ABO and Rh blood groups play a vital role in blood transfusion safety and clinical practice and are thought to be linked with disease susceptibility. The results from previous studies that focused on the association between blood groups and HBV infection remain controversial. China has the world's largest burden of HBV infection. We assessed the distribution of ABO/Rh blood groups in Chinese adults and examined the association between these groups and HBV infection. We did a nationwide cross-sectional study using data from a physical check-up programme from 31 provinces examined between 2010 and 2012. ELISA was used to test for HBsAg in serologic samples. Multivariable logistic regression was used to estimate aOR of the association between ABO and Rh blood groups and HBV infection. Among 3 827 125 participants, the proportion of participants with blood group A was highest (30.54%), followed by O (30.37%), B (29.42%) and AB (9.66%). A total of 38 907 (1.02%) were Rh-D negative. The prevalence of HBsAg in blood groups O, A, B and AB were 6.34%, 5.55%, 5.18% and 5.06%, respectively. HBsAg prevalence was 5.65% in Rh-D-positive and 3.96% in Rh-D-negative participants. After controlling for other potential risk factors, multivariate models showed that participants with blood group O (adjusted OR = 1.22, 95% CI: 1.20-1.25) were at higher risk of HBV infection compared with group AB. Rh-D-positive participants (adjusted OR = 1.44, 95% CI: 1.37-1.52) were at higher risk of HBV infection than Rh-D-negative participants. The associations between ABO/Rh blood groups and HBV infection were similar in subgroup analysis. The proportions of O, A, B and AB blood groups were approximately 3:3:3:1, and nearly 1 in 100 people was Rh-D negative among Chinese adults. Blood group O and Rh-D positivity were both associated with increased HBV infection. The risk of HBV infection and blood safety should be taken into consideration in clinical practice, especially when transfusing those with blood group O. Awareness and prevention of HBV infection is of particular importance for individuals with blood group O.

There are few extant studies on the prevalence of HBV infection in couples preparing for pregnancy. We assessed the prevalence of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in couples preparing for pregnancy in rural China, and the association between HBV prevalence and the statuses of HBsAg/HBeAg and ALT in the spouses. We performed a nationwide cross-sectional study, using data from a health check-up program for 1 936 801 rural couples from 31 provinces preparing for pregnancy between 2010 and 2012. ELISA was used to test serologic samples, and we defined couples who were either discordant or both positive for HBsAg as "POSITIVE COUPLES" (PC). Amongst the 1 936 801 couples, 202 816 (10.47%; 95% CI, 10.43%-10.51%) were PC. HBeAg (high infectiousness) was detected in 56 474 (27.84%; 95% CI, 27.65%-28.04%) of 202 816 HBsAg-positive couples. Multivariate models showed that the prevalence of HBV infection in wives increased along with the positive statuses for HBsAg/HBeAg and alanine aminotransferase (ALT) of their husbands (adjusted odds ratio increased from 2.31 to 4.98), after adjustment for potential confounders. Similarly, the prevalence of HBV infection in husbands was associated with the positive statuses of HBsAg/HBeAg and ALT of their wives (adjusted odds ratio increased from 2.04 to 4.93). The prevalence of POSITIVE COUPLES in couples preparing for pregnancy in rural China was high, and the prevalence of HBV infection was independently associated with the positive statuses of HBsAg/HBeAg and ALT of the spouses. Instead of solely focussing on mothers prior to becoming pregnant, POSITIVE COUPLES should be taken as an important unit of care.

Varicocoele is a common cause of male infertility. We undertook a population-based cross-sectional study to evaluate the prevalence of varicocoele among rural men in eastern China and its association with body mass index. A total of 39,559 rural men in six counties in Beijing, Guangdong and Shandong provinces were recruited from 2011 to 2012. The presence and severity of varicocoele were measured by physical examinations. Univariate and multivariate logistic regression models were constructed to assess the association between varicocoele and body mass index after adjusting for possible confounders. Varicocoele was diagnosed in 1911 of 39,559 participants with an overall prevalence of 4.83%. The prevalence of varicocoele was highest in underweight (6.29%) and lowest in obese patients (3.71%, p < 0.05). The prevalence also decreased as body mass index increased in all three varicocoele grades. In multivariate logistic regression analysis after adjusting for region, age, height, occupation, cigarette smoking and alcohol consumption, body mass index was still inversely and independently associated with varicocoele (p < 0.001). Compared with normal weight men, underweight men (OR = 1.34; 95% CI, 1.10-1.63) were more likely to have varicocoele, whereas overweight men (OR = 0.88; 95% CI, 0.79-0.99) and obese men (OR = 0.75; 95% CI, 0.58-0.97) were less likely to have varicocoele. This study revealed that the prevalence of varicocoele was 4.83% among rural men in eastern China; body mass index was inversely and independently associated with the presence of varicocoele. Future efforts should be made to validate the risk factors for varicocoele and strengthen the prevention and treatment of varicocoele, especially in underweight men.

No abstract