Large Population-based Case-control Study Research Articles

A nomogram for screening esophageal squamous cell carcinoma based on environmental risk factors in a high-incidence area of China: a population-based case-control study

BackgroundSelection of high-risk subjects for endoscopic screening of esophageal squamous cell carcinoma (ESCC) lacks individual predictive tools based on environmental risk factors.MethodsWe performed a large population-based case-control study of 1418 ESCC cases and 1992 controls in a high-risk area of China. Information on potential risk factors was collected via face-to-face interview using an electronic structured questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models, and predictive nomograms were established accordingly. A weighted analysis was further conducted to introduce age into predictive nomograms due to frequency matching study design.ResultsMost cases were usually exposed to 4 to 6 risk factors, but most controls were usually exposed to 3 to 5 risk factors. The AUCs of male and female predictive nomograms were 0.75 (95%CI: 0.72, 0.77) and 0.76 (95%CI: 0.73, 0.79), respectively. The weighted analysis adding age in the predictive model improved the AUC in both men and women (0.81 (95%CI: 0.79, 0.84) and 0.88 (95%CI: 0.85, 0.90), respectively).ConclusionsAn easy-to-use preclinical predictive tool is provided to select candidate population with high ESCC risk for endoscopic screening. Its usefulness needs to be further evaluated in future screening practice.

Bladder cancer risk associated with family history of cancer.

Twin studies suggest a familial aggregation of bladder cancer, but elements of this increased familial risk of bladder cancer are not well understood. To characterize familial risk of bladder cancer, we examined the relationship between family history of bladder and other types of cancer among first-degree relatives and risk of bladder cancer in 1193 bladder cancer cases and 1418 controls in a large population-based case-control study. Multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between family history of bladder cancer (defined as at least one first-degree family member with bladder cancer or a cancer of any other site). We also evaluated cancer aggregation of specific sites in family members. Participants with a first-degree relative with bladder cancer had nearly double the risk of bladder cancer (OR = 1.8, 95% CI 1.2-2.9) as those without a family history of bladder cancer. Risk was increased for having a sibling with bladder cancer (OR = 2.6, 95% CI 1.3-5.3) compared to no siblings with cancer. Bladder cancer risk was elevated when participants reported a first-degree relative with a history of female genital cancer (OR = 1.5, 95% CI 1.1-2.1), melanoma (OR = 1.9, 95% CI 1.02-3.6), and tobacco-associated cancer (OR = 1.3, 95% CI 1.06-1.6). These findings add to evidence of a familial predisposition to bladder cancer. Clarification of the aggregation of bladder cancer in families and with other cancer sites will be of interest as many loci and common polymorphisms related to bladder cancer have yet to be identified in large genomic studies.

Smoking, Genetic Predisposition, and Colorectal Cancer Risk.

INTRODUCTION:Smoking and genetic predisposition are established risk factors for colorectal cancer (CRC). We aimed to assess and compare their individual and joint impact on CRC risk using the novel approach of genetic risk equivalent (GRE).METHODS:Data were extracted from the Darmkrebs: Chancen der Verhütung durch Screening study, a large population-based case-control study in Germany. A polygenic risk score (PRS) based on 140 CRC-related single nucleotide polymorphisms was derived to quantify genetic risk. Multiple logistic regression was used to estimate the individual and joint impact of smoking and PRS on CRC risk, and to quantify the smoking effect in terms of GRE, the corresponding effect conveyed by a defined difference in PRS percentiles.RESULTS:There were 5,086 patients with CRC and 4,120 controls included. Current smokers had a 48% higher risk of CRC than never smokers (adjusted odds ratio 1.48, 95% confidence interval 1.27–1.72). A PRS above the 90th percentile was significantly associated with a 3.6-, 4.3-, and 6.4-fold increased risk of CRC in never, former, and current smokers, respectively, when compared with a PRS below the 10th percentile in never smokers. The interaction between smoking and PRS on CRC risk did not reach statistical significance (P = 0.53). The effect of smoking was equivalent to the effect of having a 30 percentile higher level of PRS (GRE 30, 95% confidence interval 18–42).DISCUSSION:Both smoking and the PRS carry essentially independent CRC risk information, and their joint consideration provides powerful risk stratification. Abstinence from smoking can compensate for a substantial proportion of genetically determined CRC risk.

