Introduction
Sickle cell disease (SCD), an autosomal recessive disorder of the red
blood cell, is the commonest monogenic disease with more than 300,000
affected births annually worldwide, mostly in low and middle-income
countries.1,2 The deformed red cells in SCD lead to
recurrent acute vaso - occlusive episodes, hemolysis, anemia, organ
damage resulting in impaired quality of life, and premature
mortality.3 SCD was first described in India in 1952
among the Toda and Irula tribes living in the mountainous regions to the
southeast of the Gudalur Valley in the Nilgiri Hills of Tamil Nadu, in
southern India. 4 The βs gene is now
known to be widespread among the aboriginal population of the Deccan
plateau of Central India, Orissa, Wayanad district of Kerala with a
frequency between 5% to 31%.5 Piels et al estimated
that, in 2010, three countries, India, Nigeria, and the Democratic
Republic of the Congo accounted for more than half the births with this
disease globally.1 In India, the aboriginal or
scheduled tribes (ST) populations form 8.6% of the total population
constituting 104 million individuals.6 It is estimated
that in 2010 approximately 44,400 babies with SCD were born in
India,1 which is more than 20 times the number born in
the US.7
While SCD is associated with loss of approximately 22 years of life
expectancy, this is likely to be impacted by genetic, environmental,
socioeconomic factors.8 A previous study from the
State of Orissa,9 had suggested that the clinical
phenotype of SCD observed in the aboriginal population may be milder. A
study from the neighboring District of Wayanad in Kerala stated that
they survive longer than individuals of African or Caribbean descent.
However, this latter observation may be erroneous, being based on a
relatively small cross-sectional study.10 As there is
limited literature on the mortality rate of SCD in the aboriginal
population, we undertook a retrospective cohort study to determine the
rates and causes of mortality due to SCD in this community.