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 analyze the deaths attributed to ambient air pollution in China between 2006 and 2016. Methods: The data were collected from the project of Global Burden of Disease in 2016 (GBD2016). The Data Integration Model for Air Quality were used to estimate exposure to particulate matter smaller than 2.5 μm in aerodynamic diameter (PM(2.5)). The attributable death number was calculated based on the calculation of population attributable fraction (PAF), and the results were compared by gender, diseases and provinces. An average world population age structure was adopted to calculate age-standardized rates. Results: In 2016, a total of 1 075 000 deaths attributed to ambient air pollution occurred in China, accounting for 11.1% of the total deaths, and 57.6% of the deaths attributed to ambient air pollution were due to ischemic heart disease and stroke. The death number among men was 1.7 times higher than that in women, Compared with 2006, the proportion of ambient air pollution related deaths in total deaths decreased by 6.8%; the age- standardized death rate attributed to ambient air pollution decreased by 26.5% and the decrease rate of lower respiratory infections (37.6%) and chronic obstructive pulmonary disease (42.1%) were greater than ischemic heart disease (5.3%). The age-standardized rate of death attributed to ambient air pollution decreased both in men and in women, but the decrease rate was higher in women (34.8%) than that in men (20.4%). The PAFs varied among provinces, it was highest in Tianjin (13.9%), lowest in Tibet (6.1%), and it was relatively higher in Beijing, Hebei, Shandong, Henan and the three provinces in the northeast and relatively lower in Hong Kong, Macao, Fujian and Hainan etc.. The age-standardized rate of death attributed to ambient air pollution was highest in Xinjiang (120.1/100 000) and lowest in Hong Kong (30.9/100 000), and it was relatively higher in Qinghai, Guizhou, Henan and relatively lower in Macao, Shanghai and Fujian, etc.. Compared with 2006, the PAFs of 17 provinces decreased, the decrease rate ranged from 4.1% to 16.8%, whereas the PAF of Jilin (5.0%) and Heilongjiang (8.1%) increased, and the PAFs of other 14 provinces showed no significant change. The attributable age-standardized death rate decreased in all provinces with the decrease rate ranging from 11.9% (Heilongjiang) to 43.2% (Fujian), and the decrease rate was relatively higher in Guangdong, Zhejiang and Guizhou, and lower in the three provinces in the northeast, Hubei and Hebei etc. Conclusions: In 2016, the disease burden attributable to PM(2.5) in China was heavy, but mitigated compared with 2006. The gender and area specific distributions of deaths attributed to ambient air pollution were observed.
Adolescent ; Adult ; Air Pollution/adverse effects* ; Asian People/statistics & numerical data* ; Cause of Death ; China/epidemiology* ; Female ; Humans ; Male ; Middle Aged ; Mortality ; Pulmonary Disease, Chronic Obstructive/mortality* ; Sex Distribution ; Young Adult

Objective: To explore the association between gestational weight gain (GWG) and adverse pregnancy outcomes. Methods: A prospective study was conducted among 1 220 healthy singleton pregnant women in the first trimester of pregnancy, from Chengdu city, Sichuan province. Pre-gestational body mass and other basic information were collected through a set of questionnaires. Weight at the last week before delivery was measured and GWG was classified by IOM criteria (2009). Related information on pregnancy outcomes was collected after delivery, through the hospital information system. Multiple non-conditional logistic regression models were used to test the association between GWG and adverse pregnancy outcomes. Results: In total, data on 1 045 pregnant women were analyzed. Compared with adequate GWG, excessive GWG was associated with the increased risks of cord entanglement and large for gestational age (OR=1.641, 95%CI: 1.197-2.252; OR=1.678, 95%CI: 0.132-2.488), respectively. Additionally, when compared with the adequate GWG, insufficient GWG was associated with the increased risk of preterm delivery (OR=3.189, 95%CI: 1.604-6.341). Conclusions: Both excessive and insufficient GWG appeared associated with the pregnancy outcomes. Weight monitoring should be strengthened for pregnant women to reduce related risks on adverse pregnancy outcomes.
Adult ; Birth Weight ; Body Mass Index ; China/epidemiology* ; Female ; Gestational Weight Gain ; Humans ; Infant, Newborn ; Pregnancy ; Pregnancy Complications/epidemiology* ; Pregnancy Outcome/epidemiology* ; Prospective Studies

