In the studies of modern epidemiology, exposure in a short term cannot fully elaborate the mechanism of the development of diseases or health-related events. Thus, lights have been shed on to life course epidemiology, which studies the exposures in early life time and their effects related to the development of chronic diseases. When exploring the mechanism leading from one exposure to an outcome and its effects through other factors, due to the existence of time-variant effects, conventional statistic methods could not meet the needs of etiological analysis in life course epidemiology. This paper summarizes the dynamic path analysis model, including the model structure and significance, and its application in life course epidemiology. Meanwhile, the procedure of data processing and etiology analyzing were introduced. In conclusion, dynamic path analysis is a useful tool which can be used to better elucidate the mechanisms that underlie the etiology of chronic diseases.
Chronic Disease/epidemiology* ; Epidemiologic Studies ; Humans ; Models, Theoretical ; Risk Factors ; Time

Objective: To carry out a quantitative estimate that related to the effects of short-term exposure to PM(2.5) on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis. Methods: We selected all the studies published before March 2018 from China National Knowledge Infrastructure, Wanfang database, PubMed and EMBASE and data on relative risk (RR), excess risk (ER) and their 95%CIs: appeared in these papers were extracted. According to the differences in the size or direction (heterogeneity) of the results, we computed summary estimates of the effect values using a random-effect or fixed effect model. We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias. Results: A total of 33 original studies, indexed in databases, were identified. Among those studies, 39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 μg/m(3), for 10 μg/m(3) increases in PM(2.5) concentrations, it would increase the daily numbers of deaths by 0.49% (95%CI: 0.39%-0.59%) and 0.30% (95%CI: 0.10%-0.51%) for all-cause deaths and all-cause emergency-room visits, respectively. For subgroup analysis, the combined effect of PM(2.5) in causing short-term all-cause deaths in the northern areas (ER=0.42%, 95%CI: 0.30%-0.54%) seemed lower than that in the southern areas (ER=0.63%, 95%CI: 0.44%-0.82%). The combined effect of PM(2.5) concentration below 75 μg/m(3) (ER=0.50%, 95%CI: 0.37%-0.62%) was higher than that of PM(2.5) concentration ≥75 μg/m(3) (ER=0.39%, 95%CI: 0.26%-0.52%). Conclusion: Within the concentration range from 47.7 to 176.7 μg/m(3), short-term exposure to current level of PM(2.5) might increase both the all-cause daily mortality and daily emergency visits in China.
Air Pollutants ; Air Pollution/statistics & numerical data* ; China ; Databases, Factual ; Emergency Service, Hospital/statistics & numerical data* ; Environmental Exposure/statistics & numerical data* ; Female ; Humans ; Male ; Particulate Matter/toxicity* ; Time Factors

Objective: To describe the prevalence of preterm birth (PB), low birth weight (LBW), and small for gestational age (SGA) among HIV-infected pregnant women and to identify associated risk factors in Hunan province. Methods: This study appeared a retrospective one on HIV-infected pregnant women retrieved from Information System of Prevention of Mother-to-child Transmission of HIV management in Hunan province, between January 2011 and December 2017. Information regarding demographic characteristics, pregnancy, antiretroviral therapy (ART), husbands/partners' relevant situation and pregnancy outcomes, among these HIV-infected pregnant women were collected and analyzed. The incidence rates on PB, LBW and SGA were calculated. Multivariate logistic regression was used to analyze the associated risk factors. Results: A total of 780 HIV-infected pregnant women were enrolled. The prevalence rates on PB, LBW and SGA in HIV- infected pregnant women appeared as 7.9% (62/780), 9.9% (77/780) and 21.3% (166/780), respectively. Results from the multivariate logistic regression analysis showed that factors as pregnancy related diseases as moderate/severe anemia, hypertensive, initial time of ART <14 gestational weeks (compared to those women without ART during pregnancy) and husbands/partners' age >35 years old (compared to husbands/partners' age 26-30 years old) etc., were associated with an increased risk of PB with adjusted OR as 4.59 (95%CI: 1.51-13.95), 4.90 (95%CI: 1.56-15.46), 2.40 (95%CI: 1.26- 4.56) and 2.29 (95%CI: 1.21-4.36). For LBW, pregnancy moderate/severe anemia, pregnancy HBV infection and initial time of ART <14 gestational weeks were associated with an increased risk of LBW, with adjusted OR as 3.28 (95%CI: 1.13-9.54), 4.37 (95%CI: 1.42-13.44) and 2.68 (95%CI: 1.51-4.76), respectively. For SGA, pregnancy HBV infection and initial time of ART <14 gestational weeks were risk factors for SGA, with adjusted OR as 4.41 (95%CI: 1.43-13.63) and 2.67 (95%CI: 1.51-4.73), respectively. Conclusion: Preterm birth, LBW and SGA were common adverse pregnancy outcomes for HIV-infected pregnant women and were associated with factors as pregnancy complications, ART and husbands/partners' age.
Adult ; Birth Weight ; Child ; China/epidemiology* ; Female ; Gestational Age ; HIV Infections/epidemiology* ; Humans ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Small for Gestational Age ; Pregnancy ; Pregnancy Complications, Infectious/virology* ; Premature Birth/etiology* ; Prevalence ; Retrospective Studies ; Risk Factors

