Environmental determinants of aplastic anemia in Pakistan: a case-control study.
OBJECTIVE
Aplastic anemia (AA) affects the Asian population two to three fold more than people in other regions. Besides the host genetics and socioeconomic status, several other environmental exposures have been linked with an AA etiology. We aimed to examine the association of various environmental exposures with AA occurrence among Pakistani individuals.


METHODS
A case-control study was conducted in Karachi, Pakistan, where cases (diagnosed AA patients) were selected from the National Institute of Blood Disease and Bone Marrow Transplantation (NIBD), while for each case, a single control (who was free of AA and visited the outpatient department of the same hospital for the treatment of minor ailments) was selected matched by age and sex. A total of 428 participants were included in this study with equal proportions of cases and controls. Information related to disease characteristics, sociodemographics and exposure to chemicals was collected through a survey questionnaire, laboratory investigations and medical records. Descriptive results were reported as frequencies and proportions, adjusted odds ratios with 95 % confidence intervals and population attributable risk (PAR) as percentage.


RESULTS
Among study participants (n= 428), AA was significantly associated with various environmental exposures. Participants residing in rural settings (OR = 2.29, 95 % CI 1.12-4.67,p-value < 0.01) and those who reported exposure to pesticides (OR = 3.58, 95 % CI 1.27-10.10,p-value 0.01; PAR = 18.16 %) were significantly more likely to report AA. Participants with a formal education were significantly less likely to have AA (OR = 0.27, 95 % CI 0.10-0.71,p-value < 0.01).


CONCLUSIONS
This study observed a significant association of aplastic anemia with a lower socioeconomic profile, and certain environmental exposures among the Pakistani population. The evidence may be helpful in understanding the pathophysiology of aplastic anemia in the context of environmental exposures.
Department of Clinical Hematology, National Institute of Blood Disease Center and Bone Marrow Transplantation, Karachi, Pakistan.
Mehwesh
M
Taj
Department of Clinical Hematology, National Institute of Blood Disease Center and Bone Marrow Transplantation, Karachi, Pakistan.
Tayyaba
T
Shah
School of Public Health, Dow University of Health Sciences, Karachi, Pakistan.
Syeda Kanwal
SK
Aslam
School of Public Health, Dow University of Health Sciences, Karachi, Pakistan.
Sidra
S
Zaheer
School of Public Health, Dow University of Health Sciences, Karachi, Pakistan.
Faryal
F
Nawab
Department of Research and Development, National Institute of Blood Disease Center and Bone Marrow Transplantation, Karachi, Pakistan.
Sumaira
S
Shaheen
School of Public Health, Dow University of Health Sciences, Karachi, Pakistan ; Institute of Health and Wellbeing, Public Health, University of Glasgow, 1-Lilybank Gardens, Glasgow, UK G12 8RZ.
Kashif
K
Shafique
Department of Clinical Hematology, National Institute of Blood Disease Center and Bone Marrow Transplantation, Karachi, Pakistan.
Tahir Sultan
TS
Shamsi
Aplastic anemia; Arsenic; Case-control study; Environmental exposures; Pesticides
ScientificWorldJournal. 2014;2014:304524
25374935
J Diabetes Metab Disord. 2014 Dec 14;13(1):117
25530951
J Clin Virol. 2012 May;54(1):96-7
22441030
J Occup Med. 1993 Nov;35(11):1106-16
8295035
Med Klin (Munich). 2009 Mar 15;104(3):197-203
19337709
Blood. 1975 Mar;45(3):355-63
1090310
Environ Int. 2011 Feb;37(2):479-97
21087795
Asia Pac J Public Health. 2011 May;23(3):369-77
21490113
Am J Public Health. 1997 Sep;87(9):1551-4
9314815
Trends Parasitol. 2006 Aug;22(8):363-6
16798088
Haematologica. 2008 Apr;93(4):489-92
18379007
Clin Biochem. 2006 Jul;39(7):762-6
16729992
Blood. 1990 Apr 15;75(8):1646-53
2183887
Virol J. 2011 Feb 28;8:87
21352606
Bone Marrow Transplant. 2008 Aug;42 Suppl 1:S114-S117
18724282
J Pak Med Assoc. 2001 Dec;51(12):443-5
11850982
Environ Int. 2007 Nov;33(8):1107-22
17765971
Environ Toxicol. 2014 Jan;29(1):84-97
21987380
Trop Doct. 2001 Jul;31(3):184
11444353
Virol J. 2011 Jan 21;8:30
21251303
Haematologica. 2009 Sep;94(9):1220-6
19734415
Br J Haematol. 1995 Sep;91(1):80-4
7577657
Int J Hematol. 2002 Aug;76 Suppl 2:173-4
12430921
Cancer Causes Control. 2007 Dec;18(10):1209-26
17874193
Environ Geochem Health. 2009 Apr;31 Suppl 1:9-21
19137402
Toxicol Sci. 2014 Nov;142(1):93-104
25092648
Int J Stem Cells. 2015 May;8(1):1-8
26019749
Bull Environ Contam Toxicol. 2012 Dec;89(6):1138-41
23064423
J Public Health (Oxf). 2016 Jun;38(2):223-8
25755247
Haematologica. 2008 Apr;93(4):518-23
18322256
Am J Epidemiol. 1985 Nov;122(5):904-14
4050778
Ecotoxicol Environ Saf. 2015 May;115:187-94
25704277