Study of unstimulated salivary flow rate, total protein, albumin concentration and estimated albumin globulin ratio changes in normal adults according to age and gender
Brishna Dawlaty1*, Shamsulrahim Rahim2
1MD, Msc, Assistant Professor, Department of Biochemistry, Faculty of allied Health Sciences,
Kabul University of Medical Sciences, Kabul Afghanistan.
2PharmD, Professor, Department of Biochemistry, Faculty of Allied Health Sciences,
Kabul University of Medical Sciences, Kabul, Afghanistan.
*Corresponding Author E-mail: brishna.db@gmail.com
ABSTRACT:
Background: Saliva which has a vital role in oral health is a complex fluid provided by salivary glands. Aging causes salivary glands hypofunction that affects the quantity and quality of saliva. Hence in this study flow rate, protein, albumin and albumin globulin ratio of saliva was compared in two age groups, in order to have broader assumption of gender and age-related changes of oral health in normal adults. Material and method: This is an analytical cross-sectional study, conducted on 250 healthy adult volunteers after approval from Kabul University of medical sciences research committee. Before collecting saliva, the informed consent form was signed by them. Unstimulated whole saliva was collected in sterile tube by drooling method for five minutes. Flow rate collected for five minutes and calculated on milliliters per minutes. After centrifugation for five minutes at 600rpm salivary total protein, albumin was measured by semi-autoanalyzer. Estimated Albumin globulin ratio was calculated by dividing albumin to estimated globulin concentration. Total protein and albumin were calculated by the biuret and bromocresol green method respectively. Data were analyzed in SPSS version 21. Mann Whitney U test was performed for comparison of variables between age group 18-30 and 31-65 years old. Result: In this study among 250 volunteers there were 128 males and 122 females. The mean age was 32 years old. There were 136 participants in age group 18-30 years and 114 in the age group 31-65 years. Flow rate, total protein concentration was lower in group of 31-65 than 18-30 years. The flow rate was lower in females than males but decrease in protein concentration was not gender dependent. Albumin, albumin globulin ratio increased in age group 31-65 years. Albumin was not gender dependent but the albumin globulin ratio was significantly higher in males than females. Conclusion: Flow rate significantly decreased in the age group 31-65 years and more distinct in women than men so suggestive of increased incidence of caries in women. Increased level of albumin in age group 31-65years is suggestive of increase risk of oral inflammatory diseases in this age group. In addition, as the level of albumin globulin ratio was higher after age 30 and more obvious in male adults so it can be assumed that resistance against oral cavity diseases is much lower in men than women in the age group 31-65years.
KEYWORDS: Unstimulated saliva, salivary flow rate, Salivary total protein, Salivary albumin, Salivary albumin globulin ratio.
INTRODUCTION:
Saliva which is provided by salivary glands is a complex fluid that has an important role in oral health.
More functions of saliva depend on salivary proteins. There are overlapping of plasma and salivary proteins but proteins such as statherin and histatin are specific for saliva and not present in plasma. The exact mechanism of overlapping of proteins such as immunoglobulins in plasma and saliva is not known but likely due to leakage from plasma to salivary system.8,9 Main functions of salivary proteins are remineralization of enamel, caries prevention and antimicrobial activity.10
Albumin in the saliva is considered as plasma ultrafiltrate in the oral cavity and may diffuse in mucosal secretions.it may be used to assess the integrity of mucosal function. In many studies considered as marker for inflammation.11,12 Salivary immunoglobulins which are glycoproteins of gamma globulin family prevents bacterial colonization.13,14 Many studies have shown that estimated salivary albumin globulin ratio decreased in different diseases of the oral cavity as gingivitis and chronic periodontitis.15,16
When using saliva for investigation, there is two methods for collecting saliva, stimulating the production of saliva by external stimuli, and the collection of saliva that accumulated on the floor of the mouth without any stimulation which is referred as unstimulated whole saliva. Collection method of saliva can affect flow rate, as higher flow rate obtained in stimulated saliva than unstimulated saliva. Unstimulated salivary flow rate is usually used as a measure of the quantity of saliva. low salivary flow rate has a negative effect on lubricant activity of saliva.17
Changes in quantity (flow rate) and composition of saliva especially salivary proteins have impact on oral health. Therefore, in this study changes of flow rate and proteins of saliva that can impact the most important function of saliva and oral health are compared between age 18-30 years and 31-65 years in regard to gender, in order to have a broader assumption of gender and age-related changes of oral health in normal adults.
MATERIAL AND METHOD:
This is a cross sectional study conducted at the Department of biochemistry among 250 healthy adults after approval by research committee of Kabul university of medical sciences. All of them were informed about the research and signed an informed consent form. All healthy adults except those who were pregnant, smoker, had systemic and oral disease, had a history of orofacial radiography in the last three month were selected for collecting of saliva sample.
