| Concern | Facts |
|---|
| Cause | Unknown (possibly related to delayed maturation of cardiorespiratory system) |
| Incidence | Almost 2500 cases annually; leading cause of death between ages 1 month and 1 year |
| When | Occurs during sleep (nap, night) |
| Age | Peak at 2–4 months; 95% of cases occur by age 6 months |
| Sex | More common in boys |
| Race | More common in African Americans, Native Americans, and Hispanics |
| Season | More common in winter, peaks in January |
| Siblings | May have greater incidence |
| Perinatal | More common in preterm infants, in multiple births, in infants with low Apgar scores, and with maternal smoking |
| Socioeconomic | More common in lower socioeconomic classes |
| Feeding habits | More common in infants who are bottle-fed, less common in infants who are breastfed. |
| Means of prevention |  Supine (on back) sleeping position (mnemonic: “back to sleep”); avoid soft bedding and overheating during sleep; avoid cigarette smoking in house. |