Lifestyle-based subtypes of childhood obesity and their association with cardiometabolic factors: A cluster analysis.

BACKGROUND: Lifestyle factors play an important role in the development and management of childhood obesity and its related cardiometabolic complications. OBJECTIVE/METHODS: We aimed to explore childhood obesity subtypes based on lifestyle factors and examine their association with cardiometabolic health. We included 1550 children with obesity from the National Health and Nutrition Examination Survey. Cluster analysis identified obesity subtypes based on four lifestyle factors (physical activity, diet quality, sedentary time and smoking). Multiple linear regression assessed their association with cardiometabolic factors. RESULTS: Five subtypes of childhood obesity were identified: unhealthy subtype (n = 571; 36.8%), physically active subtype (n = 185; 21.1%), healthy diet subtype (n = 404; 26.1%), smoking subtype (n = 125; 8.1%) and non-sedentary subtype (n = 265; 17.1%). Compared with the unhealthy subtype, the physically active subtype had lower insulin and HOMA-IR levels, and smoking subtype was associated with lower HDL levels. When compared with children with normal weight, all obesity subtypes had worse cardiometabolic profile, except the physically active subtype who had similar DBP, HbA1c and TC levels; smoking subtype who had similar TC levels; and healthy diet and non-sedentary subtypes who had similar DBP levels. CONCLUSION: Children of different lifestyle-based obesity subtypes might have different cardiometabolic risks. Our new classification system might help personalize assessment of childhood obesity.

Infancy weight gain and neurodevelopmental outcomes among term-born infants at age one year: A large prospective cohort study in China.

To investigate the association between infancy weight gain and neurodevelopment among term-born infants. Singleton term-born infants (n = 5837) were included from the Born in Guangzhou Cohort Study. Absolute weight gain was obtained by calculating the weight difference from birth to exactly 12 months. The primary outcome was neurodevelopment at age one year, which included five developmental domains. Global developmental delay was defined as delays in ≥3 domains. Multivariable logistic regression was used to examine the associations between infancy weight gain and neurodevelopment. Compared with infants gaining 6001-7000 g (reference group), infants gaining ≤5000 g had higher odds of delay in adaptive, gross motor, fine motor, social, and global developmental delay, infants gaining 5001-6000 g had higher odds of gross motor delay and social delay. A sex-stratified analysis showed that compared with the reference group, gaining ≤5000 g was associated with higher odds of fine motor delay in male infants, while gaining >7000 g was associated with higher odds of fine motor delay in females. Inadequate infancy weight gain is associated with higher odds of poor neurodevelopment at age one year among term-born infants.

Identification of maternal continuous glucose monitoring metrics related to newborn birth weight in pregnant women with gestational diabetes.

PURPOSE: To identify the specific glucose metrics derived from maternal continuous glucose monitoring (CGM) data, which were associated with a higher percentile of offspring birth weight. METHODS: In this cohort study, we recruited singleton pregnant women with GDM who underwent CGM for 5-14 days at a mean of 28.8 gestational weeks between Jan 2017 and Nov 2018. Commonly used single summary glucose metrics of glucose exposure (including mean 24-h, daytime, and nighttime glucose level) and variability (including J-index and mean amplitude of glycaemic excursions) were derived from CGM data. A novel comprehensive glucose metric-hours per-day spent in a severe variability glucose mode (HSSV)-was identified using the spectral clustering method, which reflects both glucose level and variability. Multiple linear regression models were used to estimate the associations of sex- and gestational age-adjusted birth weight percentile with CGM parameters. RESULTS: Ninety-seven women comprising 127,279 glucose measurements were included. Each 1-SD increase in maternal nighttime mean glucose level and HSSV was associated with 6.0 (95% CI 0.4, 11.5) and 6.3 (95% CI 0.4, 12.2) percentage points increase in birth weight percentile, respectively. No associations were found between other glucose metrics and birth weight percentile. CONCLUSION: Nighttime mean glucose level has a comparable effect size to HSSV in association with fetal growth, suggesting that endogenous hyperglycemia might drive the association between maternal hyperglycemia and birth weight. Further studies need to examine the effect of lowering nighttime glucose level and/or HSSV on preventing fetal overgrowth in GDM women.

Maternal circulating leptin profile during pregnancy and gestational diabetes mellitus.

