Blood methylomics in response to arsenic exposure in a low-exposed US population

Exposure to arsenic (As) has been associated with a number of diseases such as cancers, cardiovascular diseases (CVD), and neurological disorders. To explore the possible underlying epigenetic mechanisms, a nested case-control study was conducted within the Coronary Artery Risk Development in Young Adults (CARDIA) study by randomly selecting 46 non-smoker and non-diabetic White participants with low (N=23) and high (N=23) As exposure based on toenail total As measures at examination year 2. We conducted methylomic profiling of white blood cell (WBC) DNA collected at examination year 15 using the Illumina HumanMethylation450 BeadChip, and performed association tests using multiple linear regression models adjusting for age, sex, and estimated WBC proportions. We observed 22 CpG sites with methylation levels associated with high As exposure at a nominal significance level of 10(-4). However, the statistical significance disappeared after correction for multiple testing. Some genes annotated by these 22 CpG sites are known to be involved in As-associated diseases. Replication in larger samples of individuals with low levels of As exposure will be required.

Dietary iron intake and body iron stores are associated with risk of coronary heart disease in a meta-analysis of prospective cohort studies

The link between iron intake as well as body iron stores and coronary heart disease (CHD) has been contentiously debated, and the epidemiologic evidence is inconsistent. We aimed to quantitatively summarize the literature on the association between dietary iron intake/body iron stores and CHD risk by conducting a meta-analysis of prospective cohort studies. PubMed was used to find studies published through June 2013 in peer-reviewed journals. Embase or a hand search of relevant articles was used to obtain additional articles. The pooled RRs of CHD incidence and mortality with 95% CIs were calculated by using either a random-effects or fixed-effects model, as appropriate. Twenty-one eligible studies (32 cohorts) including 292,454 participants with an average of 10.2 y of follow-up were included. Heme iron was found to be positively associated with CHD incidence (RR: 1.57; 95% CI: 1.28, 1.94), whereas total iron was inversely associated (RR: 0.85; 95% CI: 0.73, 0.999). Neither heme-iron nor total iron intakes were significantly associated with CHD mortality. Both transferrin saturation and serum iron were inversely related to CHD incidence [RR (95% CI): 0.76 (0.66, 0.88) and 0.68 (0.56, 0.82), respectively], but only transferrin saturation was inversely associated with CHD mortality (RR: 0.85; 95% CI: 0.73, 0.99). In conclusion, total iron intake and serum iron concentrations were inversely associated with CHD incidence, but heme iron intake was positively related to CHD incidence. Elevated serum transferrin saturation concentration was inversely associated with both CHD incidence and mortality. Future research is needed to establish the causal relation and to elucidate potential mechanisms.

Genome-wide analysis of DNA methylation variations caused by chronic glucolipotoxicity in beta-cells

There is a growing body of literature suggesting the role of interactions between genes and the environment in development of type 2 diabetes mellitus (T2DM). However, the interplay between environment and genetic in developing and progressing T2MD is not fully understood. To determine the effects of high-glucose-lipid on the status of DNA methylation in beta cells, and clarify the mechanism of glucolipotoxicity on beta-cell deterioration, the DNA methylation profile was detected in beta-cells cultured with high-glucose-lipid medium.We utilized a high throughput NimbleGen RN34 CpG Island & Promoter Microarray to investigate the DNA methylation profile in beta-cells cultured with high-glucose-lipid medium. To validate the results of microarray, the immunoprecipitation (MeDIP) PCR was used to test the methylation status of some selected genes. The mRNA and protein expression of insulin and Tcf7l2 in these cells were quantified by RT-PCR and western blot, respectively.We have identified a lot of loci which experienced aberrant DNA methylation in beta-cells cultured with high-glucose-lipid medium. The results of MeDIP PCR were consistency to the microarray. An opposite regulation in transcription and translation of Tcf7l2 gene was found. Furthermore, the insulin mRNA and protein expression in beta-cells also decreased after cultured with high-glucose-lipid medium compared with the control cells.We conclude that chronic glucolipotoxicity could induce aberrant DNA methylation of some genes and may affect these genes expression in beta-cells, which might contribute to beta-cell function failure in T2DM and be helpful to explain, at least partially, the mechanism of glucolipotoxicity on beta-cells deterioration.

