Dietary Patterns and Risk of Pancreatic Cancer in a Large Population-Based Case-Control Study in the San Francisco Bay Area

Pancreatic cancer is highly lethal, and identifying modifiable risk factors could have substantial public health impact. In this population-based case-control study (532 cases, 1701 controls), we used principal component analysis and multivariable unconditional logistic regression models to examine whether a particular dietary pattern was associated with risk of pancreatic cancer, adjusting for other known risk factors. A prudent dietary pattern, characterized by greater intake of vegetables, fruit, fish, poultry, whole grains, and low-fat dairy, was associated with an approximate 50% reduction in pancreatic cancer risk among men [odds ratio (OR) = 0.51, 95% confidence intervals (CI) = 0.31–0.84, P trend = 0.001] and women (OR = 0.51, 95% CI = 0.29–0.90, P trend = 0.04). A Western dietary pattern, characterized by higher intake of red and processed meats, potato chips, sugary beverages, sweets, high fat dairy, eggs, and refined grains, was associated with a 2.4-fold increased risk of pancreatic cancer among men (95% CI = 1.3–4.2, P trend = 0.008) but was not associated with risk among women. Among men, those in the upper quintiles of the Western diet and lower quintiles of the prudent diet had a threefold increased risk. Consistent with what has been recommended for several other chronic diseases, consuming a diet rich in plant-based foods, whole grains, and white meat, might reduce risk of pancreatic cancer.     

Intake of vitamins D and A and calcium and risk of non-Hodgkin lymphoma: San Francisco Bay Area population-based case-control study

Several nutrients identified as potentially cancer protective have been inconsistently associated with non-Hodgkin lymphoma (NHL) risk. Dietary history data, including use of vitamin supplements, were collected using a semiquantitative food frequency questionnaire administered during in-person interviews with 4,133 participants (2,052 cases, 2,081 controls) in a San Francisco Bay Area population-based case-control study. Data were used to determine the association of intake levels of vitamins D and A and calcium with risk of NHL and NHL subtypes. Odds ratios (OR) and 95% confidence intervals (CI) were computed as estimates of relative risk using adjusted unconditional logistic regression. Increasing vitamin D intake from food and supplements was positively associated with NHL risk in men (5th quintile: OR = 1.6, 95% CI = 1.0-2.4, P(trend) = 0.07) and with diffuse large B-cell lymphoma (DLBCL) in women and men (5th quintile: OR = 1.6, 95% CI = 1.0-2.5, P(trend) = 0.02); that was largely due to the effect in men (P(trend) = 0.03). These results do not support a strong role for vitamin D intake with NHL risk, with the exception of a potential association for DLBCL risk in men. Our results should be interpreted conservatively until further investigation in larger pooled studies can be conducted to better assess the role of vitamin D intake in lymphomagenesis.     

Dietary Iron Intake and Risk of Endometrial Cancer: A Population-Based Case-Control Study in Shanghai,China

Dietary red meat and animal fat have been linked to endometrial cancer (EC) risk, but the impact of bioavailable iron in animal-derived foods has been less well studied. Our objective was to investigate the effects of iron and fats on the risk of EC in a large, population-based, case-control study. The Shanghai Endometrial Cancer Study enrolled 1,204 EC cases and 1,212 controls who completed in-person interviews, including a food frequency questionnaire. Animal-derived iron and fat intakes were calculated from dietary intakes and food composition tables. Logistic regression models were used to evaluate independent and joint effects of iron and fat on EC risk. Animal-derived iron intake was positively associated with EC risk [adjusted OR = 1.9; 95% CI = 1.4–2.7, P _trend < 0.01, highest vs. lowest quartile], predominantly after menopause (OR = 2.2; 95%CI = 1.4–3.4, P _trend < 0.01) and in women with BMI ≥ 25 kg/m ² (OR = 3.2; 95% CI = 1.4–7.5 in postmenopausal obese women, P _trend < 0.01). Animal-derived fat was also associated with postmenopausal EC risk (OR = 1.7; 95% CI = 1.2–2.5, P _trend < 0.01). Multiplicative interactions between animal-derived iron and BMI or animal-derived fat intake were not observed. Animal-derived iron intake is associated with increased risk of EC after menopause and among obese women. Avoidance of animal-derived (heme) iron may reduce the risk of EC in these women.     