AIMS: To evaluate the difference in maternal circulating leptin profile between pregnant women with and without gestational diabetes mellitus (GDM). METHODS: This is a nested case-control study embedded in the Born in Guangzhou Cohort Study in Guangzhou Women and Children's Medical Center, with 198 GDM cases and 192 controls included. Maternal plasma leptin profile was defined as leptin concentrations measured at early (baseline) and late pregnancy, as well as a ratio of concentration at late to that at early pregnancy (RL1L0). General linear regression was used to assess the associations between GDM and log-transformed leptin measurements. RESULTS: Women with GDM had a higher baseline leptin concentration and lower RL1L0 compared to those without GDM. The log leptin concentration at baseline (ß: 0.19, 95%CI: 0.04, 0.34) and the log RL1L0 (ß: -0.22, 95%CI: -0.41, -0.03) were associated with GDM status. The RL1L0 decreased significantly along with the increase of 1-hour glucose and the difference between 1-hour and fasting glucose levels in both GDM and non-GDM women. CONCLUSIONS: Women with GDM had a certain profile of circulating leptin, with higher baseline concentration but less increase during pregnancy, suggesting an impaired compensatory response to increasing insulin resistance along with the progress of pregnancy.

Association between serum progesterone concentration in early pregnancy and duration of pregnancy: a cohort study.

Objective: To examine the association between progesterone concentration in early pregnancy and duration of pregnancy and risk of preterm delivery.Methods: Women enrolled in the Born in Guangzhou Cohort Study from 2013-2014, with a singleton pregnancy, who had serum progesterone measured at least one time between 4 and 10 weeks of gestation were included. The association between progesterone concentration both continuous and as categorical variable (quartile) and the risk of preterm delivery was assessed with Cox proportional hazards regression. Differences of length of gestation in four progesterone concentration quartiles were assessed using the Log-rank test.Results: We studied 1860 mother-newborn pairs. The mean overall progesterone concentration was 65.7 ± 21.3 nmol/L, with mean progesterone concentrations in the four quartiles of 42.4 ± 6.2 nmol/L (n = 463), 56.2 ± 3.3 nmol/L (n = 462), 68.9 ± 4.5 nmol/L (n = 470), and 95.1 ± 15.3 nmol/L (n = 465). There was no significantly difference in duration of gestation in four progesterone concentration groups (p=.511). There was no relation between progesterone level and preterm delivery (adjusted hazard ratio (HR) per 10 nmol/l progesterone level 1.00 (95% confidence interval (CI) 0.90, 1.11)). After adjusting for potential confounders, the HR of any preterm delivery for quartiles 1, 2 and 3 versus the highest quartile of progesterone level (> 77.3 nmol/L) was 1.04 (95% CI 0.52, 2.07), 1.17 (95% CI 0.60, 2.28), and 1.46 (95% CI 0.76, 2.78), respectively. When analysis was done for spontaneous preterm delivery only, also no association with first trimester progesterone was found.Conclusion: Lower first trimester serum progesterone concentration is not associated with reduction of length of gestation or increased risk of preterm delivery.

Family socioeconomic position and abnormal birth weight: evidence from a Chinese birth cohort.

BACKGROUND: Birth weight is a strong determinant of infant short- and long-term health outcomes. Family socioeconomic position (SEP) is usually positively associated with birth weight. Whether this association extends to abnormal birth weight or there exists potential mediator is unclear. METHODS: We analyzed data from 14,984 mother-infant dyads from the Born in Guangzhou Cohort Study. We used multivariable logistic regression to assess the associations of a composite family SEP score quartile with macrosomia and low birth weight (LBW), and examined the potential mediation effect of maternal pre-pregnancy body mass index (BMI) using causal mediation analysis. RESULTS: The prevalence of macrosomia and LBW was 2.62% (n = 392) and 4.26% (n = 638). Higher family SEP was associated with a higher risk of macrosomia (OR 1.30, 95% CI 0.93-1.82; OR 1.53, 95% CI 1.11-2.11; and OR 1.59, 95% CI 1.15-2.20 for the 2nd, 3rd, and 4th SEP quartile respectively) and a lower risk of LBW (OR 0.69, 95% CI 0.55-0.86; OR 0.76, 95% CI 0.61-0.94; and OR 0.61, 95% CI 0.48-0.77 for the 2nd, 3rd, and 4th SEP quartile respectively), compared to the 1st SEP quartile. We found that pre-pregnancy BMI did not mediate the associations of SEP with macrosomia and LBW. CONCLUSIONS: Socioeconomic disparities in fetal macrosomia and LBW exist in Southern China. Whether the results can be applied to other populations should be further investigated.

