Inspection of Floating Offshore Wind Turbines Using Multi-Rotor Unmanned Aerial Vehicles: Literature Review and Trends.

Operations and maintenance (O&M) of floating offshore wind turbines (FOWTs) require regular inspection activities to predict, detect, and troubleshoot faults at high altitudes and in harsh environments such as strong winds, waves, and tides. Their costs typically account for more than 30% of the lifetime cost due to high labor costs and long downtime. Different inspection methods, including manual inspection, permanent sensors, climbing robots, remotely operated vehicles (ROVs), and unmanned aerial vehicles (UAVs), can be employed to fulfill O&M missions. The UAVs, as an enabling technology, can deal with time and space constraints easily and complete tasks in a cost-effective and efficient manner, which have been widely used in different industries in recent years. This study provides valuable insights into the existing applications of UAVs in FOWT inspection, highlighting their potential to reduce the inspection cost and thereby reduce the cost of energy production. The article introduces the rationale for applying UAVs to FOWT inspection and examines the current technical status, research gaps, and future directions in this field by conducting a comprehensive literature review over the past 10 years. This paper will also include a review of UAVs' applications in other infrastructure inspections, such as onshore wind turbines, bridges, power lines, solar power plants, and offshore oil and gas fields, since FOWTs are still in the early stages of development. Finally, the trends of UAV technology and its application in FOWTs inspection are discussed, leading to our future research direction.

Type IIA topoisomerase (TOP2A) triggers epithelial-mesenchymal transition and facilitates HCC progression by regulating Snail expression.

Type IIA topoisomerase (TOP2A) is upregulated in hepatocellular carcinoma (HCC) and its expression is positively correlated with poor prognosis. However, the underlying molecular mechanism of this connection are poorly understood. Hence, the present work aimed to examine the possible mechanisms which may be useful in identifying a potential therapeutic strategy. The differential expression of TOP2A mRNA in HCC as compared with adjacent normal tissue was analyzed using the Oncomine database. The expression levels of TOP2A in HCC specimens and cell lines were assessed by Western blot and RT-qPCR. Stable cell lines were generated to knockdown or overexpress TOP2A, and then cell growth, migration, and invasion were analyzed. Furthermore, this study examined epithelial-mesenchymal transition (EMT) as well as the activation of related pathways. Additionally, the correlation between TOP2A levels and E-cadherin/Snail expression was determined in 72 HCC specimens. Higher expression levels of TOP2A were observed in HCC in Oncomine datasets, and the results were verified using 40 pairs of HCC specimens and peritumoral tissues. TOP2A expression levels were remarkably elevated in cells with great metastatic capacity. In addition, HCC cell growth, migration, and invasion were suppressed after TOP2A knockdown in MHCC97H cells (MHCC97H-shRNA-TOP2A), while these capabilities were promoted in TOP2A-overexpressing Hep3B cells (Hep3B-TOP2A). Furthermore, EMT was inhibited in MHCC97H-shRNA-TOP2A cells, but induced in Hep3B-TOP2A cells. The induction of EMT by TOP2A was shown to be mediated by Snail, as TOP2A promoted Snail expression through the p-ERK1/2/p-SMAD2 signaling pathway. TOP2A level showed a negative correlation with E-cadherin, whereas a positive correlation with that of vimentin and Snail in human HCC specimens by immunohistochemistry analyses. Kaplan-Meier survival curves revealed that TOP2A upregulation showed a positive correlation with poor prognosis patients. Taken together, TOP2A possibly enhances the metastasis of HCC by promoting EMT through the mediation of the p-ERK1/2/p-SMAD2/Snail pathway. This indicates that TOP2A maybe a potential factor to predict the prognosis of HCC.

Construction of Cholesterol Oxime Ether Derivatives Containing Isoxazoline/Isoxazole Fragments and Their Agricultural Bioactive Properties/Control Efficiency.

