OBJECTIVES: To investigate possible seasonal patterns of pre-term birth in Korea. METHODS: A total number of 2,669,357 single live births reported to the National Statistical Office from 1995 to 1998 were analyzed. Composite monthly cohorts of ongoing pregnancies were constructed for each month of the year and the probability of pre-term birth was estimated. RESULTS: Increases in the probability of a pre-term birth occurred during winter for the birth of first child and during summer for the birth of second or later child. This seasonal variation was similar among groups divided by sex, residency, age of mother, and education of mother. CONCLUSIONS: These findings suggests that some environmental factors related to season may partially explain the incidence of premature births.
Child ; Cohort Studies ; Education ; Humans ; Incidence ; Internship and Residency ; Korea* ; Live Birth ; Mothers ; Parturition* ; Pregnancy ; Premature Birth ; Seasons*

We aimed to determine the maternal characteristics (demographics, an obstetric history, and prior cervical excisional procedure) associated with a short mid-trimester cervical length (CL, defined as a CL of ≤ 25 mm) and whether having a short cervix explains the association between these maternal characteristics and spontaneous preterm delivery (SPTD, defined as a delivery before 34 weeks). This is a single-center retrospective cohort study of 3,296 consecutive women with a singleton pregnancy who underwent routine CL measurement between 20 and 24 weeks. Data were collected on maternal age, weight, height, parity, obstetric history (nulliparity; a history of at least 1 SPTD; and at least 1 term birth and no preterm birth [low-risk history group]), and prior cervical excisional procedure. In the multivariate regression analysis, an obstetric history, prior cervical excisional procedure, and gestational age at measurement were the variables significantly associated with short CL. In contrast, maternal weight, height, age, and parity were not significantly associated with short CL. By using the likelihood of SPTD as an outcome variable, logistic regression indicated that short CL and obstetric history, but not prior cervical excisional procedure, were significantly associated with SPTD after adjustment for potential confounders. A history of SPTD and prior cervical excisional procedure were associated with an increased risk of a short mid-trimester CL. A history of SPTD, but not prior cervical excisional procedure, is associated with an increased risk of SPTD, independent of a short CL.
Cervix Uteri ; Cohort Studies ; Female ; Gestational Age ; Humans ; Logistic Models ; Maternal Age ; Parity ; Pregnancy ; Premature Birth ; Retrospective Studies ; Term Birth

OBJECTIVES: The prevalence rate of sleep problems in children in China is increasing in recent years. There are inconsistencies in the relationship between physical activity and sleep, and the impact of screen time on young children seems more obvious.This study aims to understand the current situation of outdoor activity time, screen time and sleep (total sleep duration, bedtime, and wake-up time) and the associations between outdoor activity time and screen time with sleep for children aged 36-54 months in Kaifu District of Changsha. METHODS: Using the cluster sampling method, 1 286 newborns delivered in 3 community health service centers in Kaifu District, Changsha from January to December 2015 were selected as the research subjects to establish a prospective birth cohort. According self-designed questionnaire and household follow-up to select 36, 42, 48, 54 months Children's data. The mixed linear model was used to explore the associations of outdoor activity time and screen time with sleep. RESULTS: The 36-54 months children's total sleep duration was decreased from 11.60 h/d to 10.92 h/d (P<0.001); bedtime time delayed from 21:58 to 22:00 (P=0.124); wake-up time advanced from 7:52 to 7:37 (P<0.001); outdoor activity time was decreased from 2.58 h/d to 1.94 h/d (P<0.001), and screen time was decreased from 1.28 h/d to 1.09 h/d (P<0.001). With aging, the prevalence of sleep <10 h/d and outdoor activity time <2 h/d was increased significantly, and the prevalence of screen time ≥1 h/d was decreased (P<0.05). Mixed linear models showed that longer outdoor activity time was related to increased total sleep duration (β=0.22, 95% CI 0.00 to 0.44) and delayed wake-up time (β=0.16, 95% CI 0.00 to 0.32), and longer screen time was related to delayed bedtime (β=0.22, 95% CI 0.05 to 0.39) and wake-up time (β=0.24, 95% CI 0.08 to 0.41). These associations were different in gender. Longer outdoor activity time was related to delayed wake-up time (β=0.37, 95% CI 0.14 to 0.59) in boys, but not in girls (β=-0.16, 95% CI -0.33 to 0.01). Longer screen time was associated with delayed bedtime (β=0.40, 95% CI 0.09 to 0.63) and wake-up time (β=0.33, 95% CI 0.15 to 0.51) in girls, but only related to delayed wake-up time (β=0.29, 95% CI 0.06 to 0.52) in boys, and the degree of association was lower than that of girls. CONCLUSIONS Among children aged 36-54 months in Kaifu District, Changsha, there are problems including going to bed late and getting up late, insufficient physical activity, and long screen time. Outdoor activity time and screen time are related to sleep. Increasing outdoor activity time and reducing screen time can help to improve children's sleep.
Infant, Newborn ; Male ; Child ; Female ; Humans ; Child, Preschool ; Screen Time ; Cohort Studies ; Birth Cohort ; Prospective Studies ; Sleep