Comparison of the INTERGROWTH-21st standard and a new reference for head circumference at birth among newborns in Southern China.

BACKGROUND: Previous studies proposed that there were racial or ethnic disparities in fetal growth, challenging the use of international standards in specific populations. This study was to evaluate the validity of applying the INTERGROWTH-21st standard to a Chinese population for identifying abnormal head circumference (HC), in comparison with a newly generated local reference. METHODS: There were 24,257 singletons delivered by low-risk mothers in four perinatal health-care centers in Southern China. New HC reference was constructed and comparison in distribution of HC categories was performed between the INTERGROWTH-21st standard and new reference after applying these two tools in study population. Logistic regression was used to examine the association between abnormal HC and adverse neonatal outcomes. RESULTS: There were 4.40% of the newborns identified with microcephaly (HC > 2 standard deviation below the mean) using the INTERGROWTH-21st standard, comparing to the proportion of 2.83% using new reference. The newborns identified with microcephaly only by the INTERGROWTH-21st standard were not at a higher risk of adverse neonatal outcome, compared with those identified as non-microcephaly by both tools (OR 0.73, 95% CI 0.47-1.13). CONCLUSION: The new HC reference may be more appropriate for newborn assessment in Chinese populations than the INTERGROWTH-21st standard.

Predictions of Preterm Birth from Early Pregnancy Characteristics: Born in Guangzhou Cohort Study.

Preterm birth (PTB, <37 weeks) is the leading cause of death in children <5 years of age. Early risk prediction for PTB would enable early monitoring and intervention. However, such prediction models have been rarely reported, especially in low- and middle-income areas. We used data on a number of easily accessible predictors during early pregnancy from 9044 women in Born in Guangzhou Cohort Study, China to generate prediction models for overall PTB and spontaneous, iatrogenic, late (34⁻36 weeks), and early (<34 weeks) PTB. Models were constructed using the Cox proportional hazard model, and their performance was evaluated by Harrell's c and D statistics and calibration plot. We further performed a systematic review to identify published models and validated them in our population. Our new prediction models had moderate discrimination, with Harrell's c statistics ranging from 0.60⁻0.66 for overall and subtypes of PTB. Significant predictors included maternal age, height, history of preterm delivery, amount of vaginal bleeding, folic acid intake before pregnancy, and passive smoking during pregnancy. Calibration plots showed good fit for all models except for early PTB. We validated three published models, all of which were from studies conducted in high-income countries; the area under receiver operating characteristic for these models ranged from 0.50 to 0.56. Based on early pregnancy characteristics, our models have moderate predictive ability for PTB. Future studies should consider inclusion of laboratory markers for the prediction of PTB.

Early life vitamin D status and asthma and wheeze: a systematic review and meta-analysis.

BACKGROUND: Vitamin D deficiency has been linked to an increased risk of asthma. This study aimed to quantify the effect of early life vitamin D status on asthma and wheeze later in life. METHODS: PubMed, Embase, CINAHL, and CNKI databases, the Cochrane Central Register of Controlled Trials, and Google Scholar were searched up to July 2017. We included randomized controlled trials (RCTs) and cohort studies with vitamin D level in blood (maternal or cord or infant) or intake (maternal intake during pregnancy or infant intake) and asthma and/or wheeze. Two reviewers independently extracted data. Fixed- and random-effects models were used to summarize the risk estimates of comparisons between highest vs. lowest vitamin D categories. RESULTS: Of the 1485 studies identified, three RCTs and 33 cohort studies were included. We did not include the RCTs (1619 participants) in the meta-analysis as the comparators and outcome definitions were heterogenous. Three RCTs reported a non-statistically significant effect of vitamin D supplementation during pregnancy on offspring wheeze/asthma at 3 years of age. Pooled estimates of cohort studies suggest no association between antenatal blood vitamin D levels or vitamin D intake and offspring asthma assessed either > 5 years or ≤ 5 years. The estimate for blood vitamin D remained unchanged when two studies assessing asthma in adulthood were excluded, but a significant inverse association emerged between vitamin D intake and childhood asthma. We found no association between antenatal vitamin D level and wheeze. On the other hand, vitamin D intake during pregnancy may have a protective effect against wheeze. CONCLUSIONS: The pooled estimates from cohort studies show no association between antenatal blood vitamin D level and asthma/wheeze in later life. Whereas, the pooled estimates from cohort studies suggest that antenatal vitamin D intake may have an effect on childhood asthma > 5 years or childhood wheeze. The inconsistent results from studies assessing vitamin D either in blood or intake may be explained by previously reported non-linear association between blood vitamin D3 and childhood asthma. Further trials with enough power and longer follow-up time should be conducted to confirm the results.

