Safety critical occupations: is it safe to employ people with insulin-treated diabetes?

Historically, people living with diabetes requiring treatment with insulin have been prevented from gaining employment in a number of safety critical occupations, due to a perceived unacceptable risk to public safety.

The primary risk is posed by hypoglycaemia (low blood glucose) leading to cognitive impairment that can cause slowing of reaction times and poor judgement. These effects can last for as long as 60 minutes even after blood glucose levels return to normal, suggesting safety critical tasks should not be resumed immediately. In addition, long term diabetes-related complications such as vision loss, altered sensation or a serious cardiovascular event, for example a stroke, will also impact an individual’s ability to perform specific duties.

However, with advances in the management of diabetes, including insulin types, delivery methods and glucose monitoring systems, an individual’s ability to achieve glycaemic control has radically improved. This, coupled with the implementation of legislation against discrimination, means that insulin-treated diabetes should no longer be a barrier to employment. Instead, employers are expected to perform an individual risk assessment to determine a person’s fitness to perform the skills and responsibilities of the job safely.

Commercial flying has led the way for change since Canada allowed carefully selected pilots with insulin-treated diabetes to fly commercial aircraft in 2002. In 2012, the UK Civil Aviation Authority (CAA) developed a protocol to ensure safe flying for UK based insulin-treated pilots. Ireland and Austria have since adopted the protocol which now operates under the guidance of the EU Aviation Safety Agency (EASA). The protocol uses a traffic light system to govern acceptable blood glucose ranges and direct appropriate corrective action. Pilots are required to cross-check blood glucose measurements with the co-pilot and hand over control of the aircraft if any value is below 72 mg/dL (4.0 mmol/L) or above 360 mg/dL (20.0 mmol/L). The protocol is practical to implement within the confined space of the cockpit and to date no events compromising safety have been reported.

The aviation industry lends itself to the successful implementation of such a protocol: most commercial flights are short in duration; safety checks and emergency procedures are an integral part of the profession; and the presence of a co-pilot enables safe control of the aircraft to be maintained in the unlikely event the pilot is incapacitated for any reason, not just hypoglycaemia. In November 2019, the US Federal Aviation Authority (FAA) announced that the USA, like Canada, UK, Ireland and Austria, will now allow pilots with insulin-treated diabetes to fly commercial aircraft.

In contrast, other safety critical occupations require operators to work alone, for long periods of time and within unpredictable circumstances. Maritime workers, for example, have a physically demanding job with irregular working hours and a number of solo duties. These factors, along with seasickness, can cause difficulties balancing carbohydrate intake and insulin dosing, making hypoglycaemia more likely. The UK Maritime and Coastguard Agency (MCA) standards, which reflect international guidelines, recommend insulin-treated seafarers are restricted to work on vessels operating near coastal waters and that duties are adjusted to prevent solo watchkeeping, lone working and working at heights. Fitness to work beyond coastal waters may be possible with limited duties provided a doctor is on board the vessel.

Drivers of heavy goods and large passenger carrying vehicles, similarly to pilots, must apply for entitlement of a license by demonstrating good diabetes control. In the UK, a category 2 license issued by the Driving and Vehicle Licensing Authority (DVLA) for a person requiring insulin is valid for one year provided specific criteria are met. The driver must perform regular blood glucose monitoring, specifically within two hours before the start of a journey and every two hours while driving, not have experienced a severe hypoglycaemic event (requiring assistance from another person to treat) in the previous 12 months and have full hypoglycaemic awareness. The licence application must also be supported by a medical report from a consultant specialising in diabetes.

Employment within one of the emergency services on the other hand presents a whole variety of unpredictable working conditions, including irregular breaks, periods of intense physical exertion, prolonged periods of driving (frequently at high speeds), rapid decision-making and managing extreme stress and intense emotions. These factors may impact negatively on a person’s ability to maintain adequate glycaemic control and make it difficult to implement and enforce a strict protocol . In the US, insulin-treated law enforcement officers are required to measure their blood glucose before every shift and every two hours while on duty. They must also carry fast-acting carbohydrates on their person at all times. In addition, officers who operate a vehicle must maintain their blood glucose above 100 mg/dL (5.5 mmol/L). If blood glucose falls below 125 mg/dL (7.0 mmol/L) prior to driving, an officer must consume carbohydrates.

However, in certain occupations, it may not be possible to amend duties or implement a protocol to manage a level of risk acceptable to personal and public safety. The UK Armed Forces still prohibit anyone with insulin-treated diabetes from joining. However, if a serving member subsequently develops diabetes requiring treatment with insulin, their fitness to undertake deployable duties is reviewed. In 2017, 162 serving UK Armed Forces personnel across the Royal Navy, Army and Royal Air Force were diagnosed with insulin-treated diabetes.

Safety critical occupations are varied. Regular blood glucose monitoring, stable glycaemic control and full hypoglycaemic awareness are essential to ensure public safety. The examples discussed demonstrate that, with proper oversight and a defined protocol, it is possible for people with insulin-treated diabetes to adequately perform safety-critical occupations previously thought impossible. In doing so, their actions encourage employers of other safety-critical occupations to adopt open-minded individualised risk assessments that should see an end to the blanket restrictive attitudes of the past.