To explore natural-product-based pesticidal candidates and high value-added application of cholesterol in agriculture, oximinoether derivatives of cholesterol-containing isoxazoline/isoxazole fragments (I-1∼I-16 and II-1∼II-18) were semiprepared by structural optimization of cholesterol. Their structures were characterized by optical rotation, high-resolution mass spectrometry (HRMS), IR, and 1H NMR spectroscopy. Particularly, the Z configurations of oxime fragments at the C-7 position of target compounds were undoubtedly determined by X-ray crystallography. Against Mythimna separata Walker, compounds 3e, I-8, I-14, and II-3 showed 2.4-2.7-fold growth inhibitory activity of the precursor cholesterol. Against Plutella xylostella Linnaeus, compounds I-6, I-7, and I-9 showed 2.4-2.7-fold oral toxicity of cholesterol. Against Aphis citricola Van der Goot, compounds 2e and II-15 exhibited 4.9 and 5.8-fold aphicidal activity of cholesterol, respectively. Notably, they showed good control effects (3.0-5.0-fold promising control efficiency of 1) against A. citricola in the greenhouse. Structure-activity relationships (SARs) suggested that the C-3 hydroxyl group and the C-7 position of cholesterol are two important modification sites. It will pave the way for future structural optimization and application of cholesterol derivatives as potential pesticidal agents in agriculture.

Cholesterol: Bioactivities, Structural Modification, Mechanisms of Action, and Structure-Activity Relationships.

Cholesterol, steroid alcohol, was discovered by M.E. Chevreul in 1815. Cholesterol and its derivatives showed a large variety of biological properties such as anticancer activity, anticardiac activity, anti-inflammatory activity, antimicrobial activity, anti-psychotic activity, antioxidant activity, drug-loaded activity, etc. In this mini-review, the advances of structural modification of cholesterol from 2014 to 2020 are summarized. In addition, the bioactivities, mechanisms of action and structureactivity relationships of cholesterol and its related derivatives are also discussed.

Two-way single-photon-level frequency conversion between 852†nm and 1560†nm for connecting cesium D2 line with the telecom C-band.

A compact setup for two-way single-photon-level frequency conversion between 852 nm and 1560 nm has been implemented with the same periodically-poled magnesium-oxide-doped lithium niobate (PPMgO:LN) bulk crystals for connecting cesium D2 line (852 nm) to telecom C-band. By single-pass mixing a strong continuous-wave pump laser at 1878 nm and the single-photon-level periodical signal pulses in a 50-mm-long PPMgO:LN bulk crystal, the conversion efficiency of ∼ 1.7% (∼ 1.9%) for 852-nm to 1560-nm down-conversion (1560-nm to 852-nm up-conversion) have been achieved. We analyzed noise photons induced by the strong pump laser beam, including the spontaneous Raman scattering (SRS) and the spontaneous parametric down-conversion (SPDC) photons, and the photons generated in the cascaded nonlinear processes. The signal-to-noise ratio (SNR) has been improved remarkably by using the narrow-band filters and changing polarization of the noise photons in the difference frequency generation (DFG) process. With further improvement of the conversion efficiency by employing PPMgO:LN waveguide, instead of bulk crystal, our study may provide the basics for cyclic photon conversion in quantum network.

Evaluation of andrographolide-based analogs derived from Andrographis paniculata against Mythimna separata Walker and Tetranychus cinnabarinus Boisduval.

To discover new natural-product-based pesticides, we structurally modified andrographolide, a labdane diterpenoid isolated from Andrographis paniculata, and stereoselectively prepared a series of 12α-(substituted)benzylamino-14-deoxyandrographolide derivatives (I-V). Three-dimensional structures of compounds 3c, 3d, IIIa and IIIb were further determined by single-crystal X-ray diffraction. Compounds IIa (R1 = n-C3H7, R2 = PhCH2) exhibited more promising insecticidal activity against Mythimna separata than toosendanin. Compounds 3a (R1 = H), Ib (R1 = H, R2 = 4-ClPhCH2), and IVa (R1 = 4-ClPh, R2 = PhCH2) showed potent acaricidal activity against Tetranychus cinnabarinus.

Efficacy and Safety of apatinib in patients with intermediate/advanced hepatocellular carcinoma: A prospective observation study.