Association Between Maternal Hyperglycemia and Composite Maternal-Birth Outcomes.

Objective: The overall impact of maternal hyperglycemia on maternal and birth outcomes is largely underestimated, therefore quantifying the true burden of hyperglycemia in a whole population it is a challenging task. This study aims at examining the association between blood glucose concentration during pregnancy and a composite score of adverse maternal-birth outcomes in a large-scale prospective cohort study in China. Methods: Pregnant women within "the Born in Guangzhou Cohort Study" China who underwent a standard 75-g oral-glucose-tolerance-test (OGTT) between 22 and 28 gestational weeks were included. A composite score of stillbirth, duration of pregnancy, birth weight, preeclampsia, and cesarean section was developed based on a published maternal-fetal outcomes scale, weighed by the relative severity of the outcomes. Multiple linear regression models were used to assess the associations between OGTT glucose measurements and log composite score. Logistic regression models were used to assess relations with outcome as a categorical variable (0, 1- < 3, and ≥3). Findings: Among 12,129 pregnancies, the composite score ranged from 0 to 100 with a median of 2.5 for non-zero values. Elevated fasting glucose level was associated with higher composite score (adjusted coefficients 0.03 [95% CI, 0.02-0.04] for 1-SD increase). For 1-SD increase in fasting glucose, the risk of having a composite score 1- < 3 and ≥3 rises by 13% (95% CI, 8-17%) and 15% (95% CI, 7-23%), respectively. Similar association and increase in risk was found for 1 and 2-h glucose. Conclusion: Elevated fasting, 1 and 2-h glucose levels are associated with a range of adverse maternal-birth outcomes. The composite score model can be applied to the risk assessment for individual pregnant women and to evaluate the benefits for controlling glucose levels in the population.

Connections between the human gut microbiome and gestational diabetes mellitus.

The human gut microbiome can modulate metabolic health and affect insulin resistance, and it may play an important role in the etiology of gestational diabetes mellitus (GDM). Here, we compared the gut microbial composition of 43 GDM patients and 81 healthy pregnant women via whole-metagenome shotgun sequencing of their fecal samples, collected at 21-29 weeks, to explore associations between GDM and the composition of microbial taxonomic units and functional genes. A metagenome-wide association study identified 154 837 genes, which clustered into 129 metagenome linkage groups (MLGs) for species description, with significant relative abundance differences between the 2 cohorts. Parabacteroides distasonis, Klebsiella variicola, etc., were enriched in GDM patients, whereas Methanobrevibacter smithii, Alistipes spp., Bifidobacterium spp., and Eubacterium spp. were enriched in controls. The ratios of the gross abundances of GDM-enriched MLGs to control-enriched MLGs were positively correlated with blood glucose levels. A random forest model shows that fecal MLGs have excellent discriminatory power to predict GDM status. Our study discovered novel relationships between the gut microbiome and GDM status and suggests that changes in microbial composition may potentially be used to identify individuals at risk for GDM.

Birth weight changes in a major city under rapid socioeconomic transition in China.

Estimates of trends in birth weight may be useful in evaluating population health. We aimed to determine whether temporal changes in birth weight have occurred amongst 2.3 million neonates born in Guangzhou, China, during 2001-2015 and investigate the socioeconomic determinants of any changes. Trends in mean birth weight and annualized changes with the associated 95% confidence intervals (CIs) in the incidence of small for gestational age (SGA) and large for gestational age (LGA), defined as birth weight <10th or >90th centile respectively for gestational age and sex, were examined using linear and Poisson regression models. We found that mean birth weight declined by 1.07 grams/year from 2001 to 2015. After adjustment for gestational length, the decline in birth weight was attenuated (0.37 grams/year). The incidence of both SGA and LGA significantly decreased during the study period (annual decrease of 1.6% [95% CI, 1.5% to 1.7%] for SGA, 1.6% [95% CI, 1.5% to 1.8%] for LGA). We found a narrowing of disparities in SGA and LGA incidence across different maternal educational levels and residence location. Our results demonstrate that there has been an increase in the proportion of neonates born in the healthy birth weight range in Guangzhou.

