Population versus hospital controls for case-control studies on cancers in Chinese hospitals

Cardiovascular risk factors among patients with acute unilateral inner ear hypofunction: A case-control study

Objectives

To assess the prevalence of cardiovascular risk factors (CVRFs) and their impact on acute unilateral inner ear hypofunction (AUIEH), including acute unilateral peripheral vestibulopathy (AUPVP), sudden sensorineural hearing loss (SSNHL) and acute unilateral audiovestibular hypofunction (AUAVH).

Methods

One hundred and twenty-five patients consecutively diagnosed with AUPVP, SSNHL or AUAVH and 250 sex- and age-matched controls were included. Cases presented a mean age of 58.6 ± 14.7 years and included 59 women and 66 men. The correlation between CVRFs (high blood pressure [HBP], diabetes mellitus [DM], dyslipidemia [DLP], cardiocerebrovascular disease [CCVD]) and AUIEH was assessed by multivariate conditional logistic regression analysis.

Results

A higher prevalence of CVRFs was identified in patients than in controls (30 individuals with DM, 53 with HBP, 45 with DLP and 14 with a previous history of CCVD, p < .05). A significantly elevated risk of AUIEH was found in patients with two or more CVRFs (adjusted odds ratio [OR] 5.11; 95% CI 2.23-11.70). Previous CCVD individually predicted AUIEH (OR 8.41; 95% CI 2.36-29.88). Subgroup analysis showed the same tendency for AUPVP and SSNHL.

Conclusion

Acute unilateral inner ear hypofunction patients presented significantly more CVRFs than controls, and the presence of two or more CVRFs was associated with AUIEH. Future studies evaluating vascular risk in AUIEH may include AUPVP and SSNHL patients from the same source population to better characterize risk profiles that can indicate a vascular origin.

Level of Evidence

3b.

Dietary inflammatory index and breast cancer risk: an updated meta-analysis of observational studies

This updated meta-analysis sought to determine whether the pro-inflammatory potential of diet is a risk factor for breast cancer (BrCa) development, for the first time focusing on the effects of design heterogeneity. The search was performed using Scopus, PubMed, and Embase databases. Data were extracted from twenty-one eligible studies, including eleven cohorts (336,085 participants/20,033 incidence cases), and ten case-control studies (9,833 cases/12,752controls). The random-effect was used to calculate the relative risk (RR) using STATA 16 software. The highest dietary inflammatory index (DII) vs. the lowest category showed 16% increased risk of BrCa (95% CI: 1.06-1.26; I² = 62.8%, P (I²) < 0.001). This was notable in post-menopausal status (RR = 1.13, 95% CI: 1.04-1.22), women with body mass index (BMI) ≥ 30 kg/m² (RR = 1.35, 95% CI: 1.07-1.63), and study populations from developing countries (RR = 1.79, 95% CI: 1.12-2.47). Methodological covariates were subject to subgroup meta-analyses and showed stronger results among case-control studies (RR = 1.50, 95% CI: 1.20-1.80), studies considered age-matched controls (RR = 1.56, 95% CI: 1.19-1.93) and hospital-based controls (RR = 2.11, 95% CI: 1.58-2.64), and cohort studies identified by prolong follow-up durations (RR = 1.13, 95% CI: 1.03-1.22). This updated meta-analysis highlighted the pro-inflammatory diet as a risk factor for BrCa, especially among women in post-menopausal status, obese groups, and developing countries. Meta-analysis in methodological subgroups could improve results, less affected by heterogeneity, and suggested subclassification with important implications for future epidemiological designs and even clinical management.

