The Long-Term Mortality Effects Associated with Exposure to Particles and NOx in the Malmö Diet and Cancer Cohort

Henrik Olstrup; Erin Flanagan; Jan-Olov Persson; Ralf Rittner; Hanne Krage Carlsen; Leo Stockfelt; Yiyi Xu; Lars Rylander; Susanna Gustafsson; Mårten Spanne; Daniel Oudin Åström; Gunnar Engström; Anna Oudin

doi:10.3390/toxics11110913

The Long-Term Mortality Effects Associated with Exposure to Particles and NO_x in the Malmö Diet and Cancer Cohort

Toxics. 2023 Nov 7;11(11):913. doi: 10.3390/toxics11110913.

Authors

Henrik Olstrup^{1

2}, Erin Flanagan¹, Jan-Olov Persson³, Ralf Rittner¹, Hanne Krage Carlsen⁴, Leo Stockfelt^{5

6}, Yiyi Xu⁶, Lars Rylander¹, Susanna Gustafsson⁷, Mårten Spanne⁷, Daniel Oudin Åström^{1

2}, Gunnar Engström⁸, Anna Oudin^{1

2}

Affiliations

¹ Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, 223 63 Lund, Sweden.
² Sustainable Health, Department of Public Health and Clinical Medicine, Umeå University, 901 87 Umeå, Sweden.
³ Department of Mathematics, Stockholm University, 106 91 Stockholm, Sweden.
⁴ School of Public Health and Community Medicine, Institute of Medicine, Center of Registers, Sahlgrenska Academy, University of Gothenburg, 413 45 Gothenburg, Sweden.
⁵ Occupational and Environmental Medicine, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden.
⁶ Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, 413 90 Gothenburg, Sweden.
⁷ Environment Department, City of Malmö, 205 80 Malmö, Sweden.
⁸ Department of Clinical Sciences at Malmö, CRC, Lund University, 221 00 Lund, Sweden.

Abstract

In this study, the long-term mortality effects associated with exposure to PM₁₀ (particles with an aerodynamic diameter smaller than or equal to 10 µm), PM_2.5 (particles with an aerodynamic diameter smaller than or equal to 2.5 µm), BC (black carbon), and NO_x (nitrogen oxides) were analyzed in a cohort in southern Sweden during the period from 1991 to 2016. Participants (those residing in Malmö, Sweden, born between 1923 and 1950) were randomly recruited from 1991 to 1996. At enrollment, 30,438 participants underwent a health screening, which consisted of questionnaires about lifestyle and diet, a clinical examination, and blood sampling. Mortality data were retrieved from the Swedish National Cause of Death Register. The modeled concentrations of PM₁₀, PM_2.5, BC, and NO_x at the cohort participants' home addresses were used to assess air pollution exposure. Cox proportional hazard models were used to estimate the associations between long-term exposure to PM₁₀, PM_2.5, BC, and NO_x and the time until death among the participants during the period from 1991 to 2016. The hazard ratios (HRs) associated with an interquartile range (IQR) increase in each air pollutant were calculated based on the exposure lag windows of the same year (lag0), 1-5 years (lag1-5), and 6-10 years (lag6-10). Three models were used with varying adjustments for possible confounders including both single-pollutant estimates and two-pollutant estimates. With adjustments for all covariates, the HRs for PM₁₀, PM_2.5, BC, and NO_x in the single-pollutant models at lag1-5 were 1.06 (95% CI: 1.02-1.11), 1.01 (95% CI: 0.95-1.08), 1.07 (95% CI: 1.04-1.11), and 1.11 (95% CI: 1.07-1.16) per IQR increase, respectively. The HRs, in most cases, decreased with the inclusion of a larger number of covariates in the models. The most robust associations were shown for NO_x, with statistically significant positive HRs in all the models. An overall conclusion is that road traffic-related pollutants had a significant association with mortality in the cohort.

Keywords: Cox regression; air pollution; hazard ratio; long-term exposure; nitrogen oxides; particles; proportional hazard.

Abstract

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