Objective: To describe the epidemic characteristics of esophageal cancer mortality in Qidong from 1972 to 2016, and to provide baseline for making control measures and strategies for prevention. Methods: The cancer registry data were collected and analyzed on mortality of oesophagus cancer during 1972-2016 in Qidong in different sex, age and time. Indices of statistics included crude mortality rate (CR), China age-standardized rate (CASR), world age-standardized rate (WASR), 35-64 years truncated rate, 0-74 years cumulative rate, cumulative risk, average annual percentage change (AAPC), mortality by period and mortality in the birth cohort. Results: A total of 4 795 esophageal cancer cases (male: 3 315, female: 1 480) died during the 45 years, accounting for 4.85% of all cancer deaths. The crude mortality was 9.48/10(5) (CASR: 3.62/10(5,) WASR: 6.30/10(5)) from 1972 to 2016. The crude mortality was significantly increased with age. In 2016, the crude mortality was 11.61/10(5) (CASR: 2.64/10(5,) WASR: 4.89/10(5)), respectively. The average annual percentage change (AAPC) were 0.99%、-2.03%、-1.72%. The mortalities of esophageal cancer in all age groups from 35 to 74 have been decreasing since the 1980s. The age-birth cohort analysis showed a decline in mortality rates in age groups from 40 to 79. Conclusions: The crude mortality rate of esophageal cancer increases slightly in Qidong, while the China age-standardized rate and world age-standardized rate decrease significantly. However, esophageal cancer is still one of the malignant tumors that affects the health of residents and seriously threatens the people's lives and health. The situation of cancer prevention and control is still serious in Qidong.
Male ; Humans ; Female ; Esophageal Neoplasms ; China/epidemiology* ; Registries ; Cohort Studies ; Birth Cohort ; Incidence ; Rural Population ; Mortality ; Urban Population

OBJECTIVETo study the association between depression during pregnancy and low birth weight in neonates, and to provide a scientific basis for the prevention of low birth weight.

METHODSCohort studies on the association between depression during pregnancy and low birth weight were collected and a Meta analysis was performed. Data were extracted independently by two investigators, and quality assessment was performed according to Newcastle-Ottawa Scale. The Egger's test was used to evaluate publication bias.

RESULTSA total of 12 cohort studies with 37 192 samples were included. The results of the Meta analysis showed that depression during pregnancy was associated with low birth weight (Z=2.08, P=0.038), and the neonates whose mothers had depression during pregnancy tended to have a high risk of low birth weight (RR=1.303, 95%CI: 1.015-1.672). The sensitivity analysis showed that the results of this Meta analysis were stable and reliable, and the Egger's test showed no publication bias.

CONCLUSIONSDepression during pregnancy may be a risk factor for low birth weight in neonates.