Associations between Preserved foods and Breast Cancer Risk in Hong Kong Chinese Women

Preserved food such as cured foods may contain nitrate and nitrite that may contribute to the breast cancer development. Evidence on the associations between these preserved food intakes and risk of breast cancer is sparse. This study aimed to examine the associations between preserved foods (i.e. cured meat, pickled vegetables, canned meat, canned fruit/vegetables) and breast cancer risk in Hong Kong Chinese women. A total of 1307 breast cancer cases and 1050 age-matched controls were recruited from three hospitals during 11/2011-01/2018. We used a standardized questionnaire to collect information on dietary factors including preserved foods. Unconditional multiple logistic regression was performed to calculate the adjusted odds ratio(AOR) of breast cancer in relation to preserved food with adjustment of potential confounders. We further performed stratified analysis according to the breast cancer biology subtypes. We found that cured meat consumption was significantly associated with the risk of breast cancer [AOR=1.32, 95% confidence interval 95%CI)=1.06-1.64]. Compared to no cured meat consumption, cured meat intake {greater than or equal to} once per week was associated with an AOR of 2.66 (95%CI=1.38-5.35). Women with canned fruit/vegetable {greater than or equal to} consumption once per week had a higher risk of breast cancer (OR=1.19, 95%CI=1.00-1.41), particularly for the HER2-positive subtypes, but it became borderline after adjustment of confounders. Our study reveals a positive association between consumption of cured meat and breast cancer risk in Chinese population. Cured meat intake might be a potential novel risk factor for breast cancer but this would have to be confirmed by large prospective cohort studies.

Allopurinol-induced severe cutaneous adverse reactions in Vietnamese: the role of HLA alleles and other risk factors

Aim: To reveal the association of three class I HLA alleles, including HLA-A*33:03, HLA-B*58:01 and HLA-C*03:02, and allopurinol-induced severe cutaneous adverse reactions (SCARs) in Vietnamese patients. Methods: A case–control study on 100 allopurinol-induced SCARs patients, 183 tolerant controls and 810 population controls was performed. The HLA-A*33:03 and HLA-C*03:02 alleles were detected with the nested allele-specific PCR method; the HLA-B*58:01 allele was detected with the sequence-specific primer PCR method. Results: There were strong associations between HLA-B*58:01 and HLA-C*03:02 and allopurinol-induced SCARs. Specific associations were found between HLA-B*58:01 and Stevens–Johnson syndrome/toxic epidermal necrolysis and between HLA-C*03:02 and drug reaction with eosinophilia and systemic symptoms, with a gene dosage effect. The multivariate regression analysis indicated two significant independent risk factors: HLA-B*58:01/HLA-C*03:02 and estimated glomerular filtration rate <60 ml/min/1.73 m2. The specificity, positive predictive value and negative predictive value of HLA-B*58:01 testing were higher than the HLA-C*03:02 or the multiplex testing, especially in patients with impaired renal function. Conclusion: The results supported pre-treatment HLA-B*58:01 testing in Vietnamese patients with declined renal function to prevent SCARs.

Algorithm for sample availability prediction in a hospital-based epidemiological study spreadsheet-based sample availability calculator

Looking at the population's behavior by taking samples is quite uncertain due to its big and dynamic structure and unimaginable variability. All quantitative sampling approaches aim to draw a representative sample from the population so that the results of the studying samples can then be generalized back to the population. The probability of detecting a true effect of a study largely depends on the sample size and if taking small samples will give lowers statistical power, higher risk of missing a meaningful underlying difference. The probability of rejecting the null hypothesis i.e., finding significant difference using the sample largely depends upon the statistical power. There are a lot of online tools used for calculating the sample size, but none tell us about the availability of samples from single site in a fixed span. This study aims to provide an efficient calculation method for the availability of samples during a specific period of a research study which is an important question to be answered during the research study design. So, we have designed a spreadsheet-based sample availability calculator tool implemented in MS-Excel 2007.

