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Dose‐dependent associations between prenatal caffeine consumption and small for gestational age, preterm birth, and reduced birthweight in the Japan Environment and Children's Study
Author(s) -
Kobayashi Sumitaka,
Sata Fumihiro,
Murata Katsuyuki,
Saijo Yasuaki,
Araki Atsuko,
Miyashita Chihiro,
Itoh Sachiko,
Minatoya Machiko,
Yamazaki Keiko,
Ait Bamai Yu,
Kishi Reiko
Publication year - 2019
Publication title -
paediatric and perinatal epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.667
H-Index - 88
eISSN - 1365-3016
pISSN - 0269-5022
DOI - 10.1111/ppe.12551
Subject(s) - medicine , quartile , gestational age , small for gestational age , obstetrics , pregnancy , gestation , birth weight , confidence interval , prospective cohort study , relative risk , caffeine , cohort study , biology , genetics
Background Few previous studies have investigated the association between prenatal caffeine intake and birth size (small for gestational age [SGA], preterm birth, and birthweight Z‐score) in Japan. Objectives We examined the dose‐dependency of this association (prenatal caffeine consumption and birth size) as part of the Japan Environment and Children's Study. Methods A prospective birth cohort included 94 876 fetuses in Japan. Participants were enrolled between January 2011 and March 2014. Adjusted multiple linear regression and Cox regression models were used to examine the association between prenatal caffeine levels and infant birth size. Results The median estimated caffeine consumption during pregnancy was 125.5 mg/day, as determined by self‐administered questionnaires. There were 7252 SGA infants (7.6%) and 4281 preterm birth infants (4.5%). Compared with infants of mothers whose caffeine consumption during pregnancy was in the lowest quartile (4.2 to <86.4 mg/day), infants of mothers whose caffeine consumption was in the highest quartile 4 (205.5‐5080.0 mg/day) were at an increased risk of SGA (relative risk [RR] 1.18, 95% confidence interval [CI] 1.10, 1.27), and at an increased risk of preterm birth at the second trimester of gestation (RR 1.94, 95% CI 1.12, 3.37), with a 0.32‐day reduction in gestational age (95% CI −0.52, −0.12) and with a 0.07 reduction in birthweight Z‐score observed (95% CI −0.09, −0.05). Conclusions Prenatal caffeine consumption was associated with birth size. However, as the association between prenatal caffeine consumption and birth size was likely confounded by unpredicted potential factors, our confidence in the true causality of the association is moderate.