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Environmental Toxins as Causes of Brain Degeneration in Sub-Saharan Africa

  • Tom H. A. M. Olewe

Abstract

Brain degeneration, especially Dementia is a complex human disease. The Alzheimer’s Association estimates that one in 10 persons over 65 and nearly half of those over 85 have Alzheimer’s disease. There is paucity of data on the prevalence of dementia in Sub-Saharan Africa. Available data suggests a general prevalence of dementia at 6.4 % in Tanzania and HIV related dementia at 31 % in Uganda. Despite the growing burden of dementia in low-income countries, there are few previous data on the prevalence, causes and risk factors of dementia in sub-Saharan Africa.

Therefore, it is important to identify protective and risk factors for dementia to prevent this disease at an early stage. Several factors are related to dementia, e.g. age, ethnicity, sex, genetic factors, physical activity, smoking, drug use, education level, alcohol consumption, body mass index, co-morbidity, and environmental factors. Due to paucity of Sub-Saharan African data, this review looks at studies done elsewhere to evaluate the association between environmental toxins and risk of dementia, especially Alzheimer’s and Parkinson’s diseases. We have examined whether evidence from previous studies on association between toxin environmental exposures and dementia is of sufficient strength to warrant specific recommendations for behavioral, lifestyle, or pharmaceutical interventions/modifications targeted to these endpoints. We also suggest future research directions for researchers in dementia-related fields in Sub-Saharan Africa.

