NORMAL FEMORAL ARTERY INTIMA-MEDIA THICKNESS AMONG HEALTHY NIGERIAN ADULTS; RELATIONSHIP WITH AGE, GENDER AND BODY MASS INDEX.

BACKGROUND

Ultrasonographic intima media thickness is now the imaging modality of choice for the clinical evaluation of large arterial wall thickening (atherosclerosis). It is a proven simple, reliable, accurate, reproducible, affordable and ionizing radiation-free marker of atherosclerosis. Carotid intima media thickness (IMT) values have been widely employed as a surrogate marker of atherosclerosis; normal values have been documented for Nigerians and values above the nomogram are regarded as evidence of atherosclerosis. However, recent scientific evidence shows that the femoral artery intima-media thickness is a better indicator of atherosclerosis, compared to the IMT of the carotid artery. Despite the femoral IMT being a better indicator of atherosclerosis, there is paucity of data on femoral intima media thickness among healthy Nigerian adults.

OBJECTIVE

To determine the femoral IMT among a healthy, normotensive, normoglycemic adult Nigerian cohort, and its relationship with age, sex and body mass index among the study population.

MATERIALS AND METHODS

This was a hospital-based cross-sectional study among a cohort of normotensive, non-diabetic adult healthy volunteers. The socio-demographic characteristics, anthropometric and clinical parameters, as well as the B-mode ultrasonographic IMT of both common femoral arteries were evaluated. The data was analysed using IBM SPSS version 23.0. The student t-test and One-way-ANOVA were used to test the association between age, sex and FIMT as appropriate. The correlations between the FIMT and age and BMI were assessed by Pearson's correlation coefficients; linear regression analysis was done to determine the equation relating FIMT to factors with significant correlation coefficients among the subjects. p values <0.05 were taken as statistically significant.

RESULTS

A total of 106 femoral arteries in 53 individuals were evaluated in this preliminary study. The mean age was 50.7(SD14.4) years (range 27-77 years). Twenty-eight (52.8%) were males and 25 (47.2%) were females. The mean Femoral Intima Media Thickness (FIMT) for the whole group was 0.53(SD0.05) mm. The FIMT in males, 0.54(SD0.05) mm was not significantly different from that in females, 0.52(SD0.06) mm (p= 0.221). The mean left FIMT, 0.54(SD0.05) mm was significantly higher than the right FIMT, 0.52(SD0.06) mm (p<0.001)There was a significant positive Pearson correlation coefficient between FIMT and age, (r=0.719, p<0.001). The linear regression equation was FIMT = 0.39 + 0.003*Age (years) indicating a mean increase of 0.003 mm in FIMT for every one-year increase in age.There was no significant correlation between BMI and FIMT, (r=0.008, p=0.952).

CONCLUSION

The overall mean FIMT among a cohort of South-West Nigerian adults without cardiovascular risk factors was 0.53(0.05) mm. The mean FIMT in males was not significantly different from that in females, but the mean FIMT on the left was significantly higher than that on the right. There was a significant positive correlation between FIMT and age, with an increase in FIMT of 0.003mm for every one-year increase in age. There was no correlation between FIMT and BMI. Screening FIMT may help in the early discovery of increased IMT, which would be of value in re-classification of cardiovascular risk.