This prospective study aimed to evaluate the efficacy and safety of apatinib in patients with intermediate/advanced hepatocellular carcinoma (HCC).The patients with intermediate/advanced HCC, who met predetermined inclusion and exclusion criteria, underwent oral treatment of apatinib 500 mg daily. The drug-related adverse effects were monitored by regular follow-up and workup including laboratory tests and imaging examinations. Tumor response was assessed by response evaluation criteria in solid tumor criteria. The time to tumor progression (TTP) and overall survival rate (OS) were calculated using the Kaplan-Meier method.A total of 31 patients were enrolled in the study from October 28, 2015 to December 28, 2016. The number of patients with intermediate and advanced HCC was 4 (12.90%) and 27 (87.10%), respectively. The mean tumor size was 9.47 ± 5.48 cm (range: 1.2-19 cm). Vascular invasion was seen in 14 patients (45.16%). A total of 21 (67.74%) patients exhibited extrahepatic metastases. On the basis of first follow-up computed tomography and magnetic resonance imaging at 6 weeks after treatment, 10 (32.26%), 15 (48.39%), and 6 (19.35%) of 31 patients achieved a partial response, stable disease, and progression of disease, respectively. Response rate and disease control rate were 32.26% and 80.65%, respectively. The median TTP was 4.8 months (95% confidence interval: 3.75-5.86 months). Furthermore, 6- and 12-month OS rates were 73.8% and 55.4%, respectively. Grade 3 thrombocytopenia (6.45%) and hypertension (48.39%) were the most common hematologic and nonhematologic toxicities. Grade 3 elevation of either serum total bilirubin or aminotransferase (6.45%) was observed as the top incidence among important indexes of liver function.Our preliminary findings suggest apatinib is a safe and effective therapy in intermediate/advanced HCC patients with high tumor response and survival rates.

High Wilms' tumor 1 mRNA expression correlates with basal-like and ERBB2 molecular subtypes and poor prognosis of breast cancer.

The role of Wilms' tumor 1 (WT1) in breast cancer and the relationship between WT1 expression and clinicopathological factors, molecular subtypes and prognosis of breast cancer patients have not been clarified to date. We used publicly available microarray datasets of 266 early breast cancer patients to perform bioinformatics analysis on the relationship between WT1 mRNA expression and breast cancer. Results showed that WT1 mRNA expression was correlated with higher histological grades, ER-negative and basal-like and ERBB2 molecular subtypes in breast cancer. With regard to disease-free survival analysis, the WT1 high expression group showed worse prognosis than the low expression group in univariate analysis, and WT1 was demonstrated to be an independent prognostic indicator in multivariate analysis. This study confirms an oncogenic role of WT1 and demonstrates a possible relation between WT1 and progression of breast cancer.

A qualitative exploration of the role of antiretroviral therapy on Chinese rural life.

OBJECTIVE: To explore factors influencing the quality of life of people living with HIV/AIDS (PLHA) and receiving antiretroviral therapy (ART) in rural China. METHODS: In-depth interviews with 20 PLHA were conducted in March 1999. Participants were recruited from the USAID-funded Longitudinal Enhanced Evaluation of ART Project, which tracks a cohort of eligible PLHA receiving treatment at five collaborating treatment centers in Guangxi Autonomous Region, China. An interview guide (semi-structured with open-ended questions) was developed to provide a qualitative examination of the quality of life of PLHA. RESULTS: Participants identified that ART affects physical health, including the experience of pain, side effects, and opportunistic infections. ART imposes lifestyle constraints such as reduced mobility due to drug procurement, and social restrictions due to the daily drug regimen. Participants discussed the psychological burden of taking drugs, and the fear of accidental transmission to others, or having their disease status known by others, as well as optimistic feelings about their future due to ART. ART poses a significant drain on individual's economic resources due to related medical costs, and inability to seek seasonal migrant labor due to reduced mobility. CONCLUSION: While China's national free ART program improved the physical health of those surveyed, their social and economic needs were left unaddressed. To improve life outcomes for PLHA, and by extension, the wider Chinese population, quality of life measures should be included when evaluating the success of the ART program.

Combinatorial Optimization of (Lu1₋(x)Gd(x))3Al5O12:Ce3(y) yellow phosphors as precursors for ceramic scintillators.

A combinatorial chemistry method was employed to screen the yellow phosphors of (Lu1₋(x)Gd(x))3Al5O12:Ce3(y) as luminescent materials. An array of 81 compositions was synthesized by inkjetting nitrate solutions into microreactor wells and sintering at high temperature. The candidate formulations were evaluated by luminescence pictures, and the optimal composition was determined to be Lu(2.7)Gd(0.3)Al(5)O(12):Ce(0.045) after scale-up and detailed characterization. Lu2.7Gd0.3Al5O12:Ce0.045 was also found to have a short decay time (≤53.97 ns). These results demonstrate the great potential of the Lu2.7Gd0.3Al5O12:Ce0.045 as a component of ceramic scintillators.