Consumption of ultra-processed foods and drinks and colorectal, breast, and prostate cancer

To study whether the consumption of ultra-processed foods and drinks is associated with breast, colorectal, and prostate cancers. Multicentric population-based case-control study (MCC-Spain) conducted in 12 Spanish provinces. Participants were men and women between 20 and 85 years of age with diagnoses of colorectal (n=1852), breast (n=1486), or prostate cancer (n=953), and population-based controls (n=3543) frequency-matched by age, sex, and region. Dietary intake was collected using a validated food frequency questionnaire. Foods and drinks were categorized according to their degree of processing based on the NOVA classification. Unconditional multivariable logistic regression was used to evaluate the association between ultra-processed food and drink consumption and colorectal, breast, and prostate cancer. In multiple adjusted models, consumption of ultra-processed foods and drinks was associated with a higher risk of colorectal cancer (OR for a 10% increase in consumption: 1.11; 95% CI 1.04-1.18). The corresponding odds for breast (OR 1.03; 95% CI 0.96-1.11) and prostate cancer (OR 1.02; 95% CI 0.93-1.12) were indicative of no association. Results of this large population-based case-control study suggest an association between the consumption of ultra-processed foods and drinks and colorectal cancer. Food policy and public health should include a focus on food processing when formulating dietary guidelines.

The effect of family history on screening procedures and prognosis in breast cancer patients - Results of a large population-based case-control study

BackgroundThe potential benefit of additional breast cancer screening examinations in moderate risk patients (patients with a history of breast cancer in one or two family members) remains unclear. MethodsA large population-based case–control study on breast cancer in postmenopausal women in Germany recruited 2002–2005 (3813 cases and 7341 age-matched controls) was used to assess the association of family history with breast cancer risk. Analysis of family history, participation in screening procedures, and tumor size regarding prognosis in patients was based on follow-up data until 2015. ResultsA first degree family history of breast cancer was associated with higher breast cancer risk (OR 1.39, p < 0.001). Patients with a first degree family history of breast cancer were more likely to have had >10 mammograms (MG) (42.7% vs. 24.9%, p < 0.001) and showed a higher rate of imaging-detected tumors (MG or ultrasound) (45.8% vs. 31.9%, p < 0.001). A smaller tumor size at initial diagnosis (below 2 cm) was more likely in patients with a positive family history (OR 1.45, p < 0.001) and a higher number of MG (≥10 MG: OR 2.29). After accounting for tumor characteristics, mammogram regularity (HR 0.72, p < 0.001) and imaging-assisted tumor detection (HR 0.66, p < 0.001) were associated with better overall survival but not with a positive family history. DiscussionPatients with a positive family history had a higher rate of imaging detected tumors with smaller size at initial diagnosis compared to patients without affected family members. Screening was associated with improved survival after a breast cancer diagnosis, irrespective of a positive family history.

Does Exposure to Agricultural Chemicals Increase the Risk of Prostate Cancer among Farmers?

