Yan Yan

Dr. Yan Yan

Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University
orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 August 2018 in PLOS ONE
Verified
Journal Article
Open access
PDF file
CCCheng Chen
Cheng Chen
XXXianglong Xu
Xianglong Xu
YYYan Yan
Yan Yan
To estimate the global and country-level burden of overweight and obesity among pregnant women from 2005 to 2014. Publicly accessible country-level data were collected from the World Health Organization, the World Bank and the Food and Agricultural Organization. We estimated the number of overweight and obese pregnant women among 184 countries and determined the time-related trend from 2005 to 2014. Based on panel data model, we determined the effects of food energy supply, urbanization, gross national income and female employment on the number of overweight and obese pregnant women. We estimated that 38.9 million overweight and obese pregnant women and 14.6 million obese pregnant women existed globally in 2014. In upper middle income countries and lower middle income countries, there were sharp increases in the number of overweight and obese pregnant women. In 2014, the percentage of female with overweight and obesity in India was 21.7%, and India had the largest number of overweight and obese pregnant women (4.3 million), which accounted for 11.1% in the world. In the United States of America, a third of women were obese, and the number of obese pregnant women was 1.1 million. In high income countries, caloric supply and urbanization were positively associated with the number of overweight and obese pregnant women. The percentage of employment in agriculture was inversely associated with the number of overweight and obese pregnant women, but only in upper middle income countries and lower middle income countries. The number of overweight and obese pregnant women has increased in high income and middle income countries. Environmental changes could lead to increased caloric supply and decreased energy expenditure among women. National and local governments should work together to create a healthy food environment.

CLChao Li
Chao Li
GCGang Cheng
Gang Cheng
TSTingtng Sha
Tingtng Sha
WCWenwei Cheng
Wenwei Cheng
YYYan Yan
Yan Yan
Evidence suggests that excessive screen time in early childhood is related to children’s physical and mental health. This study aimed to review the relationships between screen media use and several health indicators in infants, toddlers, and preschoolers. A systematic search was conducted by two independent reviewers on PubMed, Web of Science, Embase, and Cochrane Library to identify the eligible studies, with an end date of 13 August 2019. Included studies (published in English) were peer-reviewed and met the determinate population (children aged 0–7 years with screen media exposure and related health outcomes). The AHRQ, NOS, and the Cochrane Handbook were used to evaluate the cross-sectional study, cohort study, and RCT, respectively. A meta-analysis and narrative syntheses were employed separately. Eighty studies (23 studies for meta-analysis) met the inclusion criteria for the systematic review. Strong evidence of the meta-analysis suggested that excessive screen time was associated with overweight/obesity and shorter sleep duration among toddlers and preschoolers. Excessive screen use was associated with various health indicators in physical, behavioral, and psychosocial aspects. Better-quality research on newer media devices, on various kinds of contents in young children, and on dose–response relationships between excessive screen use and health indicators are needed to update recommendations of screen use.

1 August 2019 in Reproductive BioMedicine Online
Verified
Journal Article
Closed access
TSTingting Sha
Tingting Sha
XWXiaojuan Wang
Xiaojuan Wang
WCWenwei Cheng
Wenwei Cheng
YYYan Yan
Yan Yan

2 May 2017 in BMC Pregnancy and Childbirth
Verified
Journal Article
Open access
PDF file
SLShiping Liu
Shiping Liu
YYYan Yan
Yan Yan
XGXiao Gao
Xiao Gao
SXShingting Xiang
Shingting Xiang
TSTingting Sha
Tingting Sha
QHQiong He
Qiong He
Postpartum depression causes harm to both mothers and infants. The purpose of this study was to find out several potential risk factors, and to identify the intrinsic interrelationships between factors and postpartum depression by constructing a path model. The results of this study may help to control the increasing incidence of maternal postpartum depression. The study was based on a sample of mothers from a cross-sectional study which was set up at 4 weeks after a mother had childbirth and was conducted in three streets at Kaifu District of Changsha in Hunan province from January to December 2015. Questionnaires were distributed to subjects who responded to questions concerning factors related to pregnancy, delivery and infants within 4 weeks after childbirth. The Edinburgh Postnatal Depression Scale (EPDS) was used to measure postpartum depression. Chi-square test was used to detect significant differences between non-postpartum depression group and postpartum depression group. A path model was constructed to explore the interrelationships between variables, and to verify the relationships between variables and postpartum depression. The proportion of maternal postpartum depression was 6.7%. Univariate analysis showed that there were significant differences between non-postpartum depression group and postpartum depression group (all P-values <0.05) on the part of maternal age, parity, frequent exposure to mobile phone during pregnancy, gestational hypertensive disorders, fetus number, premature delivery, birth weight, initiation of breastfeeding, mode of feeding, infant illness within 4 weeks after delivery and infant weight at 4 weeks. Path analysis results showed that the final model could be fitted well with sample data (P = 0.687, CMIN/DF = 0.824, NFI = 0.992, RFI = 0.982, IFI = 1.002, TLI =1.004, CFI = 1.000 and RMSEA < 0.001). Frequent exposure to mobile phone during pregnancy, maternal age and gestational hypertensive disorders had both direct and indirect effects on postpartum depression. Mode of feeding and infant weight at 4 weeks, which was the most total effect on postpartum depression, had only a direct impact on postpartum depression. Fetus number, premature delivery, initiation of breastfeeding and birth weight had only an indirect influence on postpartum depression. The findings of this study suggest that constructing a path analysis model could identify potential factors and explore the potential interrelations between factors and postpartum depression. It is an effective way to prevent maternal postpartum depression by taking appropriate intervention measures and carrying out health education for pregnant women.