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

BACKGROUND/OBJECTIVES

The aim of this study was to quantitatively summarize the association of dietary magnesium (Mg) intake with serum C-reactive protein (CRP) levels in the general population.

SUBJECTS/METHODS

Observational and experimental studies through February 2013 were reviewed in PubMed and EMBASE. Additional information was retrieved through Google or hand search of related reference lists. The main outcome is either adjusted geometric mean of CRP or odds ratio (OR) of having serum CRP ≥ 3 mg/l. Meta-regression was used to determine the linear association of dietary Mg intake and adjusted geometric means of CRP levels. A fixed-effects model was used to pool ORs of interest, comparing those in the lowest with those in the highest group of dietary Mg intake.

RESULTS

A data set derived from seven cross-sectional studies including 32,918 participants was quantitatively assessed. A weighted inverse association between Mg intake and serum CRP levels was observed (β-coefficient: -0.0028; 95% confidence interval (CI), -0.0043 to -0.0013; P(trend) = 0.001) from four cross-sectional studies. The pooled OR (95% CI) of having CRP ≥ 3 mg/l was 1.49 (1.18-1.89) on comparing the lowest to the highest group of Mg intake from three studies with the data available. Qualitative assessment among five intervention studies also showed a potential beneficial effect of Mg intake on serum CRP levels.

CONCLUSIONS

This meta-analysis and systematic review indicates that dietary Mg intake is significantly and inversely associated with serum CRP levels. The potential beneficial effect of Mg intake on chronic diseases may be, at least in part, explained by inhibiting inflammation.

Fasting insulin concentrations and incidence of hypertension, stroke, and coronary heart disease: a meta-analysis of prospective cohort studies

BACKGROUND

Insulin resistance is a precursor of numerous chronic diseases, including cardiovascular disease (CVD). The fasting insulin concentration is considered a reasonable surrogate of insulin resistance, especially among nondiabetic individuals.

OBJECTIVE

We aimed to quantitatively summarize the literature on the association of fasting insulin concentrations with risk of hypertension, stroke, and coronary heart disease (CHD) by conducting a meta-analysis of prospective cohort studies.

DESIGN

Eligible studies were identified by searching PubMed and EMBASE through January 2013. Additional information was retrieved through Google Scholar or a hand review of the reference lists from relevant articles. Prospective cohort studies that reported RRs and corresponding 95% CIs for the association of interest were identified. Data were extracted independently by 2 investigators, and the weighted RRs and 95% CIs for the associations were obtained by using a random-effects model.

RESULTS

Of the 22 identified studies, 10 reported results on hypertension (36,617 individuals and 4491 cases), 7 on stroke (27,887 individuals and 1550 cases), and 9 on CHD (22,379 individuals and 1986 cases). Comparison of the highest with the lowest quantile of fasting insulin concentrations showed a pooled RR (95% CI) of 1.63 (1.35, 1.97) for hypertension, 1.18 (0.87, 1.60) for stroke, and 1.50 (1.28, 1.77) for CHD. Each 50-pmol/L increment in fasting insulin was associated with a 25% increase in risk of hypertension [RR: 1.25 (1.14, 1.36)] and a 16% increase in risk of CHD [RR: 1.16 (1.10, 1.22)] but was not associated with risk of stroke [RR: 0.999 (0.99, 1.01)].

CONCLUSIONS

A higher fasting insulin concentration or hyperinsulinemia was significantly associated with an increased risk of hypertension and CHD but not stroke. This meta-analysis suggests that early fasting insulin ascertainment in the general population may help clinicians identify those who are potentially at high risk of CVD.

