Sir.—I read with interest the article by Hayward et al1 on nutritional rickets in San Diego. I returned recently from Kenya where I was a visiting professor of pediatrics at Kenyatta National Hospital. The climate in Nairobi is similar to that of San Diego, being quite warm and sunny. I saw several infants with rickets during my brief visit there. All of these infants had been breast-fed, and all had a history similar to that of the child described by Hayward et al of being confined indoors for an extensive period, with little exposure to sunlight. The reasons given by mothers included the need for both parents to work away from the home and concern that exposure to fresh air would increase the likelihood of respiratory tract infection.