Keywords

Dementia Alzheimer’s disease Environmental toxins Sub-Saharan Africa 

References

  1. 1.
    Shaji KS, et al. Caregivers of patients with Alzheimer’s disease: a qualitative study from the Indian 10/66 Dementia Research Network. Int J Geriatr Psychiatry. 2002;18:1–6.CrossRefGoogle Scholar
  2. 2.
    Saunders AM, et al. Association of apolipoprotein E allele e4 with late-onset familial and sporadic Alzheimer’s disease. Neurology. 1993;43:1467–72.CrossRefPubMedGoogle Scholar
  3. 3.
    Lisa RS, Rikus HC. Down’s syndrome and dementia. Adv Psychiatr Treat. 2004;10:50–8.CrossRefGoogle Scholar
  4. 4.
    Evert DL, Oscar-Berman M. Alcohol-related cognitive impairments: an overview of how alcoholism may affect the workings of the brain. Alcohol Health Res World. 1995;19(2):89–96.Google Scholar
  5. 5.
    Smith DM, Atkinson RM. Alcoholism and dementia. In: Gurnack AM, editor. Older adults’ misuse of alcohol, medicines, and other drugs: research and practice issues. New York: Springer; 1997. p. 132–57.Google Scholar
  6. 6.
    Tyas SL. Are tobacco and alcohol use related to Alzheimer’s disease? A critical assessment of the evidence and its implications. Addict Biol. 1996;1:237–54.CrossRefPubMedGoogle Scholar
  7. 7.
    Casserly I, Topol E. Convergence of atherosclerosis and Alzheimer’s disease: inflammation, cholesterol, and misfolded proteins. Lancet. 2004;363:1139–46.CrossRefPubMedGoogle Scholar
  8. 8.
    Obisesan TO. Hypertension and cognitive function. Clin Geriatr Med. 2009;25(2):259–88. doi: 10.1016/j.cger.2009.03.002.CrossRefPubMedCentralPubMedGoogle Scholar
  9. 9.
    Skoog I, et al. 15-year longitudinal study of blood pressure and dementia. Lancet. 1996;347:1141–5.CrossRefGoogle Scholar
  10. 10.
    Watanabe T, Koba S, Kawamura M, Itokawa M, Idei T, Nakagawa Y, Iguchi T, Katagiri T. Small dense low-density lipoprotein and carotid atherosclerosis in relation to vascular dementia. Presented in part at the 13th International Symposium on Atherosclerosis, Kyoto, Japan, September 28-October 2, 2003. Metabolism. 2004;53(Apr):476–82.Google Scholar
  11. 11.
    Kivipelto M, et al. Midlife vascular risk factors and Alzheimer’s disease in later life: longitudinal, population based study. BMJ. 2001;322:1447–51.CrossRefPubMedCentralPubMedGoogle Scholar
  12. 12.
    Barnes DE, Yaffe K, Byers AL, McCormick M, Schaefer C, Whitmer RA. Midlife vs late-life depressive symptoms and risk of dementia: differential effects for Alzheimer disease and vascular dementia. Arch Gen Psychiatry. 2012;69(5):493–8.CrossRefPubMedCentralPubMedGoogle Scholar
  13. 13.
    Velayudhan L, Poppe M, Archer N, Proitsi P, Brown RG, Lovestone S. Risk of developing dementia in people with diabetes and mild cognitive impairment. Br J Psychiatry. 2010;196:36–40.CrossRefPubMedGoogle Scholar
  14. 14.
    Rapp SR, Espeland MA, Shumaker SA, WHIMS Investigators, et al. Effect of estrogen plus progestin on global cognitive function in postmenopausal women: the Women’s Health Initiative Memory Study: a randomized controlled trial. JAMA. 2003;289(20):2663–72.CrossRefPubMedGoogle Scholar
  15. 15.
    Shumaker SA, Legault C, Rapp SR, WHIMS Investigators, et al. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women’s Health Initiative Memory Study: a randomized controlled trial. JAMA. 2003;289(20):2651–62.CrossRefPubMedGoogle Scholar
  16. 16.
    den Heijer T, Geerlings MI, Hofman A, et al. Higher estrogen levels are not associated with larger hippocampi and better memory performance. Arch Neurol. 2003;60(2):213–20.CrossRefGoogle Scholar
  17. 17.
    Garcia A, Zanibbi K. Homocysteine and cognitive function in elderly people. Can Med Assoc J. 2004;171(8):897–904.CrossRefGoogle Scholar
  18. 18.
    Ott A, Slooter AJ, Hofman A, et al. Smoking and risk of dementia and Alzheimer’s disease in a population-based cohort study: the Rotterdam Study. Lancet. 1998;351:1840–3.CrossRefGoogle Scholar
