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American Journal of Epidemiology [journal]
- Coarse Particles and Respiratory Emergency Department Visits in California. [JOURNAL ARTICLE]
- Am J Epidemiol 2013 May 31.
Although respiratory disease has been strongly connected to fine particulate air pollution (particulate matter <2.5 μm in diameter (PM2.5)), evidence has been mixed regarding the effects of coarse particles (particulate matter from 2.5 to 10 μm in diameter), possibly because of the greater spatial heterogeneity of coarse particles. In this study, we evaluated the relationship between coarse particles and respiratory emergency department visits, including common subdiagnoses, from 2005 to 2008 in 35 California counties. A time-stratified case-crossover design was used to help control for time-invariant confounders and seasonal influences, and the study population was limited to those residing within 20 km of pollution monitors to mitigate the influence of spatial heterogeneity. Significant associations between respiratory emergency department visits and coarse particle levels were observed. Asthma visits showed associations (for 2-day lag, excess risk per 10 μg/m(3) = 3.3%, 95% confidence interval: 2.0, 4.6) that were robust to adjustment by other common air pollutants (particles <2.5 μm in diameter, ozone, nitrogen dioxide, carbon monoxide, and sulfur dioxide). Pneumonia and acute respiratory infection visits were not associated, although some suggestion of a relationship with chronic obstructive pulmonary disease visits was present. Our results indicate that coarse particle exposure may trigger asthma exacerbations requiring emergency care, and reducing exposures among asthmatic persons may provide benefits.
- Liver Aminotransferases and Risk of Incident Type 2 Diabetes: A Systematic Review and Meta-Analysis. [JOURNAL ARTICLE]
- Am J Epidemiol 2013 May 31.
We evaluated the associations of liver aminotransferases with risk of type 2 diabetes (T2D) in general populations by conducting a systematic review and meta-analysis of published prospective studies. Studies were identified in a literature search of PubMed, EMBASE, and Web of Science from 1950 through October 2012. Of the 2,729 studies reviewed, 17 studies involving 60,359 participants and 3,890 incident T2D events were included. All of the studies assessed associations between alanine aminotransferase (ALT) level and T2D, with heterogeneous findings (I(2) = 88%, 95% confidence interval (CI): 82, 92; P < 0.001). The pooled fully adjusted relative risk of T2D was 1.26 (95% CI: 1.14, 1.41) per 1-standard-deviation change in log baseline ALT level. This association became nonsignificant after trim-and-fill correction for publication bias. Nine studies evaluated associations between aspartate aminotransferase (AST) levels and T2D risk, with a corresponding relative risk of 1.02 (95% CI: 0.99, 1.04). The relative risk of T2D per 5-IU/L increase in ALT level was 1.16 (95% CI: 1.08, 1.25). Available data indicate moderate associations of ALT with risk of T2D events, which may be attributable to publication bias. There was no evidence for an increased risk of T2D with AST. Large prospective studies may still be needed to establish the magnitude and nature of these associations.
- Intake of Caffeinated, Carbonated, or Citrus Beverage Types and Development of Lower Urinary Tract Symptoms in Men and Women. [JOURNAL ARTICLE]
- Am J Epidemiol 2013 May 30.
Evidence to substantiate recommendations for restriction of caffeinated or acidic beverages as self-management for lower urinary tract symptoms (LUTS) is limited. We examined longitudinal and acute associations between beverage intake and LUTS in the Boston Area Community Health (BACH) cohort (n = 4,145) between 2002 and 2010. Multivariable models tested associations between baseline intakes and progression of LUTS at 5-year follow-up, between follow-up intakes and International Prostate Symptom Scores at follow-up, and between 5-year intake changes and LUTS progression. Greater coffee or total caffeine intake at baseline increased the odds of LUTS progression in men (coffee: >2 cups/day vs. none, odds ratio = 2.09, 95% confidence interval: 1.29, 3.40, P-trend = 0.01; caffeine: P-trend < 0.001), particularly storage symptoms. Women who increased coffee intake by at least 2 servings/day during follow-up (compared with categories of decreased or unchanged intakes) had 64% higher odds of progression of urgency (P = 0.003). Women with recently increased soda intake, particularly caffeinated diet soda, had higher symptom scores, urgency, and LUTS progression. Citrus juice intake was associated with 50% lower odds of LUTS progression in men (P = 0.02). Findings support recommendations to limit caffeinated beverage intake for LUTS, and in men, they suggest benefits of citrus juice consumption. Further clinical research is warranted, particularly of the precise role of sodas containing artificial sweeteners in bladder sensations and urological function.
- Dietary flavonoid intake, black tea consumption, and risk of overall and advanced stage prostate cancer. [Journal Article]
- Am J Epidemiol 2013 Jun 15; 177(12):1388-98.
