Environments affect blood pressure in toddlers: The Japan Environment and Children’s Study

Background: The primary objective of this study was to examine risk factors for toddler’s hypertension. Methods: Subjects of this study were children and parents participating in a national birth cohort study in Japan, the Japan Environment and Children’s Study. We measured the children’s blood pressure (BP) at 2 and 4 years old. We obtained children’s and parents’ backgrounds from the questionnaire. We investigated the factors that affect BP elevation. Results: Within 4988 participants, the mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls. The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls. Parental smoking was associated with elevated values of BP at 2 and 4 years old. Obesity, gestational hypertension, and parental lower education were associated with elevated values of BP at 4 years old. Hypertensive group had a significantly higher obesity rate. The mother’s lower education and parental smoking were involved in hypertensive groups. Conclusion: Parental smoking had a significant effect on BP even in early toddlers. We emphasize the importance of avoiding second-hand smoking from early infancy to prevent future lifestyle-related illnesses including hypertension. Impact: The mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls.The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls.Obesity, parental smoking, and lower education were associated with hypertension at 4 years old.Parental smoking was associated with hypertension at 2 and 4 years old.We emphasize the importance of avoiding second-hand smoking from early infancy.