Fish and fish oil intake in relation to risk of asthma: a systematic review and meta-analysis

Although laboratory studies suggest that long-chain n-3 polyunsaturated fatty acids (LCn3PUFAs) may reduce risk of asthma, epidemiological data remain controversial and inconclusive. We quantitatively reviewed the epidemiological studies published through December 2012 in PubMed and EMBASE by using a fixed-effects or random-effects model. Eleven studies, comprised of 99,093 individuals (3,226 cases), were included in the final dataset. Of them, 7 studies examined associations between intake of fish or LCn3PUFA and risk of asthma: 4 studies in children (996 cases from 12,481 children) and 3 in adults (1,311 cases from 82,553 individuals). Two studies (69 cases from 276 infants) investigated LCn3PUFA levels in mothers' milk, and two studies assessed maternal fish consumption (786 cases from 2,832 individuals) during lactation and/or plasma LCn3PUFA levels during pregnancy (64 cases from 951 infants) in relation to offspring's asthma. The pooled relative risk of child asthma were 0.76 (95% CI, 0.61-0.94) for fish consumption and 0.71 (95% CI, 0.52-0.96) for LCn3PUFA intake. No statistically significant association was found in studies among adults. Epidemiological data to date indicate that fish or LCn3PUFA intake may be beneficial to prevent asthma in children. Further studies are needed to establish causal inference and to elucidate the potential mechanisms.

White blood cell count in young adulthood and coronary artery calcification in early middle age: coronary artery risk development in young adults (CARDIA) study

White blood cell (WBC) count is associated with incident coronary heart disease (CHD). Data are sparse regarding its association in young adults with future coronary artery calcification (CAC). Our study was conducted among coronary artery risk development in young adults (CARDIA) participants (n=3,094). We examined the association between baseline (Y0) WBC counts and CHD risk factors using linear regression models. We further assessed prospective associations between Y0 WBC and inflammatory biomarkers during the follow-up, and the presence of CAC 15 and 20 years later. In total, 272 and 566 subjects had CAC scores>0 at year (Y) 15 and Y20, respectively. Baseline total WBC counts were cross-sectionally associated with SBP, BMI, and smoking, or HDL-cholesterol (p≤0.01) at Y0, and prospectively associated with C-reactive protein at Y7, Y15, and Y20, and fibrinogen at Y5 and Y20 (p<0.01). After adjustment for potential confounding factors, baseline neutrophil count was borderline associated with CAC presence 15 years later (OR=1.18 per unit, 95% CI 1.00-1.44) and total WBC (OR=1.07, 95% CI 0.96-1.19) or eosinophil (OR=1.12, 95%CI 1.00-1.25) was borderline associated with CAC presence at Y20. Baseline total WBC counts in young adults was associated prospectively with CAC presence 20 years later after adjusting for age, sex, and race. Results are attenuated when other risk factors are accounted for. Our results suggest the possible early involvement of WBC, particularly eosinophils, in the early stages of atherosclerosis.

Serum fatty acids and incidence of ischemic stroke among postmenopausal women

BACKGROUND AND PURPOSE

Although studies have linked types of fatty acids with coronary heart disease, data on individual fatty acids and risk of ischemic stroke are limited. We aimed to examine the associations between serum fatty acid concentrations and incidence of ischemic stroke and its subtypes.

METHODS

We conducted a prospective case-control study nested in the Women's Health Initiative Observational Study cohort of postmenopausal US women aged 50 to 79 years. Between 1993 and 2003, incident cases of ischemic stroke were matched 1:1 to controls on age, race, and length of follow-up (964 matched pairs). Conditional logistic regression was used to estimate odds ratios and 99.9% confidence intervals (CI) for ischemic stroke and its subtypes.