Saliva collection:
Unstimulated whole saliva was taken in a sterile tube by drooling method in a setting position. saliva was collected from each individual between 9:00 to 11:00 am for five minutes. the participants were instructed not to brush or eat or drink at least one hour prior to the time of saliva collection. Immediately after collection, the samples were evaluated for flow rate then total protein and albumin concentrations were measured after centrifugation at 600 rpm for five minutes.
Flow Rate Measurement:
Flow rate was calculated by the following formula
Flow rate = total volume of saliva collected(ml)/ collected period(min)
Total salivary protein and salivary albumin measurement:
Total salivary protein concentration was analyzed by the biuret method using a commercially available kit (Diasys, lot no.60131490). Proteins in saliva form a blue colored complex when treated with cupric ions in an alkaline solution. The intensity of blue color is proportional to protein concentration. Salivary albumin was measured by bromocresol green method using a commercially available kit (Diasys, lot no 60131161). Salivary albumin reacts with bromocresol green which causes a color change that is proportional to albumin concentration. Concentration determination of total protein and albumin was performed in semi autoanalyzer Microlab 300.
Estimation of Albumin globulin ratio:
First estimated Globulin was calculated by subtracting albumin concentration from total protein concentration and finally estimated ratio of albumin to globulin was measured by dividing albumin concentration to estimated globulin.
Data analysis:
All data were analyzed in SPSS version 21 with CI=95% and α=0.05 concerned. After the determination of the distribution of data, Descriptive statistics were shown. All participants were divided in two age groups, 18-30 years (young adults) and 31-65 years old. The difference of variables in each age group with the concern of gender was investigated by Mann Whitney U test.
RESULTS:
In this research from 250 volunteers who were participated 128(51.2%) were male and 122(48.8%) were female. The mean age was 32 years. Descriptive statistics for all data are shown in Table 1. The age group 18-30 years and 31-65 years covered 136 (54.4%) and 114 (45.6%) participants respectively. Kolmogorov -Smirnov normality test with p<0.05 (p=0.00) shows that the data is not normally distributed. Therefore, the Mann Whitney U test was performed for comparing variables between groups. The median of variables between mentioned age groups with consideration to gender is shown in graph 1. There are significant differences in all variables in the two age groups as shown in Table 2.
Table 1: Descriptive statistics
|
Statistics |
|||||||
|
|
Age (years) |
Flow rate (ml/min) |
Total protein Concentration (g/dl) |
Albumin Concentration (g/dl) |
Estimated globulin Concentration (g/dl) |
Estimated Albumin globulin ratio |
|
|
N |
Valid |
250 |
250 |
250 |
250 |
250 |
250 |
|
Missing |
0 |
0 |
0 |
0 |
0 |
0 |
|
|
Mean |
32.98 |
.76 |
1.43 |
.85 |
.58 |
2.25 |
|
|
Median |
29.00 |
.60 |
1.40 |
1.10 |
.40 |
1.73 |
|
|
Std. Deviation |
13.24 |
.52 |
.66 |
.40 |
.47 |
1.75 |
|
|
Minimum |
18.00 |
.13 |
.20 |
.10 |
.10 |
.07 |
|
|
Maximum |
65.00 |
3.00 |
4.80 |
1.50 |
3.40 |
6.50 |
|
Figure 1. Median of variables in different age groups according to gender
Table 2: Differences of variables between two age groups in U test
|
Ranks |
|
||||
|
|
Age (years) |
N |
Mean Rank |
Sum of Ranks |
Asymp. Sig. (two- tailed) |
|
flowrate |
18-30 |
136 |
141.05 |
19183.00 |
0.000 |
|
31-65 |
114 |
106.95 |
12192.00 |
||
|
Total |
250 |
|
|
||
|
Total protein concentration |
18-30 |
136 |
139.32 |
18947.00 |
0.001 |
|
31-65 |
114 |
109.02 |
12428.00 |
||
|
Total |
250 |
|
|
||
|
Albumin concentration |
18-30 |
136 |
115.06 |
15648.00 |
0.011 |
|
31-65 |
114 |
137.96 |
15727.00 |
||
|
Total |
250 |
|
|
||
|
Estimated Globulin concentration |
18-30 |
136 |
154.14 |
20963.50 |
0.000 |
|
31-65 |
114 |
91.33 |
10411.50 |
||
|
Total |
250 |
|
|
||
|
Albumin globulin ratio |
18-30 |
136 |
97.18 |
13216.50 |
0.000 |
|
31-65 |
114 |
159.29 |
18158.50 |
||
|
Total |
250 |
|
|
||
In age 18-30 years flow rate, estimated globulin is gender dependent as flow rate has tendency to be more in males (P=0.019) and estimated globulin has a tendency to decrease in males (P=0.047). But changes in total protein and albumin and estimated albumin globulin ratio are not gender dependent. In age 31-65 Years the flow rate was much more in males (P=0.000), estimated globulin has tendency to decrease in males (p=0.045) and estimated albumin globulin ratio has a tendency to increase in males (P=0.003) but there are no significant gender dependent differences in total protein, and albumin.