Association of TNF-alpha-238G/A and 308 G/A gene polymorphisms with pulmonary tuberculosis among patients with coal worker's pneumoconiosis.

OBJECTIVES: Tumor necrosis factor-alpha (TNF-alpha) may play an important role in host's immune response to mycobacterium tuberculosis (M. tuberculosis) infection. This study was to investigate the association of TNF-alpha gene polymorphism with pulmonary tuberculosis (TB) among patients with coal worker's pneumoconiosis (CWP). METHODS: A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-alpha gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism (PCR-RFLP). Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher's exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplicative model with combined OR. All data were analyzed using SAS version 8.2 software. RESULTS: No significant difference in frequency of the TNF-alpha-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls (chi2 = 5.44, P = 0.07). But difference in frequency of the TNF-alpha-308 A allele was identified between them (chi2 = 5.14, P = 0.02). No significant difference in frequencies of the TNF-alpha-238 genotype and allele (P = 0.23 and P = 0.09, respectively) was found between cases and controls either, with combined (GG and AA) OR of 3.96 (95% confidence interval of 1.30-12.09) at the -308 locus of the TNF-alpha gene, as compared to combination of the TNF-alpha-238 GG and TNF-alpha-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-alpha-238 GG and TNF-alpha-308 GA genotypes was 1.98 (95% CI of 1.06-3.71) for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-alpha-308 GG genotype and body mass index (OR = 4.92), as well as an interaction between the TNF-alpha-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-alpha-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated. CONCLUSIONS: TNF-alpha-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-alpha-238 A allele was otherwise.

Combinatorial optimization of (Y(x)Lu(1-x-y))(3)Al(5)O(12):Ce(3y) green-yellow phosphors.

A combinatorial chemistry method was used to synthesize and screen (Y(x)Lu(1-x-y))(3)Al(5)O(12):Ce(3y) green-yellow phosphors. The material libraries were obtained using an inkjet delivery system and screened for their fluorescence under an ultraviolet light of 365 nm. The optimized composition was identified to be (Y(0.2)Lu(0.788))(3)Al(5)O(12):Ce(3+)(0.036). Scale-up experiments confirmed that the optimized composition of the phosphor showed the highest luminescence intensity and an excellent scintillation performance with a short decay time (<60 ns). The results indicated that the (Y(x)Lu(1-x-y))(3)Al(5)O(12):Ce(3y) could be potentially useful as green-yellow phosphors for ceramic scintillators.

An HIV/AIDS intervention programme with Buddhist aid in Yunnan Province.

BACKGROUND: The prevalence of HIV/AIDS in Chinese ethnic minorities is an important component of China's AIDS issues. In this study, we launched an intervention programme in Yunnan Province of China, where the Dai people live, to carry out the community-based HIV/AIDS health education and behavioral interventions on ordinary Dai farmers. The Dai people believe in Theravada Buddhism. METHODS: Four rural communities were randomly divided into two groups. In one group (Buddhist group), HIV/AIDS health education and behavioral intervention were carried out by monks. The other group (women group) was instructed by women volunteers. The intervention continued for one year and the data were collected before and after the intervention project. RESULTS: In the Buddhist group, the villagers' AIDS related knowledge score was boosted from 3.11 to 3.65 (P < 0.001), and some indices of the villagers' behavior using condoms improved after the intervention. But this improvement was poorer than that in the women group. In the Buddhist group, the villager's attitude score towards the people living with HIV and AIDS (PLWHA) also increased significantly from 1.51 to 2.16 (P < 0.001). CONCLUSION: The results suggested that the Buddhist organization has limited success in promoting the use of condoms, but plays an important role in eliminating HIV/AIDS related discrimination.

HIV/AIDS related discrimination in health care service: a cross-sectional study in Gejiu City, Yunnan Province.

