The short-term effect of air pollution on cardiovascular mortality in Tianjin, China: comparison of time series and case-crossover analyses

Background

Many studies have illustrated that ambient air pollution negatively impacts on health. However, little evidence is available for the effects of air pollution on cardiovascular mortality (CVM) in Tianjin, China. Also, no study has examined which strata length for the time-stratified case-crossover analysis gives estimates that most closely match the estimates from time series analysis.

Objectives

The purpose of this study was to estimate the effects of air pollutants on CVM in Tianjin, China, and compare time-stratified case-crossover and time series analyses.

Method

A time-stratified case-crossover and generalized additive model (time series) were applied to examine the impact of air pollution on CVM from 2005 to 2007. Four time-stratified case-crossover analyses were used by varying the stratum length (Calendar month, 28, 21 or 14 days). Jackknifing was used to compare the methods. Residual analysis was used to check whether the models fitted well.

Results

Both case-crossover and time series analyses show that air pollutants (PM₁₀, SO₂ and NO₂) were positively associated with CVM. The estimates from the time-stratified case-crossover varied greatly with changing strata length. The estimates from the time series analyses varied slightly with changing degrees of freedom per year for time. The residuals from the time series analyses had less autocorrelation than those from the case-crossover analyses indicating a better fit.

Conclusion

Air pollution was associated with an increased risk of CVM in Tianjin, China. Time series analyses performed better than the time-stratified case-crossover analyses in terms of residual checking.     

A Quarter of a Century of Progress to Prevent Vitamin A Deficiency Through Supplementation

A quarter of century has passed since FRI published its first comprehensive review on vitamin A deficiency (VAD) and its prevention. At the time, the major impetus to prevent VAD was to reduce xerophthalmia in preschool children. Today, we have a broader understanding of the public health implications of VAD, with disorders including xerophthalmia, mortality, severe infection, and anemia in preschool children and pregnant women. While deficiency affects most developing countries, nearly half of all deficient children and women live in Southern Asia. Prevention has made substantial strides. High potency vitamin A supplementation (with 200,000 IU) remains a prophylactic mainstay, delivered through fixed facilities, enhanced outreach activities, and national child health day campaigns twice annually. Surprisingly, the costs of semi-annual delivery of vitamin A have changed little over the years, with new cost estimates remaining comparable to earlier figures of US ～$0.50 per child per year. Emerging is the potential to reduce infant mortality by ～20% in Southern Asia by giving a single, oral, 50,000 IU dose of vitamin A to newborns. While ～500 million vitamin A capsules are routinely distributed worldwide each year to achieve effective control, progress has been slower with efforts to improve diet on a purposeful global public health scale. Future advances through effective dietary diversification and various means of food fortification will be required before periodic supplementation can be phased down as a major population strategy for controlling vitamin A deficiency.     

Electrolyte minerals intake and cardiovascular health

ABSTRACT

Appropriate intake of micronutrient, such as electrolyte minerals is critical for the well-being of the cardiovascular health system. However, there are some debates regarding the impacts of dietary and/or supplemental intake of these minerals, on the risk of cardiovascular events and associated risk factors. High sodium intake is adversely associated with the risk of hypertension. Although many reports refered to the positive association of Na intake and cardiovascular events and all-cause mortality, however, other studies indicated that low Na intake is related to higher risk of all-cause mortality and HF-related events. By contrast, dietary potassium, magnesium and calcium have an inverse correlation with cardiovascular events and risk factors, especially with blood pressure. There are some controversies about cardiovascular effects and all-cause mortality of high Ca intake, including no effect, preventive or adverse effect with or without vitamin D. Calcium supplementation might be beneficial for prevention of cardiovascular events and all-cause mortality only in individuals with low intake. Moreover, calcium intake showed a J- or U-shaped association with the risk of cardiovascular diseases. Due to the controversies of the effect of electrolyte minerals especially sodium and calcium intake on cardiovascular events, large scale, well-designed long-term randomized clinical trials are required to evaluate the effect of minerals intake on cardiovascular events and all-cause mortality. In this review, we discuss the role of dietary and or supplemental sodium, potassium, magnesium, calcium, in cardiovascular health, as well as their clinical applications, benefits, and risks for the primary prevention of cardiovascular disease, in general population.     

A Bayesian threshold-linear model evaluation of perinatal mortality, dystocia, birth weight, and gestation length in a Holstein herd

The objective of this research was to estimate genetic parameters for a multiple-trait evaluation of dystocia (DYS), perinatal mortality (PM), birth weight (BWT), and gestation length (GL) in Holsteins. The data included 5,712 calving records collected between 1968 and 2005 from the Iowa State University dairy breeding herd in Ankeny. The incidence of PM was 8.8% and that of DYS 28.8%; mean BWT was 40.5 kg, and GL was 279 d. A threshold-linear animal model included the effects of year, season, sex of calf, parity, sire group, direct genetic, maternal genetic, and maternal permanent environment. Direct heritabilities for DYS, PM, BWT, and GL were 0.11 (0.04), 0.13 (0.05), 0.26 (0.04), and 0.51 (0.05), respectively. Maternal heritabilities were 0.14 (0.04), 0.15 (0.03), 0.08 (0.01), and 0.08 (0.02), for DYS, PM, BWT, and GL, respectively. The heritabilities are the posterior means of the Gibbs samples with their standard deviations in parentheses. The direct genetic correlation between PM and DYS was estimated at 0.67 (0.19), whereas the maternal genetic correlation was 0.45 (0.16). Direct and maternal PM and DYS are partially controlled by the same genes. Selection on only calving ease is not sufficient to control PM. With moderate genetic correlations between all 4 traits, BWT and GL should be included with DYS and PM in an evaluation of calving performance.     

乳酸杆菌无机陶瓷膜微滤浓缩条件的研究

采用无机陶瓷膜管微滤技术浓缩乳酸杆菌发酵液。实验中比较了不同膜管孔径、膜管面积、操作压力等对乳酸杆菌发酵液浓缩效果的影响。结果表明,选择无机陶瓷膜管孔径为0.1μm,膜面积为0.24 m2,操作压力为0.15 MPa,可得到体积浓缩5.6倍,活菌死亡比0.2,截留率达96%的乳酸杆菌浓缩液。无机陶瓷膜可用于乳酸杆菌发酵液的浓缩处理。     

Happy Birthday Marlboro: the cigarette whose taste outlasts its customers

Marlboro is 50 years old—and still killing its customers     

Erratum to Rodin and Langer.

Reports an error in "Long-term effects of a control-relevant intervention with the institutionalized aged" by Judith Rodin and Ellen J. Langer (Journal of Personality and Social Psychology, 1977[Dec], Vol 35[12], pp. 897-902). On page 900, the z score should be changed. The outcome is therefore only marginally significant, and a more cautious interpretation of the mortality findings than originally given is necessary. (The following abstract of this article originally appeared in record 1979-29338-001.) Reevaluated 26 elderly nursing home residents who were tested by the present authors (see record 1976-28515-001) as part of an intervention designed to increase feelings of choice and personal responsibility over daily events. Nurses' ratings and health and mortality indicators suggest that the experimental treatment and/or the processes that it set in motion had sustained beneficial effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)