Naomi Tamura1,2,3, Tomoyuki Hanaoka1, Kumiko Ito1,4, Atsuko Araki1,2, Chihiro Miyashita1, Sachiko Ito1, Sumitaka Kobayashi1, Yoichi Ito3, Hisanori Minakami5, Kazutoshi Cho5, Toshiaki Endo6, Tsuyoshi Baba6, Kazuo Sengoku7, Toshinobu Miyamoto7, Katsuhiko Ogasawara8, Reiko Kishi9. 1. Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan. 2. Graduate School of Health Science, Hokkaido University, Sapporo, Japan. 3. Research Center for Medical and Health Data Science, The Institute of Statistical Mathematics, Tokyo, Japan. 4. Graduate School of Medicine, Hokkaido University, Sapporo, Japan. 5. Departments of Obstetrics and Gynecology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan. 6. Departments of Obstetrics and Gynecology, School of Medicine, Sapporo Medical University, Sapporo, Japan. 7. Departments of Obstetrics and Gynecology, Asahikawa Medical University, Asahikawa, Japan. 8. Faculties of Health Science, Hokkaido University, Sapporo, Japan. 9. Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan. rkishi@med.hokudai.ac.jp.
Abstract
OBJECTIVES: Previous studies indicated a significant association between small for gestational age (SGA) in infants and their parents' socioeconomic status (SES). Thus, this study aimed to examine if parental factors, such as maternal smoking, and the pre-pregnancy body mass index (BMI) could mediate the associations between parental SES and SGA. METHODS: The participants of this study were pregnant women who enrolled in an ongoing birth cohort study, the Hokkaido study, during the first trimester of their pregnancies. A total of 14,593 live singleton births were included in the statistical analysis, of which 1011 (6.9%) were SGA. Two structural equation models were employed to evaluate the associations between parental SES, parental characteristics, and SGA. RESULTS: The effect of low SES on SGA was directly mediated by maternal pre-pregnancy BMI, smoking during the third trimester, and alcohol consumption during the first trimester in the first model, which was based the assumption of independent associations between mediating factors. In the second model, which additionally considered the mediating factors from the first model, smoking during pregnancy mediated decline in parental SES, consequently increased SGA. Moreover, an increase in pregnancy smoking status increased the prevalence of lower maternal pre-pregnancy BMI and its effect on SGA. CONCLUSIONS FOR PRACTICE: In this study, we observed the independent mediating effect of maternal pre-pregnancy BMI, smoking, and alcohol consumption during pregnancy on low SES and, consequently, SGA, with the additional mediating pathway of SES to smoking to low BMI on SGA.
OBJECTIVES: Previous studies indicated a significant association between small for gestational age (SGA) in infants and their parents' socioeconomic status (SES). Thus, this study aimed to examine if parental factors, such as maternal smoking, and the pre-pregnancy body mass index (BMI) could mediate the associations between parental SES and SGA. METHODS: The participants of this study were pregnant women who enrolled in an ongoing birth cohort study, the Hokkaido study, during the first trimester of their pregnancies. A total of 14,593 live singleton births were included in the statistical analysis, of which 1011 (6.9%) were SGA. Two structural equation models were employed to evaluate the associations between parental SES, parental characteristics, and SGA. RESULTS: The effect of low SES on SGA was directly mediated by maternal pre-pregnancy BMI, smoking during the third trimester, and alcohol consumption during the first trimester in the first model, which was based the assumption of independent associations between mediating factors. In the second model, which additionally considered the mediating factors from the first model, smoking during pregnancy mediated decline in parental SES, consequently increased SGA. Moreover, an increase in pregnancy smoking status increased the prevalence of lower maternal pre-pregnancy BMI and its effect on SGA. CONCLUSIONS FOR PRACTICE: In this study, we observed the independent mediating effect of maternal pre-pregnancy BMI, smoking, and alcohol consumption during pregnancy on low SES and, consequently, SGA, with the additional mediating pathway of SES to smoking to low BMI on SGA.
Entities:
Keywords:
Birth cohort study; Parental tobacco smoking; Small for gestational age; Socioeconomic status; Structure equation modeling