ObjectiveColorectal cancer (CRC) screening has been widely implemented in many countries. However, evidence on participation and diagnostic yield of population-based CRC screening in China is sparse.DesignThe analyses were conducted in the context of the Cancer Screening Program in Urban China, which recruited 1 381 561 eligible participants aged 40–69 years from 16 provinces in China from 2012 to 2015. 182 927 participants were evaluated to be high risk for CRC by an established risk score system and were subsequently recommended for colonoscopy. Participation rates and detection of colorectal neoplasms in this programme were reported and their associated factors were explored.Results25 593 participants undertook colonoscopy as recommended, with participation rate of 14.0%. High level of education, history of faecal occult blood test, family history of CRC and history of colonic polyp were found to be associated with the participation in colonoscopy screening. Overall, 65 CRC (0.25%), 785 advanced adenomas (3.07%), 2091 non-advanced adenomas (8.17%) and 1107 hyperplastic polyps (4.33%) were detected. Detection rates of colorectal neoplasms increased with age and were higher for men. More advanced neoplasms were diagnosed in the distal colon/rectum (65.2%). Several factors including age, sex, family history of CRC, dietary intake of processed meat and smoking were identified to be associated with the presence of colorectal neoplasms.ConclusionThe diagnostic yield was not optimal using colonoscopy screening in high-risk populations given the relatively low participation rate. Our findings will provide important references for designing effective population-based CRC screening strategies in the future.

BackgroundThe effect of sleep duration on cancer risk remains controversial. We aimed to quantify the available evidence on this relationship using categorical and dose–response meta-analyses.MethodsPopulation-based cohort studies and case-control studies with at least three categories of sleep duration were identified by searching PubMed, EMBASE, and the Cochrane Library database up to July 2017.ResultsSixty-five studies from 25 articles were included, involving 1,550,524 participants and 86,201 cancer cases. The categorical meta-analysis revealed that neither short nor long sleep duration was associated with increased cancer risk (short: odds ratio [OR] = 1.01, 95% confidence intervals [CI] = 0.97–1.05; long: OR = 1.02, 95% CI = 0.97–1.07). Subgroup analysis revealed that short sleep duration was associated with cancer risk among Asians (OR = 1.36; 95% CI: 1.02–1.80) and long sleep duration significantly increased the risk of colorectal cancer (OR = 1.21; 95% CI: 1.08–1.34). The dose–response meta-analysis showed no significant relationship between sleep duration and cancer risk. When treated as two linear piecewise functions with a cut point of 7 h, similar nonsignificant associations were found (per 1-h reduction: OR = 1.02, 95% CI = 0.98–1.07; per 1-h increment: OR = 1.003, 95% CI = 0.97–1.03).ConclusionCategorical meta-analysis indicated that short sleep duration increased cancer risk in Asians and long sleep duration increased the risk of colorectal cancer, but these findings were not consistent in the dose–response meta-analysis. Long-term randomized controlled trials and well-designed prospective studies are needed to establish causality and to elucidate the mechanism underlying the association between sleep duration and cancer risk.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-5025-y) contains supplementary material, which is available to authorized users.