Several studies suggest that farmers may be at increased risk of prostate cancer. The present analysis, based on a large population-based case-control study conducted among men in the Montreal area in the early 1980's, aim at identifying occupational chemicals which may be responsible for such increases. The original study enrolled 449 prostate cancer cases, nearly 4,000 patients with other cancers, as well as 533 population controls. Subjects were interviewed about their occupation histories, and a team of industrial hygienists assigned their past exposures using a checklist of some 300 chemicals. The present analysis was restricted to a study base of men who had worked as farmers earlier in their lives. There were a total of 49 men with prostate cancers, 127 with other cancers and 56 population controls. We created a pool of 183 controls combining the patients with cancers at sites other than the prostate and the population controls. We then estimated the odds ratio for prostate cancer associated with exposure to each of 10 agricultural chemicals, i.e., pesticides, arsenic compounds, acetic acid, gasoline engine emissions, diesel engine emissions, polycyclic aromatic hydrocarbons from petroleum, lubricating oils and greases, alkanes with >or=18 carbons, solvents, and mononuclear aromatic hydrocarbons. Based on a model adjusting for age, ethnicity, education, and respondent status, there was evidence of a two-fold excess risk of prostate cancer among farmers with substantial exposure to pesticides [odds ratio (OR)=2.3, 95% confidence interval (CI) 1.1-5.1], as compared to unexposed farmers. There was some suggestion, based on few subjects, of increased risks among farmers ever exposed to diesel engine emissions (OR=5.7, 95% CI 1.2-26.5). The results for pesticides are particularly noteworthy in the light of findings from previous studies. Suggestions of trends for elevated risks were noted with other agricultural chemicals, but these are largely novel and need further confirmation in larger samples.

Diabetes Mellitus and Risk of Plasma Cell and Lymphoproliferative Disorders: A Population Based Study Including 94,579 Cases and 368,348 Matched Controls

Diabetes Mellitus and Risk of Plasma Cell and Lymphoproliferative Disorders: A Population Based Study Including 94,579 Cases and 368,348 Matched Controls

Abstract C030: Alcohol consumption and risk of young-onset breast cancer among non-Hispanic Black and White women in the Young Women’s Health History Study

Abstract The incidence of young-onset breast cancer (YOBC) is increasing, and is higher among Non-Hispanic Black (NHB) than Non-Hispanic White (NHW) women. While alcohol consumption is consistently linked to breast cancer risk, its role in YOBC specifically, is poorly understood. Moreover, it is unclear whether associations of alcohol and YOBC vary by tumor subtype or whether it contributes to disparities by race and/or socioeconomic position (SEP). We examined associations of lifetime alcohol use and YOBC overall and by tumor subtype, and assessed whether associations varied by race, and SEP. We hypothesized that alcohol consumption would be positively associated with YOBC risk, with stronger associations for estrogen receptor (ER)-positive subtypes and similar associations across race and SEP categories. Data are from the Young Women’s Health History study, a large population-based case-control study of breast cancer among NHB and NHW women &amp;lt; 50 years of age, from the Los Angeles and Detroit SEER registries. Controls (n=1,381) were identified through area-based sampling and frequency matched to invasive breast cancer cases (n=1,812) by age-group, study site and race. Lifetime average alcohol consumption was collected from in-person interviews, using life history calendars to facilitate accurate recall. Molecular subtypes were defined as: Luminal A (ER-positive and/or progesterone receptor (PR)-positive and human epidermal growth factor 2 (HER2)-negative with grades 1 or 2); luminal B (ER-positive and/or PR-positive and HER2-positive or ER-positive and/or PR-positive and HER2-negative with grade 3); HER2-type (ER-negative and/or PR-negative and HER2-positive); and triple negative (TN; negative for ER, PR, and HER2). Weighted multivariable logistic regression models, adjusted for established risk factors, were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations of alcohol consumption and YOBC by subtype. Statistical interaction of alcohol by race and SEP was evaluated using the Wald’s test for the cross-product term. Women who consumed &amp;gt;20 g/day of alcohol were slightly leaner, less likely to have a college education and have a family history of breast cancer and more likely to have smoked than nondrinkers. Alcohol consumption was not significantly associated with YOBC risk overall, or within molecular subtype [LumA (&amp;gt;20 g/day vs. nondrinkers OR (95%CI) = 0.66 (0.43, 1.00), LumB=0.83 (0.53, 1.31), HER2=1.43 (0.63, 3.23), and TN=0.82 (0.52, 1.29)]. We did not observe any interaction by race (pint=0.62) or SEP (pint=0.94) overall or in models of tumor subtypes (all pint&amp;gt;0.28). Alcohol consumption of &amp;gt;20 g/day was inversely associated with LumA among NHW [OR (95%CI) =0.50 (0.28, 0.89)], however, no significant association was observed for LumA in NHB [OR (95%CI) =1.14 (0.61, 2.12)]. Our findings suggest that alcohol consumption is not strongly linked to YOBC risk, and that associations do not appear to vary by molecular subtype, race, or SEP. Citation Format: Kelly A Hirko, Darek R Lucas, Dorothy R Pathak, Nicole Bohme Carnegie, Richard T Houang, Kendra Schwartz, Ellen M Velie. Alcohol consumption and risk of young-onset breast cancer among non-Hispanic Black and White women in the Young Women’s Health History Study [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C030.

