Background Duration of marriage (DoM) and age are important characteristics of married individuals, who are the critical population for eliminating mother-to-child transmission (MTCT) of syphilis. A deep understanding of the preconception syphilis seroprevalence (PSS) and its distribution among this population may be able to help to eliminate MTCT. However, few population-based epidemiological studies have been focused on this group, and the association of DoM and age with PSS remains unclear. Methodology/Principal findings This study used data from 4,826,214 married individuals aged 21–49 years who participated in the National Free Preconception Health Examination Project in Guangdong Province, China, between 2014 and 2019. Syphilis was screened using the rapid plasma reagin (RPR) test. The seroprevalence time series, seroprevalence map, and hot spot analysis (HSA) were employed to visualize the spatiotemporal distribution. The restricted cubic spline (RCS) based on multivariate logistic regression was used to model the association of DoM and age with PSS. The interactions on the additive scale of DoM and age were also assessed. The PSS was 266.61 per 100,000 persons (95% CI: 262.03–271.24) and the burden was higher in economically underdeveloped area within the province. A strong J-shaped non-linearity association was observed between age and PSS. Specifically, the risk of seropositivity was relatively flat until 27 years of age among men and increased rapidly afterwards, with an adjusted odds ratio (aOR) of 1.13 (95% CI: 1.12–1.13) per unit. Among women, the risk of seropositivity was relatively flat until 25 years of age and increased rapidly afterwards with an aOR of 1.08 (95% CI: 1.08–1.09) per unit. DoM was negatively associated with PSS among married individuals. Moreover, the combined effects of age and DoM appeared to be synergistic. Conclusions/Significance Our findings suggest that attention should be paid to preventing syphilis in underdeveloped areas and that syphilis screening in newly married individuals who are in their late 20s or older should be recommended. Additionally, early syphilis prevention strategies should be implemented among young people as early as possible.

BackgroundSyphilis remains a major public health problem worldwide, and its prevention requires knowledge of factors that go beyond the individual-level. However, most syphilis-related studies have focused on individual-level and regional-level factors, neglecting couple-level factors. Thus, this study aimed to explore couple-level determinants of syphilis infection among heterosexual married couples.MethodsThis population-based cross-sectional study used data from heterosexual married couples who participated in the National Free Preconception Health Examination Project in Guangdong Province, China during 2014–2019. The syphilis infection was tested by the rapid plasma reagin test. Couple-level data were obtained by combining information provided by the man and woman living in the same household. Multivariate logistic models were employed to explore the couple-level determinants of syphilis infection by gender after adjusting for potential confounders.ResultsA total of 1,755,156 couples were recruited in this analysis. The seroprevalence was 0.25% (95%CI: 0.24–0.25%) and 0.26% (95%CI: 0.25–0.27%) among men and women, respectively. The median age was 28.0 (interquartile range, IQR: 25.0–31.0) years, and the median duration of marriage was 0.2 (IQR: 0.0–2.5) years. After adjusting for individual and regional-level variables, duration of marriage was a protective factor for syphilis infection in men (adjusted odds ratios, AOR: 0.97; 95% CI: 0.96–0.98) and women (AOR: 0.95, 95% CI: 0.94–0.96). The age gap and the difference in education level between the husband and wife were associated with syphilis infection, but these associations were somewhat different between men and women. Condom use was negatively associated with syphilis infection in men (AOR: 0.77; 95% CI: 0.70–0.84) and women (AOR: 0.77, 95% CI: 0.71–0.84). Our results also showed that couple mobility and the number of children were not statistically significant determinants of syphilis infection among heterosexual married couples.ConclusionThis study contributes to a more comprehensive understanding of syphilis outcomes in individuals in the context of marriage in China. Several couple-level factors are indeed associated with syphilis infection, but these associations differ between men and women. Couple-based strategies that engage both women and men and efforts to promote condom use among heterosexual married couples need to be developed and further evaluated for syphilis prevention.

Background TORCH infections are the most common prenatal infections causing congenital malformation and infant mortality, especially in developing countries. Migrant women might be vulnerable to TORCH infections, but little is known about the association between migration-related characteristics and TORCH infection risk. This study aimed to investigate the impact of migrant status, migration distance, and the spouse’s migrant status on the TORCH epidemic among women of childbearing age. Methods Based on the National Free Preconception Health Examination Project, we analyzed a representative dataset of TORCH infections among women of childbearing age (15–49 years old) in Guangdong Province of China (2014–2019, n = 2,451,297). The past and/or recent infection status of TORCH infections (Toxoplasma gondii [TOX], Cytomegalovirus [CMV], and Rubella virus [RV]) were identified. Demographic and migration-related characteristics were collected. We thoroughly assessed the prevalence of TORCH infections in both migrant and native women and estimated adjusted odd ratios (aOR) for migration-related characteristics using multivariable logistic regression after adjusting the other sociodemographic factors. Results Among all 2,451,297 participants, 443,725 (18.1%) were migrant women. Migrant women presented a lower risk of past TOX infection (aOR: 0.89, 0.88–0.91) suggesting a healthy migrant effect (HME), but a higher risk of recent TOX infection (aOR: 1.88, 1.77–1.99), past CMV infection (aOR: 1.26, 1.25–1.28) and RV infection in natural ways (aOR: 1.05, 1.04–1.06). Compared with intra-provincial migrants, inter-provincial migrants had a lower past TOX infection (aOR: 0.88, 0.85–0.91), but a higher risk of recent TOX infection (aOR: 1.16, 1.05–1.27) and RV infection (aOR: 1.33, 1.31–1.36). In addition, having a migrant spouse was associated with a higher risk for all types of infection. Conclusion This study reported the association of migrant status and migration distance with TORCH infections, although the significance and directionality of these associations varied between pathogens. The spouse’s migrant status further amplified the infection risk for all types of pathogens. Our findings suggested interventions for preventing the spread of CMV and RV infection and new acquisition of TOX infection for migrants in southern China, to narrow the native-migrant health inequity and decrease the incidence of prenatal infections and related adverse outcomes.