Nonclinical Features in Predictive Modeling of Cardiovascular Diseases: A Machine Learning Approach

BACKGROUND

In the broader healthcare domain, the prediction bears more value than an explanation considering the cost of delays in its services. There are various risk prediction models for cardiovascular diseases (CVDs) in the literature for early risk assessment. However, the substantial increase in CVDs-related mortality is challenging global health systems, especially in developing countries. This situation allows researchers to improve CVDs prediction models using new features and risk computing methods. This study aims to assess nonclinical features that can be easily available in any healthcare systems, in predicting CVDs using advanced and flexible machine learning (ML) algorithms.

METHODS

A gender-matched case-control study was conducted in the largest public sector cardiac hospital of Pakistan, and the data of 460 subjects were collected. The dataset comprised of eight nonclinical features. Four supervised ML algorithms were used to train and test the models to predict the CVDs status by considering traditional logistic regression (LR) as the baseline model. The models were validated through the train-test split (70:30) and tenfold cross-validation approaches.

RESULTS

Random forest (RF), a nonlinear ML algorithm, performed better than other ML algorithms and LR. The area under the curve (AUC) of RF was 0.851 and 0.853 in the train-test split and tenfold cross-validation approach, respectively. The nonclinical features yielded an admissible accuracy (minimum 71%) through the LR and ML models, exhibiting its predictive capability in risk estimation.

CONCLUSION

The satisfactory performance of nonclinical features reveals that these features and flexible computational methodologies can reinforce the existing risk prediction models for better healthcare services.

Heterogeneous Associations Between Obesity and Reproductive-Related Factors and Specific Breast Cancer Subtypes Among Hong Kong Chinese Women

Previous studies reported heterogeneous associations between obesity and reproductive-related breast cancer risk factors and breast cancer intrinsic subtypes; however, few studies have been conducted in Asian populations. Here, we aimed to examine whether risks associated with established breast cancer risk factors varied by breast cancer subtypes in Chinese women. We conducted a hospital-based case-control study in Hong Kong, including a total of 2169 Chinese women. Unconditional polytomous logistic regression models were used to calculate adjusted odds ratios (AORs) and 95% confidence intervals(95%CIs) to estimate relative risks associated with examined risk factors in case-control analyses and to test for heterogeneity across breast cancer subtypes in case-case analyses. In case-case analyses, compared with luminal A patients, luminal B (AOR = 1.76, 95% CI = 1.07-2.88), HER2 overexpressing (AOR = 3.40, 95% CI = 1.56-7.39), and triple negative (TNBC, AOR = 2.39, 95% CI = 1.18-4.82) patients were more likely to be postmenopausal. In case-control analyses, reduced risks associated with parity and younger age at first birth were only seen for luminal A and B cases especially among postmenopausal women, whereas having ≥ 3 children was associated with increased risk for HER2 overexpressing and TNBC among premenopausal women. Obesity was associated with increased risk for all subtypes. We found heterogeneous associations between parity-related risk factors by menopausal status and breast cancer subtypes among Chinese patients, which is similar to those observed in Western populations. Interestingly, obesity was associated with increased breast cancer risk regardless of menopausal status or subtypes, except for premenopausal luminal patients, which appears to be unique in Asian populations.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Dietary Habits and Breast Cancer Risk: A Hospital-Based Case-Control Study in Chinese Women

PURPOSE

To investigate the relationship between dietary habits and breast cancer (BC) risk in Chinese women.

PATIENTS AND METHODS

We performed a hospital-based matched case-control study that included 654 BC cases and 654 healthy controls matched by age and residence. A qualified structured questionnaire was used to collect detailed sociodemographic factors and information about dietary habits. The odds ratios (ORs) and 95% confidence intervals were calculated with unconditional logistic regression analysis; the patients were grouped according to their estrogen receptor (ER) status and analyzed separately. The propensity score analysis was performed according to different postmenopause status.

