Physiologic and behavioral responses to stress, temperament, and incidence of infection and atopic disorders in the first year of life: a pilot study.

The purpose of this pilot study was to explore relationships among physiologic and behavioral responses to a standardized stressor (routine immunization), parent-reported temperament, and numbers of infections and atopic disorders in the first year of life. Infants were studied during 2- (n = 30) and 4-month (n = 24) routine clinic visits. Behavioral data were coded from videotapes filmed for 90 seconds after immunizations. Salivary cortisol measured physiologic arousal; specimens were obtained before and after immunizations. Two-month-old infants with higher levels of cortisol required more time to calm after immunization. Relationships were found between the temperament characteristics of persistence and adaptability and infections at 12 months.