Objective: To analyze the burden of disease (BOD) on diabetes attributable to high BMI in China from 1990 to 2016. Methods: Data based on population of the 2016 Global Burden of Disease Study for China were used to analyze the attributable fractions (PAF) of BOD for diabetes attributable to high BMI. Measurements for attributable BOD of diabetes included disability adjusted life years (DALY), years of lost life (YLL), years living with disability (YLD), death number and mortality rate. The average world population from 2010 to 2035 was used as a reference. Results: In 2016, death number of diabetes attributable to high BMI was 40 310, which was significantly higher than that in 1990 (15 008). Age-standardized death rate of diabetes attributable to high BMI increased from 2.01/100 000 in 1990 to 2.60/100 000 in 2016, which showed a more significant increasing trend in both males and people aged 15-49 years. DALYs of diabetes attributable to high BMI increased from 1.09 million person years to 3.30 million person years. YLL and YLD also showed increasing trends. The highest increasing rate of YLD was in people aged 15-49 years. High BMI was responsible for 26.01% of the diabetes deaths in 2016 in China, an increase of 39.39% compared with that in 1990 (18.66%). Most provinces in China experienced a sharp increase of DALY of diabetes attributable to high BMI from 1990 to 2016. Inner Mongolia, Xinjiang, Zhejiang, Macao SAR, Sichuan and Qinghai had the most significant increase tendency in terms of DALY rate during this period. Conclusions: There was a rapid increase of the deaths and mortality rate of diabetes attributable to high BMI, causing a heavy disease burden, in China from 1990 to 2016. The BOD varied in both different age and gender groups. More attention should be paid to males and people aged 15-49 years in the prevention and control programs of diabetes.
Adolescent ; Adult ; Body Mass Index ; China/epidemiology* ; Cost of Illness ; Diabetes Mellitus/ethnology* ; Disabled Persons ; Humans ; Macau ; Male ; Middle Aged ; Quality-Adjusted Life Years ; Sickness Impact Profile ; Young Adult

Objective: To understand the epidemiological and molecular characteristics of a norovirus- borne outbreak caused by GⅡ.4 Sydney 2012 in a university of Guangzhou to provide evidence for the prevention and control strategy on norovirus-caused epidemics. Methods: A self-designed questionnaire was used to collect clinical information from the patients as well as other data related to the epidemic. Pathogen detections were performed through anal swab specimens from the patients, kitchen workers and samples from the environment. Positive samples were further sequenced for phylogenetic analysis. A case-control study was employed to identify the risk factors related to this outbreak. Results: A total of 226 cases of norovirus-borne infection were identified between September 17 and 21, 2017, including 223 students, with an attack rate of 0.73% (223/30 711), and 3 kitchen workers. Students staying in the A dormitory area had the highest attack rate (1.73%, 164/9 459). No clustering was found in different colleges or classes. Results from the case-control study revealed that people who ate at the canteen in A dormitory area during September 18 to 20 was at risk for the onset of illness (OR=10.75, 95%CI: 5.56-20.79). The highest risk was related to the dinner on September 18. Another significant risk factor (OR=3.65, 95%CI: 1.92-6.94) was close personal contact in the same room of the dorm. The 3 norovirus infected kitchen workers were all from the canteen in A dormitory area where the positive rate of norovirus identified in kitchen workers was 26.67% (12/45). Positive samples were sequenced and sub-typed with results showing that the GⅡ.4 Sydney 2012 variant and the nucleotide sequences of cases and kitchen workers were 100% identical. Conclusions: The outbreak was caused by norovirus GⅡ.4 Sydney 2012 variant at campus. Similar outbreaks had been seen since 2013, with the routes of transmission most likely due to food-borne or personal contact.
Adolescent ; Adult ; Caliciviridae Infections/epidemiology* ; Case-Control Studies ; China/epidemiology* ; Disease Outbreaks ; Female ; Foodborne Diseases/virology* ; Gastroenteritis/virology* ; Humans ; Male ; Norovirus/isolation & purification* ; Phylogeny ; Surveys and Questionnaires