PURPOSE: 'Programming' describes the process that stimulus at a critical period of development has lifelong effects. The fact that low birth weight links to the risk of elevated blood pressures in adult life is well known. This study aims to examine whether this link is evident in the newborn by investigating the relationship of the intrauterine growth indices and neonatal blood pressure(BP). METHODS: We studied 127 neonates who were born at Ewha Womans' Hospital and their mothers enrolled our cohort study during pregnancy. Data on the mothers and details of the birth records were tracked and collected from medical charts. Neonatal BP was measured within 24 hours after birth. RESULTS: Neonatal SBP was positively correlated to intrauterine growth indices; birth weight(BW)(r= 0.4), head circumference(HC)(r=0.4), and birth height(r=0.3). However, an inverse relationship existed, between HC/BW ratio and neonatal SBP(r=-0.4). After adjusting for the baby's sex, maternal BP, and gestational age, neonatal SBP still associated with intrauterine growth indices. SBP was 7 mmHg higher in the highest BW group(> or =90 percentiles) compared to the lowest group(<10 percentiles). On the other hand, SBP was 17 mmHg lower in the highest HC/BW group(> or =90 percentiles) compared in the lowest group(<10 percentiles). CONCLUSION: This study could not find the evidence that intrauterine growth retardation affect on elevated neonatal BP. It suggests that the initiating events of BP programming may occur during postnatal growth period. To identify the critical starting period that intrauterine growth retardation leads to elevated BP, a study tracking BP changes from birth to childhood is required.
Adult ; Birth Certificates ; Blood Pressure* ; Cohort Studies ; Critical Period (Psychology) ; Fetal Growth Retardation ; Gestational Age ; Hand ; Head ; Humans ; Infant, Low Birth Weight ; Infant, Newborn ; Mothers ; Parturition ; Pregnancy

To examine the relationship between birth characteristics and childhood cancer mortality, a retrospective cohort study of Korean children was conducted using data collected by the national birth register between 1995 and 2006, which were then individually linked to death data. A cohort of 6,479,406 children was followed from birth until their death or until December 31, 2006. Poisson regression analyses were used to calculate rate ratios of childhood cancer deaths according to birth characteristics. A total of 1,469 cancer deaths were noted and the childhood cancer mortality rate was found to be 3.43 per 100,000 person-years in Korea during the period of 1995-2006. The birth characteristics examined in this study (i.e. , birth weight, gestational age, multiple births, parental ages, and number of siblings) were generally found to be not significantly associated with childhood cancer mortality, and the associations did not vary meaningfully with gender nor with cancer sites. However, among children aged 5-11 yr, higher birth weight was associated with elevated childhood cancer mortality (rate ratio = 1.28, 95% confidence interval 1.04-1.58). Our results offer no overall associations between childhood cancer mortality and birth characteristics, but suggest that the association may be specific to age group.
Birth Weight ; Child ; Child, Preschool ; Cohort Studies ; Gestational Age ; Humans ; Multiple Birth Offspring ; Neoplasms/*mortality ; Parents ; Republic of Korea ; Retrospective Studies ; Risk Factors ; Siblings ; Socioeconomic Factors

OBJECTIVES: The objective of this study was to conduct a systematic review to provide summarized evidence on the association between maternal exposure to particulate air pollution and birth weight (BW) and preterm birth (PTB) after taking into consideration the potential confounding effect of maternal smoking. METHODS: We systematically searched all published cohort and case-control studies examining BW and PTB association with particulate matter (PM, less than or equal to 2.5μm and 10.0 μm in diameter, PM₂.₅ and PM₁₀, respectively) from PubMed and Web of Science, from January 1980 to April 2015. We extracted coefficients for continuous BW and odds ratio (OR) for PTB from each individual study, and meta-analysis was used to combine the coefficient and OR of individual studies. The methodological quality of individual study was assessed using a standard protocol proposed by Downs and Black. Forty-four studies met the inclusion criteria. RESULTS: In random effects meta-analyses, BW as a continuous outcome was negativelyassociated with 10 μg/m³ increase in PM₁₀ (-10.31 g; 95% confidence interval [CI], -13.57 to -3.13 g; I-squared=0%, p=.947) and PM₂.₅ (-22.17 g; 95% CI, -37.93 to -6.41 g; I-squared=92.3%, p<0.001) exposure during entire pregnancy, adjusted for maternal smoking. A significantly increased risk of PTB per 10 μg/m³ increase in PM₁₀ (OR, 1.23; 95% CI, 1.04 to 1.41; I-squared=0%, p=0.977) and PM2.5 (OR, 1.14; 95% CI, 1.06 to 1.22; I-squared=92.5%, p<0.001) exposure during entire pregnancy was observed. Effect size of change in BW per 10 μg/m³ increase in PM tended to report stronger associations after adjustment for maternal smoking. CONCLUSIONS: While this systematic review supports an adverse impact of maternal exposure to particulate air pollution on birth outcomes, variation in effects by exposure period and sources of heterogeneity between studies should be further explored.
Air Pollution ; Birth Weight ; Case-Control Studies ; Cohort Studies ; Female ; Maternal Exposure ; Odds Ratio ; Particulate Matter* ; Parturition* ; Population Characteristics ; Pregnancy ; Premature Birth ; Smoke ; Smoking

