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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 1, January/February 2016
24
AFRICA
Various studies have shown cardiovascular risk factors
such as type 2 diabetes mellitus,
9,10
insulin resistance,
11
and
hypertension
12
were associated with the risk allele A for
FTO
rs9939609 and the risk allele C for
MC4R
rs17782313, regardless
of BMI.
9,10
But in Marcadenti and colleagues’ study, common
genetic variants of
FTO
rs9939609 had positive associations
with BMI and neck circumference and
MC4R
rs17782313 in
women, but a negative association with diastolic and mean blood
pressure in hypertensive men in southern Brazil.
13
However, these
associations need to be confirmed by further replication studies,
particularly in other ethnic populations. Brazilians and Chinese
are different in their environmental risk factors, medical profiles,
body composition and genetic backgrounds.
This study has some limitations that should be taken into
account when interpreting the results. The analysis of genotype
by gender was exploratory and it was underpowered to detect
small differences. Therefore, some associations that achieved
statistical significance in the overall analysis remained only as a
trend towards that association. The association of gene variants
with anthropometric indices should be confirmed in further
studies with statistical power to carry out analysis by gender.
Conclusion
We found that the
FTO
and
MC4R
genes were risk factors for
nocturnal hypertension in this Chinese Han population, and
their combined effects played an important role in nocturnal
hypertension. However, even if a gene were considered associated
with hypertension in certain populations, to expand the
conclusion to all human populations is arbitrary. Furthermore,
in the investigation of hypertension, obesity or diabetes, not
only genetic factors but other factors, such as environment or
geographic location could play a role. All these factors could
have different effects on obesity or diabetes and they could
impact on each other. Therefore whether or how a single gene
could be associated with nocturnal hypertension is a complicated
question. To decipher this, one would need long-term studies
with numerous patients.
FTO
is a new gene reported by Yi-Cheng
and co-workers in 2007,
2
and thus far we have not answered all
the questions since there has been minimal research on this gene
among the different nations. We need more studies, since from
a population perspective, only the combined effect of the most
potent genetic variants should be considered.
This study was funded by the Hubei Provincial Bureau of Health Science
Foundation for Young Scholars (grant QJX2008-29).
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