Pesticides and cognitive impairment in older adults: evidence from southern Colombia

Abstract Background Environmental exposure to specific chemical groups of pesticides (Carbamates, Organophosphates, Pyrethroids, and Organochlorines), as well as the non or inadequate use of personal protective equipment during pest management, have been associated to cognitive decline and increased risk of dementia (Hayden et al., 2010). This study investigated cognitive functioning in older adults exposed to pesticides in southern Colombia. Methods A sample of 353 older adults was recruited. Of these, 279 had not been exposed to pesticides (n-Exp) and 74 had (Exp). They were matched according to age [n-Ex: 63.80 (3.25), Ex: 63.30 (6.96), t = 0.618, p = 0.538] and years of education [n-Ex: 9.29 (6.28), Ex: 8.95(6.35), t = 0.418, p = 0.676]. They were assessed with a battery of cognitive tests including CERAD (Aguirre-Acevedo et al., 2016), The Addenbrooke?s Cognitive Examination (ACE-R), the Free and Cued Selective Reminding Test (FCSRT) and questionnaires. Results FDR corrected comparisons revealed overall lower cognitive abilities in the Exp group (ACE-R, q = 0.027). They also displayed Memory (FCSRT, q = 0.020; World List Learning q = 0.014) and Constructional Praxis (q = 0.007) impairments. Of those exposed, 73% reported no use of personal protective equipment, and neither the participants nor their family members reported concerns about cognitive decline [Self-reported: n-Exp: 14.27 (7.44), Exp: 14.92 (7.98), t = -0.654, p = 0.513; Family-reported: n-Exp: 10.43 (7.12), Exp: 10.26 (7.45), t = -0.182, p = 0.856]. Conclusion Older adults from southern Colombia who have been exposed to pesticides show significant cognitive impairments, which have gone unnoticed by both the affected individuals and their family. Cognitive abilities found to be affected have been associated with risk of dementia caused by Alzheimer?s Disease or Parkinson?s Disease (FCSRT and Constructional Praxis). These types of dementia have been previously associated with this environmental risk factor (Chin-Chan et al., 2015). More awareness about environmental factors and actions to mitigate their risk are urgently needed, and should be considered by future recommendations (e.g., Livingston et al., 2020). Aguirre-Acevedo et al. (2016). Int. Psychogeriatr, 28(3), 503-510. https://doi.org/S1041610215001660. Chin-Chan et al. (2015). Frontiers in Cellular Neuroscience, 9. https://www.frontiersin.org/articles/10.3389/fncel.2015.00124 Hayden et al. (2010). Neurology, 74(19), 1524-1530. https://doi.org/10.1212/WNL.0b013e3181dd4423 Livingston et al. (2020). Lancet, 396(10248), 413-446. https://doi.org/10.1016/S0140-6736(20)30367-6