A retrospective chart review of 28 children (15 males, 14 females) treated with the ketogenic diet for epilepsy for more than 6 years was conducted at Johns Hospital Hospital. Response was documented by attendance at clinic and by telephone. Patients were aged 7 to 23 years at follow-up. Diet duration was 6 to 12 years. Seizure frequency was decreased in 90% patients. Side effects included kidney stones in 7 (25%), skeletal fractures in 6 (21%), and an increase in the number of children with height below the 10th centile from 10 at initiation of the diet to 23 at follow-up (p=0.001). Overall lipid profiles were generally within the normal range, and cholesterol and triglycerides did not increase significantly. 
COMMENT. In this report, the efficacy of the ketogenic diet in the treatment of childhood epilepsy was maintained after long-term use, but side effects, especially growth retardation, kidney stones, and fractures, need to be monitored and may be serious.
Several previous reports of long-term use of the diet, or of adults, 40-50 years of age, previously treated with the ketogenic diet have been published, some from the above authors' institution (Livingston S, 1972) and earlier, from the Mayo Clinic where the diet was first introduced (Keith HM, 1963; Wilder RM, 1921). Livingston allayed concerns about the high fat diet and possible cardiac complications in later life; he found no increased evidence of arteriosclerosis, hypertension, ECG abnormalities, or elevated cholesterol levels in the adults examined. He referred to Haddow Keith, my former colleague and mentor regarding use of the diet, and his report of follow-up data on 530 patients with idiopathic epilepsy treated for periods varying up to 36 years. Of 32 followed for 25 to 30+ years, 24 were well and 8 improved. Of the total of 530 patients, 30% were completely free of attacks, 24% were improved, and 39% were not benefited; 34 (6%) had died, 4 in status epilepticus.