Cured meat, vegetables, and bean-curd foods in relation to childhood acute leukemia risk: a population based case-control study.

BACKGROUND: Consumption of cured/smoked meat and fish leads to the formation of carcinogenic N-nitroso compounds in the acidic stomach. This study investigated whether consumed cured/smoked meat and fish, the major dietary resource for exposure to nitrites and nitrosamines, is associated with childhood acute leukemia. METHODS: A population-based case-control study of Han Chinese between 2 and 20 years old was conducted in southern Taiwan. 145 acute leukemia cases and 370 age- and sex-matched controls were recruited between 1997 and 2005. Dietary data were obtained from a questionnaire. Multiple logistic regression models were used in data analyses. RESULTS: Consumption of cured/smoked meat and fish more than once a week was associated with an increased risk of acute leukemia (OR = 1.74; 95% CI: 1.15-2.64). Conversely, higher intake of vegetables (OR = 0.55; 95% CI: 0.37-0.83) and bean-curd (OR = 0.55; 95% CI: 0.34-0.89) was associated with a reduced risk. No statistically significant association was observed between leukemia risk and the consumption of pickled vegetables, fruits, and tea. CONCLUSION: Dietary exposure to cured/smoked meat and fish may be associated with leukemia risk through their contents of nitrites and nitrosamines among children and adolescents, and intake of vegetables and soy-bean curd may be protective.

A population-based, case-control study of green tea consumption and leukemia risk in southwestern Taiwan.

OBJECTIVE: This study investigated the association between green tea consumption and leukemia. METHODS: A total of 252 cases (90.3% response) and 637 controls (53.4% response) were enrolled. Controls were matched for cases on age and gender. Information was collected on participants' living habits, including tea consumption. Green tea was used as a standard to estimate the total amount of individual catechin consumption. We stratified individual consumption of catechins into four levels. Conditional logistic regression models were fit to subjects aged 0-15 and 16-29 years to evaluate separate associations between leukemia and catechin consumption. RESULTS: A significant inverse association between green tea consumption and leukemia risk was found in individuals aged 16-29 years, whereas no significant association was found in the younger age groups. For the older group with higher amounts of tea consumption (>550 units of catechins), the adjusted odds ratio (OR) compared with the group without tea consumption was 0.47 [95% confidence interval (CI) = 0.23-0.97]. After we adjusted for smoking status and medical irradiation exposure, the overall OR for all participants was 0.49 (95% CI = 0.27-0.91), indicating an inverse relation between large amounts of catechins and leukemia. CONCLUSION: Drinking sufficient amounts of tea, especially green tea, which contains more catechins than oolong tea and black tea, may reduce the risk of leukemia.

Maternal and offspring genetic variants of AKR1C3 and the risk of childhood leukemia.

The aldo-keto reductase 1C3 (AKR1C3) gene located on chromosome 10p15-p14, a regulator of myeloid cell proliferation and differentiation, represents an important candidate gene for studying human carcinogenesis. In a prospectively enrolled population-based case-control study of Han Chinese conducted in Kaohsiung in southern Taiwan, a total of 114 leukemia cases and 221 controls <20 years old were recruited between November 1997 and December 2005. The present study set out to evaluate the association between childhood leukemia and both maternal and offspring's genotypes. To do so, we conducted a systematic assessment of common single-nucleotide polymorphisms (SNPs) at the 5' flanking 10 kb to 3' UTR of AKR1C3 gene. Gln5His and three tagSNPs (rs2245191, rs10508293 and rs3209896) and one multimarker (rs2245191, rs10508293 and rs3209896) were selected with average 90% coverage of untagged SNPs by using the HapMap II data set. Odds ratios and 95% confidence intervals were adjusted for age and gender. After correcting for multiple comparisons, we observed that risk of developing childhood leukemia is significantly associated with rs10508293 polymorphism on intron 4 of the AKR1C3 gene in both offspring alone and in the combined maternal and offspring genotypes (nominal P < 0.0001, permutation P < 0.005). The maternal methylenetetrahydrofolate reductase A1298C polymorphism was found to be an effect modifier of the maternal intron 4 polymorphism of the AKR1C3 gene (rs10508293) and the childhood leukemia risk. In conclusion, this study suggests that AKR1C3 polymorphisms may be important predictive markers for childhood leukemia susceptibility.

Cost-effectiveness of elderly health examination program: the example of hypertension screening.

The National Health Insurance (NHI) and social welfare agencies have implemented the Elderly Health Examination Program (EHEP) for years. No study has ever attempted to evaluate whether this program is cost-effective. The purposes of this study were, firstly, to understand the prevalence and incidence rates of hypertension and, secondly, to estimate the cost and effectiveness of the EHEP, focusing on hypertension screening. The data sources were: (1) hypertension and clinical information derived from the 1996 and 1997 EHEP, which was used to generate prevalence and incidence rates of hypertension; and (2) claim data of the NHI that included treatment costs of stroke patients (in- and outpatients). Hypothetical models were used to evaluate the cost-effectiveness of the hypertension screening program in various conditions. Sensitivity analysis was also employed to evaluate the effect of each estimation indicator on the cost and effectiveness of the hypertension screening program. A total of 28.3% of the elderly population in Kaohsiung (25,174 of 88,812) participated in the 1996 EHEP; 14,915 of them participated in the following 1997 EHEP, with a retention rate of 59.3%. Criteria from the Sixth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) (systolic blood pressure/diastolic blood pressure>or=160/95 mmHg or taking antihypertensive drugs) were used; we found that prevalence and incidence rates of hypertension were 24.6% and 6.6%, respectively. Hypertension rates are increasing in the aging process as shown in both prevalence and incidence models. In comparison with non-participants, the prevalence model indicates that each hypertension patient who had attended the EHEP not only saved NT$34,570-34,890 in medical and associated costs, but also increased their lifespan by 128 days. The present findings suggest that the EHEP is a cost-effective program with health and social welfare policy implications. With the relatively low participation rate of the EHEP, health and social agencies need to put more effort into the promotion of this free health examination program to attract potential participants. In doing so, the population at risk for hypertension would be identified for early treatment, and the probability of having stroke could be decreased. Consequently, health care expenditures for treatment and caregiving of stroke patients would be minimized. Finally, it should be noted that the sensitivity and values of selected parameters can modify the results of cost-effectiveness analysis. Interpretations of the effects of prevention services on costs and effectiveness need to be treated with caution.