  19. 19.
    Merchant C, Tang MX, Albert S, et al. The influence of smoking on the risk of Alzheimer’s disease. Neurology. 1999;52:1408–12.CrossRefPubMedGoogle Scholar
  20. 20.
    Schofield P. Dementia associated with toxic causes and autoimmune disease. Int Psychogeriatr. 2005;17:S129–47. doi: 10.1017/S1041610205001997.CrossRefPubMedGoogle Scholar
  21. 21.
    Dobbs MR. Toxic encephalopathy. Semin Neurol. 2011;31(2):184–93.CrossRefPubMedGoogle Scholar
  22. 22.
    Ghosh A. Endocrine, metabolic, nutritional, and toxic disorders leading to dementia. Ann Indian Acad Neurol. 2010;13 Suppl 2:S63–8. doi: 10.4103/0972-2327.74247.CrossRefPubMedCentralPubMedGoogle Scholar
  23. 23.
    Jennrich P. Schwermetalle – Ursache von Zivilisationskrankheiten und ihre erfolgreiche Behandlung [Heavy metals – a cause of lifestyle diseases and their successful treatment], Fachmagazin, CO’MED, 03/06. Various sources: daily and scientific press.Google Scholar
  24. 24.
    L’aluminium empoisonne notre vie quotidienne. Le Monde, 15 September 2010; Virginie Belle, Quand l’aluminiumnous empoisonne, Editions Max Milo, 2010.Google Scholar
  25. 25.
    Navas-Acien A, et al. Arsenic exposure and prevalence of type 2 diabetes in US adults. www.jama.com (November 2010).
  26. 26.
    First Nations Environmental Health Innovation Network, Cadmium fact sheet, Canada. www.fnehin.ca (2008).
  27. 27.
    Nyland JF. Mercury linked to immune changes seen in autoimmune disease. Synopsis of a 2010 study by Gardner, Nyland, Silva, Ventura, deSouza and Silbergeld. www.environmentalhealthnews.org (April 2010).
  28. 28.
    Boffetta et al. Mortality from cardiovascular diseases and exposure to inorganic mercury. Occup Environ Med. 2001. www.oem.bmj.com
  29. 29.
    Ontario Ministry of the Environment. Fact sheet: nickel in the environment; April 2011.Google Scholar
  30. 30.
    GDS/Sous-direction de la gestion des risques des milieux: Les effets du plomb sur la santé, Paris; 2002.Google Scholar
  31. 31.
    Gauthier E, Fortier I, Courchesne F, et al. Environmental pesticide exposure as a risk factor for Alzheimer’s disease: a case-control study. Environ Res. 2001;86:37–45.CrossRefPubMedGoogle Scholar
  32. 32.
    Blain PG. Aspects of pesticide toxicology. Adverse drug react. Acute Poison Rev. 1990;9:37–68. http://health.usnews.com/health-conditions/brain-health/alzheimers-disease, downloaded on 30 Oct 2012.
  33. 33.
    Campdelacreu J. Parkinson disease and Alzheimer disease: environmental risk factors. Neurologia, 13 Jun 2012. PubMed PMID: 22703631.Google Scholar
  34. 34.
    Arlien-Soborg P, Hansen L, Ladefoged O, et al. Report on a conference on organic solvents and the nervous system. Neurotoxicol Teratol. 1992;14(1):81–2.CrossRefPubMedGoogle Scholar
  35. 35.
    Kukull WA, Larson EB, Bowen JD, et al. Solvent exposure as a risk factor for Alzheimer’s disease: a case-control study. Am J Epidemiol. 1995;141(11):1059–79.PubMedGoogle Scholar
  36. 36.
    Sobel E, Davanipour Z, Sulkava R, et al. Occupation with exposure to electromagnetic fields: a possible risk factor for Alzheimer’s disease. Am J Epidemiol. 1995;142(5):515–24.PubMedGoogle Scholar
  37. 37.
    Ernst A, Zibrak JD. Carbon monoxide poisoning. N Engl J Med. 1998;339:1603–8. http://health.usnews.com/health-conditions/brain-health/alzheimers-disease, downloaded on 30 Oct 2012.
  38. 38.
    Williams JW, Plassman BL, Burke J, Holsinger T, Benjamin S. Preventing Alzheimer’s disease and cognitive decline. Evidence report/technology assessment no. 193 (Prepared by the Duke Evidence-based Practice Center under Contract No. HHSA 290-2007-10066-I.) AHRQ Publication No. 10-E005. Rockville: Agency for Healthcare Research and Quality; April 2010.Google Scholar
  39. 39.
