Characteristic and dynamic of HIV-1 subtype distribution in men who have sex with men in Guangzhou, 2008-2015 / 中华流行病学杂志

Objective: To understand the characteristics and dynamic of HIV-1 subtype distribution in men who have sex with men (MSM) in Guangzhou between 2008 and 2015. Methods: HIV-1 RNAs were extracted from serum samples of the individuals newly diagnosed with HIV-1 infection among MSM living in Guangzhou between 2008 and 2015. The pol gene segments of HIV-1 genome from these RNA samples were amplified by nested reverse transcription polymerase chain reaction (nested-PCR) and were sequenced. Subsequently, the phylogenetic tree was reconstructed using pol sequences of samples and references together and the subtype of HIV-1 was determined. The distributions of HIV-1 subtypes detected in MSM with different demographic characteristics in different years were compared. Results: A total of 2 210 pol gene segments were successfully obtained from 2 473 serum samples of the MSM. The average age of 2 210 MSM was 30.19 years with standard deviation of 8.22 years, the unmarried MSM and those in Han ethnic group accounted for 73.39% and 90.81%, respectively. The proportion of subtype CRF07_BC (38.10%) was highest, followed by CRF01_AE (34.84%), CRF55_01B (14.62%), B (6.06%), URFs (3.58%), CRF59_01B (2.17%) and other subtypes (0.63%). The annual proportions of subtype B (P=0.000, 99%CI:0.000-0.000), CRF07_BC (χ(2)=14.965, P=0.036), CRF55_01B (χ(2)=18.161, P=0.011) and URFs (P=0.001, 99% CI: 0.000-0.001) were significantly different. The proportion of subtype B showed a gradual decrease from 14.08% to 4.33% (P=0.000, 99%CI: 0.000-0.000), while the proportion of URFs rapidly increased from 0% to 6.40% (P=0.000, 99% CI: 0.000-0.000). The rate of URFs was significantly higher in farmers and migrant workers than in other groups (P=0.017, 99%CI: 0.014- 0.020) and the rate of URFs was higher in individuals who had multi sexual partners (χ(2)=5.733, P=0.017). Conclusions: CRF07_BC and CRF01_AE were the predominant HIV-1 subtypes and multiple subtypes co-circulated among MSM in Guangzhou between 2008 and 2015. The recombinations of HIV-1 continue to occur in MSM. Strengthening behavioral intervention for farmers, migrant workers and individuals who have multi sexual partners has the important epidemiological significance against the emerging and circulating of the novel recombinant virus among MSM in Guangzhou.

Characteristics and influencing factors regarding social relations among men who have sex with men / 中华流行病学杂志

Objective: To study the characteristics of social relations and relative factors among MSM in Guangzhou. Methods: Data was collected through a cross-sectional study in Guangzhou from November 2016 to May 2017. Sample size was estimated and participants were recruited from the voluntary counseling and testing services (VCT) which were set for MSM population, by nongovernmental organizations (NGOs) and the Centers for Disease Control and Prevention (CDC). Social ties and demographic characteristics of the respondents and their sexual partners were analyzed through both Chi square test and generalized estimating equations (GEE). Results: A total of 1 073 MSM, together with their nominated 4 301 partners were successfully recruited and involved in this study. Age (OR=1.2, P=0.01) and non-internet based intercourse (OR=1.65, P<0.01) were easy to form close relation with strong ties. Compared with MSM traditional venues (chess and cards room, tea room bathhouse, club), general public venue (bars, KTV, parks, shopping malls, schools, restaurants) (OR=1.46-3.12, P<0.01) showed close relation with strong ties. Our finding showed that MSM at the age of 18-25 preferred to build weak ties with the older MSM, while the 26-30-year-olds and 31-40-year-olds prefer to establish weak ties with younger partners but the 41-50-year-olds preferred to develop weak ties with one that were ten years younger. Conclusions: Clusters were noticed in the MSM populations when grouping and making friends with ones at different age. Characteristics regarding the relationship between sexual partners in choosing venues and ways of dating were different. Targeted intervention programs need to be explored innovatively.

Analysis of body composition and resting metabolic rate of 858 middle-aged and elderly people in urban area of Beijing / 中华流行病学杂志

Objective: To understand the overweight rate and obesity rate in middle-aged and elderly people in urban area of Beijing, and analyze the changes of body composition and resting metabolic rate with age. Methods: From November 2014 to December 2015, body composition measurement and resting metabolic rate detection were conducted among 858 people aged 51 to 99 years, including 760 men, 98 women, who received physical examination at Beijing Hospital. Results: The overweight rate was 51.4%, and the obesity rate was 16.9%. The overweight rate was 26.5% and the obesity rate was 14.3% in women, significantly lower than those in men (54.6% and 17.2%) (P<0.001). The distribution of skeletal muscle volume, muscle index, body fat percentage, visceral fat area and resting metabolic rate in different age groups were different (P<0.001). In the normal weight group, the skeletal muscle volume, muscle index and resting metabolic rate in age group ≥80 years decreased obviously (P<0.05). At the same time, the body fat percentage and visceral fat area increased obviously (P<0.05). However, the skeletal muscle volume, muscle index and resting metabolic rate of the overweight and obese groups began to decrease obviously in age group 70- years (P<0.05), and the decrease in age group ≥80 years was more obvious. At the same time, body fat percentage and visceral fat area increased significantly in age group 70- years (P<0.05). Conclusion: The overweight and obesity rates were high in the middle-aged and elderly people in the urban area of Beijing, and the rates were higher in men than in women. With the increase of age, the skeletal muscle volume, muscle index and resting metabolic rate gradually decreased, while the percentage of body fat and visceral fat area increased; Overweight and obese people had earlier changes in body composition and resting metabolic rate.

Effects of plants development and pollutant loading on performance of vertical subsurface flow constructed wetlands

The influent concentration has a great effect on nutrients removal efficiency in vertical subsurface flow constructed wetland systems, but treatment performance response to different C: N: P ratios in the influent are unclear at present. At the first growing seasons, the effects of the plants present or not, season, the different C: N: P ratio in influent condition and their interaction on treatment performances were studied in the planted or the unplanted wetlands in greenhouse condition. Each set of units was operated at hydraulic loading rates of 40 L/d. Low, medium and high-strength [100, 200, 400 mg/L of chemical oxygen demand or 20, 40, 80 mg/L total nitrogen] synthetic sewage were applied as influent. According to the first growing season results, the average removal efficiencies for the unplanted and the planted wetlands were as follows: chemical oxygen demand [44-58% and 55-61% respectively], total nitrogen [26-49% and 31-54%] and total phosphorus [36-64% and 70-83%]. The both wetlands system was operated as an efficient treatment system of highest average removal rates of both chemical oxygen demand and total phosphorus when medium-strength synthetic sewage were applied. When high strength synthetic sewage was applied, the planted wetlands usually had a higher nutrients removal rates than the unplanted over the study period. The plants grew well under any high loading treatment over the study period. Anyhow, it also proved that the wetland systems have a good capacity to treat different strength wastewater in greenhouse condition