Twin Research and Human Genetics


Development of Body Mass Index of Japanese Triplets From Birth Until the Onset of Puberty

Yoshie Yokoyamaa1 c1, Janne Pitkäniemia2, Jaakko Kaprioa2a3a4 and Karri Silventoinena5

a1 Department of Public Health Nursing, Osaka City University, Osaka, Japan

a2 Hjelt Institute, Department of Public Health, University of Helsinki, Helsinki, Finland

a3 Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland

a4 Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland

a5 Population Research Unit, Department of Social Research, University of Helsinki, Helsinki, Finland


We aimed to analyze the characteristics of development of relative weight in Japanese triplets from birth until 12 years of age. Data were collected through a mailed questionnaire sent to mothers of triplets asking for information recorded in medical records. Altogether we had information on 1,061 triplet children of 354 mothers born between 1978 and 2006. For these births, data on triplets’ height and weight growth, gestational age, sex, parity, and maternal age at delivery were obtained from records in the maternal and child health handbooks and records from the schools where children receive health check-ups. In addition, information on maternal height and weight was obtained. Triplets have a lower ponderal index at birth and lower body mass index (BMI) compared with the general population until 12 years of age, except for the period during 1 and 3 years of age. Moreover, birth weight had the strongest contribution to BMI of triplets until 6 years of age. After 9 years of age, maternal BMI was a significant factor affecting BMI of triplets.

(Received November 15 2012)

(Accepted May 06 2013)

(Online publication June 13 2013)


  • triplet;
  • birth weight;
  • maternal body mass index


c1 address for correspondence: Yoshie Yokoyama, Department of Public Health Nursing, Osaka City University, Osaka, Japan. E-mail: