] • Most severe multiple-fatality incidents occur at wildland fires [76, 78, 80] • Causes of death include heart attacks, vehicle accidents, other medical causes, burn overs, aircraft accidents, falling trees/snags/rocks [90, 91] |
Inflammation and Oxidative Stress | • Urinary 1-hydroxypyrene correlated with estimated exposure after 48 h [5] • Mean increase in 1-hydroxypyrene in urine samples collected post shift in 76% of participants [20] • Dermal exposure: absorbed polycyclic aromatic hydrocarbons increased in urine samples post shift [20] • Firefighters with drip torches: increase in IL-8, C-Reactive Protein, and serum amyloid [92] • Significant positive association of IL-8 and segmented neutrophils cross-shift [92] • Significant changes in pH, 8-isoprostane and pentraxin-3 [93], marginal increase in 8-isoprostane on burn days [95] • Significant increased airway and systemic inflammation after acute exposure [96] • Significant increase in IL-6 and IL-8 and significant decrease in IL-10 after 12 h of fire suppression [97] • Significant increase in sputum granulocytes post-shift [98] • Significant increase in IL-6, IL-8, and monocyte chemotaxic protein [98] • No significant changes in H2O2, protein D or myeloperoxidase post wood smoke exposure [93], urinary 1-hydroxypyrene or pulmonary function after pile burns [99], malondialdehyde or 8-oxo-7,8-dihydro-2-deoxyguanosine, except for 8-oxo-7,8-dihydro-2-deoxyguanosine levels for firefighters with under 2 years of experience [100] | • None reported | • Increased scores on the Skin Exposure Mitigation Index significantly related to decrease 1-hydroxypyrene [5] • Additional hygiene measures are effective in reducing dermal polycyclic aromatic hydrocarbons exposure and contamination [20] • Significant association between sputum macrophages with phagocytosed particles and circulating band cells [98] • Firefighting significantly associated with an increased level of basal DNA damage [101] • Increased IL-6 in the morning significantly associated with increased daily cortisol [102] |
Hearing | • None reported | • None reported | • Noise exposure regularly exceeds occupational limits [103], • Highest noise exposure from chainsaws, chippers, and masticators [103] • 54% of noise exposure exceeds recommendations [94] • Limited hearing protection use, minimal training on hearing protection [94] |
Temperature Regulation | • No significant change in heart rate, skin temperature, rectal temperature, or sweat rate pre- to post-shift [109] | • None reported | • Measures of thermal stress (core temperature, skin temperature and thermal sensation) were significantly higher in participants exposed to higher temperatures while performing wildland firefighting tasks in a simulated environment [110] • Evidence of a multiplying effect for mean skin temperature where wildland firefighters exposed to higher temperature work environment had greater mean skin temperature with each additional work task circuit [110] • Significant increase in skin temperature but no significant increase in cardiovascular or thermal strain while working in-field [111] • Job tasks of higher physical exertion associated with greater changes in core temperature [112] |
Mercury Toxicity | • None reported | • None reported | • No significantly elevated levels of mercury toxicity in wildland firefighters [104] |
Nutrition | • Sleep restriction and heat did not impact feelings of hunger and fullness across the day, and did not lead to greater cravings for snacks [113] • Discrepancy between total energy expenditure and total energy intake [114] | • None reported | • Wildland firefighters required to work in hot conditions while sleep restricted more likely to consume food between 12:30 and 14:30 h [113] |