Dietary Vitamin D and Calcium Intake and Premenopausal Breast Cancer Risk in a German Case-Control Study

Epidemiological studies and laboratory data suggest that vitamin D may protect against the development of cancer, including breast cancer. Vitamin D supply affects the bioavailability of dietary calcium, which might also have anticarcinogenic effects. However, few studies considered them jointly. We used a population-based case-control study in Germany to examine the independent and joint effects of dietary vitamin D and calcium on premenopausal breast cancer risk. Dietary information was assessed using a validated food frequency questionnaire from 278 premenopausal cases and 666 age-matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariate models adjusting vitamin D models for calcium intake and vice versa. Breast cancer risk was significantly inversely associated with vitamin D intake. The OR and 95% CI for the highest intake category (≥ 5 μ g/day) was 0.50 (95% CI = 0.26–0.96) compared with the lowest (< 2 μ g/day; P_trend = 0.02). Dietary calcium intake was not associated with breast cancer (OR = 0.73, 95% CI = 0.41–1.29) for the highest (≥ 1,300 mg/day) versus the lowest category (< 700 mg/day), P_trend = 0.29). No statistically significant interaction between the 2 nutrients was observed. Our data support a protective effect of dietary vitamin D on premenopausal breast cancer risk independent of dietary calcium intake.     

Dairy Products,Calcium Intake,and Breast Cancer Risk: A Case-Control Study in China

The results of dairy food consumption and breast cancer risk are conflicting, and their relationship has not previously been studied in China. The objective of this study is to examine the association between dairy products, calcium intake, and breast cancer risk among Chinese women. A hospital-based case-control study was conducted among Chinese women in the Guangdong province from June 2007 to August 2008. Four hundred and thirty-eight consecutively recruited cases with primary breast cancer were frequency-matched to 438 controls on age and residence. Dietary intake information was collected by interviewers using a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using unconditional multiple logistic regression adjusted for various potential confounders. We observed a statistically significant inverse association of dietary calcium intake with breast cancer risk, with the adjusted OR (95% CI) of 0.35 (0.22–0.56) comparing the highest with the lowest quartile. No significant association was found between dairy products measured either by dry weight of dairy product or dairy product protein intake and breast cancer risk. Our study supports a protective effect of high intake of dietary calcium on breast cancer risk, and no association with dairy product intake.     

Folate Intake and Prostate Cancer Risk: A Case-Control Study

Folate deficiency has been implicated in the carcinogenesis of several tumor types. The role of folate in prostate cancer remains indeterminate. We investigated folate as a risk factor for prostate cancer among 140 biopsy-confirmed prostate cancer patients, 230 age-matched clinic controls, and 250 negative prostate biopsy controls. Dietary folate intake was inversely associated with overall risk of prostate cancer as compared to clinic controls (P for a linear trend = 0.003). When stratified by disease severity, dietary folate and folate from natural sources were associated with reduced risk of high-grade cancer as compared to both clinic controls (P for a linear trend = 0.0009 and 0.02, respectively) and biopsy negative controls (P for a linear trend = 0.03 and 0.05, respectively). There was no interaction between alcohol consumption and folate intake. These analyses support an inverse association between dietary folate intake and prostate cancer risk and primarily risk of high-grade prostate cancer.     

Fiber Intake and Risk of Nasopharyngeal Carcinoma: A Case-Control Study

Some studies examined the inverse relation between nasopharyngeal carcinoma (NPC) risk and dietary fibers in endemic populations. By means of a hospital-based case-control study, we verified whether this association was also present in Italy in connection with various types of dietary fibers. Cases were 198 patients with incident, histologically confirmed, NPC admitted to major teaching and general hospitals during 1992–2008. Controls were 594 patients admitted for acute, nonneoplastic conditions to the same hospital network of cases. Information was elicited using a validated food frequency questionnaire including 78 foods, food groups, or dishes. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated for quartiles of intake of different types of fiber after allowance for energy intake and other potential confounding factors. Total fiber intake was inversely related to risk of NPC (OR = 0.58 for the highest vs. the lowest quartile of intake; 95% CI: 0.34–0.96). We found an inverse association for total soluble (OR = 0.58; 95% CI: 0.35–0.96) and total insoluble fiber (OR = 0.56; 95% CI: 0.33–0.95), in particular cellulose (OR = 0.57; 95% CI: 0.33–0.96), and lignin (OR = 0.51; 95% CI: 0.31–0.85). In conclusion, this study suggests that dietary intake of soluble and insoluble fibers is inversely related to NPC risk in a nonendemic southern population.     

