Cardiovascular Journal of Africa: Vol 27 No 5 (September/October 2016)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 5, September/October 2016

AFRICA

285

atherosclerosis was more frequent in men than women and was

significantly associated with age.

An Asian study performed in

Taiwan also found that CIMT was significantly greater in men

than women.

A Korean multicentre epidemiological study found carotid

plaques in 17% of a healthy population with a mean age of 49

years and in 35% of hyperlipidaemic, hypertensive patients with

a mean age of 51 years.

Our study found a similar prevalence

of carotid plaques (26.0% of the total study population and

30.5% of men and 20.2% of women). In addition, our results

revealed the characteristics of arterial aging and growth of

intimal smooth muscle cells that increased with age, along with

the presence of vascular plaque.

Along with an earlier study,

our study found that the

prevalence of fatty liver disease was significantly higher in men

than women. Many factors may contribute to gender differences

in the prevalence of fatty liver disease. First, the men had a

significantly larger waist-to-hip ratio than the women. The

prevalence of fatty liver disease is significantly higher in people

with a large waist-to-hip ratio. An increased waist-to-hip ratio

is directly correlated with increased visceral adipose tissue,

which is associated with hepatic insulin resistance in men; and

insulin resistance is also associated with fatty liver disease.

21,22

Other factors, including sex hormones and gender lifestyle

differences may also be associated with gender differences in the

prevalence of fatty liver disease.

We suspect that the baseline

characteristics of men, including factors indicating the presence

of the metabolic syndrome, may also have contributed to the

higher prevalence of fatty liver disease and carotid plaque,

as well as higher CIMT values in the male than in the female

participants in our study.

Vascular remodelling, which presents with signs of endothelial

dysfunction, increasing thickness of the carotid intima–media,

and vascular plaque, is associated with aging.

BMI, metabolic

risk factors, including increased waist circumference, blood

pressure, glycated haemoglobin level, HDL-C and triglyceride

levels, and lifestyle risk factors, including smoking and alcohol

consumption, are also associated with increased CIMT and risk

of atherosclerosis.

24,25

Because the male participants in our study had many factors

at baseline that indicated a significantly worse clinical profile

than the female participants, we analysed the association of

some of the components of the metabolic syndrome with CIMT

values or presence of carotid plaque, stratified by gender. Our

study found different gender-based risk factors for increased

CIMT or prevalence of carotid plaque. Among the metabolic

risk factors of the women, waist circumference, dyslipidaemic

status, and fatty liver disease had significantly more effect on the

presence of CIMT and carotid plaque than those factors in men.

To determine the hazard ratio of fatty liver disease for developing

subclinical atherosclerosis, we adjusted these components of the

metabolic syndrome for multivariate analysis.

As we have shown, the prevalence of fatty liver disease is

lower in women of reproductive age compared to men of the

same age. There was no difference in the prevalence of fatty liver

disease between women after menopause (older than 60 years)

and men of the same age. These findings may be associated

with the protective effect of oestrogen, which is an important

regulator of lipid metabolism and has a protective effect against

the progression of liver steatohepatitis.

26,27

Previous studies found that oestrogen receptor-gene

knockout, aromatase knockout, and double oestrogen receptor-

gene knockout mice displayed elevated triglyceride levels; and

mice with congenital oestrogen deficiency developed fatty liver

disease.

27-30

We believe that women who have fatty liver disease

may have an abnormal oestrogen receptor-signalling pathway

associated with the regulation of lipid metabolism. In addition,

oestrogen has been known to prevent age-related adverse vascular

remodelling via the inhibition of smooth muscle cell proliferation

and endothelial dysfunction, and by improving vascular tone.

23,31

Hence, we believe that women with fatty liver disease who have

a defective oestrogen receptor-signalling pathway may have

endothelial dysfunction and subclinical atherosclerosis.

Our findings demonstrate that carotid artery evaluation

for patients with fatty liver disease, especially for women, has

an important role. We believe there should be gender-based

screening for subclinical atherosclerosis and modification of

risk factors for cardiovascular events. Assessment of CIMT, as

a surrogate of subclinical atherosclerosis, may help to further

predict cardiovascular events in female patients.

Our study has several limitations. The main limitation was

that it was a retrospective observational study. Also, our cross-

sectional study could not infer causality. Third, our data were

derived from an Asian cohort at a single institution; therefore,

the study findings on the association of fatty liver disease with

CIMT may not necessarily be transferable to other ethnicities.

Conclusion

The men had more fatty liver disease, more carotid plaque and

higher CIMT values than the women in our study. Fatty liver

disease was a useful predictor of atherosclerosis, especially for

the female study patients. Women with fatty liver disease should

undergo monitoring by carotid ultrasound for early detection

of atherosclerosis and timely protection against cardiovascular

events.

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