    Santibanez M, Bolumar F, Garcia AM, et al. Occupational risk factors in Alzheimer’s disease: a review assessing the quality of published epidemiological studies. Occup Environ Med. 2007;64(11):723–32.CrossRefPubMedCentralPubMedGoogle Scholar
  40. 40.
    Baldi I, Lebailly P, Mohammed-Brahim B, et al. Neurodegenerative diseases and exposure to pesticides in the elderly. Am J Epidemiol. 2003;157(5):409–14.CrossRefPubMedGoogle Scholar
  41. 41.
    Tyas SL, Manfreda J, Strain LA, et al. Risk factors for Alzheimer’s disease: a population-based, longitudinal study in Manitoba, Canada. Int J Epidemiol. 2001;30(3):590–7.CrossRefPubMedGoogle Scholar
  42. 42.
    Salib E, Hillier V. A case-control study of Alzheimer’s disease and aluminium occupation. Br J Psychiatry. 1996;168(2):244–9.CrossRefPubMedGoogle Scholar
  43. 43.
    Gun RT, Korten AE, Jorm AF, et al. Occupational risk factors for Alzheimer disease: a case-control study. Alzheimer Dis Assoc Disord. 1997;11(1):21–7.CrossRefPubMedGoogle Scholar
  44. 44.
    Graves AB, Rosner D, Echeverria D, et al. Occupational exposures to solvents and aluminium and estimated risk of Alzheimer’s disease. Occup Environ Med. 1998;55(9):627–33.CrossRefPubMedCentralPubMedGoogle Scholar
  45. 45.
    Rondeau V, Jacqmin-Gadda H, Commenges D, et al. Aluminum and silica in drinking water and the risk of Alzheimer’s disease or cognitive decline: findings from 15-year follow-up of the PAQUID cohort. Am J Epidemiol. 2009;169(4):489–96.CrossRefPubMedCentralPubMedGoogle Scholar
  46. 46.
    Kroger E, Verreault R, Carmichael PH, et al. Omega-3 fatty acids and risk of dementia: the Canadian Study of Health and Aging. Am J Clin Nutr. 2009;90(1):184–92.CrossRefPubMedGoogle Scholar
  47. 47.
    Kamel F, Tanner C, Umbach D, Hoppin J, Alavanja M, Blair A, Comyns K, Goldman S, Korell M, Langston J, Ross G, Sandler D. Pesticide exposure and self-reported Parkinson’s disease in the agricultural health study. Am J Epidemiol. 2007;165(4):364–74.CrossRefPubMedGoogle Scholar
  48. 48.
    Lee PC, Bordelon Y, Bronstein J, Ritz B. Traumatic brain injury, paraquat exposure, and their relationship to Parkinson disease. Neurology. 2012;79(20):2061–6.CrossRefPubMedCentralPubMedGoogle Scholar
  49. 49.
    Longdon AR, Paddick SM, Kisoli A, Dotchin C, Gray WK, Dewhurst F, Chaote P, Teodorczuk A, Dewhurst M, Jusabani AM, Walker R. The prevalence of dementia in rural Tanzania: a cross-sectional community-based study. Int J Geriatr Psychiatry. 2012. doi: 10.1002/gps.3880.PubMedGoogle Scholar
  50. 50.
    Sacktor N, Wong M, Nakasujja N, Musisi S, et al. Risk factors For HIV-dementia in sub-Saharan Africa. J Neurovirol. 2004;10:S3–83.CrossRefGoogle Scholar
  51. 51.
    Sacktor N, Nakasujja N, Musisi S, Wong M, et al. The international HIV dementia scale: a new rapid screening test for dementia. AIDS. 2005;19:1367–74.PubMedGoogle Scholar
  52. 52.
    Wong MH, Robertson K, Nakasujja N, Skolasky R, Musisi S, Katabira E, McArthur JC, Ronald A, Sacktor N. Frequency of and risk factors for HIV dementia in an HIV clinic in sub-Saharan Africa. Neurology. 2007;68(5):350–5.CrossRefPubMedGoogle Scholar
  53. 54.
    Espeland MA, Gu L, Masaki KH, et al. Association between reported alcohol intake and cognition: results from the Women’s Health Initiative Memory Study. Am J Epidemiol. 2005;161(3):228–38.CrossRefPubMedGoogle Scholar
  54. 55.
    Blood Lead Levels And Potental Environmental Exposures Among Children Under Five Years In Kibera Slums, Nairobi. Tom M. Olewe; Mwanthi, Mutuku A.; Wang’ombe, Joseph K.; Griffiths, Jeffrey K. // East African Journal Of Public Health;Apr 2009, Vol. 6 Issue 1, P6Google Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.School of Public Health, Kenyatta Hospital CampusUniversity of NairobiNairobiKenya

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