Short-term ambient particle radioactivity level and renal function in older men: Insight from the Normative Aging Study.

BACKGROUND

Whole-body and thoracic ionizing radiation exposure are both associated with the development of renal dysfunction. However, whether low-level environmental radiation from air pollution affects renal function remains unknown.

OBJECTIVES

We investigated the association of particle radioactivity (PR) with renal function defined by the estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) in the Normative Aging Study.

METHODS

This longitudinal analysis included 2491 medical visits from 809 white males enrolled between 1999 and 2013. The eGFR was calculated using the CKD-EPI and MDRD equations, and CKD cases were identified as those with an eGFR <60 mL/min/1.73 m. Gross β activity measured by five monitors of the U.S. Environmental Protection Agency's RadNet monitoring network was utilized to represent PR.

RESULTS

Ambient PR levels from 1 to 28 days prior to clinical visit demonstrated robust negative associations with both forms of eGFR, but not with the increased odds of CKD. An interquartile range higher 28-day average ambient PR level was significantly associated with 0.83-mL/min/1.73 m lower eGFR estimated by the CKD-EPI equation (95% confidence interval: -1.46, -0.20, p-value = 0.01). Controlling for PM or black carbon in the model slightly attenuated the PR effects on eGFR. However, in individuals with the highest levels (3rd tertile) of C-reactive protein (CRP) or fibrinogen, we observed robust associations of PR with eGFR and CKD, suggesting that systemic inflammation may modify the PR-eGFR and PR-CKD relationships.

CONCLUSIONS

Our study reveals adverse health effects of short-term low-level ambient PR on the renal function, providing evidence to guide further study of the interplay between PR, inflammation, and renal health.