AIMS: This study investigated the association between maternal age and early and late gestational diabetes mellitus (GDM). METHODS: In total, 72,270 pregnant women were included in this prospective birth cohort study. Associations between maternal age and early GDM (diagnosed at <24 gestational weeks) and late GDM (diagnosed at ≥24 gestational weeks) were evaluated using a multinomial logistic regression model with possible confounding factors. The reference category was maternal age of 30-34.9 years. RESULTS: Higher maternal age was associated with higher odds of early and late GDM (P-value for trend <0.0001 and <0.0001, respectively). The adjusted odds ratios (aORs) for early GDM with maternal age of 35-39.9 years and ≥40 were 1.399 (95% confidence interval [CI]: 1.134-1.725) and 2.494 (95% CI: 1.828-3.402), respectively. The aORs for late GDM with maternal age of 35-39 years and ≥40 were 1.603 (95% CI: 1.384-1.857) and 2.276 (95% CI: 1.798-2.881), respectively. CONCLUSIONS: Higher maternal age was associated with an increased risk of GDM regardless of when GDM was diagnosed. The association between maternal age and early GDM was similar to that between maternal age and late GDM.

OBJECTIVES: This study aimed to investigate the association and population-attributable fraction (PAF) of maternal smoking and secondhand smoke (SHS) exposure during pregnancy with placental abruption. DESIGN: Prospective cohort study. SETTING: 15 regional centres in Japan. PARTICIPANTS: Pregnant women registered between January 2011 and March 2014 from the Japan Environment and Children's Study. OUTCOME MEASURES: Data were transcribed from medical records and two self-administered questionnaires. The outcome measure was the incidence of placental abruption. Maternal smoking exposure during pregnancy was categorised based on the number of cigarettes smoked (≤10 or ≥11 cigarettes per day). SHS exposure during pregnancy was evaluated by frequency and duration (almost never or never, 1-3 days/week and/or <1 hour/day and 4-7 days/week and ≥1 hour/day). A modified Poisson regression model, adjusted for known placental abruption risk factors, calculated the risk ratio (RR) and PAF for placental abruption with a 95% Cl. RESULTS: Of the 81 974 eligible pregnant women, pregnant women smoking ≥11 cigarettes/day during pregnancy had a significantly higher risk of placental abruption. The adjusted RR (aRR) was 2.21 (95% CI 1.21 to 4.06), and the adjusted PAF (aPAF) was 1.90% (95% CI 0.09 to 3.71%). Pregnant women among never-smokers with SHS exposure of 4-7 days/week and ≥1 hour/day had a significantly higher risk (aRR: 2.34, 95% CI 1.29 to 4.28), and the aPAF was 1.89% (95% CI -0.05 to 3.83). Additionally, pregnant women among those who smoked during pregnancy with similar SHS exposure had a significantly higher risk (aRR: 2.21, 95% CI 1.30 to 3.76), with the aPAF of 2.29% (95% CI 0.11 to 4.48). CONCLUSIONS: Maternal smoking and SHS exposure during pregnancy significantly contribute to the risk of placental abruption in Japan. Therefore, preventive interventions and measures to reduce exposure are required to prevent placental abruption.

This study investigates the association between parity and type 2 diabetes mellitus (T2DM) in Japanese women, considering the clinical history of gestational diabetes mellitus (GDM) and menopausal status, which are known risk factors for T2DM. Overall, 30,116 Japanese women (6,588 premenopausal and 23,528 postmenopausal) were included in this cross-sectional study. They were divided into two groups according to menopausal status (premenopausal and postmenopausal women), and the association between parity and T2DM was evaluated using a multiple logistic regression model with possible confounders, including a clinical history of GDM. The association between parity and T2DM was not statistically significant in premenopausal women. In contrast, a linear graded association between parity and T2DM was found in postmenopausal women. Furthermore, the association between parity and T2DM in postmenopausal women was attenuated after adjusting for body weight gain after the age of 20 years. A clinical history of GDM was significantly associated with a high risk for T2DM, regardless of adjustment for body weight gain after the age of 20 years in both premenopausal and postmenopausal women. Parity is associated with an increased risk of T2DM in postmenopausal women but not in premenopausal women. Maintaining appropriate body weight would be beneficial in attenuating the risk of T2DM in postmenopausal women. A clinical history of GDM is a risk factor for T2DM in both pre- and postmenopausal women; therefore, women with a clinical history of GDM require continuous medical care to survey for T2DM.

AIMS: This study aimed to investigate the association of maternal birth weight (MBW) with early and late gestational diabetes mellitus (GDM). METHODS: A total of 69318 pregnant Japanese women were included in this birth cohort study. The associations between maternal birth weight and early gestational diabetes mellitus (diagnosed at <24 gestational weeks) and late GDM (diagnosed at ≥24 gestational weeks) were investigated using a multinomial logistic regression model, with an maternal birth weight of 3000-3499 g as the reference category. RESULTS: Lower maternal birth weight was associated with higher odds of developing early and late gestational diabetes mellitus (P < 0.0001 and P < 0.0001, respectively). The adjusted odds ratios (aORs) for early gestational diabetes mellitus in participants with a MBW of <2500 g and 2500-2999 g were 1.345 (95% confidence interval [CI]: 0.912-1.984) and 1.338 (95% CI: 1.098-1.629), respectively. The aORs for late gestational diabetes mellitus in participants with a MBW of <2500 g and 2500-2999 g were, 1.657 (95% CI: 1.298-2.115) and 1.218 (95% CI: 1.058-1.402), respectively. CONCLUSIONS: Regardless of the gestational age when gestational diabetes mellitus was diagnosed, a lower maternal birth weight was associated with an increased risk of gestational diabetes mellitus. Furthermore, the association of a MBW <2500 g with late gestational diabetes mellitus tended to be stronger than that with early gestational diabetes mellitus.

