Survey data suggest reported cumulative pesticide exposure was associated with increased risk of amyotrophic lateral sclerosis (ALS), a progressive and fatal neurodegenerative disease, according to an article published online by JAMA Neurology.
Eva L. Feldman, M.D., Ph.D., of the University of Michigan, Ann Arbor, and coauthors examined occupational exposures and environmental factors on the risk of developing ALS in Michigan. The authors evaluated assessments of environmental pollutants in the blood and detailed exposure reporting through a survey. The study recruited 156 patients with ALS and 128 control patients for comparison; 101 patients with ALS and 110 controls had complete demographic and pollutant data.
Pesticide exposure was associated with increased risk of ALS in survey data and by blood measurements, according to the results.
“Finally, as environmental factors that affect the susceptibility, triggering and progression of ALS remain largely unknown, we contend future studies are needed to evaluate longitudinal trends in exposure measurements, assess newer and nonpersistent chemicals, consider pathogenic mechanisms, and assess phenotypic variations,” the study conclude.
About this ALS research
Source: Haley Otman – JAMA Network Image Source: The image is in the public domain. Original Research: Full open access research for “Association of Environmental Toxins With Amyotrophic Lateral Sclerosis” by Feng-Chiao Su, PhD; Stephen A. Goutman, MD; Sergey Chernyak, PhD; Bhramar Mukherjee, PhD; Brian C. Callaghan, MD; Stuart Batterman, PhD; and Eva L. Feldman, MD, PhD in JAMA Neurology. Published online May 9 2016 doi:10.1001/jamaneurol.2016.0594
Association of Environmental Toxins With Amyotrophic Lateral Sclerosis
Importance Persistent environmental pollutants may represent a modifiable risk factor involved in the gene-time-environment hypothesis in amyotrophic lateral sclerosis (ALS).
Objective To evaluate the association of occupational exposures and environmental toxins on the odds of developing ALS in Michigan. Design, Setting, and Participants Case-control study conducted between 2011 and 2014 at a tertiary referral center for ALS. Cases were patients diagnosed as having definitive, probable, probable with laboratory support, or possible ALS by revised El Escorial criteria; controls were excluded if they were diagnosed as having ALS or another neurodegenerative condition or if they had a family history of ALS in a first- or second-degree blood relative. Participants completed a survey assessing occupational and residential exposures. Blood concentrations of 122 persistent environmental pollutants, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs), were measured using gas chromatography–mass spectrometry. Multivariable models with self-reported occupational exposures in various exposure time windows and environmental toxin blood concentrations were separately fit by logistic regression models. Concordance between the survey data and pollutant measurements was assessed using the nonparametric Kendall τ correlation coefficient.
Main Outcomes and Measures Occupational and residential exposures to environmental toxins, and blood concentrations of 122 persistent environmental pollutants, including OCPs, PCBs, and BFRs.
Results Participants included 156 cases (mean [SD] age, 60.5 [11.1] years; 61.5% male) and 128 controls (mean [SD] age, 60.4 [9.4] years; 57.8% male); among them, 101 cases and 110 controls had complete demographic and pollutant data. Survey data revealed that reported pesticide exposure in the cumulative exposure windows was significantly associated with ALS (odds ratio [OR] = 5.09; 95% CI, 1.85-13.99; P = .002). Military service was also associated with ALS in 2 time windows (exposure ever happened in entire occupational history: OR = 2.31; 95% CI, 1.02-5.25; P = .046; exposure ever happened 10-30 years ago: OR = 2.18; 95% CI, 1.01-4.73; P = .049). A multivariable model of measured persistent environmental pollutants in the blood, representing cumulative occupational and residential exposure, showed increased odds of ALS for 2 OCPs (pentachlorobenzene: OR = 2.21; 95% CI, 1.06-4.60; P = .04; and cis-chlordane: OR = 5.74; 95% CI, 1.80-18.20; P = .005), 2 PCBs (PCB 175: OR = 1.81; 95% CI, 1.20-2.72; P = .005; and PCB 202: OR = 2.11; 95% CI, 1.36-3.27; P = .001), and 1 BFR (polybrominated diphenyl ether 47: OR = 2.69; 95% CI, 1.49-4.85; P = .001). There was modest concordance between survey data and the measurements of persistent environmental pollutants in blood; significant Kendall τ correlation coefficients ranged from −0.18 (Dacthal and “use pesticides to treat home or yard”) to 0.24 (trans-nonachlor and “store lawn care products in garage”).
Conclusions and Relevance In this study, persistent environmental pollutants measured in blood were significantly associated with ALS and may represent modifiable ALS disease risk factors.
“Association of Environmental Toxins With Amyotrophic Lateral Sclerosis” by Feng-Chiao Su, PhD; Stephen A. Goutman, MD; Sergey Chernyak, PhD; Bhramar Mukherjee, PhD; Brian C. Callaghan, MD; Stuart Batterman, PhD; and Eva L. Feldman, MD, PhD in JAMA Neurology. Published online May 9 2016 doi:10.1001/jamaneurol.2016.0594