The effects of RhD blood group genotype on physical and mental health: A preregistered cross-sectional study - data

Data for the paper The effects
of RhD blood group genotype on physical and mental health: A preregistered
cross-sectional study

Background

The stable coexistence of
RhD-positive and RhD-negative subjects in a population is an evolutionary
conundrum because carriers of the less numerous allele as a rule suffer from
lower fecundity due to frequent haemolytic anaemia of (RhD-positive) newborns
born to RhD-negative women. One explanation of continued stable existence of
RhD polymorphism is based on the idea of selection in favour of heterozygotes.
In the past eleven years, numerous studies demonstrated that RhD-positive
subjects score better in psychomotor tests and health-related variables than
RhD-negative homozygotes. Nevertheless, evidence of better health and
performance of heterozygotes is scarce and merely indirect.

Methods

In this preregistered study, we compared the physical and mental health
of 2,539 subjects whose RhD genotype could be estimated based on their and
their parents’ RhD phenotype. We also compared the prevalence of 23 mental
health disorders in RhD-negative and RhD-positive subjects. We confirmed that
RhD-negative homozygotes are in worse physical and mental health than subjects
with RhD-positive phenotype and that RhD-positive heterozygotes enjoy better
health than a mixed population of all other genotypes. RhD-negative subjects are
more frequently diagnosed with obsessive-compulsive disorder (OR=2.25, C.I.95
= 1.08–4.54) and with epilepsy (OR=2.57, C.I.95 = 1.10–5.82),
whereby both values remained significant after correction for multiple tests.

Results

For the first time, we demonstrated that
RhD-positive homozygotes suffer from worse health than RhD-negative
homozygotes, which strongly supports the heterozygote advantage hypothesis.
When subjects with RhD-negative and RhD-positive phenotype are compared, the
worse health of RhD-positive homozygotes could outweigh the better health of
RhD-positive heterozygotes especially in countries with a low frequency of
alleles for RhD-negativity, where most RhD positive individuals are
homozygotes. This suggests that the effects of RhD genotypes, not phenotypes,
should be compared in future studies.