RESULTS

ER-negative BC participants with intake of cured foods had increased BC risk (adjusted OR, 2.72, P = .017). Participants diagnosed as having ER-positive BC with intake of grilled foods had increased BC risk compared to those who did not consume such foods (adjusted OR, 2.14, P = .026). After propensity score analysis, fried (OR, 3.19, P = .001) and grilled (OR, 1.77, P = .031) food were considered to be risk factors for BC in premenopausal women; and fried (OR, 1.61, P = .006), grilled (OR, 4.62, P = .001), and smoked foods (OR, 2.28, P = .001) are considered risk factors for BC in postmenopausal women.

CONCLUSION

Chinese women who ate cured, grilled, and fried foods had higher BC risk. Consumption of smoked food might contribute to increased BC risk in Chinese women.

Associations between Coffee Products and Breast Cancer Risk: a Case-Control study in Hong Kong Chinese Women

Coffee contains caffeine and diterpenes that were associated with decreased breast cancer risk, but results remained inconsistent. The study purpose was to investigate the associations between coffee products and breast cancer risk among Hong Kong Chinese women. We conducted a hospital-based case-control study in three public hospitals. 2169 Chinese women aged 24-84 years old were interviewed using a standardized questionnaire with questions asking types, cups and duration on coffee drinking. We used unconditional multivariate logistic regression to calculate the adjusted odds ratio (AOR) and 95% confidence interval (95% CI) for breast cancer risk with different coffee products. 238 (20.6%) cases and 179 (17.7%) controls are habitual coffee drinkers. No association was found between overall coffee drinking and breast cancer risk. Compared to the non-habitual coffee drinkers, women who consumed instant coffee (AOR = 1.50, 95% CI = 1.10-2.03) were significantly associated with an increased breast cancer risk. Women who drank brewed coffee (AOR = 0.48, 95% CI = 0.28-0.82) were negatively associated with breast cancer risk. A positive association between instant coffee and breast cancer risk was observed, contradicted to the outcomes of drinking brewed coffee. Larger studies are warranted to ascertain the role of different types of coffee products in breast cancer risk.

Green tea consumption and risk of breast cancer: A systematic review and updated meta-analysis of case-control studies

BACKGROUND

As the most popular beverage in East Asia, green tea (GT) has various biological activities effects such as anti-mutation, anti-oxidation, and anti-tumor. In this study, we aimed to evaluate whether GT consumption could be an effective way to decrease the risk of breast cancer.

METHODS

We had performed a systematic review and updated meta-analysis of published case-control studies to evaluate the association between GT intake and the risk of breast cancer. Searching strategies were performed by the following keywords "Breast cancer," "breast neoplasm," and "green tea," with derivations and different combinations. The following databases were searched: PubMed, Cochrane Library, EMBASE, Web of science, China National Knowledge Infrastructure, WanFang, and China Biology Medicine disc. Studies published in both English and Chinese were considered for inclusion. Risk of bias was assessed through the Newcastle-Ottawa Scale (NOS). All data were analyzed through using Review Manager 5.1 software.

RESULTS

Fourteen studies fulfilled inclusion criteria for meta-analysis, yielding a total of 14,058 breast cancer patients and 15,043 control subjects. Individuals with the habit of drinking GT were found to have a negative association with the risk of future breast cancer (odds ratio 0.83; 95% confidence interval: 0.72-0.96) despite significant heterogeneity. In subgroup analyses, the negative correlation was still found in studies using registry-based controls, NOS grades ≥6 and the number of cases <500.

CONCLUSIONS

GT consumption may have a decreased incidence of breast cancer despite significant heterogeneity. However, owing to the quality of available studies, more properly designed trials are warranted to clarify the association between GT consumption and breast cancer.

Breed susceptibility for common surgically treated orthopaedic diseases in 12 dog breeds

Background

A retrospective case–control study was conducted to estimate breed predisposition for common orthopaedic conditions in 12 popular dog breeds in Norway and Sweden. Orthopaedic conditions investigated were elbow dysplasia (ED); cranial cruciate ligament disease (CCLD); medial patellar luxation (MPL); and fractures of the radius and ulna. Dogs surgically treated for the conditions above at the Swedish and Norwegian University Animal Hospitals between the years 2011 and 2015 were compared with a geographically adjusted control group calculated from the national ID-registries. Logistic regression analyses (stratified for clinic and combined) were used to calculate odds ratios (OR) and 95% confidence intervals. Mixed breed dogs were used as reference.