Occupation and adult gliomas in the San Francisco Bay Area

The etiology of gliomas is not well understood. Some jobs might involve sustained and elevated exposures to carcinogens. This study compares lifetime job histories of 879 glioma cases diagnosed between August 1991 to April 1994 and May 1997 to August 1999 in the San Francisco Bay Area and 864 controls. Logistic analyses compared longest and ever held occupations of 1 year or more for all astrocytic and nonastrocytic cases and controls overall with adjustment for age, gender, and ethnicity and separately for men and women. Two-fold or higher or statistically significant elevated odds ratios were found overall and in men among those with longest held occupations, as firefighters, physicians, material moving equipment operators, and janitors; such elevated odds ratios were also observed for longest-held occupations among male motor vehicle operators and personal service workers and female messengers, legal/social service workers, electronic equipment operators, painters, and food processors. Odds ratios of 0.50 or less, but not statistically significant, were found for those with longest held jobs as writers/journalists, biological scientists, paper workers, mechanics, chemists, and photographers/photoprocessors. This study supports previously observed occupational associations and is one of the few studies with sufficient numbers to separately analyze occupations by gender.     

Dietary Polyamines Intake and Risk of Colorectal Cancer: A Case-Control Study

Polyamines (including putrescine, spermidine, and spermine) are small, cationic molecules that are necessary for cell proliferation and differentiation. Few studies have examined the association of dietary polyamines intake with colorectal cancer risk. The aim of this study was to evaluate total polyamines, putrescine, spermidine, and spermine intake in relation to colorectal cancer risk in China. In total, 2502 colorectal cancer cases and 2538 age-(5-year interval) and sex-matched controls were recruited from July 2010 to April 2019. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by multivariable unconditional logistic regression after adjustment for various potential confounding factors. Higher intake of total polyamine, putrescine and spermidine was significantly associated with reduced risk of colorectal cancer. The adjusted ORs for the highest compared with the lowest quartile of intake were 0.60 (95% CI 0.50, 0.72; P_trend < 0.001) for total polyamines, 0.35 (95% CI 0.29, 0.43; P_trend < 0.001) for putrescine and 0.79 (95% CI 0.66, 0.95; P_trend = 0.001) for spermidine, respectively. However, higher intake of spermine was associated with increased risk of colorectal cancer, with an adjusted OR of 1.58 (95% CI 1.29, 1.93; P_trend < 0.001). This data indicate that higher intake of total polyamines, putrescine and spermidine, as well as lower intake of spermine, is associated with a decreased risk of colorectal cancer.     

Association Between Zolpidem Use and Glaucoma Risk: A Taiwanese Population-Based Case-Control Study

Background

To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed.

Methods

We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (±5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables.

Results

The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02–1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03–1.68).

Conclusions

This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue.Key words: zolpidem, glaucoma, Taiwanese     

No Association Observed between Coffee Intake and Risk of Non-Hodgkin Lymphoma among Postmenopausal Women

