Long-term exposure to traffic-related air pollution and diabetes-associated mortality: a cohort study.
OBJECTIVE
The aim of this study was to investigate whether air pollution from traffic at a residence is associated with mortality related to type 1 or type 2 diabetes.


METHODS
We followed up 52,061 participants in the Danish Diet, Cancer and Health cohort for diabetes-related mortality in the nationwide Register of Causes of Death, from baseline in 1993-1997 up to the end of 2009, and traced their residential addresses since 1971 in the Central Population Registry. We used dispersion-modelled concentration of nitrogen dioxide (NO₂) since 1971 and amount of traffic at the baseline residence as indicators of traffic-related air pollution and used Cox regression models to estimate mortality-rate ratios (MRRs) with adjustment for potential confounders.


RESULTS
Mean levels of NO₂ at the residence since 1971 were significantly associated with mortality from diabetes. Exposure above 19.4 μg/m³ (upper quartile) was associated with a MRR of 2.15 (95% CI 1.21, 3.83) when compared with below 13.6 μg/m³ (lower quartile), corresponding to an MRR of 1.31 (95% CI 0.98, 1.76) per 10 μg/m³ NO₂ after adjustment for potential confounders.


CONCLUSIONS
This study suggests that traffic-related air pollution is associated with mortality from diabetes. If confirmed, reduction in population exposure to traffic-related air pollution could be an additional strategy against the global public health burden of diabetes.
Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen Ø, Denmark. ole@cancer.dk
O
O
Raaschou-Nielsen
M
M
Sørensen
M
M
Ketzel
O
O
Hertel
S
S
Loft
A
A
Tjønneland
K
K
Overvad
Z J
ZJ
Andersen
D000393:Air Pollutants / Q000633:toxicity*; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D003718:Denmark / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology / Q000401:mortality*; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000633:toxicity; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D012111:Residence Characteristics; D011795:Surveys and Questionnaires; D013997:Time Factors; D014504:Urban Health; D001335:Vehicle Emissions / Q000633:toxicity*
D000393:Air Pollutants; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide