Is black carbon associated with cardiovascular and cancer mortality? Evidence from the Malmö Diet and Cancer Cohort.

BACKGROUND: Black carbon (BC) is an air pollutant of growing concern due to its adverse impacts on health and climate. Growing evidence suggests that BC could have a number of negative impacts on morbidity and mortality, but more evidence is needed.

OBJECTIVE: The objectives of this study are to quantify any associations between BC exposure and cause-specific (cardiovascular and cancer) mortality outcomes.

METHODS: Using the Malmö Diet and Cancer Cohort linked with a high-resolution dispersion model, we examined the association between long-term exposure to locally emitted BC, nitrogen oxides (NO) and fine particulate matter (PM) with cardiovascular and cancer mortality.

RESULTS: In fully adjusted models, BC exposure was consistently associated with cardiovascular mortality (HR 1.15 [1.06-1.26] per IQR increase), an association that was stronger and more robust than for PM2.5 or NO. This association was present across all models, all time periods and both sets of exposure intervals. This association was stronger than with the other pollutants. Less clear association was found between any pollutant and cancer mortality.

CONCLUSION: This study shows associations between BC exposure and especially cardiovascular mortality, consistent with international evidence showing similar impacts. For cancer mortality, there were tendencies of an association with BC but less clear than for cardiovascular mortality. These findings suggest a unique role of BC in air pollution-related cardiovascular mortality and support the need for action on mitigation of air pollution in general and BC in particular.