Transmission cluster and network of HIV-1 CRF01_AE strain in China, 1996-2014 / 中华流行病学杂志

Objective: To understand the transmission patterns and risk factors of HIV-1 strain CRF01_AE subtypes in China, and to provide guidance for the implementation of precise intervention. Methods: A total of 2 094 CRF01_AE pol sequences were collected in 19 provinces in China between 1996 and 2014. Phylogenetic tree was constructed by PhyML 3.0 software to select the transmission clusters. Transmission network was constructed by Cytoscape 3.6.0, which was further used for exploring of the major risk factors. Results: Of the 2 094 sequences, 12.18% (255/2 094) were in clusters. A total of 82 transmission clusters were identified. The numbers of clusters and contained sequences in intra-provincial transmission (61, 173) were significantly more than those in inter-provincial transmission (21, 82). The ratio of transmission clustering in MSM increased over time from 2.41% (2/83) during 1996-2008 to 23.61% (72/305) during 2013-2014, showing a significant upward trend (χ(2)=27.800, df=1, P=0.000). The proportion of MSM with inter-provincial transmission clusters were higher than those with intra-provincial transmission clusters, which increased from 0.67% (2/297) during 1996-2008 to 6.36%(30/472) during 2013-2014, showing a significant upward trend (χ(2)=20.276, df=1, P=0.000). The transmission rate in homosexuals of the inter-transmission clusters (86.59%, 71/82) was higher than that of intra-provincial transmission clusters (56.65%, 98/173), and the difference was statistically significant (χ(2)=22.792, P=0.000). The proportion of inter-provincial transmission clusters with more than 2 transmission routes (33.33%, 7/21) was higher than that of intra-provincial clusters (13.11%, 8/61), and the difference was statistically significant (χ(2)=4.273, P=0.039). Results from the transmission network analysis indicated that the proportion of high risk population (degree≥4) with inter-provincial transmission clusters (51.22%, 42/82) was significantly higher than that with intra-provincial transmission clusters (26.59%, 46/173), and the difference was statistically significant (χ(2)=14.932, P=0.000). Inter-provincial clusters were mainly detected in and and MSM. Conclusions: Complex transmission networks were found for HIV-1 CRF01_AE strains in the mainland of China. Inter-provincial transmission clusters increased rapidly, MSM played an important role in the wide spread of the strain. More researches in transmission networks are needed to guide the precision intervention.

Effect of docosahexenoic acid supplementation on infant's growth and body mass index during maternal pregnancy / 中华流行病学杂志

Objective: To investigate the effects of docosahexenoic acid (DHA) supplementation on infant's growth and BMI during pregnancy. Methods: A total of 1 516 healthy pregnant women delivered their babies in two maternal and child health care hospitals in Beijing and were chosen as the subjects in this cohort study from May to October 2015. Self-developed questionnaires were used to gather general information of the subjects, including age, height, weight, weight gain during pregnancy, delivery mode, DHA supplementation etc., before giving birth. Information on body length, weight, head circumference and BMI at birth and 6 months postnatal, of the infants were recorded. Breast milk was collected to test the fatty acid profiles by using the gas chromatography (GC) method at one to three months postnatally. Results: The overall rate of DHA supplementation was 47.76% among the pregnant women, in which introduction of DHA from the early and second stage of the pregnancy accounted for 49.31% and 39.64% respectively. When DHA supplementation began from the early pregnant stage, the DHA concentration showed an increase in the milk (P<0.05), whereas the supplementation began from the second and third stages did not affect the milk DHA concentration (P>0.05). Higher height and lower BMI were seen in the infants at birth and 6 months in the supplementation group when comparing to the non-supplementary group (P<0.05), with the greatest effects noticed in the earliest supplementation group. Specifically, the head circumference appeared larger from the early pregnant stage in the DHA supplementary group, than that in the non-supplement group (P=0.001). The increment of head circumference was larger than that in the other groups when the infants were 6-month old (P<0.01). Results from the partial regression analysis showed that during pregnancy, there were positive correlations between DHA supplementation and height (r=0.324, r=0.216), head circumference (r=0.221, r=0.302) as well as the increment of head circumference (r=0.276) at birth and 6 months (P<0.05). Whereas, a negative correlation was shown between DHA and the infants' BMI (r=-0.310, r=-0.371) (P<0.05) when supplementation was given during maternal pregnancy. Conclusions: When DHA supplementation program was carried out during maternal pregnancy, it could increase the height and head circumference and inhibit the rapid increase of BMI in the infants BMI. Our findings seemed helpful in promoting brain development and preventing the childhood obesity.