Residential exposure to petrochemicals and the risk of leukemia: using geographic information system tools to estimate individual-level residential exposure.

The authors conducted a population-based, case-control study in Kaohsiung, southern Taiwan, Republic of China, to investigate the association between residential petrochemical exposure and leukemia risk among subjects 29 years of age and younger. Between November 1997 and June 2003, 171 cases and 410 controls matched for age and sex were recruited. Since assessment of petrochemical impacts depends on accurate exposure estimates, the authors developed a procedure using geographic information system tools to assign subjects' exposure. The resulting individual-level exposure estimates (the exposure opportunity score) are an integrated exposure measure that accounts for subjects' mobility, length of stay at each residence, distance to petrochemical plant(s), monthly prevailing wind direction, and multiple petrochemical pollution sources. Different conditional logistic regression models were fitted for subjects aged 0-19 and 20-29 years to evaluate separately childhood versus adulthood leukemia. No overall association was observed for the younger age group. However, residential petrochemical exposure was a significant risk factor for leukemia for the older age group. For one unit of increase in the log-transformed exposure opportunity score, the adjusted odds ratio was 1.54 (95 percent confidence interval: 1.14, 2.09). This study illustrates the utility of geographic information system tools for providing refined exposure estimates for residential exposure to petrochemical pollution.

Effect of leukocyte depletion on endothelial cell activation and transendothelial migration of leukocytes during cardiopulmonary bypass.

BACKGROUND: Although leukocyte depletion from systemic circulation during cardiopulmonary bypass (CPB) has been studied, the effect of leukocyte depletion on the leukocyte-endothelial cascade remains poorly understood. So far, there has been no published work on the effects of leukocyte filters during cardiac operations from the viewpoint of endothelial activation and transendothelial neutrophil migration. METHODS: Thirty-two patients undergoing elective heart operations were randomly allocated to a leukocyte-depletion (LD) group or a control group. Blood samples were collected at seven time points: before sternotomy, at 30 minutes and at 60 minutes of CPB, at 5 minutes after coronary reperfusion, at the end of CPB, and at 2 hours and 24 hours after the cessation of CPB. The plasma concentrations of P-selectin, intercellular adhesion molecule-1 (ICAM-1), interleukin-8, and platelet-endothelial cell adhesion molecule-1 (PECAM-1) were measured using enzyme-linked immunosorbent assays. Plasma malondialdehyde (MDA) concentration was determined by measurement of thiobarbituric acid-reactive substances in plasma. In addition, blood samples collected at intervals before and after operation were used for arterial blood gases. RESULTS: Our studies show significant increases of plasma levels of P-selectin, ICAM-1, interleukin-8, PECAM-1, and MDA during and after CPB in the control group. Interestingly, a significant decrease of plasma levels of P-selectin, ICAM-1, interleukin-8, PECAM-1, and MDA, and better preservation of lung function could be found in the LD group compared with the control group. CONCLUSIONS: Our results demonstrate a rationale for using a leukocyte filter in patients undergoing cardiac surgery to attenuate the endothelial-mediated component of the CPB-induced inflammatory response by reducing endothelial activation and neutrophil transmigration.

Leukocyte depletion attenuates expression of neutrophil adhesion molecules during cardiopulmonary bypass in human beings.

BACKGROUND: On the basis of scanty information, the effects of a leukocyte filter during cardiac operations in human beings have been examined from the viewpoint of the expression of neutrophil adhesion molecules. This study was therefore designed to determine whether leukocyte depletion during cardiopulmonary bypass may interfere with neutrophil adhesion properties. METHODS: Twenty-four patients undergoing elective heart operations were randomly allocated to a leukocyte-depletion group or a control group. Blood samples were collected at 7 points: before sternotomy, at 10, 30, and 60 minutes of cardiopulmonary bypass, at termination of cardiopulmonary bypass, 5 minutes after protamine administration, and 2 hours after cardiopulmonary bypass. The expression of the neutrophil surface adhesion molecules L-selectin and beta2-integrins was determined by flow cytometric analysis in whole blood. RESULTS: (1) CD11a expression did not change significantly in either group. There were no significant differences between control and leukocyte-depletion groups (P =.63). (2) There was a significantly higher expression of CD11b on the neutrophils during cardiopulmonary bypass in the control group than in the leukocyte-depletion group (P =.01). (3) CD11c expression was initially up-regulated from the onset of cardiopulmonary bypass, reaching a peak at 60 minutes after bypass in the control group (P =.02). The expression of CD11c did not differ significantly between groups (P =.23). (4) L-selectin expression was significantly lower in the leukocyte-depletion group than in the control group (P =.03). CONCLUSIONS: The major findings of the present study in human subjects undergoing elective cardiac operations with cardiopulmonary bypass are as follows: (1) bypass was associated with an up-regulation of the adhesion molecules L-selectin, CD11b, and CD11c but with no significant change in CD11a expression, and (2) the clinical use of a leukocyte-depleting filter could down-regulate the expression of CD11b and L-selectin.