BackgroundHuman papillomavirus (HPV) is one of the most prevalent sexually transmitted viruses. Despite the increasing evidence of HPV prevalence in semen, the worldwide distribution of HPV types in semen and risk for male infertility remain inconclusive.MethodsFour electronic databases were searched for English language studies conducted between January 1990 and December 2016 that reported HPV DNA prevalence in semen. Based on the PRISMA guidelines, HPV prevalence was estimated among general population and fertility clinic attendees, respectively, and heterogeneity testing was performed using Cochran’s Q and I 2 statistics. The association between HPV positivity and male infertility was evaluated by a meta-analysis of case-control studies.ResultsA total of 31 eligible studies comprising 5194 males were included. The overall prevalence of HPV DNA in semen was 11.4% (95% CI = 7.8-15.0%) in general population (n = 2122) and 20.4% (95% CI = 16.2-24.6%) in fertility clinic attendees (n = 3072). High-risk type prevalence was 10.0% (95% CI = 5.9-14.0%) and 15.5% (95% CI = 11.4-19.7%), respectively. HPV16 was the most common type, with a prevalence of 4.8% (95% CI = 1.7-7.8%) in general population and 6.0% (95% CI = 3.8-8.2%) in fertility clinic attendees. A significantly increased risk of infertility was found for males with HPV positivity in semen (OR = 2.93, 95% CI = 2.03-4.24).ConclusionsSeminal HPV infection is common worldwide, which may contribute to the risk of male infertility.Electronic supplementary materialThe online version of this article (10.1186/s12879-017-2812-z) contains supplementary material, which is available to authorized users.

Elevated mammographic density (MD) is an established breast cancer risk factor. Studies examining relationships between MD and breast cancer risk factors are limited in China, where established breast cancer risk factors are less prevalent but dense breasts are more prevalent than Western countries. This study included 11,478 women (45-69 years; 36% premenopausal) participating in an ongoing national cancer screening program in 11 urban provinces in China and predicted as having high-risk for breast cancer. Polytomous logistic regression was performed to assess associations between MD and risk factors by comparing each higher Breast Imaging Reporting and Data System (BI-RADS) category (2, 3, or 4) to the lowest category (BI-RADS, 1). We found associations of increasing age, body mass index, weight, postmenopausal status, and parity with lower MD. Higher levels of education, increasing height, and later first birth were associated with higher MD. These associations did not vary by menopausal status. Additionally, the association between longer period of breastfeeding and lower MD was seen among postmenopausal women only (Pinteraction = 0.003). Having first-degree relatives with breast cancer diagnosed before 50 years was associated with lower MD only among premenopausal women (Pinteraction = 0.061). We found effects of established breast cancer risk factors on MD showed similar directions in Chinese and Western women, supporting the hypothesis that MD represents cumulative exposure to breast cancer risk factors over the life course. Our findings help to understand the biological basis of the association of MD with breast cancer risk and have implications for breast cancer prevention research in China.

To investigate the independent and joint associations of blood lipids and lipoproteins with lung cancer risk in Chinese males, a prospective cohort study was conducted. A total of 109,798 males with baseline information on total cholesterol (TC), triglycerides (TG), low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C) and non‐HDL were prospectively observed from 2006 to 2015 for cancer incidence. Cox proportional hazards models and restricted cubic spline (RCS) analysis were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During a 9‐year follow‐up, a total of 986 lung cancer cases were identified. Multivariable analyses showed that both males with low TC (HRQ1vs.Q2 = 1.27, 95%CI: 1.02–1.60) and males with high TC (HRQ5vs.Q2 = 1.30, 95%CI: 1.04–1.63) had an increased lung cancer risk, and the U‐shaped association was also revealed in the RCS analysis (poverall = 0.013, pnonlinear = 0.006). Furthermore, both low TG (HRQ1vs.Q2 = 1.24, 95%CI: 0.99–1.54) and high TG (HRQ5vs.Q2 = 1.27, 95%CI: 1.01–1.59) were associated with increased lung cancer risk, while low LDL‐C (HRQ1vs.Q2 = 1.38, 95%CI: 1.11–1.72) was associated with increased lung cancer risk. When TC, TG and LDL‐C were considered jointly, the number of abnormal indicators was linearly associated with an increased risk of lung cancer (ptrend < 0.001), as subjects with three abnormal indicators had a twofold higher risk of developing lung cancer (HR = 2.02, 95%CI: 1.62–2.54). Notably, these associations were statistically significant among never smokers, never drinkers and overweight/obese males. These findings suggest that dyslipidemia may potentially be a modifiable risk factor that has key scientific and clinical significance for lung cancer prevention.