RESULTS

The multivariable-adjusted odds ratios and 99.9% CI of ischemic stroke associated with a 1-SD increment in serum fatty acid concentration were 1.38 (99.9% CI, 1.05-1.83) for linoelaidic acid (18:2tt, SD=0.04%), 1.27 (99.9% CI, 1.06-1.51) for palmitic acid (16:0, SD=2.74%), 1.20 (99.9% CI, 1.01-1.43) for oleic acid (18:1n9, SD=2.32%), 0.72 (99.9% CI, 0.59-0.87) for docosapentaenoic acid (22:5n3, SD=0.18%), 0.72 (99.9% CI, 0.59-0.87) for docosahexaenoic acid (22:6n3, SD=0.91%), and 0.81 (99.9% CI, 0.67-0.98) for arachidonic acid (20:4n6, SD=2.02%). These associations were generally consistent for atherothrombotic and lacunar stroke but not cardioembolic stroke.

CONCLUSIONS

These findings suggest that individual serum trans, saturated, and monounsaturated fatty acids are positively associated with particular ischemic stroke subtypes, whereas individual n3 and n6 polyunsaturated fatty acids are inversely associated.

Egg consumption in relation to risk of cardiovascular disease and diabetes: a systematic review and meta-analysis

BACKGROUND

The associations of egg consumption with cardiovascular disease (CVD) and diabetes are still unclear.

OBJECTIVE

We aimed to quantitatively summarize the literature on egg consumption and risk of CVD, cardiac mortality, and type 2 diabetes by conducting a meta-analysis of prospective cohort studies.

DESIGN

A systematic literature review was conducted for published studies in PubMed and EMBASE through March 2012. Additional information was retrieved through Google or a hand review of the reference from relevant articles. Studies were included if they had a prospective study design, were published in English-language journals, and provided HRs and 95% CIs for the associations of interest. Data were independently extracted by 2 investigators, and the weighted HRs and 95% CIs for the associations of interest were estimated by using a random-effects model.

RESULTS

A total of 22 independent cohorts from 16 studies were identified, including participants ranging in number from 1600 to 90,735 and in follow-up time from 5.8 to 20.0 y. Comparison of the highest category (≥1 egg/d) of egg consumption with the lowest (<1 egg/wk or never) resulted in a pooled HR (95% CI) of 0.96 (0.88, 1.05) for overall CVD, 0.97 (0.86, 1.09) for ischemic heart disease, 0.93 (0.81, 1.07) for stroke, 0.98 (0.77, 1.24) for ischemic heart disease mortality, 0.92 (0.56, 1.50) for stroke mortality, and 1.42 (1.09, 1.86) for type 2 diabetes. Of the studies conducted in diabetic patients, the pooled HR (95% CI) was 1.69 (1.09, 2.62) for overall CVD.

CONCLUSIONS

This meta-analysis suggests that egg consumption is not associated with the risk of CVD and cardiac mortality in the general population. However, egg consumption may be associated with an increased incidence of type 2 diabetes among the general population and CVD comorbidity among diabetic patients.

Mercury exposure in young adulthood and incidence of diabetes later in life: the CARDIA Trace Element Study

OBJECTIVE

Laboratory studies suggest that exposure to methylmercury at a level similar to those found in fish may induce pancreatic islet β-cell dysfunction. Few, if any, human studies have examined the association between mercury exposure and diabetes incidence. We examined whether toenail mercury levels are associated with incidence of diabetes in a large prospective cohort. RESEACH DESIGN AND METHODS: A prospective cohort of 3,875 American young adults, aged 20-32 years, free of diabetes in 1987 (baseline), were enrolled and followed six times until 2005. Baseline toenail mercury levels were measured with instrumental neutron-activation analysis. Incident diabetes was identified by plasma glucose levels, oral glucose tolerance tests, hemoglobin A1C levels, and/or antidiabetes medications.