Spearman correlation was performed in order to observe the effect of flow rate to total protein, albumin, estimated globulin, and estimated albumin globulin ratio, but there was no significant correlation for flow rate and total protein (correlation coefficient = 0.017, p=0.792) albumin, estimated globulin and estimated albumin and globulin ratio.
DISCUSSION:
It has been reported that a reduction in flow rate increase the chance of dental caries because a low flow rate decrease washing out of cariogenic microorganisms.17,18,19 Beside these histological changes in the salivary gland occurs that results in salivary gland hypofunction and ends in low flow rate in elders.20 In this study flow rate was significantly reduced in the age group 31-65 rather than 18-30 and also reduction was significant in females rather than males. The result of flow rate in this study is similar to the study conducted by Hiba Khaldoun Al-Tamimi and Nadia Aftan Al-Rawi 21 which shows a reduction of flow rate with increasing age in adult men that describes the role of aging on flow rate without considering gender. in addition, Rose-Anna Grace Pushpass et al 22in their study reported a low flow rate in older adults. Meanwhile, Ana Carolina Mosca et al 23 also observed a decrease of flow rate with aging which was higher in men than women.
Generally, Proteins in saliva prevent diffusion of acids on tooth surface helps remineralization and prevent microbial activity so has a protective role against dental carries.14 in this study total salivary protein decrease after age 30 and this change is not depending on gender. study of Drashti Bhuptani et al10 despite of higher concentration of protein in females, obvious that salivary protein concentration is much lower in adults and elders than adolescents and children which is in accordance with this study. A study of iroanya et al24 also reported low concentration of protein in elders than young adults. Although both salivary flow rate and total protein decreased in age 31-65 years, there was no significant correlation between the mentioned variables. However, Andrei Prodan25 reported a negative correlation of flow rate with total protein concentration.
The level of albumin in the saliva is an indicator of mucosal integrity. research conducted by V. Gopinath et al12 observed higher level of albumin in chronic periodontitis patients rather than normal individuals. in this study, salivary albumin concentration was higher in age over 30 than young adult groups this change is not related to gender but the study of Lyudmila V. Bel'skaya et al26 conducted on 46 females and 61 males established that with age, level of salivary albumin in women is significantly increased. This might be due to difference in total sample and females’ numbers in Lyudmila V Belskaya et al study and this study. According to this study loss of integrity of oral mucosa normally occurs in age 31-65 years and adults in this category of age might be more prone to oral inflammatory diseases.
Immunoglobulins are important defense factors that act on the neutralization of bacteria.13,27 in this study estimated globulin considers all proteins of saliva such as enzymes, immunoglobulins, mucin, except albumin. These proteins are mostly protective factors that are at a low level in saliva of older adults.21 This study also shows a lower level of estimated globulin in age 31-65 than 18-30 years. In both age groups, it is lower in men than women. Estimated albumin globulin ratio rises in many oral diseases such as chronic gingivitis and periodontitis.15,16 In this study because of high albumin level and low estimated globulin which consists of protective factors, the estimated albumin globulin ratio was higher in the age group 31-65 years than young adults, and more in men than women.
It can be concluded that the salivary flow rate decreases after age 30 in healthy adults more significantly in women hence can be assumed of increased risk of caries between women age 31-65 years than young adults. Total protein decreased and albumin increased after 30 years old in both gender that is suggestive of increased incidence of oral cavity diseases in adults over 30 years old than young adults. The estimated albumin globulin ratio was higher between men of age group 31-65 years than females. Because estimated globulin (proteins other than albumin that included immunoglobulin) that consists of protective proteins are lower in men over 30 years than women, so it can be assumed that resistance against inflammatory and other diseases of the oral cavity is lower in healthy adult males after age 30 years. It should be mention that each age group does not have same number of participants also numbers of male and females in each age group was unequal. In addition, a small sample size was another limitation to this study. Hence in future studies it is better to consider these limitations.
ACKNOWLEDGMENTS:
The authors would like to thank all participants for devoting their time to collecting saliva.
CONFLICTS OF INTEREST:
The authors declare that there are no conflicts of interest.
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Received on 07.10.2021 Modified on 14.03.2022
Accepted on 12.06.2022 © RJPT All right reserved
Research J. Pharm. and Tech. 2022; 15(7):3190-3194.
DOI: 10.52711/0974-360X.2022.00534