Methodological issues in estimating smoking-attributable mortality in the United States

The authors explored two methodological issues in the estimation of smoking-attributable mortality for the United States. First, age-specific and age-adjusted relative risk, attributable fraction, and smoking-attributable mortality estimates obtained using data from the American Cancer Society's second Cancer Prevention Study (CPS II), a cohort study of 1.2 million participants (1982-1988), were compared with those obtained using a combination of data from the National Mortality Follow-back Survey (NMFS), a representative sample of US decedents in which information was collected from informants (1986), and the National Health Interview Survey (NHIS), a nationally representative household survey (1987). Second, the potential for residual confounding of the disease-specific age-adjusted smoking-attributable mortality estimates was addressed with a model-based approach. The estimated smoking-attributable mortality based on the CPS II for the four most common smoking-related diseases-lung cancer, chronic obstructive pulmonary disease, coronary heart disease, and cerebrovascular disease-was 19% larger than the estimated smoking-attributable mortality based on the NMFS/NHIS, yet the two data sources yielded essentially the same smoking-attributable mortality estimate for lung cancer alone. Further adjustment of smoking-attributable mortality for disease-appropriate confounding factors (education, alcohol intake, hypertension status, and diabetes status) indicated little residual confounding once age was taken into account.     

The association between extreme precipitation and waterborne disease outbreaks in the United States, 1948-1994

OBJECTIVES: Rainfall and runoff have been implicated in site-specific waterborne disease outbreaks. Because upward trends in heavy precipitation in the United States are projected to increase with climate change, this study sought to quantify the relationship between precipitation and disease outbreaks. METHODS: The US Environmental Protection Agency waterborne disease database, totaling 548 reported outbreaks from 1948 through 1994, and precipitation data of the National Climatic Data Center were used to analyze the relationship between precipitation and waterborne diseases. Analyses were at the watershed level, stratified by groundwater and surface water contamination and controlled for effects due to season and hydrologic region. A Monte Carlo version of the Fisher exact test was used to test for statistical significance. RESULTS: Fifty-one percent of waterborne disease outbreaks were preceded by precipitation events above the 90th percentile (P = .002), and 68% by events above the 80th percentile (P = .001). Outbreaks due to surface water contamination showed the strongest association with extreme precipitation during the month of the outbreak; a 2-month lag applied to groundwater contamination events. CONCLUSIONS: The statistically significant association found between rainfall and disease in the United States is important for water managers, public health officials, and risk assessors of future climate change.     

Characterizing the confluence of air pollution risks in the United States

The US National Research Council in 2004 recommended that the US Environmental Protection Agency “strive to take an integrated multipollutant approach to controlling emissions of pollutants that pose the most significant risks.” Several urban pilot studies have since explored the merits and feasibility of this technique. These studies found that such policies can achieve this policy goal but will confront both legal constraints and data limitations. The Clean Air Act prescribes certain requirements for air quality polices reducing common (or “criteria”) air pollutants including ground-level ozone and fine particles that differ from those affecting toxic air pollutants such as benzene; due in part to these requirements, policy makers have traditionally designed programs to characterize and mitigate risk on a pollutant-by-pollutant basis. Multipollutant policies are also greatly constrained by the emissions, air quality, and health data available to identify opportunities for reducing population risks across air pollutants. We introduce a novel approach to identify the confluence of particulate matter 2.5 μm and smaller (PM_2.5), ozone, and toxic air pollutant risk throughout the USA. We account for the federal statutes governing air pollution policy targeting these pollutants and address differences in the health data used to characterize the risks of these pollutants. We demonstrate a proof-of-concept technique for identifying areas of the USA where there may be a confluence of these risks. We argue that planners could use this approach as a resource as they achieve the goals identified by the National Research Council in 2004.     

Assessing waterborne risks: an introduction

Information in this paper can help readers evaluate the results of epidemiologic studies of waterborne disease risks. It is important that readers understand the various epidemiologic study designs, their strengths and limitations, and potential biases. Terminology used by epidemiologists to describe disease risks can be confusing. Thus, readers should not only evaluate the adequacy of the information to estimate waterborne risks but should also understand how the risk was estimated. For example, one author's definition of attributable risk may be quite different from another author's in terms of the population to which the risk may apply and how it should be interpreted.     