Results

Breeds found at-risk for ED were the Labrador retriever (OR = 5.73), the Rottweiler (OR = 5.63), the German shepherd dog (OR = 3.31) and the Staffordshire bull terrier (OR = 3.08). The Chihuahua was the only breed where an increased risk for MPL (OR = 2.80) was identified. While the Rottweiler was the only breed predisposed for CCLD (OR = 3.96), the results were conflicting for the Labrador retriever (OR = 0.44 in Sweden, 2.85 in Norway); the overall risk was identical to mixed-breed dogs.

Conclusions

Most results are in concordance with earlier studies. However, an increased risk of CCLD was not identified for the Labrador retriever, the Staffordshire bull terrier was found to have an increased risk of ED and some country-specific differences were noted. These results highlight the importance of utilising large caseloads and appropriate control groups when breed susceptibility is reported.

Electronic supplementary material

The online version of this article (10.1186/s13028-019-0454-4) contains supplementary material, which is available to authorized users.

Allium vegetables are associated with reduced risk of colorectal cancer: A hospital-based matched case-control study in China

AIM

The present study aimed to investigate and identify the association between the intake of allium vegetables and colorectal cancer (CRC) in population.

METHODS

A hospital-based matched case-control study was conducted between June 2009 and November 2011 in three hospitals. Eight hundred thirty three consecutively recruited cases of CRC were frequency matched to 833 controls by age (within 2.5 years of difference), sex, and residence area (rural/urban). Demographic and dietary information were collected via face-to-face interviews using a validated food frequency questionnaire. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated by using unconditional logistic regression.

RESULTS

A decreased CRC risk was observed for the consumption of total (aORs of high total allium intake compared with low total allium intake = 0.21, 95% CI = 0.14-0.30, P trend <0.001) and several individual allium vegetables including garlic, garlic stalks, leek, onion, and spring onion (P trend <0.05). By further sex-stratified analysis, allium vegetable intake was demonstrated to be inversely associated with the risk of CRC in both men and women. However, the association of garlic intake with cancer risk was not significant among those with distal colon cancer (aOR = 0.53, 95% CI = 0.27-1.05, P trend = 0.248).

CONCLUSION

In this analysis in a Northeast Chinese population, both men and women that the consumption of allium vegetables is associated with a reduced risk of CRC, regardless of colonic tumor subsite, with the exception of garlic intake in distal colon cancer.

An inverse association between tea consumption and colorectal cancer risk

It is well known that the tea extracts, mainly polyphenols as chemo-preventive elements, could act as cancer progression blockers. Although the association between tea consumption and colorectal cancer risk has been widely investigated, the results still remain inconsistent. We conducted a dose-response meta-analysis to evaluate their relationships by enrolling qualified 29 literatures. The summary odds ratio (OR) of colorectal cancer for the highest vs. lowest tea consumption was 0.93 with 0.87–1.00 of 95% confidence intervals (CIs) among all studies with modest heterogeneity (P = 0.001, I² = 43.4%). Stratified analysis revealed that tea, especially green tea, had a protective effect among female and rectal cancer patients. Particularly, the dose-response analysis showed that there was a significant inverse association between an increment of 1 cup/day of tea consumption and colorectal cancer risk in the subgroup of the green tea drinking (OR = 0.98, 95% CI = 0.96–1.01, P_nonlinear = 0.003) and female (OR = 0.68, 95% CI = 0.56-0.81, P_nonlinear < 0.001). Our findings indicate that tea consumption has an inverse impact on colorectal cancer risk, which may have significant public health implications in the prevention of colorectal cancer and further similar researches.