The role of dietary antioxidant index and index of nutritional quality in MS onset: finding from an Iranian population-based incident case–control study

ABSTRACT Introduction: The role of nutritional factors in MS etiology is a matter of debate. Employing dietary antioxidant index (DAI) as well as index of nutritional quality (INQ) we aimed to investigate the possible link between diet and MS risk. Methods This was a large population-based case–control study recruiting 547 incident cases and 1057 population controls between August 2013 and February 2015. DAI and INQ were calculated based on the adolescence dietary intake of the participants. Logistic regression was employed for estimating adjusted odds ratios (OR) and their 95% confidence interval in 2018. Results Participants with less than median DAI values had two-fold increased risk of MS onset (adjusted OR 2.05, 95% CI: 1.64–2.58, P < 0.001). A significant dose–response pattern for DAI (adjusted OR 1.35, 95% CI: 1.18–1.55, P for trend <0.001) was also detected. In the case of INQ, the strongest decreased risk were detected for vitamin D (OR = 0.09) and Zinc (OR = 0.34), followed by vitamin A (OR = 0.49), Calcium (OR = 0.49) and vitamin B6 (OR = 0.51) (All P-values < 0.05). Conclusion Considering the inherent limitation of case–control designs, an appropriate intake of nutrient antioxidants may have a role in decreasing the likelihood of MS risk. Moreover, those with healthier diet assessed by index of nutritional quality were at decreased risk for MS.

Epidemiological features of rosacea in Changsha, China: A population-based, cross-sectional study.

Rosacea is a common chronic skin disorder of unknown etiology. While population prevalence rates range 0.2-22% in Europe and North America, prevalence in China is currently undetermined. We conducted a large population-based case-control study to determine the present epidemiological status of rosacea in China, involving 10095 participants aged 0-100years (mean age, 35.5±19.1; 50.5% female). A census of rosacea among 15 communities in Changsha in south central China was conducted with skin examination by board-certified dermatologists. Rosacea was observed in 3.48% (95% confidence interval, 3.13-3.85%) of the study population. Subtype distribution was erythematotelangiectatic in 47.6%, papulopustular in 35.0% and phymatous in 17.4%. Family history was noted in 37.8% and ocular symptoms in 31.3%. Associations with rosacea were observed for melasma, hypertension, hyperthyroidism and breast cancer in females (P<0.05), and also for hyperthyroidism and peptic ulcers in males (P<0.05). Our results provide baseline information about epidemiological aspects of rosacea in China.

Estimation of Absolute Risk of Colorectal Cancer Based on Healthy Lifestyle, Genetic Risk, and Colonoscopy Status in a Population-Based Study