Occupational risks for idiopathic pulmonary fibrosis mortality in the United States

Metal and wood dust exposures have been identified as possible occupational risk factors for idiopathic pulmonary fibrosis (IPF). We analyzed mortality data using ICD-10 code J84.1--"Other interstitial pulmonary diseases with fibrosis," derived age-adjusted mortality rates for 1999-2003, and assessed occupational risks for 1999, by calculating proportionate mortality ratios (PMRs) and mortality odds ratios (MORs) using a matched case-control approach. We identified 84,010 IPF deaths, with an age-adjusted mortality rate of 75.7 deaths/million. Mortality rates were highest among males, whites, and those aged 85 and older. Three industry categories with potential occupational exposures recognized as risk factors for IPF were identified: "Wood buildings and mobile homes" (PMR = 4.5, 95% confidence interval (CI) 1.2-11.6 and MOR = 5.3, 95% CI 1.2-23.8), "Metal mining" (PMR = 2.4, 95% CI 1.3-4.0 and MOR = 2.2, 95% CI 1.1-4.4), and "Fabricated structural metal products" (PMR = 1.9, 95% CI 1.1-3.1 and MOR = 1.7, 95% CI 1.0-3.1). Workers in these industry categories may benefit from toxicological studies and improved surveillance for this disease.     

Recognizing waterborne disease and the health effects of water contamination: a review of the challenges facing the medical community in the United States

Preservation of water quality and prevention of waterborne disease is a complicated task requiring a coordinated effort from many diverse disciplines including physicians, healthcare providers, epidemiologists, microbiologists, academic scientists, science researchers, local and national health authorities, public and environmental health specialists, water engineers and water purveyors. Any successful strategy to ensure water quality and safety in the United States must include the medical community as a valued stakeholder and active participant in this ongoing public health challenge. Unfortunately, the majority of practicing healthcare providers in the US has received limited training in the recognition and evaluation of water-related disease and faces many significant challenges and numerous barriers to diagnosing waterborne disease and the health effects of water pollution in their patients. The purpose of this review is to define the specific challenges facing the medical community with regard to clinical recognition of water-related disease and to provide recommendations for the development of specialized clinical resources and targeted educational outreach programs to assist the medical community in improving their ability to appropriately address water-related disease in their patients.     

Ranking cancer risks of organic hazardous air pollutants in the United States

BACKGROUND: In this study we compared cancer risks from organic hazardous air pollutants (HAPs) based on total personal exposure summed across different microenvironments and exposure pathways. METHODS: We developed distributions of personal exposure concentrations using field monitoring and modeling data for inhalation and, where relevant, ingestion pathways. We calculated risks for a nonoccupationally exposed and nonsmoking population using U.S. Environmental Protection Agency (EPA) and California Office of Environmental Health and Hazard Assessment (OEHHA) unit risks. We determined the contribution to risk from indoor versus outdoor sources using indoor/outdoor ratios for gaseous compounds and the infiltration factor for particle-bound compounds. RESULTS: With OEHHA's unit risks, the highest ranking compounds based on the population median are 1,3-butadiene, formaldehyde, benzene, and dioxin, with risks on the order of 10(-4)-10(-5). The highest risk compounds with the U.S. EPA unit risks were dioxin, benzene, formaldehyde, and chloroform, with risks on a similar order of magnitude. Although indoor exposures are responsible for nearly 70% of risk using OEHHA's unit risks, when infiltration is accounted for, inhalation of outdoor sources contributed 50% to total risk, on average. Additionally, 15% of risk resulted from exposures through food, mainly due to dioxin. CONCLUSIONS: Most of the polycyclic aromatic hydrocarbon, benzene, acetaldehyde, and 1,3-butadiene risk came from outdoor sources, whereas indoor sources were primarily responsible for chloroform, formaldehyde, and naphthalene risks. The infiltration of outdoor pollution into buildings, emissions from indoor sources, and uptake through food are all important to consider in reducing overall personal risk to HAPs.     

