ACRT Journal

Given the recently published reassuring results of the ARA MED 330 protocol from the European Union Aviation Safety Agency (EASA) involving pilots on insulin for years 3, the continuous progress in diabetes technology and the strong commitment to the best lifestyle and glucose control management practice to keep fitfor-job and the current, extremely safe insulin treatment strategies, hypoglycemia could be seen as a negligible incapacitation risk factor for ATCOs in general. Indeed, we could not find any hypoglycemic events in our cases.

On the other hand, the two subjects also proved to never go beyond the upper level of the “green range” accepted for pilots included in the ARA MED 330 protocol (15.0 mmol/L or 270 mg/dL), which was acceptable in terms of work efficiency [3].

Stress can be defined as a human reaction to emotional, cognitive, and physical challenges, especially, yet not necessarily, when subjects are vigilant against imminent dangers. Indeed, ATCOs are working in situations characterized by high stressful communication/ management needs and environmental constraints as integral part of their job, which is classified by the U.S. Department of Labor at the upper fourth level [4]. As a consequence of that, the vast majority of controllers retire before the expected age with stressrelated work disabilities [5].

Explaining ATCO stress only by the level of air traffic activity and potential conflicts may not be far-sighted. However, to be accepted in the starting ATCO course, all candidates have to pass specific psycho-technical tests and group dynamics exercises to provide the system with sufficient guarantees of their ability to cope with highly stressing conditions despite a well-tested overload mitigation system of the work environment they are expected to live in.

At the beginning of this century, Costa et al. analyzed the psychological pattern of ATCOs, trying to sort out the most relevant components of work stress (WS) [6]. They found that WS was related primarily to mental load, time pressure, and the burden of responsibility. Stressed individuals mainly reported digestive, neuropsychic, and cardiovascular psycho-somatic symptoms, although less frequently than observed in the general population. Regional center ATCOs reported such symptoms more frequently than Airport tower ATCOs; the same applied to those operating in radar than non-radar positions, respectively. However, family history, lifestyle, sleep pattern, chronotype (morningness being better for early shifts), and neurotic personality traits seemingly influence results [6].

At the same time, shiftwork has become less problematic due to the current excellent shift schedules. A common source of stress is 24hour sleep deprivation (SD), potentially occurring as a function of sudden job requirements and inappropriate shift schedules as part of specific occupational environments. Indeed, SD makes people more susceptible to making errors by impairing attention and working memory through increased serum concentrations of stress hormones, including cortisol, epinephrine, and norepinephrine, without causing any changes in glucose and inflammatory markers compared to baseline [7].

Due to that, according to Iavicoli et al., occupational medicine specialists should allow complication-free, eumetabolic persons with diabetes (PwD) to fully implement their skills in any jobs by considering the least invasive organizational interventions in terms of acceptable shiftwork and night-time rosters and assuring easy access to fluid/electrolyte sources and tight blood glucose monitoring [8].

Indeed, considering the relatively null effect of real-life workingrelated stress on glucose levels in our two cases, we might speculate that stress experienced during duties has no substantial impact on their carbohydrate and insulin intake and, therefore, on their glucose profiles, thus causing neither relevant hyperglycemic spikes nor significant hypoglycemic troughs.

Such a conclusion is also in line with what was found by Wiesli et al. in T1DM patients undergoing acute psychosocial stress through the Trier Social Stress Test (TSST) under basal and postprandial conditions. They found no glucose changes in the fasting state, and there was only a significantly delayed glucose decrease in the postprandial period [9].

Another group investigating people with T1DM waking up in response to an alarm clock at 4 a.m. found CGM-based glucose concentrations to significantly increase by 18±6 mg/dl (1.0±0.3 mmo/L) only in the absence of nurse assistance [10]. According to Walker et al., adults with diabetes under higher work stress levels experience slightly higher HbA1c levels, witnessing the well-known hyperglycemic effect of stress and, therefore, the hypoglycemia-related incapacitation is a highly unexpected event unless PwD happen to reduce their CHO intake [11]. Such an observation had already been reported nine years before by Gonder-Frederick et al. in pump-wearing T1DM patients recording carbohydrate intake, insulin doses, and psychological stress ratings: the authors suggested the need for specific education in stress management and accurate insulin dose adaptation to changed carbohydrate intake [12].

Conclusion

Being an insulin-treated subject can take many resources. Also, some days can be more challenging than others. However, professionals with diabetes are commonly aware of the high risk they incur in terms of both life-threatening attitudes and failure to maintain their jobs and related income.

Therefore, once they have attained metabolic control, all flight personnel will do their best to stay safe and avoid extreme glucose excursions as much as possible. Especially when using advanced hybrid pumps that enable semi-automatic glucose management throughout the day and consistently commit to the best glucose management, ATCOs on insulin will be very good at keeping in the tightest optimal range.

Provided their glucose control is acceptable for a sufficiently long period during and around working hours, forbidding professionals with T1DM to be or become ATCOs would seem unfair nowadays. Permitting them to obtain a fitness certificate appears logical and safe worldwide, not only in countries like the USA, where the Federal Aviation Administration (FAA) already paved the way to a CGM-based flight safety risk mitigation protocol for exercising airline transport or commercial pilot privileges [13]. Aeromedical examiners should employ a rigorous and structured evaluation process when assessing insulin-treated ATCOs for continued certification. A case-by-case assessment of individuals with diabetes seeking to become or continue as ATCOs is now warranted. This approach will promote positive outcomes such as increased motivation and job satisfaction. Allowing ATCOs diagnosed with T1DM after their qualification to continue with their current role will entitle society to make the best use of the significant time and financial resources spent on challenging, highly specialized job training given the growing reduction in staff for planned retirements in the next few years.

Acknowledgments

We are deeply indebted to Mrs. M.I. and Mr. C.B. for their strong support in understanding ATCOs environmental stress factors and for their written informed consent to the utilization of their CGM readings for research and publication purposes.

References

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