Estimates of absolute risk of colorectal cancer (CRC) are needed to facilitate communication and better inform the public about the potentials and limits of cancer prevention. Using data from a large population-based case-control study in Germany (Darmkrebs: Chancen der Verhütung durch Screening [DACHS] study, which began in 2003) and population registry data, we calculated 30-year absolute risk estimates for development of CRC based on a healthy lifestyle score (derived from 5 modifiable lifestyle factors: smoking, alcohol consumption, diet, physical activity, and body fatness), a polygenic risk score (based on 90 single-nucleotide polymorphisms), and colonoscopy history. We analyzed data from 4220 patients with CRC and 3338 individuals without CRC. Adherence to a healthy lifestyle and colonoscopy in the preceding 10 years were associated with a reduced relative risk of CRC in men and women. We observed a higher CRC risk in participants with high or intermediate genetic risk scores. For 50-year-old men and women without a colonoscopy, the absolute risk of CRC varied according to the polygenic risk score and the healthy lifestyle score (men, 3.5%-13.4%; women, 2.5%-10.6%). For 50-year-old men and women with a colonoscopy, the absolute risk of developing CRC was much lower but still varied according to the polygenic risk score and the healthy lifestyle score (men, 1.2%-4.8%; women, 0.9%-4.2%). Among all risk factor profiles, the 30-year absolute risk estimates consistently decreased with adherence to a healthy lifestyle. In a population-based study, we found that a colonoscopy can drastically reduce the absolute risk of CRC and that the genetically predetermined risk of CRC can be further reduced by adherence to a healthy lifestyle. Our results show the magnitude of CRC prevention possible through colonoscopy and lifestyle at a predefined genetic risk. This observational study has been registered in the German Clinical Trials Register (DRKS00011793), which is a primary registry in the World Health Organization Registry Network.

Firefighter occupation is associated with increased risk for laryngeal and hypopharyngeal squamous cell carcinoma among men from the Greater Boston area

ObjectiveFirefighters are exposed to a wide variety of carcinogens during the line of duty, including several associated with head and neck cancer. Existing studies assessing head and neck cancer risk...

Welding and the risk of head and neck cancer: the ICARE study

ObjectiveTo investigate the association between occupational exposure to welding and the risk of head and neck cancer in a large French population-based case-control study, the Investigation of occupational and environmental...

Maternal occupational exposure to solvents and gastroschisis in offspring - National Birth Defects Prevention Study 1997–2011

ObjectivesThe aim of this study was to assess the association between maternal occupational exposure to solvents and gastroschisis in offspring.MethodsWe used data from the National Birth Defects Prevention Study, a...

TL 18040 - Venous thromboembolism risk in foot and ankle surgical patients

Introduction: Venous thromboembolism (VTE) is the leading cause of preventable hospital death. There are several risk factors for VTE, of which orthopedic surgery is an important one. VTE risk is highest following major orthopedic surgery, and therefore, some form of prophylactic therapy is usually recommended. In contrast, the risk for VTE following foot and ankle surgery is less clear, as are guidelines on VTE prophylaxis in these patients. Objective: To estimate the risk of VTE and the duration of the increased risk period after foot and ankle surgery. Methods: Data from a large population-based case–control study (the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis [MEGA] study) on the etiology of venous thrombosis were used (4721 cases; 5638 controls). Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex and body mass index (ORadj), were calculated for patients undergoing any foot or ankle intervention before the index date (VTE date or control date). Results: The 263 cases and 94 controls underwent any orthopedic intervention in the year before the index date for an ORadj of 3,74 (95% CI 2,91-4,80) The ORadj in the first 90 days was 11,35 (95% CI 7,28-17,70). Fifty-five cases and 20 controls had a foot or ankle intervention in the year before the index date, resulting in a three-fold increased risk for VTE (OR 3,29, 95% CI 1,98-5,49). VTE risk was highest in the first 30 (ORadj 10,15 (95% CI 3,04-33,85)) and 90 days following surgery (ORadj 12,42, 95% CI 4,43-34,84). In 34 patients, the surgery was trauma-related, while 43 patients underwent elective surgery. Traumatic surgery was associated with a higher risk than elective surgery with an OR of 13,85 (95% CI 1,77-108,36) and 8,32 (95% CI 1,87-36,94), respectively, at 30 days. Conclusion: Foot and ankle procedures were associated with an increased VTE risk, which was highest in the first 90 days following surgery. Trauma-related surgery was associated with a higher VTE risk than elective surgery. These results are important for decisions regarding thromboprophylactic measures following foot and ankle surgery.