Objective: To assess the disease burden on uterine fibroids in China in 1990 and 2016. Methods: Data were extracted from the Global Burden of Disease Study 2016. Burdens of uterine fibrosis among different age groups and provinces were measured in 1990 and 2016, with key indicators including number of cases, prevalence rates, disability-adjusted life year (DALY) and the rates of DALY. The WHO world standard population, 2010-2035 was used to calculate the age- standardized rates. Results: In 1990 and 2016, there were 13 695 567 and 27 169 312 women aged 15 years and older, suffered from uterine fibrosis respectively, with prevalence rate as 2.48% and 4.10%, DALY as 146 045.05 life years and 281 976.67 life years, and the DALY rate as 26.40/100 000 and 42.50/100 000, in 1990 and 2016 respectively. Both the prevalence rate and the DALY rate increased with age, reaching the peak on the 45-49 years-old, in both 1990 and 2016. Women aged 40-54 years accounted for 55.60% (1990) and 66.74% (2016) of the total cases while 48.37% (1990) and 60.65% (2016) of the total DALY. The first three provinces with highest DALYs were Shandong (1990: 12 574.67 life year; 2016: 22 728.12 life year), Henan (1990: 10 849.29 life year; 2016: 18 454.32 life year) and Jiangsu (1990: 10 501.55 life year; 2016: 18 274.10 life year), while the three provinces with leading standardized DALY rates were Heilongjiang (1990: 48.20/100 000; 2016: 47.00/100 000), Shanxi (1990: 44.50/100 000; 2016: 47.70/100 000) and Tianjin (1990: 43.80/100 000; 2016: 46.40/100 000) in both 1990 and 2016. Compared with 1990, the number of cases with uterine fibroids increased by 13 473 745 (with rate of change as: 98.38%), standardized prevalence rate increased by 1.88%, DALY value increased by 135 931.62 life years (with the rate of change as 93.08%) and standardized DALY rate increased by 5.92% among Chinese women, in 2016. Conclusion: Menopausal women were the ones hard hit by uterine fibrosis. Compared with data from 1990, the disease burden of uterine fibrosis increased rapidly in China, in 2016.
Adolescent ; Adult ; Asian People/statistics & numerical data* ; China/epidemiology* ; Cost of Illness ; Disabled Persons ; Female ; Humans ; Leiomyoma/psychology* ; Middle Aged ; Quality-Adjusted Life Years ; Young Adult

Objective: To study the willingness and influence factors related to "centralized slaughtering, fresh poultry listing and marketing" strategy, among the household chefs, and provide reference for government to adjust and optimize the strategy on avian influenza prevention. Methods: According to the geographical characteristics and regional functions, 6 'monitoring stations' were selected from 12 residential districts of Guangzhou, respectively. Another 21 meat markets which selling live poultry, were selected in each station and 5 household chefs of each market were invited to attend a face to face interview. Basic information, personal cognitive, willingness and influencing factors to the policy were under study. Univariate and multivariate logistic regression methods were used. Results: A total of 664 household chefs underwent the survey and results showed that the rate of support to the "centralized slaughtering, fresh poultry listing and marketing" strategy was 44.6% (296/664). Results from the multi-factor logistic regression showed that those household chefs who were males (OR=1.618, 95% CI: 1.156-2.264, P=0.005), having received higher education (OR=1.814, 95% CI: 1.296-2.539, P=0.001), or believing that the existence of live poultry stalls was related to the transmission of avian influenza (OR=1.918, 95% CI: 1.341-2.743, P<0.001) were factors at higher risk. These household chefs also intended to avoid the use of live poultry stalls (OR=1.666, 95%CI: 1.203-2.309, P=0.002) and accept the "centralized slaughtering, fresh poultry listing and marketing" strategy. Conclusion: Detailed study on this subject and, setting up pilot project in some areas as well as prioritizing the education programs for household chefs seemed helpful to the implementation of the 'freezing-fresh poultry' policy.
Animals ; Attitude to Health ; China ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza in Birds ; Influenza, Human/prevention & control* ; Male ; Marketing ; Meat-Packing Industry ; Multivariate Analysis ; Pilot Projects ; Poultry/virology* ; Surveys and Questionnaires