Meta-analysis of the association between PADI4 -92C/G polymorphism and rheumatoid arthritis in the Chinese population

Many studies have evaluated the correlation between peptidylarginine deiminase 4 (PADI4) -92C/G polymorphism and rheumatoid arthritis (RA), but the results remain inconclusive. Therefore, we performed a meta-analysis in the Chinese population to provide comprehensive data on the association between PADI4 -92C/G polymorphism and RA. Eligible studies published before May 2016 were identified in PubMed and Chinese databases. The strengths of these associations were assessed by pooled odds ratios (OR) and 95% confidence interval (CI). Eight studies documenting a total of 1351 RA cases and 1585 controls were included in this meta-analysis. In the overall analysis, a significant association between the PADI4 -92C/G polymorphism and RA was found in the Chinese population (G vs C: OR=1.32, 95%CI=1.02-1.71; GG+CG vs CC: OR=1.75, 95%CI=1.20-2.53). The subgroup analyses stratified by geographic area(s) and source of controls revealed significant results in South China, in hospital-based studies and population-based studies. In summary, this meta-analysis suggested that PADI4 -92C/G polymorphism may be associated with the RA incidence in the Chinese population, especially for South China. Further studies conducted on other ethnic groups are required for definite conclusions.

The Glioma International Case-Control Study: A Report From the Genetic Epidemiology of Glioma International Consortium

Decades of research have established only a few etiological factors for glioma, which is a rare and highly fatal brain cancer. Common methodological challenges among glioma studies include small sample sizes, heterogeneity of tumor subtypes, and retrospective exposure assessment. Here, we briefly describe the Glioma International Case-Control (GICC) Study (recruitment, 2010-2013), a study being conducted by the Genetic Epidemiology of Glioma International Consortium that integrates data from multiple data collection sites, uses a common protocol and questionnaire, and includes biospecimen collection. To our knowledge, the GICC Study is the largest glioma study to date that includes collection of blood samples, which will allow for genetic analysis and interrogation of gene-environment interactions.

Dietary isoflavone intake is associated with a reduced risk of myelodysplastic syndromes

Isoflavones have been suggested to have protective effects on certain cancers. However, the association of soya foods or dietary isoflavones with the risk of myelodysplastic syndromes (MDS) has not been examined. Thus, the aim of this hospital-based case-control study undertaken in China in 2012-2013 was to investigate the association between dietary isoflavone intake and MDS risk. The analysis included 208 cases aged 19-85 years with MDS and 208 controls individually matched to the cases by sex, birth quinquennium and residential locality. Information on habitual food intakes, including nine items of soya foods, was sought from in-person interviews using a validated 107-item FFQ. Dietary intakes of daidzein, genistein, glycitein and total isoflavones were estimated using the 2008 US Department of Agriculture Isoflavone Database. OR were calculated from conditional logistic regression after adjustment for potential confounding by demographics, lifestyle and dietary factors. The mean daily intake of total isoflavones was 19·0 mg in cases and 23·0 mg in controls. Dietary intake of isoflavones was inversely associated with the risk of MDS. The adjusted OR in the highest tertile compared with the lowest tertile of intake were 0·43 (95 % CI 0·21, 0·85) for daidzein, 0·36 (95 % CI 0·18, 0·74) for genistein, 0·49 (95 % CI 0·25, 0·97) for glycitein and 0·40 (95 % CI 0·20, 0·81) for total isoflavones. The findings suggest that higher dietary intake of isoflavones is associated with a reduced risk of MDS in a Chinese population.

Green tea consumption and glutathione S-transferases genetic polymorphisms on the risk of adult leukemia

PURPOSE

Green tea may have a beneficial role of inhibiting leukemia. Glutathione S-transferases (GSTs) are known to detoxify certain carcinogens. We investigated the roles of green tea consumption and polymorphisms of GSTM1, GSTT1 and GSTP1 on the risk of adult leukemia, and to determine whether the associations varied within GSTs genotypes.

