Monitoring the impact of desert dust outbreaks for air quality for health studies.

We review the major features of desert dust outbreaks that are relevant to the assessment of dust impacts upon human health. Our ultimate goal is to provide scientific guidance for the acquisition of relevant population exposure information for epidemiological studies tackling the short and long term health effects of desert dust. We first describe the source regions and the typical levels of dust particles in regions close and far away from the source areas, along with their size, composition, and bio-aerosol load. We then describe the processes by which dust may become mixed with anthropogenic particulate matter (PM) and/or alter its load in receptor areas. Short term health effects are found during desert dust episodes in different regions of the world, but in a number of cases the results differ when it comes to associate the effects to the bulk PM, the desert dust-PM, or non-desert dust-PM. These differences are likely due to the different monitoring strategies applied in the epidemiological studies, and to the differences on atmospheric and emission (natural and anthropogenic) patterns of desert dust around the world. We finally propose methods to allow the discrimination of health effects by PM fraction during dust outbreaks, and a strategy to implement desert dust alert and monitoring systems for health studies and air quality management.

Particulate matter air pollution components and risk for lung cancer.

BACKGROUND: Particulate matter (PM) air pollution is a human lung carcinogen; however, the components responsible have not been identified. We assessed the associations between PM components and lung cancer incidence. METHODS: We used data from 14 cohort studies in eight European countries. We geocoded baseline addresses and assessed air pollution with land-use regression models for eight elements (Cu, Fe, K, Ni, S, Si, V and Zn) in size fractions of PM2.5 and PM10. We used Cox regression models with adjustment for potential confounders for cohort-specific analyses and random effect models for meta-analysis. RESULTS: The 245,782 cohort members contributed 3,229,220 person-years at risk. During follow-up (mean, 13.1 years), 1878 incident cases of lung cancer were diagnosed. In the meta-analyses, elevated hazard ratios (HRs) for lung cancer were associated with all elements except V; none was statistically significant. In analyses restricted to participants who did not change residence during follow-up, statistically significant associations were found for PM2.5 Cu (HR, 1.25; 95% CI, 1.01-1.53 per 5 ng/m(3)), PM10 Zn (1.28; 1.02-1.59 per 20 ng/m(3)), PM10 S (1.58; 1.03-2.44 per 200 ng/m(3)), PM10 Ni (1.59; 1.12-2.26 per 2 ng/m(3)) and PM10 K (1.17; 1.02-1.33 per 100 ng/m(3)). In two-pollutant models, associations between PM10 and PM2.5 and lung cancer were largely explained by PM2.5 S. CONCLUSIONS: This study indicates that the association between PM in air pollution and lung cancer can be attributed to various PM components and sources. PM containing S and Ni might be particularly important.

Socio-demographic differences in adherence to evidence-based drug therapy after hospital discharge from acute myocardial infarction: a population-based cohort study in Rome, Italy.

WHAT IS KNOWN AND OBJECTIVE: Adherence to evidence-based drug therapy after acute myocardial infarction has increased over the last decades, but is still unsatisfactory. Our objectives are to set out to analyse patterns of evidence-based drug therapy after acute myocardial infarction (AMI), and evaluating socio-demographic differences. METHODS: A cohort of 3920 AMI patients discharged from hospital in Rome (2006-2007) was selected. Drugs claimed during the 12 months after discharge were retrieved. Drug utilization was defined as density of use (boxes claimed/individual follow-up; chronic use = 6+ boxes/365 days) and therapeutic coverage, calculated through Defined Daily Doses (chronic use: ≥80% of individual follow-up). Patterns of use of single drugs and their combination were described. The association between poly-therapy and gender, age and socio-economic position (small-area composite index based on census data) was analysed through logistic regression, accounting for potential confounders. RESULTS AND DISCUSSION: Most patients used single drugs: 90·5% platelet aggregation inhibitors (antiplatelets), 60·0%ß-blockers, 78·1% agents acting on the renin-angiotensin system (ACEIs/ARBs), 77·8% HMG CoA reductase inhibitors (statins). Percentages of patients with ≥80% of therapeutic coverage were 81·9% for antiplatelets, 17·8% for ß-blockers, 64·4% for ACEIs/ARBs and 76·1% for statins. The multivariate analysis showed gender and age differences in adherence to poly-therapy (females: OR = 0·84; 95% CI 0·72-0·99; 71-80 years age-group: OR = 0·82; 95% CI 0·68-0·99). No differences were observed with respect to socio-economic position. WHAT IS NEW AND CONCLUSION: The availability of information systems offers the opportunity to monitor the quality of care and identify weaknesses in public health-care systems. Our results identify specific factors contributing to non-adherence and hence define areas for more targeted health-care interventions. Our results suggest that efforts to improve adherence should focus on women and older patients.

The relationship between ambient particulate matter and respiratory mortality: a multi-city study in Italy.