BackgroundSome preliminary studies indicate that components in coffee may have anticarcinogenic effects. However, the association between coffee-drinking habits and the risk of non-Hodgkin lymphoma (NHL) remain controversial.ObjectiveTo examine the relationship between coffee intake and NHL incidence in a large prospective study of postmenopausal US women.Design and participants/settingThe participants included 74,935 women from the Women’s Health Initiative Observational Study who were recruited from 1993 through 1998. Information about coffee-drinking habits was collected at baseline via self-administered questionnaires.Main outcome measuresNewly diagnosed NHL was validated by medical records and pathology records. Separate analyses were performed for the following three subtypes of NHL: diffuse large B-cell lymphoma (n = 244), follicular lymphoma (n = 166), and chronic lymphocytic leukemia/small lymphocytic lymphoma (n = 64).Statistical analyses performedAge-adjusted and multivariable-adjusted Cox proportional hazards models were used to determine associations of coffee intake (specifically, the total amount of coffee consumed daily, coffee types, and coffee preparation methods) with risk of NHL.ResultsA total of 851 women developed NHL during a median 18.34 years of follow-up (range = 0.01 to 24.30 years; ± 6.63 years). Overall, no associations were observed between coffee intake and risk of NHL regardless of the total amount of daily coffee intake (P value for trend = 0.90), caffeinated (P = 0.55) or decaffeinated coffee intake (P = 0.78), and filtered or unfiltered coffee intake (P = 0.91) after controlling for sociodemographic factors, lifestyle risk factors, and clinical risk factors/current medical conditions. No significant associations were observed between coffee intake with specific subtypes of NHL. A statistically significant interaction was found between alcohol intake, coffee intake, and incident NHL (P value for interaction = 0.02) based on the adjusted analysis. Specifically, among women who frequently consumed alcohol (> 7 drinks/week), those who had moderate coffee intake (2 to 3 c coffee/day) had a significantly reduced risk of developing NHL (hazard ratio 0.61, 95% CI 0.36 to 0.98), compared with those who did not drink coffee.ConclusionsThe findings from this study do not support an association between coffee consumption and NHL risk, irrespective of the total amount of daily coffee intake, coffee types, or coffee preparation methods.     

Community Characteristics Associated with HIV Risk among Injection Drug Users in the San Francisco Bay Area: A Multilevel Analysis

Community characteristics have been associated with racial and ethnic health disparities for a wide range of ailments and conditions. Previous research has found that rates of AIDS cases among injection drug users (IDUs) vary by community characteristics. However, few studies have examined whether community characteristics are associated with HIV risk behaviors among IDUs. To address this gap in the literature, we examined the associations between census-tract-level community characteristics and injection-related and sex-related HIV risk behaviors among IDUs in the San Francisco Bay Area. Individual HIV risk behaviors were collected from 4,956 IDUs between 1998 and 2002. Using 2000 US census data, we constructed four census-level community measures: percent African American, percent male unemployment, percent of households that receive public assistance, and median household income. All community variables were measured continuously. Multilevel modeling was used to determine if community characteristics were associated with recent (in the last 6 months) receptive and distributive syringe sharing, multiple sex partners, and unprotected sex risk while controlling for potential individual-level confounders. In bivariate analysis, most of the census-tract-level community characteristics were significantly associated with injection-related HIV risk, while no community characteristics were associated with sex-related risk. However, results from multivariate multilevel models indicate that only percent African American in a census tract was associated with receptive [adjusted odds ratio (AOR) = 0.93; 95% confidence interval (CI) = 0.89, 0.99] and distributive syringe sharing (AOR = 0.94; 95% CI = 0.92, 0.99), net of individual-level characteristics. Accounting for individual-level factors in the multivariate model in the sex-related risk models revealed a significant inverse relationship between percent African American and propensity to engage in unprotected sex (AOR = 0.95; 95% CI = 0.92, 0.99); community-level characteristics remained unassociated with multiple sex partners. In this exploratory analysis, percent African American in a census tract was inversely associated with injection-related risk. The census-tract-level community characteristics we examined seem to exert little influence on individual risk among long-term chronic IDUs. More research is needed examining the influence of other community characteristics that were unmeasured in this paper but might be related to sex and drug risk among IDUs such as shooting galleries, crack houses, drug markets, and availability of preventive HIV services.     