24 January 2018 in Journal of Human Lactation
Verified
Journal Article
Closed access
PDF file
CCCheng Chen
Cheng Chen
YYYan Yan
Yan Yan
XGXiao Gao
Xiao Gao
SXShiting Xiang
Shiting Xiang
QHQiong He
Qiong He
LLLing Li
Ling Li
Background: Mothers are encouraged to exclusively breastfeed for the first 6 months. However, cesarean delivery rates have increased worldwide, which may affect breastfeeding. Research aim: This study aimed to determine the potential effects of cesarean delivery on breastfeeding practices and breastfeeding duration. Methods: This was a 6-month cohort study extracted from a 24-month prospective cohort study of mother–infant pairs in three communities in Hunan, China. Data about participants’ characteristics, delivery methods, breastfeeding initiation, use of formula in the hospital, exclusive breastfeeding, and any breastfeeding were collected at 1, 3, and 6 months following each infant’s birth. The chi-square test, logistic regression model, and Cox proportional hazard regression model were used to examine the relationship between breastfeeding practices and cesarean delivery. Results: The number of women who had a cesarean delivery was 387 (40.6%), and 567 (59.4%) women had a vaginal delivery. The exclusive breastfeeding rates at 1, 3, and 6 months were 80.2%, 67.4%, and 21.5%, respectively. Women who had a cesarean delivery showed a lower rate of exclusive breastfeeding and any breastfeeding than those who had a vaginal delivery ( p < .05). In addition, cesarean delivery was related with using formula in the hospital and delayed breastfeeding initiation. Cesarean delivery also shortened the breastfeeding duration (hazard ratio = 1.40, 95% confidence interval [1.06, 1.84]). Conclusion: Healthcare professionals should provide more breastfeeding skills to women who have a cesarean delivery and warn mothers about the dangers of elective cesarean section for breastfeeding practices.

16 February 2021 in BMC Geriatrics
Verified
Journal Article
Open access
PDF file
GCGang Cheng
Gang Cheng
YYYan Yan
Yan Yan
Background: There is still a lack of systematic investigation of comprehensive contextual factors of subjective well-being (SWB) among Chinese oldest-old. This study aimed to explore sociodemographic, health-related, and social predictors of SWB among Chinese oldest-old using a large and representative sample. Methods: The study included 49,069 individuals aged 80 and older from the Chinese Longitudinal Healthy Longevity Survey, a prospective, nationwide, community-based study conducted from 1998 to 2014. SWB was measured by eight items covering life satisfaction, positive affect (optimism, happiness, personal control, and conscientiousness), and negative affect (anxiety, loneliness, and uselessness). Generalized estimating equation models were used to explore the predictors of SWB. Results: We found that age, gender, ethnic group, education, primary occupation before retirement, current marital status, and place of residence were sociodemographic predictors of SWB among the Chinese oldest-old. The health-related predictors included self-rated health, visual function, hearing function, diet quality, smoking status, drinking status, and exercise status. SWB was influenced by some social factors, such as the number of biological siblings, the number of children, leisure activities, financial independence, and access to adequate medical service. In particular, self-rated health, access to adequate medical services, exercise status, and place of residence exert a stronger effect than other factors. Conclusions: SWB in the oldest-old is influenced by a large number of complex sociodemographic, health-related, and social factors. Special attention should be paid to the mental health of centenarians, women, rural residents, widowed, physically disabled, and childless oldest-old people. Relevant agencies can improve physical activities, leisure activities, financial support, and medical services to promote the well-being of the oldest-old.