Background: Postpartum depression (PPD) has been associated with adverse health outcomes, including maternal suicide. Mode of delivery has been suggested to be a risk factor for PPD, but no large cohort study has examined the association between mode of delivery and PPD. We aimed to examine the association between mode of delivery and risks of PPD at 1 and 6 months after childbirth.

Methods: In a nationwide study of 89,954 mothers with a live singleton birth, we examined the association between mode of delivery and risks of PPD. PPD was evaluated using the Edinburgh Postnatal Depression Scale (≥13) at 1 and 6 months after childbirth. Odds ratios (ORs) with 95% confidence intervals (CIs) of PPD were calculated using multivariable logistic regression analyses after adjustment of antenatal physical, socioeconomic, and mental factors.

Results: Among 89,954 women, 3.7% and 2.8% had PPD at 1 and 6 months after childbirth, respectively. Compared with unassisted vaginal delivery, cesarean section (CS) was marginally associated with PPD at 1 month but not at 6 months; adjusted ORs were 1.10 (95% CI, 1.00–1.21) and 1.01 (95% CI, 0.90–1.13), respectively. The association with PPD at 1 month was evident in women with antenatal psychological distress (adjusted OR 1.15; 95% CI, 1.03–1.28). The observed associations were attenuated after adjusting for infant feeding method.

Conclusion: Women who had antenatal psychological distress and underwent CS delivery may be regarded as a target for monitoring PPD.

Background: Tracking gestational weight gain (GWG) during pregnancy makes it possible to optimize pregnancy outcomes, and GWG growth curves are well suitable for this purpose. The GWG guidelines for Japanese were revised in 2021. However, currently, there are no GWG growth curves to guide women on how to gain weight to meet these guidelines.

Methods: Using data on 96,631 live births from the Japan Environment and Children’s Study (JECS), we created descriptive GWG percentile curves estimating the trajectory of GWG required to meet the GWG guidelines stratified by pre-pregnancy body mass index (BMI). For both analyses, Bayesian mixed models with restricted cubic splines adjusted for maternal characteristics were used.

Results: GWG curves substantially differed by pre-pregnancy BMI and were higher among multiparas and those with lower maternal age and with no previous disease. We estimated that underweight, normal weight, overweight, and obese women who gain 8.4 to 11.1 kg, 6.4 to 9.1 kg, 3.8 to 6.5 kg, and <1.9 kg at 30 weeks of gestation are on the trajectory to reach the new guidelines at 40 weeks of gestation.

Conclusion: We provide GWG percentiles curves for Japanese women, as well as GWG trajectory curves to meet the new GWG recommendations. These results may help pregnant women monitor weight during pregnancy.

Background: Elevated resting heart rate (RHR) is associated with an increased risk of cardiovascular disease (CVD) and all-cause mortality. However, the findings of cohort studies differed. Thus, the impact of RHR on CVD mortality might be different according to the background of the population. Therefore, we examined the relationship of RHR and CVD mortality according to serum albumin (ALB) levels in a Japanese general population.

Methods: In total, 8,363 individuals without a history of CVD were followed for 24.0 years. The participants were divided into four groups according to the quartiles of RHR (Q1–Q4), and they were further classified into the high and low ALB groups based on a median value of 44 g/L. We estimated the multivariable-adjusted hazard ratios (HRs) of CVD mortality in each RHR group based on ALB levels, and the interaction between RHR and ALB groups on CVD mortality was evaluated.

Results: We found no significant association between RHR and CVD mortality. However, the Q4 of RHR was significantly associated with an increased risk for CVD mortality (HR 1.27; 95% confidence interval [CI], 1.02–1.57) in participants with a low ALB level. Meanwhile, the Q4 of RHR was significantly correlated with a decreased risk for CVD morality in those with a high ALB level (HR 0.61; 95% CI, 0.47–0.79) after adjusting for covariates. A significant interaction between RHR and ALB for CVD mortality was shown (P < 0.001).

Conclusion: The impact of RHR on CVD mortality differed according to ALB levels in a general Japanese population.

Background: Stress coping strategies are related to health outcomes. However, there is no clear evidence for sex differences between stress-coping strategies and mortality. We investigated the relationship between all-cause mortality and stress-coping strategies, focusing on sex differences among Japanese adults.