OBJECTIVES: To investigate discrimination against people living with HIV (PLWH) and its impacts. METHODS: Forty people who were either HIV positive (7/40) or had high risk behavior (33/40) were interviewed. Focus group discussion was held in the interview with people who were suspected to be infected with HIV, and in-depth interview was conducted in the survey of HIV positive persons whose privacy was strictly protected to ensure the confidentiality of the collected information. RESULTS: It was identified that six forms of discrimination against people living with HIV occurred in health care service in Gejiu, including speaking to patients in an insulting manner, refusing to provide health care service, delaying treatment, treating differently, uncovering patients' privacy, and over-protecting themselves against patients. Discrimination against people living with HIV greatly affected their health conditions. CONCLUSIONS: Discrimination against people living with HIV in health service has negative impact on their physical and mental health.

Disentangling the stigma of HIV/AIDS from the stigmas of drugs use, commercial sex and commercial blood donation - a factorial survey of medical students in China.

BACKGROUND: HIV/AIDS related stigma interferes with the provision of appropriate care and support for people living with HIV/AIDS. Currently, programs to address the stigma approach it as if it occurs in isolation, separate from the co-stigmas related to the various modes of disease transmission including injection drug use (IDU) and commercial sex (CS). In order to develop better programs to address HIV/AIDS related stigma, the inter-relationship (or 'layering') between HIV/AIDS stigma and the co-stigmas needs to be better understood. This paper describes an experimental study for disentangling the layering of HIV/AIDS related stigmas. METHODS: The study used a factorial survey design. 352 medical students from Guangzhou were presented with four random vignettes each describing a hypothetical male. The vignettes were identical except for the presence of a disease diagnosis (AIDS, leukaemia, or no disease) and a co-characteristic (IDU, CS, commercial blood donation (CBD), blood transfusion or no co-characteristic). After reading each vignette, participants completed a measure of social distance that assessed the level of stigmatising attitudes. RESULTS: Bivariate and multivariable analyses revealed statistically significant levels of stigma associated with AIDS, IDU, CS and CBD. The layering of stigma was explored using a recently developed technique. Strong interactions between the stigmas of AIDS and the co-characteristics were also found. AIDS was significantly less stigmatising than IDU or CS. Critically, the stigma of AIDS in combination with either the stigmas of IDU or CS was significantly less than the stigma of IDU alone or CS alone. CONCLUSION: The findings pose several surprising challenges to conventional beliefs about HIV/AIDS related stigma and stigma interventions that have focused exclusively on the disease stigma. Contrary to the belief that having a co-stigma would add to the intensity of stigma attached to people with HIV/AIDS, the findings indicate the presence of an illness might have a moderating effect on the stigma of certain co-characteristics like IDU. The strong interdependence between the stigmas of HIV/AIDS and the co-stigmas of IDU and CS suggest that reducing the co-stigmas should be an integral part of HIV/AIDS stigma intervention within this context.

[Clinical features and diagnosis of pulmonary lymphangitic carcinomatosis].

BACKGROUND & OBJECTIVE: Pulmonary lymphangitic carcinomatosis (PLC) is a special type of pulmonary metastasis of carcinoma. It is easy to be misdiagnosed as other pulmonary interstitial diseases. This study was to discuss the clinical features of PLC, and provide experience information for diagnosis, differentiated diagnosis, and evaluation of prognosis of PLC. METHODS: A retrospective comparison analysis was performed on 43 PLC patients with pathologic diagnosis and 46 patients with other pulmonary interstitial diseases with clear etiology in the first affiliated hospital of Sun Yat-sen University within the past decade. RESULTS: In PLC group, 20 patients were found with primary lung cancer; 23 patients were found with primary non-pulmonary carcinoma: 9 cases of breast cancer, 8 cases of large intestinal carcinoma, and 6 cases of gastric carcinoma. The changes of imaging included linear and radiating appearances from the hilum to the outer part even extending to the pleura with nodules, ground-glass opacity of the lung. Enlargement of lymph nodes in mediastinum was present in 51.2% (22/43) and that in pleural effusion was present in 53.5% (23/43) of patients. Extrapulmonary manifestations (metastasis) included 19 cases (44.2%) of lymph nodes to the supraclavicular region, axillary fossa, and post-peritoneal region, 15 cases (34.9%) to the pleura, 9 cases (20.9%) to the bones, 6 cases (14.0%) to the liver, 3 cases (7.0%) to the pericardium, and 3 cases (7.0%) to the brain. The elevated serum level of CEA was commonly observed (23/43, 53.5%). Respiratory manifestations of PLC, such as coughing, panting, dyspnea, and so on, could not be cured by anti-spasm treatment. The development of PLC was so progressive that 31 patients (72.1%) were followed for only 2-7 months before death. The changes of imaging in other pulmonary interstitial disease group included irregular linear or reticular appearances, enlargement of lymph nodes in the mediastinum and hilum, and extrapulmonary manifestations like pleural effusion were not observed. Respiratory manifestations, such as coughing, panting, dyspnea, and so on, could be cured by anti-spasm treatment. Moreover, the development of PLC was relatively slow. CONCLUSIONS: PLC often occurs in patients with primary carcinoma in lung, breast, large intestine, stomach, and so on. More attention should be paid to the diagnosis of PLC in patients who have pulmonary interstitial lesions as described above, and whose respiratory symptoms could not be relieved by anti-spasm treatment and developed progressively. The prognosis of PLC is poor.