Synergistic action of folate intake and testosterone associated with breast cancer risk

The amount of irreparable DNA damage is a function of the rate of cell division, and the association between sex hormones and the risk of breast cancer has been explained by an increase in cell division. Folate intake insufficiency leads to disturbances in DNA replication and DNA repair. We hypothesized that folate intake insufficiency and high serum concentrations of sex hormones act synergistically on the risk of breast cancer. The aim of this study was to investigate the interaction between sex hormones (exposure of interest A) and dietary folate intake (exposure of interest B) on the risk of breast cancer. We included 342 breast cancer primary postmenopausal cases and 294 controls obtained from a large population-based case-control study. Multiple conditional logistic regression models were used for the analysis and interactions were tested. The joint effect of the lowest dietary folate intake (T1 < 259.40 mg/d) and the highest serum concentration of testosterone (T3 ≥ 0.410 on the risk of breast cancer was odds ratio = 9.18 (95% confidence interval 2.56-32.88) when compared to the lowest-risk category, namely, the group of women with the highest dietary folate intake (T3 > 381.29 mg/d) and the lowest serum concentration of testosterone (T1 ≤ 0.25 pg/mL). There were some indications that the estimated join effect was greater than the product of the estimated effects alone (P = .001). These findings have important public health implications with respect to reducing the risk of the most frequent cancer in women worldwide.

Establishing a valid approach for estimating familial risk of cancer explained by common genetic variants.

We critically examined existing approaches for the estimation of the excess familial risk of cancer that can be attributed to identified common genetic risk variants and propose an alternative, more straightforward approach for calculating this proportion using well-established epidemiological methodology. We applied the underlying equations of the traditional approaches and the new epidemiological approach for colorectal cancer (CRC) in a large population-based case-control study in Germany with 4,447 cases and 3,480 controls, who were recruited from 2003 to 2016 and for whom interview, medical and genomic data were available. Having a family history of CRC (FH) was associated with a 1.77-fold risk increase in our study population (95% CI 1.52-2.07). Traditional approaches yielded estimates of the FH-associated risk explained by 97 common genetics variants from 9.6% to 23.1%, depending on various assumptions. Our alternative approach resulted in smaller and more consistent estimates of this proportion, ranging from 5.4% to 14.3%. Commonly employed methods may lead to strongly divergent and possibly exaggerated estimates of excess familial risk of cancer explained by associated known common genetic variants. Our results suggest that familial risk and risk associated with known common genetic variants might reflect two complementary major sources of risk.

Estimating Venous Thromboembolism Risk in Foot and Ankle Surgical Patients: A Base-Population Case-Control Study

Category:ComplicationsIntroduction/Purpose:Venous thromboembolism (VTE) is the leading cause of preventable hospital death. There are several risk factors for VTE of which orthopedic surgery is an important one. VTE risk is highest following major orthopedic surgery and therefore some form of prophylactic therapy is usually recommended here. In contrast, the risk for VTE following foot and ankle surgery is less clear and so are guidelines on VTE prophylaxis in these patients. The purpose is to estimate the risk of VTE and the duration of the increased risk period after foot and ankle surgery.Methods:Data from a large population-based case–control study (the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis [MEGA] study) on the etiology of venous thrombosis were used (5129 cases; 5882 controls). Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex and body mass index (ORadj) were calculated for patients undergoing any foot or ankle intervention before the index date (VTE date or control date).Results:286 cases and 96 controls underwent any orthopedic intervention in the year before the index date for an ORadj of 3.7 (95%CI 2.9-4.8) The ORadj in the first 90-days was 11.4 (95%CI 7.3-17.7). 57 cases and 20 controls had a foot or ankle intervention in the year before the index date, resulting in a three-fold increased risk for VTE (OR 3.3, 95% CI 1,9-5.5). VTE risk was highest in the first 30 (ORadj 10.2,95%CI 3.0-33.9) and 90-days following surgery (ORadj 12.4, 95% CI 4.4-34.8). In 34 patients the surgery was trauma related while 43 patients underwent elective surgery. Traumatic surgery was associated with a higher risk compared with elective surgery for an OR of 13.9 (95%CI 1.8-108.4) and 8.3 (95%CI 1.9-36.9), respectively at 30-days.Conclusion:Foot and ankle procedures were associated with an increased VTE risk which was highest in the first 90-days following surgery. Trauma related surgery was associated with a higher VTE risk than elective surgery. These results are important to decide on thromboprophylactic measures following foot and ankle surgery.

