Long-term nitrogen dioxide exposure and cause-specific mortality in the U.S. Medicare population.

BACKGROUND: Since 1971, the annual National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO2) has remained at 53 ppb, the impact of long-term NO2 exposure on mortality is poorly understood. OBJECTIVES: We examined associations between long-term NO2 exposure (12-month moving average of NO2) below the annual NAAQS and cause-specific mortality among the older adults in the U.S. METHODS: Cox proportional-hazard models were used to estimate Hazard Ratio (HR) for cause-specific mortality associated with long-term NO2 exposures among about 50 million Medicare beneficiaries living within the conterminous U.S. from 2001 to 2008. RESULTS: A 10 ppb increase in NO2 was associated with increased mortality from all-cause (HR: 1.06; 95% CI: 1.05-1.06), cardiovascular (HR: 1.10; 95% CI: 1.10-1.11), respiratory disease (HR: 1.09; 95% CI: 1.08-1.11), and cancer (HR: 1.01; 95% CI: 1.00-1.02) adjusting for age, sex, race, ZIP code as strata ZIP code- and state-level socio-economic status (SES) as covariates, and PM2.5 exposure using a 2-stage approach. NO2 was also associated with elevated mortality from ischemic heart disease, cerebrovascular disease, congestive heart failure, chronic obstructive pulmonary disease, pneumonia, and lung cancer. We found no evidence of a threshold, with positive and significant HRs across the range of NO2 exposures for all causes of death examined. Exposure-response curves were linear for all-cause, supra-linear for cardiovascular-, and sub-linear for respiratory-related mortality. HRs were highest consistently among Black beneficiaries. CONCLUSIONS: Long-term NO2 exposure is associated with elevated risks of death by multiple causes, without evidence of a threshold response. Our findings raise concerns about the sufficiency of the annual NAAQS for NO2.

Impacts of alcohol duty reductions on cardiovascular mortality among elderly Chinese: a 10-year time series analysis.

BACKGROUND: In March 2007, the Hong Kong Government halved its heavy excise taxes on beer and wine, and 1 year later, it eliminated all duties on these beverages. This study examines the impact of such duty reductions on cardiovascular disease (CVD)-related mortality among the elderly in Hong Kong. METHODS: Box-Jenkins autoregressive integrated moving average intervention time series analyses were applied to monthly morality data from 2001 to 2010 to quantify the impacts of duty reduction and exemption on CVD death rates among those aged 65 years or older. RESULTS: The alcohol duty reduction in March 2007 was associated with an estimated 13% increase (95% CI 2% to 24%) in CVD death rates among elderly men, after controlling for the other intervention, outlier, trends and seasonal variations. This was equivalent to an extra 11 CVD deaths per 100 000 elderly men each month. Much of the observed impacts on CVD death rates were found to have contributed only by that on ischaemic heart disease mortality (18% increase in rate for men (95% CI 4% to 34%); 15% increase for women (95% CI 0.4% to 31%)), not by mortality due to stroke or hypertension. The alcohol duty exemption on March 2008 was not found to have impacted the CVD death rates. CONCLUSIONS: The increase in CVD death rates among the Chinese elderly after alcohol duty reduction suggest that the purported beneficial effect of moderate alcohol use may not apply to certain Chinese populations, adding fuel to the ongoing debate on the risks and benefits of moderate alcohol consumption on mortality.