Despite advances in the field of male reproductive health, idiopathic male infertility, in which a man has altered semen characteristics without an identifiable cause and there is no female factor infertility, remains a challenging condition to diagnose and manage. Increasing evidence suggests that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated seminal reactive oxygen species levels. OS can negatively affect fertility via a number of pathways, including interference with capacitation and possible damage to sperm membrane and DNA, which may impair the sperm's potential to fertilize an egg and develop into a healthy embryo. Adequate evaluation of male reproductive potential should therefore include an assessment of sperm OS. We propose the term Male Oxidative Stress Infertility, or MOSI, as a novel descriptor for infertile men with abnormal semen characteristics and OS, including many patients who were previously classified as having idiopathic male infertility. Oxidation-reduction potential (ORP) can be a useful clinical biomarker for the classification of MOSI, as it takes into account the levels of both oxidants and reductants (antioxidants). Current treatment protocols for OS, including the use of antioxidants, are not evidence-based and have the potential for complications and increased healthcare-related expenditures. Utilizing an easy, reproducible, and cost-effective test to measure ORP may provide a more targeted, reliable approach for administering antioxidant therapy while minimizing the risk of antioxidant overdose. With the increasing awareness and understanding of MOSI as a distinct male infertility diagnosis, future research endeavors can facilitate the development of evidence-based treatments that target its underlying cause.
Antioxidants ; Classification ; Clinical Protocols ; Diagnosis ; DNA ; Embryonic Structures ; Female ; Fertility ; Health Expenditures ; Humans ; Infertility ; Infertility, Male ; Male ; Membranes ; Ovum ; Oxidants ; Oxidation-Reduction ; Oxidative Stress ; Reactive Oxygen Species ; Reducing Agents ; Reproductive Health ; Semen ; Spermatozoa ; Subject Headings

Objective: To understand the seasonal distribution of patient hospitalization due to asthma exacerbation in 7 geographic areas in China. Methods: This was a retrospective study which involved patients hospitalized for asthma exacerbation in 29 hospitals throughout 7 geographic areas in the mainland of China (northeast, north, central, east, south, northwest and southwest). The numbers of asthmatic patients and total inpatients of the respiratory department of each hospital were recorded. The monthly ratio of asthmatic patients to the total inpatients in every area was calculated and compared. Results: During the study period, 6 480 patients were admitted for asthma exacerbation, accounting for 3.14% of all the 206 135 patients admitted to the respiratory departments in the 29 hospitals. The ratio of asthmatic patients to total inpatients in the northeast area (5.61%) was highest, and the ratio in east area was lowest (1.97%). Statistical analysis showed that the difference among different areas was significant (P<0.000 1). In most areas, both the number and proportion of hospitalized asthmatic patients peaked in spring (February-April) and autumn (September-October). In the northeast area, east area and south area, the peaks in spring were more obvious, while in the north area and southwest area, the peaks in autumn were more obvious. In the northwest area the peaks occurred in winter (December-January) and summer (June-August), respectively. The differences in hospitalization due to asthma among different months were significant in the northeast, north, and southwest areas (P<0.005). Conclusion: The number of patients hospitalized for asthma exacerbation fluctuated with season in different areas in China. In most areas, more asthmatic patients were admitted to hospitals in spring and autumn.
Asthma ; China/epidemiology* ; Hospitalization/statistics & numerical data* ; Humans ; Retrospective Studies ; Seasons