300 CLINICAL CONSIDERATIONS 



plasia of the heart, which are found in patients dying of Addi- 

 son's disease. He denied, however, the tuberculous nature 

 of the adrenal involvement, for the variety of pathological 

 forms in which tuberculous lesions manifest themselves was 

 not clearly understood until a later date. 



INCIDENCE 



Addison's disease is relatively rare. In the United States 

 300 to 400 persons die annually from this cause, the death 

 rate from Addison's disease being 0.4 per 100,000 population. 

 In the British Isles the death rate is given as 0.6 while in 

 Japan it is said to be only 0.04. 260 Only 5 of the 320 persons 

 recorded in 1917 as dying from Addison's disease were negroes 

 which is surprising in view of the high incidence of tuberculosis 

 in this race. It may be that because of the impossibility of 

 detecting the pigmentation, which is so important an aid in 

 diagnosis, most cases of the disease in the dark-skinned races 

 are not recognized. 



Addison's disease is one of middle life, the majority of cases 

 occurring between the twentieth and fortieth years of life. 

 Although cases have been reported in infants and in octoge- 

 narians, the disease is rare in children under 10 years of age. 

 Except in very rare instances there is no evidence of any hered- 

 itary factor involved in the etiology of the disease. About 

 two-thirds of all cases occur in males. 540 



Many predisposing causes have been noted such as worry, 

 emotional shock, alcoholism, heredity, infections— especially 

 malaria, influenza, pneumonia, and tuberculosis, — but it is 

 doubtful if any except the last named play an etiologic role. 

 The incidence of Addison's disease was not materially increased 

 following the influenza epidemic of 1918. Hence it is very 

 doubtful if influenza can be considered as a predisposing fac- 

 tor. 260 A patient will naturally date the onset of the disease 

 to some illness which may have been incidental or have accen- 

 tuated a previously latent condition. 