The Born in Guangzhou Cohort Study (BIGCS).

The Born in Guangzhou Cohort Study (BIGCS) is a large-scale prospective observational study investigating the role of social, biological and environmental influences on pregnancy and child health and development in an urban setting in southern China. Pregnant women who reside in Guangzhou and who attend Guangzhou Women and Children's Medical Center (GWCMC) for antenatal care in early pregnancy (<20 weeks' gestation) are eligible for inclusion. Study recruitment commenced in February 2012, with an overall participation rate of 76.3%. Study recruitment will continue until December 2018 to achieve the target sample size of 30,000 mother-child pairs. At 30 April 2016, a total of 75,422 questionnaires have been collected, while 14,696 live births have occurred with planned follow-up of cohort children until age 18 years. During the same period a total of 1,053,000 biological samples have been collected from participants, including maternal, paternal and infant blood, cord blood, placenta, umbilical cord, and maternal and infant stool samples. The dataset has been enhanced by record linkage to routine health and administrative records. We plan future record linkage to school enrolment and national examination records.

Does tea consumption during early pregnancy have an adverse effect on birth outcomes?

BACKGROUND: Tea, a common beverage, has been suggested to exhibit a number of health benefits. However, one of its active ingredients, caffeine, has been associated with preterm birth and low birthweight. We investigated whether tea consumption during early pregnancy is associated with an increased risk of preterm birth and abnormal fetal growth. METHODS: A total of 8775 pregnant women were included from the Born in Guangzhou Cohort Study. Tea consumption (type, frequency, and strength) during their first trimester and social and demographic factors were obtained by way of questionnaires administered during pregnancy. Information on birth outcomes and complications during pregnancy was obtained from hospital medical records. RESULTS: Overall habitual tea drinking (≥1 serving/week) prevalence among pregnant women was low, at 16%. After adjustment for potential confounding factors (eg, maternal age, educational level, monthly income) tea drinking during early pregnancy was not associated with an increased risk of preterm birth or abnormal fetal growth (small or large for gestational age) (P>.05). CONCLUSIONS: We did not identify a consistent association between frequency of tea consumption or tea strength and adverse birth outcomes among Chinese pregnant women with low tea consumption. Our findings suggest that occasional tea drinking during pregnancy is not associated with increased risk of preterm birth or abnormal fetal growth. Given the high overall number of annual births in China, our findings have important public health significance.

Validity and Reproducibility of a Dietary Questionnaire for Consumption Frequencies of Foods during Pregnancy in the Born in Guangzhou Cohort Study (BIGCS).

This study aimed to examine the reproducibility and validity of a new food frequency questionnaire (FFQ) used in a birth cohort study to estimate the usual consumption frequencies of foods during pregnancy. The reference measure was the average of three inconsecutive 24 h diet recalls (24 HR) administrated between two FFQs, and the reproducibility was measured by repeating the first FFQ (FFQ1) approximately eight weeks later (FFQ2). A total of 210 pregnant women from the Born in Guangzhou Cohort Study (BIGCS) with full data were included in the analysis. The Spearman's correlation coefficients of FFQ1 and FFQ2 ranged from 0.33 to 0.71. The intraclass correlation coefficients of the two FFQs ranged from 0.22 to 0.71. The Spearman's correlation coefficients of the 24 HR and FFQ2 ranged from 0.23 to 0.62. Cross-classification analysis showed 65.1% of participants were classified into same and contiguous quintiles, while only 3.2% were misclassified into the distant quintiles. Bland-Altman methods showed good agreement for most food groups across the range of frequencies between FFQ1 and FFQ2. Our findings indicated that the reproducibility and validity of the FFQ used in BIGCS for assessing the usual consumption frequencies of foods during pregnancy were acceptable.

Syphilis test availability and uptake at medical facilities in southern China.