OBJECTIVES: The objective of this study was to conduct a systematic review to provide summarized evidence on the association between maternal exposure to particulate air pollution and birth weight (BW) and preterm birth (PTB) after taking into consideration the potential confounding effect of maternal smoking. METHODS: We systematically searched all published cohort and case-control studies examining BW and PTB association with particulate matter (PM, less than or equal to 2.5μm and 10.0 μm in diameter, PM₂.₅ and PM₁₀, respectively) from PubMed and Web of Science, from January 1980 to April 2015. We extracted coefficients for continuous BW and odds ratio (OR) for PTB from each individual study, and meta-analysis was used to combine the coefficient and OR of individual studies. The methodological quality of individual study was assessed using a standard protocol proposed by Downs and Black. Forty-four studies met the inclusion criteria. RESULTS: In random effects meta-analyses, BW as a continuous outcome was negativelyassociated with 10 μg/m³ increase in PM₁₀ (-10.31 g; 95% confidence interval [CI], -13.57 to -3.13 g; I-squared=0%, p=.947) and PM₂.₅ (-22.17 g; 95% CI, -37.93 to -6.41 g; I-squared=92.3%, p<0.001) exposure during entire pregnancy, adjusted for maternal smoking. A significantly increased risk of PTB per 10 μg/m³ increase in PM₁₀ (OR, 1.23; 95% CI, 1.04 to 1.41; I-squared=0%, p=0.977) and PM2.5 (OR, 1.14; 95% CI, 1.06 to 1.22; I-squared=92.5%, p<0.001) exposure during entire pregnancy was observed. Effect size of change in BW per 10 μg/m³ increase in PM tended to report stronger associations after adjustment for maternal smoking. CONCLUSIONS: While this systematic review supports an adverse impact of maternal exposure to particulate air pollution on birth outcomes, variation in effects by exposure period and sources of heterogeneity between studies should be further explored.
Air Pollution ; Birth Weight ; Case-Control Studies ; Cohort Studies ; Female ; Maternal Exposure ; Odds Ratio ; Particulate Matter* ; Parturition* ; Population Characteristics ; Pregnancy ; Premature Birth ; Smoke ; Smoking

OBJECTIVES: We aims to construct Infant Growth Cohort for evaluating whether oxidative stress in midterm pregnancy has an adverse effect on postnatal growth. METHODS AND MATERIALS: From September 2001 to April 2004, we constructed an Ewha Infant Growth Cohort connected with the Ewha Pregnant Women Cohort. We excluded mother-and-child pairs in which the mother had experienced hypertension or diabetes during pregnancy and had multiple births for this study, which gave us 233 mother-and-child pairs for analysis. We measured maternal serum homocysteine and urinary 8-hydroxyguanosine (8-OHdG) and malondialdehyde (MDA) at 24~28 weeks of pregnancy, and infant weights at birth and at 6 and 12 months postnatally. We applied repeated measures ANOVA with PROC MIXED to assess the significance of differences. RESULTS: We followed 64 and 85 infants at 6 and 12 months respectively. The mean body weights were 3146.4 g at birth, 8229.7 g at 6 months, and 1006.47 g at 12 months. The mean birth weight of infants was lower in mothers with higher homocysteine levels (third and fourth quartiles), but body weights from the first- and fourth-quartile groups of maternal homocysteine levels were lower than the others even though it was not statistically significant. Body weights at birth and at 6 months in third- and fourth-quartile groups of 8-OHdG levels were lower than the others. The body weights in the fourth quartile MDA group were significantly lower than the others at all time points. CONCLUSIONS: Maternal oxidative stress in midterm pregnancy may cause postnatal growth retardation. But, there were high rate of follow up loss and various measurement errors. Therefore, we need to have efforts for compete follow up and valid and reliable measurements.
Birth Weight ; Body Weight ; Cohort Studies ; Female ; Follow-Up Studies ; Homocysteine ; Humans ; Hypertension ; Infant ; Malondialdehyde ; Mothers ; Multiple Birth Offspring ; Oxidative Stress* ; Parturition ; Pregnancy* ; Pregnant Women ; Weights and Measures