RESULTS

A total of 288 incident cases of diabetes occurred over 18 years of follow-up. In multivariate analyses adjusted for age, sex, ethnicity, study center, education, smoking status, alcohol consumption, physical activity, family history of diabetes, intakes of long-chain n-3 fatty acids and magnesium, and toenail selenium, toenail mercury levels were positively associated with the incidence of diabetes. The hazard ratio (95% CI) of incident diabetes compared the highest to the lowest quintiles of mercury exposure was 1.65 (1.07-2.56; P for trend = 0.02). Higher mercury exposure at baseline was also significantly associated with decreased homeostasis model assessment of β-cell function index (P for trend < 0.01).

CONCLUSIONS

Our results are consistent with findings from laboratory studies and provide longitudinal human data suggesting that people with high mercury exposure in young adulthood may have elevated risk of diabetes later in life.

ADAR1 is essential for intestinal homeostasis and stem cell maintenance

Adenosine deaminase acting on RNA 1 (ADAR1) is a double-stranded RNA-editing enzyme that converts adenosine (A) to inosine (I), and essential for normal development. In this study, we reported an essential role of ADAR1 in the survival and maintenance of intestinal stem cells and intestinal homoeostasis by suppressing endoplasmic reticulum (ER) stress and interferon (IFN) signaling. ADAR1 was highly expressed in the Lgr5+ cells, and its deletion in adult mice led to a rapid apoptosis and loss of these actively cycling stem cells in the small intestine and colon. ADAR1 deletion resulted in a drastic expansion of progenitors and Paneth cells but a reduction of three other major epithelial lineages. Moreover, loss of ADAR1 induced ER stress and activation of IFN signaling, and altered expression in WNT targets, followed by intestinal inflammation. An ER stress inhibitor partially suppressed crypt apoptosis. Finally, data from cultured intestinal crypts demonstrated that loss of ADAR1 in the epithelial cells is the primary cause of these effects. These results support an essential role of ADAR1 and RNA editing in tissue homeostasis and stem cells.

Distributions and determinants of mercury concentrations in toenails among American young adults: the CARDIA Trace Element Study

Since data on mercury (Hg) levels in Caucasians and African Americans (AAs) of both genders are lacking, this study aims to present toenail Hg distributions and explore the potential determinants using data from the Coronary Artery Risk Development in Young Adults Trace Element Study. Data from 4,344 Americans, aged 20-32 in 1987, recruited from Oakland, Chicago, Minneapolis, and Birmingham were used to measure toenail Hg levels by instrumental neutron-activation method. The Hg distribution was described with selected percentiles and geometric means. Multivariable linear regression (MLR) was used to examine potential determinants of Hg levels within ethnicity-gender subgroups. The geometric mean of toenail Hg was 0.212 (95 % CI = 0.207-0.218) μg/g. Hg levels varied geographically with Oakland the highest [0.381 (0.367-0.395) μg/g] and Minneapolis the lowest [0.140 (0.134-0.147) μg/g]. MLR analyses showed that male gender and AA ethnicity were negatively associated with toenail Hg levels, and that age, living in Oakland city, education level, alcohol consumption, and total fish intake were positively associated with toenail Hg concentrations within each ethnicity-gender subgroup. Current smokers were found to have higher Hg only in AA men. This study suggested age, gender, ethnicity, study center, alcohol, education level, and fish consumption consistently predict toenail Hg levels. As fish consumption was the key determinant, avoiding certain types of fish that have relatively high Hg levels may be crucial in reducing Hg intake.

Cardiovascular health through young adulthood and cognitive functioning in midlife

OBJECTIVE

A study was undertaken to examine the association between overall cardiovascular health as recently defined by the American Heart Association in young adulthood to middle age and cognitive function in midlife. Overall ideal cardiovascular health incorporates 7 metrics, including the avoidance of overweight or obesity, a healthful diet, nonsmoking, and physical activity, total cholesterol, blood pressure, and fasting glucose at goal levels.