METHODS

A multicenter case-control study was conducted in China, 2008-2013. It comprised 442 incident, hematologically confirmed adult leukemia cases and 442 outpatient controls, individually matched to cases by gender, birth quinquennium and study site. Data were collected by face-to-face interview using a validated questionnaire. Genetic polymorphisms were assayed by PCR.

RESULTS

An inverse association between green tea consumption and adult leukemia risk was observed. Compared with non-tea drinkers, the adjusted odds ratios (95 % confidence intervals) were 0.50 (0.27-0.93), 0.31 (0.17-0.55) and 0.53 (0.29-0.99) for those who, respectively, consumed green tea >20 years, ≥2 cups daily and dried tea leaves >1000 g annually. In assessing the associations by GSTs genotypes, risk reduction associated with green tea consumption was stronger in individuals with the GSTT1-null genotype (OR 0.24; 95 % CI 0.11-0.53) than GSTT1-normal carriers (OR 0.67; 95 % CI 0.42-1.05; P interaction = 0.02). GSTM1 and GSTP1 did not significantly modify the inverse association of leukemia with green tea.

CONCLUSIONS

The results suggest that regular daily green tea consumption may reduce leukemia risk in Chinese adults regardless of GSTM1 and GSTP1 polymorphic status. The association between green tea and adult leukemia risk varied with GSTT1 genotype and highlights further study.

Diet and risk of adult leukemia: a multicenter case-control study in China

PURPOSE

Epidemiologic studies on diet and leukemia risk have shown inconsistent results. This study examined the associations between dietary factors and the risk of adult leukemia in Chinese populations.

METHODS

A multicenter case-control study was conducted in southeast and northeast China between 2008 and 2013. It included 442 incident cases with hematologically confirmed leukemia and 442 controls, individually match to cases by gender, birth quinquennium, and study site. Information on diet was sought from face-to-face interviews using a validated and reliable 103-item food frequency questionnaire. Odds ratios (ORs) and confidence intervals (CIs) were estimated by conditional logistic regression.

RESULTS

Vegetables intake was associated with decreased risk of adult leukemia, with a significant dose-response relationship and adjusted OR of 0.30 (95 % CI 0.18-0.50) for the highest versus the lowest quartiles intake. Compared with non-consumers, the adjusted OR was 0.51 (95 % CI 0.29-0.93) for those who consumed milk at the highest tertile. Intakes of fruits, red meat, poultry, and fish were not associated with the risk. Dietary nutrients, including dietary fiber, carotenoids, vitamins B1, B2, and C, niacin, and folate, were significantly associated with reduced risks. Elevated risk was related to dietary intake animal fat and dietary habits with frequent intakes of fat, deep-fried, and smoked foods ( p for trend <0.05).

CONCLUSIONS

Our findings suggest that diets rich in vegetables and adequate amount of milk reduce the risk of adult leukemia, whereas diets preferring fat, deep-fried, and smoked foods increase the risk in Chinese populations.

Hospital outpatients are satisfactory for case-control studies on cancer and diet in China: a comparison of population versus hospital controls

BACKGROUND

To investigate the internal validity of a food-frequency questionnaire (FFQ) developed for use in Chinese women and to compare habitual dietary intakes between population and hospital controls measured by the FFQ.

MATERIALS AND METHODS

A quantitative FFQ and a short food habit questionnaire (SFHQ) were developed and adapted for cancer and nutritional studies. Habitual dietary intakes were assessed in 814 Chinese women aged 18-81 years (407 outpatients and 407 population controls) by face-to-face interview using the FFQ in Shenyang, Northeast China in 2009-2010. The Goldberg formula (ratio of energy intake to basal metabolic rate, EI/BMR) was used to assess the validity of the FFQ. Correlation analyses compared the SFHQ variables with those of the quantitative FFQ. Differences in dietary intakes between hospital and population controls were investigated. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using conditional logistic regression analyses.