[Relationship between smoking and risk of esophageal cancer in 103 areas in China: a large-scale case-control study incorporated into a nationwide survey of mortality].

OBJECTIVE: To examine the relationship between smoking and risk of esophageal cancer (EC), and present a theoretical framework of control selection in population-based case-control study which was incorporated into a nationwide retrospective survey of mortality in China. METHODS: A large-scale population-based case-control study was incorporated into the nationwide retrospective survey of mortality conducted 1989 - 1991 in 24 urban cities selected by non-random sampling and 79 rural counties selected from 3000 counties included in the 1973 - 1975 cancer distribution survey by random sampling during. A questionnaire survey was conducted by home visit to investigate the death causes and smoking history of 19 734 deceased male adults who died of esophageal cancer during 1986 - 1988 at the age >or= 35. Two control groups were set up to undergo questionnaire survey by home visit to investigate the smoking history of the deceased persons and the informants. Control group I included the surviving spouses or other informants of 31 989 male adults who died of non-malignant digestive diseases during 1986 - 1988 at the age >or= 35, and control group II included 104 846 male spouses of the deceased female adults who died of different causes during 1986 - 1989 at the age >or= 35. The relative risks and population smoking attributable risks for EC were calculated using non-conditional logistic model, and the results were compared for consistency between the analyses using two different control groups. RESULTS: The EC absolute death rates were higher in the smokers than in the non-smokers in all urban and rural area groups. The total EC absolute death rate per 1000 among the non-smokers vs. smokers was 0.37:0.65 in the urban areas, 0.99:1.29 in the inland rural areas, and 1.09:1.62 in the coastal rural areas in the control group I, and there was a similar trend in the control group II. There was a significant dose-response relation between the period of smoking and the death risk of EC and between the daily cigarette consumption and the death risk of EC. The risk ratios, for example, for cigarette per day < 10, 10-, and 20- in the urban men were 1.42, 1.82, 2.22 in the control group I (trend test P < 0.01), and 1.57, 1.95, and 3.18 in the control group II (trend test P < 0.01). CONCLUSION: Smoking is an important risk factor for mortality from EC in China. Investigating the surviving spouses of the deceased patients is a creative, effective, and feasible trial, with the prerequisite of whole population-based survey, in study of the main types of death and the relevant risk factors.

Smoking and mortality from esophageal cancer in China: a large case-control study of 19,734 male esophageal cancer deaths and 104,846 living spouse controls.

An innovative population-based case-control study was conducted in a national mortality survey to assess the hazards of tobacco use on esophageal cancer among Chinese men. Cases were 19,734 males aged 35 years or older, who died of esophageal cancer during 1986-1988. Controls were 104,846 male living spouses of the same age when their wife died (of any cause) during the same period in the same county or city. The absolute esophageal cancer death rates were higher in smokers than those in nonsmokers in all geographical groups. The relative risks for esophageal cancer were 1.88 (95% CI: 1.73-2.05) and 1.39 (95% CI: 1.28-1.50) in urban and rural men, respectively, after adjustment for other relevant covariates including age group (5 years) and locality. When the calculation was restricted to men aged 35-69, the risk ratios for current cigarette smokers increased significantly with increasing number of cigarettes smoked daily and duration of smoking. Tobacco use, in any form, is an important risk factor for esophageal cancer in Chinese men. Selecting living spouses as controls is a unique and useful approach in the design of case-control studies of cigarette smoking.