Breastfeeding leads to lower blood pressure in 7-year-old Japanese children: Tohoku Study of Child Development.

This study investigated the association between breastfeeding and both self-measured home blood pressure (HBP) and conventional blood pressure (CBP) in 7-year-old Japanese children. We obtained data pertaining to breastfeeding and blood pressure for 377 mother-offspring pairs from the Tohoku Study of Child Development, which is a prospective birth cohort study. Information on breastfeeding and other factors were obtained from parental questionnaires during the follow-up period. Based on the duration of breastfeeding as a major source of nutrition, mother-offspring pairs were divided into short-term (mean, 5.1 months) and long-term (mean, 11.3 months) breastfeeding groups. At the age of 7 years (84.4±1.8 months), each child's blood pressure was measured. The HBP in the long-term breastfeeding (LBF) group (92.9 mm Hg systolic/55.1 mm Hg diastolic) was significantly lower (P=0.006/0.04) than in the short-term breastfeeding group (94.7/56.4 mm Hg); however, there were no significant differences in the CBP measurements between the short- and LBF groups. Using multiple regression analysis, the duration of breastfeeding (greater than 8 months) was more strongly associated with HBP (P=0.008/0.05) than with CBP (P=0.4/0.9). Furthermore, the adjusted R-squared values for HBP (0.25/0.12) tended to be higher than those for CBP (0.07/0.03). These findings were independent of the birth weight. In conclusion, breastfeeding has a protective effect against elevated blood pressure even in young children, and subtle, but important, differences were precisely detected by self-measurements performed at home.