Methods: A total of 79,580 individuals aged 35–69 years participated in the Japan Multi-Institutional Collaborative Cohort Study between 2004 and 2014 and were followed up for mortality. The frequency of use of the five coping strategies was assessed using a questionnaire. Sex-specific, multivariable-adjusted hazard ratios (HRs) for using each coping strategy (“sometimes,” and “often/very often” use versus “very few” use) were computed for all-cause mortality. Furthermore, relationships were analyzed in specific follow-up periods when the proportion assumption was violated.

Results: During the follow-up (median: 8.5 years), 1,861 mortalities were recorded. In women, three coping strategies were related to lower total mortality. The HRs for “sometimes” were 0.81 (95% confidence interval [CI], 0.67–0.97) for emotional expression, 0.79 (95% CI, 0.66–0.95) for emotional support-seeking, and 0.80 (95% CI, 0.66–0.98) for disengagement. Men who “sometimes” used emotional expression and sometimes or often used problem-solving and positive reappraisal had a 15–41% lower HRs for all-cause mortality. However, those relationships were dependent on the follow-up period. There was evidence that sex modified the relationships between emotional support-seeking and all-cause mortality (P for interaction = 0.03).

Conclusion: In a large Japanese sample, selected coping strategies were associated with all-cause mortality. The relationship of emotional support-seeking was different between men and women.

Background: We aimed to develop census-linked longitudinal mortality data for Japan and assess their validity as a new resource for estimating socioeconomic inequalities in health.

Methods: Using deterministic linkage, we identified, from national censuses for 2000 and 2010 and national death records, persons and deceased persons who had unique personal identifiers (generated using sex, birth year/month, address, and marital status). For the period 2010–2015, 1,537,337 Japanese men and women aged 30–79 years (1.9% in national census) were extracted to represent the sample population. This population was weighted to adjust for confounding factors. We estimated age-standardized mortality rates (ASMRs) by education level and occupational class. The slope index of inequality (SII) and relative index inequality (RII) by educational level were calculated as inequality measures.

Results: The reweighted sample population’s mortality rates were somewhat higher than those of the complete registry, especially in younger age-groups and for external causes. All-cause ASMRs (per 100,000 person-years) for individuals aged 40–79 years with high, middle, and low education levels were 1,078 (95% confidence interval [CI], 1,051–1,105), 1,299 (95% CI, 1,279–1,320), and 1,670 (95% CI, 1,634–1,707) for men, and 561 (95% CI, 536–587), 601 (95% CI, 589–613), and 777 (95% CI, 745–808) for women, respectively, during 2010–2015. SII and RII by educational level increased among both sexes between 2000–2005 and 2010–2015, which indicates that mortality inequalities increased.

Conclusion: The developed census-linked longitudinal mortality data provide new estimates of socioeconomic inequalities in Japan that can be triangulated with estimates obtained with other methods.

Background: The CD4 cell count of patients during diagnosis and distribution of CD4 cell counts in the patient population are important to understand infection-diagnosis interval and incidence rate of human immunodeficiency virus (HIV) infection, respectively. However, this information has not been published in Japan. This study aimed to describe the change in CD4 cell count trends and clarify the change in patients’ characteristics in association with the CD4 cell count information.

Methods: A descriptive study was conducted to analyze the medical records of patients with HIV who visited one of the largest acquired immunodeficiency syndrome (AIDS) core hospitals in western Japan. The basic characteristics, CD4 cell counts, viral loads, and diagnosis-treatment intervals between the first (2003–2010) and second (2011–2017) halves of the study duration were compared.

Results: The distribution of CD4 cell counts significantly changed between 2003–2010 and 2011–2017 (χ² = 20.42, P < 0.001). The proportion of CD4 cell count <200 cells/mm³ increased (38.8% in 2003 to 45.9% in 2017), whereas CD4 cell count ≥500 cells/mm³ decreased (19.4% in 2003 to 12.2% in 2017). Moreover, the distributions of age groups, history of HIV screening test, patient outcomes, HIV viral load, and diagnosis-treatment interval also significantly changed (χ² = 25.55, P < 0.001; χ² = 8.37, P = 0.015; χ² = 6.07, P = 0.014; χ² = 13.36, P = 0.020; χ² = 173.76, P < 0.001, respectively).

Conclusion: This study demonstrated the fundamental trends of the HIV epidemic in Osaka, Japan between 2003–2010 and 2011–2017 and indicated that the incidence rate of HIV was decreasing in Japan.