In this study, prevalence of dyslipidaemia was TC- 3.0%, TG- 12.0%, HDL%- 45.0 and LDL- 9.0% for serum lipids and TC- 20.5%, TG-17.5%, HDL- 76.0% and LDL- 25.0% for salivary lipids. High density lipoproteins had the highest preponderance using both medium. Though much higher with saliva medium, with a ratio of 1:1.6 serum: saliva
Aside HDL, Other fractions were also higher in saliva compared to serum values, and major factors implicated could be as a result of presence of lipids in the saliva that are not due to ultrafiltration from plasm, but rather from major exfoliation from salivary gland mucosal membranes. Contributions also from minor salivary glands was identified in previous studies,16, 18 high density lipoproteins was most prevalent concurrently for both medium, this could be attributed to protein balance, as interactions are found to exist between lipids and proteins as revealed by Slomniany et al.17 High density lipoproteins are protein bounded, and requires significant proteins to be transported, negative protein balance may therefore affect the ability of HDL to be transported, which could also be a reason for the higher preponderance, as it is the only fraction with this feature .
To further support this, many other studies9, 21–24 recorded HDL as the most prevalent lipid type both in local and international studies. The high prevalence of low HDL as shown by Yanai et al25 in Japan is attributed to less consumption of the poly unsaturated fats. In Nigeria, Oguejiofor et al12 has demonstrated that low HDL and high LDL cholesterol were the most consistent pattern of dyslipidemia in all the geopolitical zones of the country, though in adults. Contrary to the above findings Jaja and Yarhere found predominance of TG fraction (86.4%) although in children and adolescent with Diabetes Mellitus However, Bulut et al26 in Turkey also found total cholesterol and triglyceride as the most prevalent lipid abnormalities in their study. Differences in the prevalence in specific lipid abnormality among studies may be due to variations in the nature of study population and prevalent risk factors, as well as differences in sample size and cut-off criteria for the definition of dyslipidemia.9 When subjects having at least one or more abnormal lipid panel were considered, the overall prevalence of dyslipidemia in current study using the serum was high (57%) and much higher using the saliva medium(87.5%). Using the serum, prevalence of up to a combination of 3 lipid panel was obtained from some subjects, however, using the saliva, up to a combination of 4 lipid abnormalities were detected in a few subjects. The reason for higher saliva prevalence can further be explained due to the aforementioned reason; other lipid fraction exists in saliva that were not ultra-filtrate from plasma. The overall prevalence by and large conceded with earlier stated fact “dyslipdaemia is upraising in our setting”
This findings was comparable to the 60% prevalence rate observed among apparently healthy Nigerian adults.12 Such close similarity in the prevalence rates may allude the tracking effect of dyslipidemia in childhood, a phenomenon that has been well described in literature.9, 13, 27–30 However, this is not the case in the developed worlds on prevalence of dyslipidaemia, as observed in a large united state medical insurance database and National Health and Nutritional Examination survey (NHANES), prevalence of dyslipidemia in children, was found to be 22.9 and 23.9 respectively. Bulut in Turkey, also revealed overall prevalence of 26.2% from healthy children. In Mexico, Bibiloni et al revealed an overall prevalence as high as of 48.8%. The findings in current study suggested and support the fact that developing worlds, including Nigeria are demonstrating an increasing burden of dyslipidemia than it is anticipated. This could be as a result of lack of awareness and failure to adhere to preventive measures. The developing world lack better screening and treatment programs, especially for children. Generally, developing countries have a weaker health system.
Previous study on dyslipidemia did highlighted a causal link between dyslipidemia and a number of genetic and environmental factors.13, 24, 29
From current study, prevalence of dyslipidaemia revealed a statistically significant difference existing, especially as it relates to age and salivary TG, as well as socioeconomic status and serum TC, and TG. With these lipid fractions, null hypothesis was rejected. The age group > 10 years having higher prevalence for TG fractions using the saliva, it is expected in this age group as studies 28, 31, 32 showed in those above 2 years lipids appear to be relatively stable, as against approaching adolescent age, due to pubertal hormonal spurt. However, using the serum and saliva, it revealed age category 10–12 years being more prevalent for undesirable fraction for TG and LDL, while saliva medium still shows predominance of these age category for the remaining fraction. Contrarily, serum medium for TG and HDL revealed a predominance of age category 10–12 years. Aside the aforementioned above, other findings are not statistically significant, therefore, null hypothesis is not rejected. Looking at sex and prevalence of dyslipidaemia, findings revealed both serum and saliva, gave an equal preponderance for TC and TG, in favor of male and the female respectively. However, they gave an inverse preponderance for HDL and LDL, with prevalence of HDL more in female and LDL more in males using serum fraction and the reverse for the saliva. Findings are not statistically significant and hence, null hypothesis not rejected. Findings in this case are same. Bibilino et al also revealed no statistically significant sex findings.
Furthermore, prevalence of TC, and TG dyslipidaemia in relation to socioeconomic status showed a statistically significant difference with only serum lipids, and hence null rejected. The middle class having all the undesirable fraction. However, the middle class are the majority of the population 81.5%, findings are not due to chance. Triglyceride and HDL revealed social class 1 having the highest preponderance of dyslipidaemia (18.2%), for the 2 lipid parameters using serum sample. Contrarily, salivary findings are not consistent as serum findings, it shows no statistical significant findings, in this case null hypothesis is not rejected. Lower class had higher prevalence for the all the lipid tested by social class except for TC, which appear more for in upper class. Findings are same.
Similarly other studies,9, 13, 26 also revealed no statistically significant difference with age, sex, and socio-economic status of the subjects.