METHODS

This analysis of the Coronary Artery Risk Development in Young Adults study, a multicenter community-based study with 25 years of follow-up, included 2,932 participants aged 18 to 30 years at baseline (year 0) who attended follow-up examinations at years 7 and 25. Cardiovascular health metrics were measured at each examination. The Digit Symbol Substitution Test (DSST), modified Stroop test, and Rey Auditory Verbal Learning Test (RAVLT) were completed at year 25.

RESULTS

A greater number of ideal cardiovascular metrics in young adulthood and middle age were independently associated with better cognitive function in midlife (p for trend < 0.01, for all). Specifically, each additional ideal metric was associated with 1.32 more symbols on the DSST (95% confidence interval [CI] = 0.93 - 1.71), a 0.77-point lower interference score on the Stroop test (95% CI=-1.03 to -0.45), and 0.12 more words on the RAVLT (95% CI = 0.04 to 0.20). Participants who had ≥5 ideal metrics at a greater number of the 3 examinations over the 25-year period exhibited better performance on each cognitive test in middle age (p for trend < 0.01, for all).

INTERPRETATION

Ideal cardiovascular health in young adulthood and its maintenance to middle age is associated with better psychomotor speed, executive function, and verbal memory in midlife.

Disrupting the PIKE-A/Akt interaction inhibits glioblastoma cell survival, migration, invasion and colony formation

The cyclin-dependent kinase 4 (CDK4) amplicon is frequently amplified in numerous human cancers including gliomas. PIKE-A, a proto-oncogene that is one of the important components of the CDK4 amplicon, binds to and enhances the kinase activity of Akt, thereby promoting cancer progression. To define the roles of the PIKE-A/Akt interaction in glioblastoma multiform (GBM) progression, we used biochemical protein/protein interaction (PPI) assays and live cell fluorescence-based protein complementation assays to search for small peptide antagonist from these proteins that were able to block their interaction. Here, we show that disruption of the interaction between PIKE-A and Akt by the small peptides significantly reduces glioblastoma cell proliferation, colony formation, migration and invasion. Disruption of PIKE-A/Akt association potently suppressed GBM cell proliferation and sensitized the cells to two clinical drugs that are currently used to treat GBM. Interestingly, GBM cells containing the CDK4 amplicon were more responsive to the inhibition of the PIKE-A/Akt interaction than GBM cells lacking this amplicon. Taken together, our findings provide proof-of-principle that blocking a PPI that is essential for cancer progression provides a valuable strategy for therapeutic discovery.

Exome sequencing-driven discovery of coding polymorphisms associated with common metabolic phenotypes

AIMS/HYPOTHESIS

Human complex metabolic traits are in part regulated by genetic determinants. Here we applied exome sequencing to identify novel associations of coding polymorphisms at minor allele frequencies (MAFs) >1% with common metabolic phenotypes.

METHODS

The study comprised three stages. We performed medium-depth (8×) whole exome sequencing in 1,000 cases with type 2 diabetes, BMI >27.5 kg/m(2) and hypertension and in 1,000 controls (stage 1). We selected 16,192 polymorphisms nominally associated (p < 0.05) with case-control status, from four selected annotation categories or from loci reported to associate with metabolic traits. These variants were genotyped in 15,989 Danes to search for association with 12 metabolic phenotypes (stage 2). In stage 3, polymorphisms showing potential associations were genotyped in a further 63,896 Europeans.

RESULTS

Exome sequencing identified 70,182 polymorphisms with MAF >1%. In stage 2 we identified 51 potential associations with one or more of eight metabolic phenotypes covered by 45 unique polymorphisms. In meta-analyses of stage 2 and stage 3 results, we demonstrated robust associations for coding polymorphisms in CD300LG (fasting HDL-cholesterol: MAF 3.5%, p = 8.5 × 10(-14)), COBLL1 (type 2 diabetes: MAF 12.5%, OR 0.88, p = 1.2 × 10(-11)) and MACF1 (type 2 diabetes: MAF 23.4%, OR 1.10, p = 8.2 × 10(-10)).

