Sayaka Kato

Background: Poor oral hygiene, generally manifesting as dental caries, gingivitis, or periodontitis, is a common chronic condition among both children and adults worldwide and has been reportedly associated with hypertension and arterial stiffness mainly in adult patients. However, these associations have not been well-studied in children and adults in the general population. Therefore, we conducted this cross-sectional study to clarify the associations between oral hygiene indices and high blood pressure (BP)/hypertension and arterial stiffness as assessed by the cardio-ankle vascular index (CAVI) in children along with their mothers. The association between maternal oral hygiene and high BP in children was also examined based on the hypothesis that maternal awareness of oral hygiene is related to their children’s oral hygiene.Methods: This study was conducted as an Adjunct Study of the Aichi Regional Sub-Cohort of the Japan Environment and Children’s Study. Participating children (n = 220, 85–104 months old) and their mothers (n = 217, 29–52 years old) underwent dental/intra-oral examination and BP and CAVI assessment. High BP in children and hypertension in mothers were diagnosed according to corresponding American guidelines. Logistic regression analysis or analysis of covariance was used to examine the associations of poor oral hygiene indices with BP and CAVI.Results: Maternal dental caries ≥1 was associated with their hypertension (adjusted odds ratio [aOR]: 2.72, 95% confidence interval (CI): 1.12–6.61). Maternal dental plaque ≥1/3 was associated with maternal hypertension and children’s high BP (aOR, 95% CI: 4.71, 1.33–16.73 and 5.67, 1.22–25.04, respectively). Maximum pocket depth ≥4 mm was associated with children’s high BP (aOR: 6.85, 95% CI: 1.24–38.01). No associations were observed between oral hygiene indices and CAVI in children; however, there was a significant association between dental plaque and CAVI in mothers (F = 5.62, p < 0.01).Conclusions: The small sample size, especially the case number, made it necessary to refrain from drawing unambiguous conclusion. The hypothesis that warrants further investigation based on the present study results is that poor oral hygiene is associated with high BP in children and hypertension and arterial stiffness in mothers, and maternal oral hygiene is associated with high BP in children.

Later-borns tend to be shorter than first-borns in childhood and adulthood. However, large-scale prospective studies examining growth during infancy according to birth order are limited. We aimed to investigate the relationship between birth order and growth during the first 4 years of life in a Japanese prospective birth cohort study. A total of 26,249 full-term singleton births were targeted. General linear and multivariable logistic regression models were performed and adjusted for birth weight, parents’ heights, maternal age at delivery, gestational weight gain, maternal smoking and alcohol drinking status during pregnancy, household income, breastfeeding status, and Study Areas. The multivariate adjusted mean length Z-scores in “first-borns having no sibling”, “first-borns having siblings”, “second-borns”, and “third-borns or more” were −0.026, −0.013, 0.136, and 0.120 at birth and −0.324, −0.330, −0.466, and −0.569 at 10 months, respectively. Results similar to those at 10 months were observed at 1.5, 3, and 4 years. The adjusted odds ratios (95% confidence intervals) of short stature at 4 years in “first-borns having siblings”, “second-borns”, and “third-borns or more” were 1.08 (0.84–1.39), 1.36 (1.13–1.62), and 1.50 (1.20–1.88), respectively, versus “first-borns having no sibling”. Birth order was significantly associated with postnatal growth and may be a factor predisposing to short stature in early childhood.

The composition of human gut microbiota influences human health and disease over the long term. Since the flora in specimens can easily change at ambient temperature outside the body, epidemiological studies need feasible methods of stool specimen collection and storage to be established. We aimed to validate two methods: feces frozen-stored in tubes containing guanidine thiocyanate solution for two months after collection (Method B), and feces excreted in diapers and frozen-stored (Method C). Validation was by comparison with a gold standard Method A. Bacterial flora of five adults were sampled and stored by all three methods. Bacterial composition was examined by amplicon sequencing analysis. Bland–Altman analyses showed that Methods B and C might change relative abundances of certain bacterial flora. Thereafter, we analyzed the bacterial flora of 76 toddlers (two age groups) in stools sampled and processed by Method C. The diversity indices of toddlers’ flora were less than those of adults. The relative abundance of some bacteria differed significantly between children aged 1.5 and 3 years. The specimen collection and storage methods validated in this study are worth adopting in large-scale epidemiological studies, especially for small children, provided the limited accuracy for some specific bacteria is understood.