Dairy Product Consumption and Risk of Non-Hodgkin Lymphoma: A Meta-Analysis

Many epidemiologic studies have explored the association between dairy product consumption and the risk of non-Hodgkin lymphoma (NHL), but the results remain controversial. A literature search was performed in PubMed, Web of Science and Embase for relevant articles published up to October 2015. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. The dose-response relationship was assessed by restricted cubic spline. A total of 16 articles were eligible for this meta-analysis. The pooled RRs (95% CIs) of NHL for the highest vs. lowest category of the consumption of total dairy product, milk, butter, cheese, ice cream and yogurt were 1.20 (1.02, 1.42), 1.41 (1.08, 1.84), 1.31 (1.04, 1.65), 1.14 (0.96, 1.34), 1.57 (1.11, 2.20) and 0.78 (0.54, 1.12), respectively. In subgroup analyses, the positive association between total dairy product consumption and the risk of NHL was found among case-control studies (RR = 1.41, 95% CI: 1.17–1.70) but not among cohort studies (RR = 1.02, 95% CI: 0.88–1.17). The pooled RRs (95% CIs) of NHL were 1.21 (1.01, 1.46) for milk consumption in studies conducted in North America, and 1.24 (1.09, 1.40) for cheese consumption in studies that adopted validated food frequency questionnaires. In further analysis of NHL subtypes, we found statistically significant associations between the consumption of total dairy product (RR = 1.73, 95% CI: 1.22–2.45) and milk (RR = 1.49, 95% CI: 1.08–2.06) and the risk of diffuse large B-cell lymphoma. The dose-response analysis suggested that the risk of NHL increased by 5% (1.05 (1.00–1.10)) and 6% (1.06 (0.99–1.13)) for each 200 g/day increment of total dairy product and milk consumption, respectively. This meta-analysis suggested that dairy product consumption, but not yogurt, may increase the risk of NHL. More prospective cohort studies that investigate specific types of dairy product consumption are needed to confirm this conclusion.     

Red Meat-Derived Heterocyclic Amines Increase Risk of Colon Cancer: A Population-Based Case-Control Study

Formation of mutagenic heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) is one pathway believed to drive the association of colon cancer with meat consumption. Limited data exist on the associations of individual HCAs and PAHs in red or white meat with colon cancer. Analyzing data from a validated meat preparation questionnaire completed by 1062 incident colon cancer cases and 1645 population controls from an ongoing case-control study, risks of colon cancer were estimated using unconditional logistic regression models, comparing the fourth to the first quartile of mutagen estimates derived from a CHARRED based food frequency questionnaire. Total dietary intake of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) [adjusted odds ratio (aOR) = 1.87, 95% confidence interval (CI) = 1.44–2.44, P _trend < 0.0001], 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) (aOR = 1.68, 95% CI = 1.29–2.17, P _trend = 0.001) and meat-derived mutagenic activity (aOR = 1.77, 95% CI = 1.36–2.30, P _trend < 0.0001) were statistically significantly associated with colon cancer risk. Meat type specific analyses revealed statistically significant associations for red meat-derived MeIQx, DiMeIQx, and mutagenic activity but not for the same mutagens derived from white meat. Our study adds evidence supporting red meat-derived, but not white-meat derived HCAs and PAHs, as an important pathway for environmental colon cancer carcinogenesis.     

Population- and community-based recruitment of African Americans and Latinos: the San Francisco Bay Area Lung Cancer Study

Empiric data on recruitment of minorities into clinical or population studies are limited. The authors evaluated population- and community-based recruitment methods in a 1998-2001 case-control study of lung cancer among African Americans and Latinos. For lung cancer cases in the San Francisco Bay Area of California, rapid case ascertainment by the tumor registry combined with telephone screening identified 470 (9%) African Americans and 262 (5%) Latinos. When random digit dialing (RDD) and Health Care Financing Administration (HCFA) records failed to yield adequate numbers of controls in appropriate age-gender-ethnicity groups, community-based recruitment methods were used. Demographic characteristics and behavioral and occupational risk factors for controls, by recruitment method, were compared with those for lung cancer cases to evaluate potential bias. The average numbers of hours spent per control recruited were 18.6 for RDD, 11.4 for HCFA, and less than 1 for the community-based methods. The prevalence of smoking-related lung cancer risk factors was significantly higher among African-American community-based controls than for those identified through RDD (p < 0.005). Compared with HCFA controls, Latino RDD controls reported significantly higher cumulative smoking exposure (p < 0.05). Further assessment of strategies for successful recruitment of minority participants into epidemiologic studies is warranted.     