RESULTS

The partial correlation coefficients were moderate to high (0.42 to 0.80; all p<0.05) for preserved food intake, fat consumption and tea drinking variables between the SFHQ and the FFQ. The average EI/BMR was 1.93 with 88.5% of subjects exceeding the Goldberg cut-off value of 1.35. Hospital controls were comparable to population controls in consumption of 17 measured food groups and mean daily intakes of energy and selected nutrients.

CONCLUSIONS

The FFQ had reasonable validity to measure habitual dietary intakes of Chinese women. Hospital outpatients provide a satisfactory control group for food consumption and intakes of energy and nutrients measured by the FFQ in a Chinese hospital setting.

Passive smoking exposure from partners as a risk factor for ER+/PR+ double positive breast cancer in never-smoking Chinese urban women: a hospital-based matched case control study

Background

The relationship between passive smoking exposure (PSE) and breast cancer risk is of major interest.

Objective

To evaluate the relationship between PSE from partners and breast cancer risk stratified by hormone-receptor (HR) status in Chinese urban women population.

Design

Hospital-based matched case control study.

Setting

Chinese urban breast cancer patients without current or previous active smoking history in China Medical University 1st Hospital, Liaoning Province, China between Jan 2009 and Nov 2009.

Patients

Each breast cancer patient was matched 1∶1 with healthy controls by gender and age (±2 years) from the same hospital.

Measurements

The authors used unconditional logistic regression analyses to estimate odds ratio for women with PSE from partners and breast cancer risk.

Results

312 pairs were included in the study. Women who endured PSE had significantly increased risk of breast cancer (adjusted OR: 1.46; 95% CI: 1.05–2.03; P = 0.027), comparing with unexposed women. Women who exposed to >5 cigarettes/day also had significant increased risk (adjusted OR: 1.99; 95% CI: 1.28–3.10; P = 0.002), as were women exposed to passive smoke for 16–25 years (adjusted OR: 1.87 95% CI: 1.22–2.86; P = 0.004), and those exposed to > 4 pack-years (adjusted OR: 1.71 95% CI: 1.17–2.50; P = 0.004). Similar trends were significant for estrogen receptor (ER)/progesterone receptor (PR) double positive subgroup(adjusted OR: 1.71; 2.20; 1.99; 1.92, respectively), but not for ER+/PR−, ER−/PR+, or ER−/PR− subgroups.

Limitations

limitations of the hospital-based retrospective study, lack of information on entire lifetime PSE and low statistical power.

Conclusions

Our findings provide further evidence that PSE from partners contributes to increased risk of breast cancer, especially for ER/PR double positive breast cancer, in Chinese urban women.

Association between green tea and colorectal cancer risk: a meta-analysis of 13 case-control studies

OBJECTIVE

Experimental studies have suggested green tea to be a chemopreventive agent for colorectal cancer, and many studies have examined possible associations. However, the conclusions were inconsistent or even contradictory, so we performed a meta-analysis based on published case-control studies to explore if green tea is indeed a protective factor.

METHODS

PubMed was searched up to May 10th, 2012 for relevant studies, and references of included studies were manually searched. Finally 13 eligible studies, involving 12,636 cases and 38,419 controls were identified. After data extraction, a meta-analysis was performed using CMA v2 software.

RESULTS

The results indicated there may be a weak but not statistically significant reduced risk of colorectal cancer with high dose of green tea intake (OR=0.95, 95% CI:0.81-1.11, p=0.490.69-0.98). This protective effect was also found in all subgroups, except in American and European populations. Sensitivity analysis indicated the result to be robust. Publication bias was not detected by either funnel plot or Egger tests.

CONCLUSION

The results of this meta-analysis indicate a weak lower tendency for colorectal cancer development with green tea consumption, but available epidemiologic data are insufficient to conclude that green tea may protect against colorectal cancer in humans.