Infantile colic. Seasonal incidence and crying profiles

To determine the occurrence of infantile colic and its seasonal variation in an unselected population and to evaluate the amounts of crying in colicky infants and noncolicky controls.

Questionnaire survey and a prospective substudy of parental diaries of crying.

All families with a full-term, healthy-born infant in the Turku City (Finland) district during 1 year.

Colic was defined as paroxysms of crying for 3 or more hours per day for 3 days or more per week during a period of at least 3 weeks. The questionnaires containing this definition were distributed to 1221 families in postpartum wards, and an invitation to a prospective follow-up study was presented to the families if their infant showed colicky symptoms. The incidence questionnaire was to be returned after 3 months. Six hundred four (49%) of the questionnaires were returned, and an additional 355 (29%) families were reached by phone. A total of 59 families with a colicky infant enrolled in the prospective substudy when the infants were at a median age of 5 weeks; age-matched controls were invited from the same population.

The incidence of infantile colic was 13%; possible infantile colic was 8%. No seasonal variation was found. The mean amount of total crying was 241 min/d (95% confidence interval [CI], 216 to 266 minutes) in the colic group and 112 min/d (95% CI, 95 to 130 minutes) in the control group during the first recording week. The mean amount of colicky crying was 122 min/d (95% CI, 102 to 142 minutes) in the colic group and 19 min/d (95% CI, 12 to 26 minutes) in the control group.

The incidence of colic was 13% with no seasonal variation. Parental perception of infantile colic correlated well with the amount of crying.