Ready-meal consumption is increasing worldwide; however, its impact on human health remains unclear. We aimed to examine the association between processed food and beverage consumption during pregnancy and pregnancy outcomes. Pregnant women were recruited for the Japan Environment and Children’s Study (JECS), a nationwide, large-scale, prospective cohort study. This study included 104,102 registered children (including fetuses or embryos) and collected questionnaire-based data during the first and second/third trimester of pregnancy. Participants’ medical records were transcribed at pregnancy registration, immediately after delivery, and 1 month after delivery. Logistic regression analysis was used to estimate the association between processed food consumption and pregnancy outcomes. The incidence of stillbirth was higher in the group that consumed moderate (1–2 times per week) and high (≥3–7 times per week) amounts of ready-meals (adjusted odds ratio (aOR) = 2.054, 95% confidence interval (CI): 1.442–2.926, q = 0.002; aOR = 2.632, 95% CI: 1.507–4.597, q = 0.007, respectively) or frozen meals (aOR = 2.225, 95% CI: 1.679–2.949, q < 0.001; aOR = 2.170, 95% CI: 1.418–3.322, q = 0.005, respectively) than in the group that rarely consumed such foods. Processed food consumption during pregnancy should be carefully considered.

Background: Pyrethroid (PYR) insecticides are widely used for controlling various pests. There are two types that differ in terms of usage: agricultural-purpose PYR (agriculture-PYR) and hygiene purpose PYR (hygiene-PYRs). Few studies exist on the exposure to these chemicals in small children. In this study, we conducted biomonitoring of urinary pyrethroid metabolites in 1.5-year-old children throughout the year.Methods: Study subjects were 1075 children participating in an Aichi regional sub-cohort of the Japan Environment and Children’s Study as of 18-month health check-up. The concentrations of four specific hygiene-PYR metabolites including 2,3,5,6-tetrafluoro-1,4-benzenedimethanol (HOCH2-FB-Al), and five common metabolites of hygiene- and agriculture-PYRs including 3-phenoxybenzoic acid (3PBA) and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA), were measured in urine samples extracted from soiled diapers using a triple quadrupole gas chromatograph-mass spectrometer.Results: The highest detection frequencies were for 3PBA, followed by DCCA, 1R-trans-chrysanthemum dicarboxylic acid, and HOCH2-FB-Al. Among the six metabolites, urinary concentrations were seasonally varied. However, this variation was not observed in the most studied PYR metabolite, 3PBA. Spearman’s correlation analysis demonstrated a significant positive correlation between FB-Al and DCCA (r = 0.56) and HOCH2-FB-Al and 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol (r = 0.60).Conclusions: This biomonitoring survey found widespread and seasonally specific exposure to multiple hygiene- and agriculture-PYRs in 1.5-year-old Japanese children.

To discuss appropriate physical activity (PA) levels during pregnancy, this prospective cohort study examined the relationships between PA levels before and during pregnancy and physical and mental health status. Fixed data for 104,102 pregnant women were used from the Japan Environment and Children’s Study, of which data for 82,919 women were analyzed after excluding women with multiple birth and pregnancy complications. PA levels were measured using the International Physical Activity Questionnaire-Short Form. The 8-Item Short Form Health Survey was used to measure outcomes. Logistic regression with multiple imputations showed that moderate PA for over 720 min/wk and vigorous PA before pregnancy were associated with poorer mental health in the first trimester (adjusted odds ratio (AOR): 1.087–1.376. Walking in the second and third trimesters was associated with better physical and mental health (AOR: 0.855–0.932). Moderate PA over 1080 min/wk and vigorous PA in the second and third trimesters were associated with poorer mental health (AOR: 1.223–1.873). Increases over 4135.4 MET–min/wk and decreases in PA levels were associated with poorer mental and physical health (AOR: 1.070–1.333). Namely, pregnant women receiving health benefits prefer continuous walking in addition to avoiding vigorous PA and excessive changes in PA levels during pregnancy.

Context Maternal cholesterol is important for fetal development. Whether maternal serum total cholesterol (maternal TC) levels in midpregnancy are associated with small (SGA) or large (LGA) for gestational age independent of prepregnancy body mass index (BMI) and weight gain during pregnancy is inconclusive. Objective This work aimed to prospectively investigate the association between maternal TC in midpregnancy and SGA or LGA. Methods The Japan Environment and Children’s Study is a nationwide prospective birth cohort study in Japan. Participants in this study included 37 449 nondiabetic, nonhypertensive mothers with singleton birth at term without congenital abnormalities. Birth weight for gestational age less than the 10th percentile and greater than or equal to the 90th percentile were respectively defined as SGA and LGA by the Japanese neonatal anthropometric charts. Results The mean gestational age at blood sampling was 22.7 ± 4.0 weeks. After adjustment for maternal age, sex of child, parity, weight gain during pregnancy, prepregnancy BMI, smoking, alcohol drinking, blood glucose levels, household income, and study areas, 1-SD decrement of maternal TC was linearly associated with SGA (odds ratio [OR]: 1.20; 95% CI, 1.15-1.25). In contrast, 1-SD increment of maternal TC was linearly associated with LGA (OR: 1.13; 95% CI, 1.09-1.16). Associations did not differ according to prepregnancy BMI and gestational weight gain (P for interaction > .20). Conclusion Maternal TC levels in midpregnancy were associated with SGA or LGA in a Japanese cohort. It may help to predict SGA and LGA. Favorable maternal lipid profiles for fetal development must be explored.