Data on the association between air pollution and risk of ischemic stroke in China are still limited. This study aimed to investigate the association between short-term exposure to ambient air pollution and risk of ischemic strokes in Guangzhou, the most densely-populated city in south China, using a large-scale multicenter database of stroke hospital admissions. Daily counts of ischemic stroke admissions over the study years 2013–2015 were obtained from the Guangzhou Cardiovascular and Cerebrovascular Disease Event Surveillance System. Daily particulate matter <2.5 μm in diameter (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and meteorological data were collected. The associations between air pollutants and hospital admissions for stroke were examined using relative risks (RRs) and their corresponding 95% confidence intervals (CIs) based on time-series Poisson regression models, adjusting for temperature, public holiday, day of week, and temporal trends in stroke. Ischemic stroke admissions increased from 27,532 to 35,279 through 2013 to 2015, increasing by 28.14%. Parameter estimates for NO₂ exposure were robust regardless of the model used. The association between same-day NO₂ (RR = 1.0509, 95% CI: 1.0353–1.0668) exposure and stroke risk was significant when accounting for other air pollutants, day of the week, public holidays, temperature, and temporal trends in stroke events. Overall, we observed a borderline significant association between NO₂ exposure modeled as an averaged lag effect and ischemic stroke risk. This study provides data on air pollution exposures and stroke risk, and contributes to better planning of clinical services and emergency contingency response for stroke.

Colorectal cancer (CRC) is the second most commonly diagnosed cancer worldwide in females. Sex hormones may play a protective effect in CRC pathogenesis. Ovarian sex steroid levels are reduced in premenopausal women after hysterectomy. Prospective studies have revealed an 80% decrease in serum oestradiol levels after bilateral oophorectomy in premenopausal women. We aimed to elucidate the relationship between hysterectomy or oophorectomy and risk of CRC. We estimated relative risk (RR) and 95% confidence intervals (95% CIs) with the meta-analysis. Cochran's Q test and Higgins I2 statistic were used to check for heterogeneity. Subgroup and sensitivity analyses were performed as were Egger's and Begg's tests and the "trim-and-fill" method for publication bias analysis. Risk of CRC was increased 30% for women undergoing oophorectomy relative to the general population and 24% with hysterectomy relative to no surgery. The risk was increased 22% with hysterectomy with bilateral salpingoo-ophorectomy as compared with simple hysterectomy. On subgroup analysis, risk of rectal cancer was increased 28% and colon cancer 19% with hysterectomy. Europeans seem to be sensitive to the risk of CRC, with 27% increased risk after hysterectomy. The risk of CRC after oophorectomy gradually increased with age at oophorectomy. The risk was greater with bilateral oophorectomy, with 36% increased risk, than unilateral oophorectomy, with 20% increased risk. Risk was increased 66% with time since oophorectomy 1-4 years as compared with 5-9 and ≥ 10 years. Risk of CRC was increased for women undergoing hysterectomy or oophorectomy. Women with susceptibility genes for ovarian cancer or metrocarcinoma should choose oophorectomy or hysterectomy. For women not at high risk for these cancers, oophorectomy or hysterectomy should not be recommended for increasing the subsequent risk of CRC.

The role of neoadjuvant therapy combined with surgery for treating esophageal squamous cell carcinoma (ESCC) remains controversial. We performed a network meta-analysis to synthesize direct and indirect evidence to identify the optimal therapeutic method for ESCC. We identified 15 randomized controlled trials that compared any of the following 4 therapeutic measures: surgery alone (S), preoperative chemotherapy followed by surgery (CTS), preoperative radiotherapy followed by surgery (RTS), and preoperative chemoradiotherapy followed by surgery (CRTS). The main outcomes were 5-year survival, rate of radical resection, operative mortality and postoperative complications. Network meta-analysis showed that CRTS was associated with improved survival as compared with S (OR = 1.50 [95% CI 1.21 to 1.97]) and decreased occurrence of complications as compared with RTS (OR = 0.50 [95% CI 0.22 to 0.99]). Direct evidence revealed CRTS associated with improved survival (OR = 1.61 [95% CI 1.01 to 2.57]) and radical resection (OR = 4.01 [95% CI 1.66 to 9.69]) as compared with S. In terms of radical resection, CTS was more effective than S (OR = 1.73 [95% CI 1.09 to 2.76]). Findings for CTS and RTS did not differ for 5-year survival, operative mortality and postoperative complications. Overall, CRTS might be the best choice for resectable ESCC because it could increase the radical resection rate and lower the occurrence of complications, thereby prolonging survival time.