Occupational risks of bladder cancer among white women in the United States

The relation between occupation and bladder cancer in women was examined based on data collected during the National Bladder Cancer Study, a population-based, case-control study conducted in 10 areas of the United States. Occupational hazards among women have received little attention in previous bladder cancer studies, in part because most studies have included too few females to accurately estimate risks. In this large case-control study, 652 white female bladder cancer patients and 1,266 white female controls were interviewed to obtain lifetime occupational histories. Patterns of bladder cancer risk by occupation in women tended to be similar to those previously observed among men. Increased risk was apparent for women ever employed in metal working and fabrication occupations (relative risk (RR) = 1.5; 95% confidence interval (CI) 0.9-2.6). Within this summary occupation category, punch and stamping press operatives had a significant trend in risk with increasing duration of employment (p = 0.012); the RR for women employed 5 years or more was 5.6 (95% CI 1.4-26.4). The authors also observed an increased risk for women employed as chemical processing workers (RR = 2.1; 95% CI 0.9-5.1 = with a significant, contrast, a decreased risk was apparent for female textile workers (RR = 0.6; 95% CI 0.3-1.1) with a significant, negative trend in risk with increasing duration of employment (p = 0.031); the relative risk for textile workers employed 10 years or more was 0.4. The authors estimate that 11% of bladder cancer diagnosed among white women in the United States is attributable to occupational exposures; this percentage is considerably lower than the 21-25% previously reported for white men in this study.     

燕麦β-葡聚糖对小鼠肠道菌群的影响

  目的  探讨燕麦β–葡聚糖对糖尿病大鼠肾病进展的干预作用及机制。  方法  采用链脲佐菌素（65 mg/kg）一次性腹腔注射 + 单侧肾切除的方式构建糖尿病肾病大鼠模型,造模成功后随机分为4组,分别为模型组（蒸馏水）,和低、中、高剂量燕麦β–葡聚糖组（0.275、0.550、1.100 g/kg）,每组12只;同时另取10只大鼠行假手术并灌胃蒸馏水,为对照组;干预8周。采集血液和尿液,检测尿素氮（BUN）、尿酸（UA）、血肌酐（CR）和血清炎症因子白细胞介素–6（IL-6）、血管内皮生长因子（VEGF）水平,并取肾脏做病理组织检测。  结果  与对照组比较,模型组大鼠血清尿素氮、VEGF、IL-6水平[分别为（14.80 ± 3.63）mmol/L、（312.54 ± 13.39）、（145.96 ± 5.67）ng/L]明显升高（P < 0.05）;与模型组比较,燕麦β–葡聚糖0.275 g/kg组大鼠血清尿素氮水平[（10.39 ± 2.04）mmol/L]明显下降,燕麦β–葡聚糖0.550 g/kg组大鼠血清VEGF及IL-6水平[分别为（269.94 ± 16.70）、（129.71 ± 6.48）ng/L]明显下降,差异有统计学意义（P < 0.05）;与模型组比较,燕麦β–葡聚糖组大鼠肾脏组织结构损伤明显减轻。  结论  燕麦β–葡聚糖可有效改善糖尿病肾病大鼠肾功能,延缓肾脏组织结构损伤,其机制可能与下调炎症相关因子表达水平,改善机体炎症状态有关。     

A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan

A waterborne outbreak of leptospirosis occurred among US military personnel during September 1987, on the island of Okinawa, Japan. Micro-agglutination titres for leptospiral antigen of greater than or equal to 200 were detected in hospitalized adult males averaging 22.5 years of age with symptoms compatible with leptospirosis. Epidemiological findings revealed two case clusters distinguished by time and place of exposure. The overall attack rates among recreational swimmers and combat skills training participants were 467/1000 (7/15) and 183/1000 (15/82), respectively. Swallowing of water differentiated individuals with laboratory-confirmed infection from those with no infection, while water immersion alone did not appear to result in leptospiral infection. Additionally, subnormal rainfall may have contributed to the risk of exposure associated with this outbreak.