The association of air pollutants with natural and respiratory mortality has been consistently reported. However, several aspects of the relationship between particulate matter with a 50% cut-off aerodynamic diameter of 10 µm (PM(10)) and respiratory mortality require further investigation. The aim of the present study was to assess the PM(10)-respiratory mortality association in Italy and examine potentially susceptible groups. All deaths from natural (n=276,205) and respiratory (n=19,629) causes among subjects aged ≥ 35 yrs in 10 northern, central and southern Italian cities in 2001-2005 were included in the study. Pollution data for PM(10), nitrogen dioxide and ozone were also obtained. A time-stratified case-crossover analysis was carried out. Different cumulative lags were selected to analyse immediate, delayed, prolonged and best-time effects of air pollution. The shape of the exposure-response curve was analysed. Age, sex, chronic conditions and death site were investigated as potential effect modifiers. We found a 2.29% (95% CI 1.03-3.58%) increase in respiratory mortality at 0-3 days lag. The increase in respiratory mortality was higher in summer (7.57%). The exposure-response curve had a linear shape without any threshold. Sex and chronic diseases modified the relationship between particular matter (PM) and respiratory mortality. The effect of PM on respiratory mortality was stronger and more persistent than that on natural mortality. Females and chronic disease sufferers were more likely to die of a respiratory disease caused by air pollution than males and healthy people.

Does temperature modify the association between air pollution and mortality? A multicity case-crossover analysis in Italy.

Adverse health effects of particulate matter <10 microm in aerodynamic diameter (PM(10)) and high temperatures are well known, but the extent of their interaction on mortality is less clear. This paper describes effect modification of temperature in the PM(10)-mortality association and tests the hypothesis that higher PM(10) effects in summer are due to enhanced exposure to particles. All deaths of residents of nine Italian cities between 1997 and 2004 were selected. The case-crossover approach was adopted to estimate the effect of PM(10) on mortality by season and temperature level. Three strata of temperature corresponding to low, medium, and high "ventilation" were identified, and the interaction between PM(10) and temperature within each stratum was examined. Season and temperature levels strongly modified the PM(10)-mortality association: for a 10-microg/m(3) variation in PM(10), a 2.54% increase in risk of death in summer (95% confidence interval: 1.31, 3.78) compared with 0.20% (95% confidence interval: -0.08, 0.49) in winter. Analysis of the interaction between PM(10) and temperature within temperature strata resulted in positive but, in most cases, nonstatistically significant coefficients. The authors found much higher PM(10) effects on mortality during warmer days. The hypothesis that such an effect is attributable to enhanced exposure to particles in summer could not be rejected.

Factors affecting in-hospital heat-related mortality: a multi-city case-crossover analysis.

BACKGROUND: Several studies have identified strong effects of high temperatures on mortality at population level; however, individual vulnerability factors associated with heat-related in-hospital mortality are largely unknown. The objective of the study was to evaluate heat-related in-hospital mortality using a multi-city case-crossover analysis. METHODS: We studied residents of four Italian cities, aged 65+ years, who died during 1997-2004. For 94,944 individuals who died in hospital and were hospitalised two or more days before death, demographics, chronic conditions, primary diagnoses of last event and hospital wards were considered. A city-specific case-crossover analysis was performed to evaluate the association between apparent temperature and mortality. Pooled odds ratios (OR) of dying on a day with a temperature of 30 degrees C compared to a day with a temperature of 20 degrees C were estimated with a random-effects meta-analysis. RESULTS: We estimated an overall OR of 1.32 (95% confidence interval: 1.25, 1.39). Age, marital status and hospital ward were important risk indicators. Patients in general medicine were at higher risk than those in high and intensive care units. A history of psychiatric disorders and cerebrovascular diseases gave a higher vulnerability. Mortality was greater among patients hospitalised for heart failure, stroke and chronic pulmonary diseases. CONCLUSIONS: In-hospital mortality is strongly associated with high temperatures. A comfortable temperature in hospitals and increased attention to vulnerable patients during heatwaves, especially in general medicine, are necessary preventive measures.

Airport and city-centre temperatures in the evaluation of the association between heat and mortality.

A variety of ambient exposure indicators have been used to evaluate the impact of high temperature on mortality and in the identification of susceptible population sub-groups, but no study has evaluated how airport and city centre temperatures differ in their association with mortality during summer. This study considers the differences in temperatures measured at the airport and in the city centre of three Italian cities (Milan, Rome and Turin) and investigates the impact of these measures on daily mortality. The case-crossover design was applied to evaluate the association between daily mean apparent temperature (MAT) and daily total mortality. The analysis was conducted for the entire population and for subgroups defined by demographic characteristics, socioeconomic status and chronic comorbidity (based on hospitalisation during the preceding 2 years). The percentage risk of dying, with 95% confidence intervals (95% CI), on a day with MAT at the 95th percentile with respect to the 25th percentile of the June-September daily distribution was estimated. Airport and city-centre temperature distributions, which vary among cities and between stations, have a heterogeneous impact on mortality. Milan was the city with the greatest differences in mean MAT between airport and city stations, and the overall risk of dying was greater when airport MAT (+47% increase, 95%CI 38-57) was considered in comparison to city MAT (+37% increase, 95%CI 30-45). In Rome and Turin, the results were very similar for both apparent temperature measures. In all cities, the elderly, women and subjects with previous psychiatric conditions, depression, heart and circulation disorders and cerebrovascular disease were at higher risk of dying during hot days, and the degree of effect modification was similar using airport or city-centre MAT. Studies on the impact of meteorological variables on mortality, or other health indicators, need to account for the possible differences between airport and city centre meteorological variables in order to give more accurate estimates of health effects.