Macronutrients Intake and Risk of Stomach Cancer: Findings from Case-Control Study

Studies on the association between gastric cancer (GC) and the intake of nutrients in Jordan are very limited, while findings from other reports on the intake of energy and macronutrients are controversial. This study aimed to examine the associations between intake of energy and macronutrients and the risk of GC in a Jordanian population. A case-control study was carried out between March 2015 and August 2018 in four major hospitals, including an oncology center in Jordan. Study participants were 173 cases with incident and histologically confirmed GC and 314 frequency-matched controls. Interview-based questionnaires were used to obtain the study’s information. Data on nutrient intake were collected using a validated Arabic food-frequency questionnaire (FFQ). Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated through multinomial logistic regression and adjusted for potential confounders, including age, marital status, education, body mass index (BMI), smoking, period of smoking, family history of gastric cancer, history of gastric ulcer, and physical activity. Intakes of total fat, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, trans-fat, and omega-6 fatty acids were significantly associated with increased risk of GC. The ORs for the highest versus the lowest tertiles were 6.47 (95% Cl: 3.29–12.77), 2.97 (95% CI: 1.58–5.58), 6.84 (95% CI: 3.46–13.52), 6.19 (95% CI: 3.15–12.17), 3.05 (95% CI: 1.58–5.88), 8.11 (95% CI: 4.20–15.69), and 2.74 (95% CI: 1.47–5.09), respectively. No significant association was found for energy, protein, carbohydrate, sugar, fibers, and omega-3 fatty acids. The findings of this study suggest that high intake of selected types of fats was associated with an increased risk of GC.     

Sun Exposure,Vitamin D,and Risk of Hodgkin and Non-Hodgkin Lymphoma

Similarities in the epidemiology of melanoma, other skin cancers, and non-Hodgkin lymphoma (NHL) have led to the hypothesis that UV exposure, the major risk factor for cutaneous cancers, could play a role on NHL risk too. Epidemiologic studies, however, including a pooled analysis of 10 case-control studies performed by the Interlymph consortium, have failed to confirm this hypothesis. If anything, an inverse association between sun exposure and NHL risk was reported, which appeared confined to recreational sun exposure. Given that sun exposure is the major determinant of vitamin D status in several populations and that vitamin D has been suggested to protect against cancer at several sites, it has been postulated that vitamin D may protect against NHL. Studies that have investigated the association of nutritional sources of vitamin D or serum levels of 25 hydroxy-vitamin D—an indicator of vitamin D status—with NHL are scanty and not totally consistent. Thus, the epidemiologic evidence to date suggests that sun exposure is not likely to increase NHL risk, whereas the vitamin D-NHL relation remains largely undefined. The paucity of information on the relation of sun exposure or vitamin D with adult Hodgkin lymphoma (HL) or childhood lymphomas prevents any definite conclusion.     

Nitrate Intake Relative to Antioxidant Vitamin Intake Affects Gastric Cancer Risk: A Case-Control Study in Korea

The objective of this study was to determine whether the intake of nitrate relative to antioxidant vitamin rather than absolute intake of nitrate affects the risk of gastric cancer (GC). In a case-control study in Korea using a food frequency questionnaire, trained dietitians interviewed 136 GC cases and an equal number of controls matched by sex and age. As an index of nitrate intake relative to antioxidant vitamins intake, we calculated the nitrate:antioxidant vitamin consumption ratio. The mean daily nitrate intake from foods was very high in our subjects. Higher absolute intake of nitrate was not associated with GC risk [odds ratios (OR) = 1.13; 95% confidence interval (CI) = 0.42–3.06]. However, the GC risk distinctly increased as the nitrate:antioxidant vitamin consumption ratio increased, particularly with higher nitrate:vitamin E (OR = 2.78; 95% CI = 1.01–7.67) and nitrate:folate ratios (OR = 3.37; 95% CI = 1.28–8.87). Therefore, GC risk was influenced by the intake of nitrate relative to antioxidant vitamins. Our results suggest that a decrease in the intake of nitrate relative to antioxidant vitamins is considerably more effective in reducing GC risk than either a lower absolute intake of nitrate or a higher intake of antioxidant vitamins alone.     

Walking,bicycling, and urban landscapes: evidence from the San Francisco Bay Area

Some claim that car-dependent cities contribute to obesity by discouraging walking and bicycling. In this article, we use household activity data from the San Francisco region to study the links between urban environments and nonmotorized travel. We used factor analysis to represent the urban design and land-use diversity dimensions of built environments. Combining factor scores with control variables, like steep terrain, that gauge impediments to walking and bicycling, we estimated discrete-choice models. Built-environment factors exerted far weaker, although not inconsequential, influences on walking and bicycling than control variables. Stronger evidence on the importance of urban landscapes in shaping foot and bicycle travel is needed if the urban planning and public health professions are to forge an effective alliance against car-dependent sprawl.