OBJECTIVE: To examine syphilis testing capacity, screening coverage rates and types of syphilis tests used in medical facilities in southern China. METHODS: Eleven of the 14 municipalities in Guangdong province participated. Data on syphilis testing capacity, screening coverage and types of syphilis tests used were collected from all types of public medical facilities offering prenatal care (n = 109). A total of 494 680 women who delivered during 2004-2008 were studied. FINDINGS: In 2008, 54 196 pregnant women (43.1%) were not screened for syphilis. Among such women, 32 863 (60.6%) attended clinics without any syphilis testing capacity and 21 333 (39.4%) attended clinics that performed testing but were not screened. The likelihood of not having syphilis test capacity was much higher for hygiene stations (odds ratio, OR: 10; 95% confidence interval, CI: 4-25), services at the township level (OR: 33; 95% CI: 10-100) and services with ≤ 1000 deliveries per year (OR: 1.002; 95% CI: 1.001-1.003). These same service characteristics correlated with lower screening coverage rates (P < 0.01). Only one antenatal clinic had the capacity to conduct both treponemal and non-treponemal tests for diagnosing syphilis. CONCLUSION: Syphilis screening is available in very few of the basic medical facilities offering prenatal care where most neonates in southern China are delivered. In light of this and of the increasing incidence of syphilis in the area, expanding point-of-care rapid syphilis testing is a priority.

Peer-based behavioral health program for drug users in China: a pilot study.

BACKGROUND: Many injection drug users (IDUs) in China have high risk sexual behaviors that contribute to the spread of HIV infection. Although many IDUs in China move through drug rehabilitation centers, this opportunity for sexual health education has largely been overlooked. METHODS: A convenience sample of 667 drug users from two rehabilitation centers in South China was recruited in the study. Two hundred and forty seven drug users from a single Guangdong Province rehabilitation center received the peer-based education intervention, while 420 drug users from another rehabilitation center received routine HIV/STI education and was used as the control. One hundred and eighty nine (22.1%) individuals refused to participate in the study. HIV/STI behavioral and knowledge domains were assessed at 3 months in rehabilitation centers after the intervention (first follow-up) and at 2-23 months in the community after release (second follow-up). RESULTS: Drug users who completed the intervention reported more frequent condom use with casual sex partners (60.0% vs. 12.5% condom use every time, p = 0.011) and less frequent injection (56.7% vs. 26.4% no injection per day, p = 0.008) at the second follow-up compared to those in the routine education group. Loss to follow up was substantial in both control and intervention groups, and was associated with living far from the detention center and having poor HIV knowledge at baseline. CONCLUSIONS: This study shows that rehabilitation centers may be a useful location for providing behavioral HIV/STI prevention services and referral of individuals to community-based programs upon release. More research is needed on behalf of detained drug users in China who have complex social, medical, and legal needs.

Social network-based interventions to promote condom use: a systematic review.

Effective sexually transmitted infection (STIs)/HIV prevention programs are urgently needed, but translating evidence-based methods of STI/HIV prevention into sustainable programs has been difficult. Social influences are critical for establishing condom use norms. This study systematically reviewed social network-based interventions focused on condom promotion. Social networks were defined as groups who self-identified prior to the research study. Eleven eligible research studies were identified and included in this review. Only three studies measured biological endpoints and five studies used validated measures of condom use. Among the nine studies with control groups, eight showed significant improvements in at least one measure of condom use. There were large differences in how social network members were identified and involved in the interventions. This systematic review highlights the potential utility of social network-based condom promotion programs. More research is needed to show how these promising studies can be expanded.

A twin response to twin epidemics: integrated HIV/syphilis testing at STI clinics in South China.

BACKGROUND: HIV testing is still stigmatized among many high-risk groups in China, whereas routine syphilis testing has been widely accepted at sexually transmitted infection (STI) clinics. This project used the platform of a rapid syphilis screening test to expand HIV test uptake. The objective of this study was to use multilevel modeling to analyze determinants of syphilis and HIV-testing uptake at STI clinics in China. METHODS: 2061 STI patients at 6 clinics in Guangdong Province were offered free rapid syphilis and free rapid HIV testing. Test uptake was defined by patient receipt of results and a multilevel model was used to analyze predictors of uptake. RESULTS: This was the first syphilis or HIV test for the large majority (1388, 77.7%) of participants. Syphilis test uptake and HIV test uptake were high (1681, 81.6%, syphilis test uptake; 1673, 81.2% HIV test uptake). HIV test uptake was significantly concordant with syphilis test uptake (τb = 0.89, P < 0.001). The most parsimonious model of refusing HIV test uptake included the following variables: being married, having a previous HIV test, being unaccompanied, and participating in the last 2 months of the study. CONCLUSIONS: STI clinic-based screening for syphilis and HIV represents an excellent opportunity for scaling up integrated services, especially in South China where syphilis and sexually transmitted HIV cases are both rapidly increasing. Effective integration of HIV testing into routine clinical practice requires an understanding not only of individual test uptake but also of the broader social context of HIV testing.