Flavonoids are natural antioxidants found in various foods, and a major source is black tea. Some experimental evidence indicates that flavonoids could prevent prostate cancer. We investigated the associations between flavonoid intake, black tea consumption, and prostate cancer risk in the Netherlands Cohort study, which includes 58,279 men who provided detailed baseline information on several cancer risk factors. From 1986 to 2003, 3,362 prostate cancers were identified, including 1,164 advanced (stage III/IV) cancers. Cox proportional hazards regression using the case-cohort approach was used to estimate hazard ratios and 95% confidence intervals. Intake of total catechin, epicatechin, kaempferol, and myricetin and consumption of black tea were associated with a decreased risk of stage III/IV or stage IV prostate cancer. Hazard ratios of stage III/IV and stage IV prostate cancer for the highest versus the lowest category of black tea consumption (≥5 versus ≤1 cups/day) were 0.75 (95% confidence interval: 0.59, 0.97) and 0.67 (95% confidence interval: 0.50, 0.91), respectively. No associations were observed for overall and nonadvanced prostate cancer. In conclusion, dietary flavonoid intake and black tea consumption were associated with a decreased risk of advanced stage prostate cancer.
- Risk Factors for Type 2 Diabetes Mellitus Preceded by β-Cell Dysfunction, Insulin Resistance, or Both in Older Adults: The Cardiovascular Health Study. [JOURNAL ARTICLE]
- Am J Epidemiol 2013 May 24.
Insulin resistance (IR) and pancreatic β-cell dysfunction lead to type 2 diabetes mellitus (DM). We tested whether risk factors would differ for DM that was preceded predominantly by IR, β-cell dysfunction, or both among 4,384 older adults (mean age, 72.7 (standard deviation, 5.6) years) in the Cardiovascular Health Study, which was conducted in North Carolina, California, Maryland, and Pennsylvania (1989-2007). When evaluating established risk factors, we found older age, greater adiposity, higher systolic blood pressure, a lower high-density lipoprotein cholesterol level, a higher triglyceride level, and a lower alcohol intake to be independently associated with greater IR but, conversely, with better β-cell function (P < 0.001). The prospective associations between some risk factors and incident DM varied significantly depending on whether DM was preceded predominantly by IR, β-cell dysfunction, or both. For example, obesity and lower high-density lipoprotein cholesterol levels were positively associated with DM preceded predominantly by IR (hazard ratio (HR) = 5.02, 95% confidence interval (CI): 2.81, 9.00; and HR = 1.97, 95% CI: 1.32, 2.93, respectively), with a significant association with and an insignificant trend toward a lower risk of DM preceded predominantly by β-cell dysfunction (HR = 0.33, 95% CI: 0.14, 0.80; and HR = 0.78, 95% CI: 0.43, 1.39, respectively). In conclusion, among older adults, DM risk factors were differentially associated with DM preceded predominantly by IR or β-cell dysfunction. Biologic and clinical implications of putative subtypes of DM require further investigation.
- Novel Insights Into Etiologies of Leukemia: A HuGE Review and Meta-Analysis of CYP1A1 Polymorphisms and Leukemia Risk. [JOURNAL ARTICLE]
- Am J Epidemiol 2013 May 24.
We conducted a meta-analysis to investigate the association of 2 single nucleotide polymorphisms in the cytochrome P450, family 1, subfamily 1A1 gene (CYP1A1), CYP1A1*2A and CYP1A1*2C, with the risk of developing different subtypes of leukemia in adults and children. A total of 26 studies published between 1999 and 2011 were identified by searching the PubMed, EMBASE, Medline, and Web of Science databases. The odds ratios for the CYP1A1 polymorphisms and leukemia risk were calculated. The cumulative evidence in genetic associations was graded by using the Venice criteria of the Human Genome Epidemiology Network (Atlanta, Georgia). The results showed that the cumulative evidence was moderate for the association of the CYP1A1*2A variant with leukemia in Caucasians and with childhood acute lymphoid leukemia in Caucasians. In addition, there was moderate evidence that children who carry both the CYP1A1*2A variant and the glutathione S-transferase M1 null genotype have an increased risk of acute lymphoid leukemia. For the CYP1A1*2C polymorphism, the cumulative evidence of an association with leukemia risk was moderate for adults and weak for children. Logistic regression analysis demonstrated an interaction between the CYP1A1*2C polymorphism and age. This meta-analysis showed that the CYP1A1*2A and CYP1A1*2C polymorphisms were associated with an increased risk of leukemia, and that the associations might vary by ethnicity, gene-gene interactions, age, and leukemia subtype.
- The authors reply. [Comment, Letter]
- Am J Epidemiol 2013 Apr 15; 177(8):865-6.
- Two authors reply. [Comment, Letter, Research Support, Non-U.S. Gov't]
- Am J Epidemiol 2013 Apr 15; 177(8):863.