Adrenal insufficiency is a rare disorder. It may present in patients of all age groups. The incidence of autoimmune adrenalitis is more common in females in the age groups of 30 to 50 compared to males. Whereas, adrenal crisis does not show any female to male predilection. The most common cause of primary adrenal insufficiency in the developed world is autoimmune adrenalitis. Whereas, in the developing world it is Tuberculosis. The most common cause of central adrenal insufficiency is chronic glucocorticoid use.

• The incidence of adrenal insufficiency is approximately 0.8 new cases per 100,000 individuals per year individuals in the developed world. ^[1]
• The incidence of adrenal insufficiency in Europe is approximately 4.4 to 6.2 new cases per 100,000 individuals per year .^[2]

• The prevalence of primary adrenal insufficiency is approximately 117 to 221 cases per 1 million in European populations.^{[3] [4] [5] [6]}
• The prevalence of secondary adrenal insufficiency is rare, ranging from 140 to 279 per 1 million individuals .^{[7] [8] [9]}

• The mortality rate of adrenal crisis is approximately 0.5/100 patients/year. ^[10]

• Patients of all age groups may develop adrenal insufficiency.
• Primary adrenal insufficiency commonly affects individuals between 20 to 50 years of age.^[11]
• Secondary adrenal insufficiency commonly affects individuals in the 60s. ^[12]
• The incidence of adrenal crisis increase with age greater than 60 years. ^[13]

• There is no racial predilection to adrenal insufficiency. ^[14]

• Females are more commonly affected by adrenal insufficiency than males. The female to male ratio is approximately 2 to 1 for primary adrenal insufficiency. ^[15]
• Acute adrenal crisis affects males and females equally. ^[16]

• The highest incidence of adrenal insufficiency has been reported in Iceland.^[17]

Worldwide, the most common cause of primary adrenal insufficiency was Tuberculosis. However, since the 1950s the incidence of autoimmune adrenalitis has been rising. Now, the most common cause of primary adrenal insufficiency in the developed world is autoimmune adrenalitis. ^[18]

The most common cause of primary adrenal insufficiency in the developing world is Tuberculosis. ^[19]