BACKGROUND: Global studies exploring the relationship between parity and chronic kidney disease (CKD) are scarce. Furthermore, no study has examined the relationship between parity and CKD in Japan. Therefore, this study aimed to examine the relationship between parity and the prevalence of CKD in a Japanese population, considering the clinical history of hypertensive disorders of pregnancy (HDP) and current body mass index (BMI) based on menopausal status. METHODS: This cross-sectional study included 26,945 Japanese multiparous women (5,006 premenopausal and 21,939 postmenopausal women) and 3,247 nulliparous women (1,599 premenopausal and 1,648 postmenopausal women). Participants were divided into two groups based on their menopausal status (premenopausal and postmenopausal women). The relationship between parity and the prevalence of CKD was evaluated using a multiple logistic regression model adjusted for several covariates, including a clinical history of HDP and current BMI. RESULTS: The relationship between parity and the prevalence of CKD was not statistically significant in either premenopausal or postmenopausal multiparous women. A clinical history of HDP was significantly associated with an increased risk of CKD in premenopausal and postmenopausal multiparous women. However, the relationship between a clinical history of HDP and CKD in premenopausal women was weakened after adjusting for current BMI. Furthermore, the current BMI was significantly associated with an increased risk of CKD in both premenopausal and postmenopausal women. CONCLUSIONS: Parity is not significantly associated with the prevalence of CKD in premenopausal and postmenopausal multiparous women. A clinical history of HDP is a risk factor for CKD in both premenopausal and postmenopausal women. Current BMI is also associated with an increased risk of CKD in premenopausal and postmenopausal women. Therefore, continuous surveillance and preventive measures against CKD should be provided to women with a clinical history of HDP. In addition, maintaining an appropriate body weight is beneficial in reducing the risk of CKD.

Congenital malformations are functional and structural alterations in embryonic or foetal development resulting from a variety of factors including maternal health status. This study aimed to investigate the association between maternal birth weight (MBW) and the prevalence of congenital malformations in offspring using data from a nationwide birth cohort study in Japan including 103,060 pregnancies. A binary logistic regression model with adjustment for various covariates revealed that an MBW of <2500 g (low MBW) was associated with an increased risk of congenital heart disease (adjusted odds ratio: 1.388, [95% confidence interval: 1.075-1.792]), angioma (1.491 [1.079-2.059]), and inguinal hernia (1.746, [1.189-2.565]), while those with an MBW of ≥4000 g (high MBW) were associated with congenital anomalies of the urinary tract (2.194, [1.261-3.819]) and arrhythmia (1.775, [1.157-2.725]) compared with those with an MBW of 3000-3499 g. Low MBW was associated with cleft lip and/or palate (1.473, [1.052-2.064]), congenital heart disease (1.615, [1.119-2.332]), genital organs (1.648, [1.130-2.405]), hypospadias (1.804, [1.130-2.881]), and inguinal hernia (1.484, [1.189-1.851]) in male infants and CAKUT (1.619, [1.154-2.273]) in female infants, whereas high MBW was associated with congenital heart disease (1.745, [1.058-2.877]) and CAKUT (2.470, [1.350-4.517]) in male infants. The present study is the first to demonstrate a link between MBW and congenital malformations in Japanese children. While these results must be interpreted with caution, MBW should be considered a major predictor of congenital malformation risk.

This study investigated the association of parity with hypertension prevalence in Japanese women while considering a clinical history of hypertensive disorders of pregnancy (HDP) and menopausal status. This cross-sectional study included 30,530 Japanese women (6700 premenopausal; 23 830 postmenopausal). The association between parity and the prevalence of hypertension was evaluated using a multiple logistic regression model with possible confounders. In premenopausal women, no statistically significant association between parity and hypertension prevalence was found. When not adjusted for current body mass index (BMI), a linear graded association was observed between parity and the prevalence of hypertension in postmenopausal women. However, the association between parity and hypertension prevalence in postmenopausal women was attenuated after adjustment for current BMI. Both current BMI and a clinical history of HDP were significantly associated with a high risk of hypertension in both premenopausal and postmenopausal women. Our results also suggest that continuous surveillance and preventive measures for hypertension should be provided for women with HDP and high parity.

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BACKGROUND: Myocardial bridge (MB) is a myocardial bundle through which coronary segment tunnels and could compress coronary arteries causing myocardial ischemia. However, the characteristic structural findings of MB remain to be fully elucidated. Recently, we demonstrated that optical coherence tomography (OCT) enables us to visualize adventitial vasa vasorum (VV) formation in humans. In this study, we examined adventitial VV formation at the coronary segment with MB in humans using OCT. METHODS: We examined 15 consecutive patients with suspected angina pectoris and MB in the left anterior descending (LAD) coronary arteries but no angiographic coronary stenosis. MB was detected on coronary angiography as a segment with milking effect. We performed intracoronary OCT imaging along the entire LAD. Morphometric analysis was performed at MB and proximal/distal segments at every 1mm. RESULTS: OCT examination showed the absence of adventitial VV formation at MB in the LAD, while VV was clearly noted at both the proximal and distal reference segments. Adventitial VV area was significantly less at MB compared with the proximal or distal references. CONCLUSIONS: These results with OCT imaging indicate that coronary segments with MB lack adventitial VV formation in humans, suggesting that MB could influence morphological and functional changes of the coronary artery.