Development of a Job-Exposure Matrix for Assessment of Occupational Exposure to High-Frequency Electromagnetic Fields (3 kHz-300 GHz).

The aim of this work was to build a job-exposure matrix (JEM) using an international coding system and covering the non-thermal intermediate frequency (IF) (3-100 kHz, named IFELF), thermal IF (100 kHz-10 MHz, named IFRF), and radiofrequency (RF) (>10 MHz) bands. Detailed occupational data were collected in a large population-based case-control study, INTEROCC, with occupations coded into the International Standard Classification of Occupations system 1988 (ISCO88). The subjects' occupational source-based ancillary information was combined with an existing source-exposure matrix and the reference levels of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for occupational exposure to calculate estimates of level (L) of exposure to electric (E) and magnetic (H) fields by ISCO88 code and frequency band as ICNIRP ratios (IFELF) or squared ratios (IFRF and RF). Estimates of exposure probability (P) were obtained by dividing the number of exposed subjects by the total number of subjects available per job title. With 36 011 job histories collected, 468 ISCO88 (four-digit) codes were included in the JEM, of which 62.4% are exposed to RF, IFRF, and/or IFELF. As a reference, P values for RF E-fields ranged from 0.3 to 65.0% with a median of 5.1%. L values for RF E-fields (ICNIRP squared ratio) ranged from 6.94 × 10-11 to 33.97 with a median of 0.61. The methodology used allowed the development of a JEM for high-frequency electromagnetic fields containing exposure estimates for the largest number of occupations to date. Although the validity of this JEM is limited by the small number of available observations for some codes, this JEM may be useful for epidemiological studies and occupational health management programs assessing high-frequency electromagnetic field exposure in occupational settings.

Raw Garlic Consumption and Risk of Liver Cancer: A Population-Based Case-Control Study in Eastern China.

Although the major risk factors for liver cancer have been established, preventive factors for liver cancer have not been fully explored. We evaluated the association between raw garlic consumption and liver cancer in a large population-based case-control study in Eastern China. The study was conducted in Jiangsu, China, from 2003 to 2010. A total of 2011 incident liver cancer cases and 7933 randomly selected population-controls were interviewed. Epidemiological data including raw garlic intake and other exposures were collected, and serum markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection were assayed. Overall, eating raw garlic twice or more per week was inversely associated with liver cancer, with an adjusted odds ratio (aOR) of 0.77 (95% confidence interval (CI): 0.62–0.96) compared to those ingesting no raw garlic or less than twice per week. In stratified analyses, high intake of raw garlic was inversely associated with liver cancer among Hepatitis B surface antigen (HBsAg) negative individuals, frequent alcohol drinkers, those having history of eating mold-contaminated food or drinking raw water, and those without family history of liver cancer. Marginal interactions on an additive scale were observed between low raw garlic intake and HBsAg positivity (attributable proportion due to interaction (AP) = 0.31, 95% CI: -0.01–0.62) and heavy alcohol drinking (AP = 0.28, 95% CI: 0.00–0.57). Raw garlic consumption is inversely associated with liver cancer. Such an association shed some light on the potential etiologic role of garlic intake on liver cancer, which in turn might provide a possible dietary intervention to reduce liver cancer in Chinese population.