CONCLUSIONS/INTERPRETATION

We applied exome sequencing as a basis for finding genetic determinants of metabolic traits and show the existence of low-frequency and common coding polymorphisms with impact on common metabolic traits. Based on our study, coding polymorphisms with MAF above 1% do not seem to have particularly high effect sizes on the measured metabolic traits.

Types of fish consumed and fish preparation methods in relation to pancreatic cancer incidence: the VITAL Cohort Study

The associations of types of fish and fish preparation methods with pancreatic cancer risk remain unknown. The authors conducted a prospective cohort study in western Washington State among 66,616 adults, aged 50-76 years, who participated in the VITamins And Lifestyle cohort study. Diet was assessed by a food frequency questionnaire. Pancreatic cancer cases were identified by linkage to the Surveillance, Epidemiology, and End Results cancer registry. During an average follow-up of 6.8 years, 151 participants developed pancreatic cancer (adenocarcinoma). Long-chain (n-3) polyunsaturated fatty acids (LC-PUFAs) and nonfried fish intake were inversely associated with pancreatic cancer incidence. When the highest and lowest tertiles of exposure were compared, the multivariable-adjusted hazard ratio of pancreatic cancer was 0.62 (95% confidence interval: 0.40, 0.98) (P(trend) = 0.08) for LC-PUFAs and 0.55 (95% confidence interval: 0.34, 0.88) (P(trend) = 0.045) for nonfried fish. Docosahexaenoic acid showed a greater inverse association with pancreatic cancer than eicosapentaenoic acid. No statistically significant associations were observed with fried fish and shellfish consumption. The potential health impact of fish consumption may depend on the types of fish consumed and fish preparation methods. LC-PUFAs, particularly docosahexaenoic acid, and nonfried fish, but not shellfish or fried fish, may be beneficial in the primary prevention of pancreatic cancer.

Intakes of long-chain omega-3 (n-3) PUFAs and fish in relation to incidence of asthma among American young adults: the CARDIA study

BACKGROUND

Although long-chain ω-3 (n-3) PUFAs (LCω3PUFAs) have been linked to the prevention of some inflammatory disorders, little is known about the association between these fatty acids and incidence of asthma.

OBJECTIVE

The objective was to prospectively investigate the association between LCω3PUFAs and fish intake and incidence of asthma among American young adults.

DESIGN

A 20-y follow-up longitudinal analysis was conducted in a biracial cohort of 4162 Americans, aged 18-30 y, with a history of asthma at baseline in 1985. Diet was assessed by a validated interviewer-administered quantitative food-frequency questionnaire at the examinations in 1985, 1992, and 2005. Incident self-reported asthma was defined as having a physician diagnosis of asthma and/or the use of asthma medications between 1985 and 2005.

RESULTS

During the 20-y follow-up, 446 incident cases of asthma were identified. LCω3PUFA intake was significantly inversely associated with incidence of asthma after adjustment for sociodemographic, major lifestyle, and dietary confounders. The multivariable-adjusted HR for the highest quintile of LCω3PUFA intake as compared with the lowest quintile was 0.46 (95% CI: 0.33, 0.64; P-trend < 0.01). However, a higher frequency of nonfried fish consumption was not significantly associated with the risk of asthma. DHA showed a greater inverse association than did EPA. The association between LCω3PUFAs and incident asthma was not appreciably modified by sex, race, BMI, smoking status, or atopic status.

CONCLUSION

This study showed that intakes of LCω3PUFAs are inversely longitudinally associated with the incidence of asthma in American young adults.

