The causes are unknown. Some researches have shown, however, that the risk of the outbreak of the disease is made higher by environmental factors of children, such as sleeping on their faces, parents' smoking, and non-maternal feeding. Based upon the discussions results, we have agreed to strive for enlightenment activities and diffuse knowledge among not only medical professionals and people engaged in nursery care but also the general public. Accordingly, information is being offered through Maternal and Child Health Handbooks, posters, and pamphlets. The prevention of such unexpected accidents upon infants and small children are shown in the Maternal and Child Health Handbooks.
Attention is called also in mother's classes, after medical checks, etc.