Obesity

Guidance for medical examiners when assessing a patient for either a general topic or condition - Obesity.

Definition

Body Mass Index (BMI is calculated by dividing a person’s weight in kilograms by the square of their height in metres).

Classification BMI (kg/m2)
Healthy weight 18.5-24.9
Overweight 25-29.9
Obesity I 30-34.9
Obesity II 35-39.9
Morbid Obesity 40 or more

Aeromedical implications

Effect of aviation on condition

  • Limited cockpit space may constrain range of movement increasing risk of venous thrombo-embolic disease

Effect of condition on aviation

  • Increased risk of sudden incapacitation secondary to cardiovascular disease (myocardial infarction and cerebrovascular accident)
  • Increased risk of sudden and subtle incapacitation secondary to sleep apnoea
  • Increased risk of complications of type 2 diabetes
  • Increased risk of incapacitating pulmonary embolus
  • Distraction due to pain from lower back pain, gall bladder disease, osteoarthritis
  • Limited cockpit space may impact on ability to fully and safely operate controls in normal and emergency situations
  • Ability to egress aircraft in emergency may be restricted
  • Weight may exceed design limitations of seat and harnesses
  • Body weight may have significant impact on weight and balance of aircraft

Approach to medical certification

Based on the condition

  • Complications of obesity
  • Operational constraints

Based on treatment

  • Appetite suppressants are disqualifying for medical certification
  • Medications which reduce absorption of dietary fat may cause significant GI side effects, headaches and anxiety. A two week ground trial will be required with DAME review
  • Bariatric surgery will require grounding for a period of up to 3 months with a DAME and CASA AVMED review before decision on fitness to return to flying or controlling

Demonstrated stability

  • Trajectory of weight gain
  • Presence or absence of complications

Risk assessment protocol - information required

New cases

BMI >30 for applicants aged over 40 years

  • The result of a fasting glucose test (with follow up Glucose Tolerance Test if > or = 5.5mmol/L).
  • Clinical status
  • A sleep study should be performed if:
    • symptoms of OSA
    • history of congestive heart failure, atrial fibrillation, treatment refractory hypertension, type 2 diabetes, nocturnal dysrhythmias, stroke, pulmonary hypertension
    • Epworth sleep score >8
    • neck circumference >42cm for men and > 40cm in women
    • history of aircraft or motor vehicle accident.

Body mass index >35 for all applicants

  • The result of a fasting glucose test (with follow up Glucose Tolerance Test if > or = 5.5mmol/L)
  • A sleep study should be performed if:
    • symptoms of OSA
    • history of congestive heart failure, atrial fibrillation, treatment refractory hypertension, type 2 diabetes, nocturnal dysrhythmias, stroke, pulmonary hypertension
    • Epworth sleep score >8
    • neck circumference >42cm for men and > 40cm in women
    • history of aircraft or motor vehicle accident.

Body mass index >40 for all applicants

  • An assessment by the DAME using the CASA cardiovascular risk profile, and if necessary, a cardiovascular assessment by a cardiologist or consultant physician, including results of resting ECG and interval Stress ECG.  The report should detail:
    • clinical status
    • presence and control of risk factors e.g. hypertension, smoking, hyperlipidaemia (Total Cholesterol, LDL and HDL fractions should be recorded), and the result of a fasting glucose test (with follow up Glucose Tolerance Test if >5.5mmol/L)
    • risk of any acutely disabling cardiovascular event
  • A sleep study should be performed
  • An operational check
    • The operational check is to be conducted by either a Civil Aviation Safety Authority Flight Operations Inspector or a Civil Aviation Safety Authority Approved Test Officer or your local Chief Flying Instructor. To arrange this test please telephone the Manager of Flying Operations on 131 757 or your flying school
    • an operational check of the applicant with special attention being given to ability to fully utilize all controls to full extent of travel and ability to exit aircraft expediently in the event of emergency, and also pay attention to the accurate assessment of weight and balance calculations in the aircraft (please provide an example of the applicant’s calculations for his weight).

Renewal

  • As above depending on current BMI
  • If BMI increases by >=2.5 then the operational check must be repeated

Indicative outcomes

Favourable

  • Uncomplicated obesity responding to diet and exercise
  • Uncomplicated bariatric surgery following period of grounding and satisfactory review

Unfavourable

  • Uncontrolled complications of obesity
  • Positive exercise stress test
  • Appetite suppressants

Pilot and controller information

  • Nil specific pilot and controller information

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Disclaimer

The clinical practice guidelines is provided by way of guidance only and subject to the clinical practice guidelines disclaimer.

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