Agricultural exposures and stroke mortality in the Agricultural Health Study

Exposures associated with common agricultural activities may increase risk of stroke. The authors evaluated associations between self-reported agricultural activities including pesticide use and handling of crops and stroke mortality among 51,603 male pesticide applicators enrolled in the Agricultural Health Study (AHS). Vital status was obtained through 2008. Stroke mortality was defined by underlying or contributing cause of death (ICD-9 430-438, ICD-10 I60-I69). Information regarding lifetime pesticide use, working with crops or animals, engagement in other agricultural activities, and potential confounders was self-reported at enrollment. Cox proportional hazards models, with age as the time scale, were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) adjusted for state of residence, smoking status, and alcohol consumption. Median follow-up time was 13 yr, during which 308 stroke deaths occurred. No measure of overall or specific pesticide use was positively associated with mortality due to stroke. Stroke mortality was inversely associated with handling hay, grain, or silage at least once each year as reported at enrollment (HR: 0.75; 95% CI: 0.58, 0.98). There was no evidence of an association between pesticide use and stroke mortality. The inverse association between handling of hays and grains and stroke mortality may be due to (1) those engaging in such activities being healthier than those who did not or (2) exposure to some biological agent present in hays and grains. Further investigation of incident stroke, rather than stroke mortality, as well as stroke subtypes, is needed to determine the full role of agricultural exposures and stroke.

Antioxidant intake and pancreatic cancer risk: the Vitamins and Lifestyle (VITAL) Study

BACKGROUND

Oxidative stress causes damage to many components of human cells (ie, proteins, lipids, and DNA) and is involved in carcinogenesis. Nutrients with antioxidant properties may protect against oxidative stress. In this study, the authors examined the intake of antioxidants from diet and supplements in relation to pancreatic cancer risk among participants of the Vitamins and Lifestyle (VITAL) Study.

METHODS

The participants included 77,446 men and women ages 50 to 76 years who were residents of western Washington State and who completed a baseline questionnaire between 2000 and 2002. Participants reported usual diet over the past year and use of supplements over the past 10 years in addition to demographic and lifestyle factors. During a median follow-up of 7.1 years, 184 participants developed pancreatic adenocarcinoma. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for 7 antioxidants: β-carotene, lutein plus zeaxanthin, lycopene, vitamin C, vitamin E, selenium, and zinc.

RESULTS

An inverse association was observed between dietary selenium and the risk of pancreatic cancer (medium vs low intake: HR, 0.58; 95% CI, 0.35-0.94; high vs low intake: HR, 0.44; 95% CI, 0.23-0.85; Ptrend = .01); however, when supplemental and dietary exposures were combined, the association was no longer statistically significant.

CONCLUSIONS

Dietary selenium intake was inversely associated with the risk of pancreatic cancer, and the observed association was attenuated by selenium supplementation.

A comparison of the clinical characteristics of women with recurrent major depression with and without suicidal symptomatology

BACKGROUND

The relationship between recurrent major depression (MD) in women and suicidality is complex. We investigated the extent to which patients who suffered with various forms of suicidal symptomatology can be distinguished from those subjects without such symptoms.

METHOD

We examined the clinical features of the worst episode in 1970 Han Chinese women with recurrent DSM-IV MD between the ages of 30 and 60 years from across China. Student's t tests, and logistic and multiple logistic regression models were used to determine the association between suicidality and other clinical features of MD.

RESULTS

Suicidal symptomatology is significantly associated with a more severe form of MD, as indexed by both the number of episodes and number of MD symptoms. Patients reporting suicidal thoughts, plans or attempts experienced a significantly greater number of stressful life events. The depressive symptom most strongly associated with lifetime suicide attempt was feelings of worthlessness (odds ratio 4.25, 95% confidence interval 2.9-6.3). Excessive guilt, diminished concentration and impaired decision-making were also significantly associated with a suicide attempt.

CONCLUSIONS

This study contributes to the existing literature on risk factors for suicidal symptomatology in depressed women. Identifying specific depressive symptoms and co-morbid psychiatric disorders may help improve the clinical assessment of suicide risk in depressed patients. These findings could be helpful in identifying those who need more intense treatment strategies in order to prevent suicide.