Background TORCH infections are the most common prenatal infections causing congenital malformation and infant mortality, especially in developing countries. Migrant women might be vulnerable to TORCH infections, but little is known about the association between migration-related characteristics and TORCH infection risk. This study aimed to investigate the impact of migrant status, migration distance, and the spouse’s migrant status on the TORCH epidemic among women of childbearing age. Methods Based on the National Free Preconception Health Examination Project, we analyzed a representative dataset of TORCH infections among women of childbearing age (15–49 years old) in Guangdong Province of China (2014–2019, n = 2,451,297). The past and/or recent infection status of TORCH infections (Toxoplasma gondii [TOX], Cytomegalovirus [CMV], and Rubella virus [RV]) were identified. Demographic and migration-related characteristics were collected. We thoroughly assessed the prevalence of TORCH infections in both migrant and native women and estimated adjusted odd ratios (aOR) for migration-related characteristics using multivariable logistic regression after adjusting the other sociodemographic factors. Results Among all 2,451,297 participants, 443,725 (18.1%) were migrant women. Migrant women presented a lower risk of past TOX infection (aOR: 0.89, 0.88–0.91) suggesting a healthy migrant effect (HME), but a higher risk of recent TOX infection (aOR: 1.88, 1.77–1.99), past CMV infection (aOR: 1.26, 1.25–1.28) and RV infection in natural ways (aOR: 1.05, 1.04–1.06). Compared with intra-provincial migrants, inter-provincial migrants had a lower past TOX infection (aOR: 0.88, 0.85–0.91), but a higher risk of recent TOX infection (aOR: 1.16, 1.05–1.27) and RV infection (aOR: 1.33, 1.31–1.36). In addition, having a migrant spouse was associated with a higher risk for all types of infection. Conclusions This study reported the association of migrant status and migration distance with TORCH infections, although the significance and directionality of these associations varied between pathogens. The spouse’s migrant status further amplified the infection risk for all types of pathogens. Our findings suggested interventions for preventing the spread of CMV and RV infection and new acquisition of TOX infection for migrants in southern China, to narrow the native-migrant health inequity and decrease the incidence of prenatal infections and related adverse outcomes.

Background TORCH (Toxoplasma gondii [TOX], Cytomegalovirus [CMV], Rubella virus [RV], and Herpes simplex virus [HSV]) represents pathogens known to traverse the maternal-fetal barrier and cause severe neonatal anomalies. We aimed to assess the prevalence of preconception TOX, CMV, and RV infections among women with fertility desire in southern China, and identify related risk factors. Methods Data were obtained from a population-based cross-sectional study conducted as part of the National Free Preconception Health Examination Project. Women planning to conceive within the next 6 months in Guangdong Province were enrolled between 2014 and 2019. Information on sociodemographic, gynecological, and obstetric characteristics was collected. Sera were analyzed for TOX IgG, CMV IgG, and RV IgG antibodies using an enzyme-linked immunosorbent assay. Descriptive, univariate, and multivariate logistic regression analyses were performed to assess the association between TORCH infections and related factors. Results Among 2,409,137 participants, the prevalence of IgG antibodies for TOX, CMV, and RV was 3.20% (95% CI: 3.18–3.22%), 77.67% (95% CI: 77.62–77.71%) and 76.03% (95% CI: 75.98–76.07%), respectively. Of all participants, 141,047 women (5.85%, 95% CI:5.83–5.88%) reported a history of immunization for RV. Women living in the Pearl River Delta, a more developed region, have significantly lower vaccination rates than those living in other regions. The seropositivity of TOX IgG was highest among women aged 35 years and above, with primary or lower education levels, and rural registration. Factors such as being older, having a higher educational level, and being of other ethnicities were associated with a higher prevalence of naturally acquired CMV and RV infections. Women living in the Pearl River Delta showed a higher risk of TOX, CMV, and RV infections, with aORs of 2.21, 4.45, and 1.76, respectively. A history of pregnancy, gynecological diseases, and sexually transmitted infections were potentially associated with TORCH infections, but this association varied across pathogens. Conclusion The findings of this study update the baseline of preconception TORCH infections among women with fertility desire in southern China, helping to estimate the risk of congenital infection and guide the development and implementation of effective prevention measures for preconception TORCH infections.