Salivary Osmolality Research Articles

New horizons in the diagnosis and management of dehydration.

Hydration is a fundamental aspect of clinical practice and yet it is an under-researched topic, particularly in older people, leading to many areas of uncertainty. There are two types of dehydration; hypertonic, which is a water deficit, and isotonic, which is a deficit of both water and salt. Individual clinical signs and bedside tests are poor diagnostic tools, making dehydration difficult to identify. However, the diagnostic value of a holistic clinical approach is not known. The gold-standard clinical test for dehydration is serum osmolality, but this cannot diagnose isotonic dehydration and may delay diagnosis in acute situations. Salivary osmolality point-of-care testing is a promising and rapid new diagnostic test capable of detecting both hypertonic and isotonic dehydration in older people, but further evidence to support its clinical utility is needed. Daily fluid requirements may be less than previously thought in adults, but the evidence specific to older people remains limited. Hydration via the subcutaneous route is safer and easier to initiate than the intravenous route but is limited by infusion speed and volume. Prompting older adults more frequently to drink, offering a wider selection of drinks and using drinking vessels with particular features can result in small increases in oral intake in the short-term. The ongoing clinically-assisted hydration at end of life (CHELsea II) trial will hopefully provide more evidence for the emotive issue of hydration at the end of life.

Association of salivary parameters and erosive tooth wear in preschool children.

The aims of this study were to 1) assess the association between erosive tooth wear (ETW) according to the BEWE (Basic Erosive Wear Examination) scoring system and salivary parameters and 2) compare salivary parameters according to ETW severity in the subgroup of children with ETW. This cross-sectional study included 52 preschool children aged 5 years paired by sex. A calibrated examiner assessed ETW using BEWE criteria, and stimulated saliva was collected to determine salivary flow, osmolality, pH, and buffering capacity. The children were divided into two groups: without ETW (n=26; BEWE score 0) and with ETW (n=26; BEWE scores 1 and 2). Logistic regression analysis was used to determine the magnitude of the association between ETW and salivary parameters and estimates of odds ratios (OR). In the unadjusted analysis, the ETW group was more likely to have lower salivary flow (OR = 0.079; 95%CI = 0.013-0.469; p = 0.005) and lower osmolality (OR = 0.993; 95%CI = 0.985-1.000; p = 0.049). In the adjusted analysis, salivary flow remained significantly associated with ETW (OR = 0.087; 95%CI = 0.014-0.533; p = 0.008). Lower salivary osmolality values were observed in ETW, especially in preschool children with more severe ETW (BEWE score 2). Receiver operating characteristic (ROC) determined a salivary osmolality cutoff point of < 201 for the presence of ETW. In conclusion, salivary flow rate was significantly associated with ETW prevalence. Lower values of salivary osmolality were observed in preschool children with distinct erosive lesions with significant loss of tooth structure (BEWE 2).

Comparison of salivary cytokines levels among individuals with Down syndrome, cerebral palsy and normoactive.

BackgroundIndividuals with Down syndrome (DS) present increased susceptibility to infections and high prevalence of periodontal disease. The objective of this study is to evaluate the salivary concentrations of IL-1β, IL-6, IL-8, IL-10, TNFα and IL-12p70 of DS individuals and compare to cerebral palsy (CP) and normoactive patients (all with gingivitis). Material and MethodsTwenty-two individuals with DS, 24 with CP and 22 normoactive participated in this cross-sectional study. Salivary flow rate, osmolality rate, Oral Hygiene Index, Gingival Index (GI) and salivary inflammatory markers IL-1β, IL-6, IL-8, IL-10, TNFα and IL-12p70 were evaluated. Shapiro-Wilks, Chi-square, ANOVA One-Way and Kruskal Wallis tests were applied with significance level at 5%. ResultsThe groups were homogenous for gender, age, and IL12p70 cytokine (p>0.05). GI was significantly higher in DS compared to CP and healthy (p<0.05). CP presented reduced salivary flow and increased osmolality rate. CP showed significantly higher values for TNFα, IL10, and IL6 compared to DS and normoactive (p<0.05). DS and CP presented significantly higher values of IL-1β and IL8 compared to normoactive (p<0.05). ConclusionsIndividuals with CP have higher risk to develop periodontal disease due to reduced salivary flow rate, increased salivary osmolality rate and elevated TNFα, IL-10, IL-6 compared to DS. Key words:Cytokines, biomarkers, gingivitis, periodontal diseases, Down syndrome, cerebral palsy, saliva.

Fluid type influences acute hydration and muscle performance recovery in human subjects

BackgroundExercise and heat trigger dehydration and an increase in extracellular fluid osmolality, leading to deficits in exercise performance and thermoregulation. Evidence from previous studies supports the potential for deep-ocean mineral water to improve recovery of exercise performance post-exercise. We therefore wished to determine whether acute rehydration and muscle strength recovery was enhanced by deep-ocean mineral water following a dehydrating exercise, compared to a sports drink or mountain spring water. We hypothesized that muscle strength would decrease as a result of dehydrating exercise, and that recovery of muscle strength and hydration would depend on the type of rehydrating fluid.MethodsUsing a counterbalanced, crossover study design, female (n = 8) and male (n = 9) participants performed a dehydrating exercise protocol under heat stress until achieving 3% body mass loss. Participants rehydrated with either deep-ocean mineral water (Deep), mountain spring water (Spring), or a carbohydrate-based sports drink (Sports) at a volume equal to the volume of fluid loss. We measured relative hydration using salivary osmolality (Sosm) and muscle strength using peak torque from a leg extension maneuver.ResultsSosm significantly increased (p < 0.0001) with loss of body mass during the dehydrating exercise protocol. Males took less time (90.0 ± 18.3 min; P < 0.0034) to reach 3% body mass loss when compared to females (127.1 ± 20.0 min). We used a mono-exponential model to fit the return of Sosm to baseline values during the rehydrating phase. Whether fitting stimulated or unstimulated Sosm, male and female participants receiving Deep as the hydrating fluid exhibited the most rapid return to baseline Sosm (p < 0.0001) regardless of the fit parameter. Males compared to females generated more peak torque (p = 0.0005) at baseline (308.3 ± 56.7 Nm vs 172.8 ± 40.8 Nm, respectively) and immediately following 3% body mass loss (276.3 ± 39.5 Nm vs 153.5 ± 35.9 Nm). Participants experienced a loss. We also identified a significant effect of rehydrating fluid and sex on post-rehydration peak torque (p < 0.0117).ConclusionWe conclude that deep-ocean mineral water positively affected hydration recovery after dehydrating exercise, and that it may also be beneficial for muscle strength recovery, although this, as well as the influence of sex, needs to be further examined by future research.Trial registrationclincialtrials.gov PRS, NCT02486224. Registered 08 June 2015.

Rehydrating efficacy of maple water after exercise-induced dehydration

Dehydration impairs physiological function and physical performance, thus understanding effective rehydration strategies is paramount. Despite growing interest in natural rehydrating beverages, no study has examined maple water (MW).PurposeTo investigate the rehydrating efficacy of MW after exercise-induced dehydration.MethodsUsing a single-blind, counterbalanced, crossover design, we compared the rehydrating efficacy of MW vs. maple-flavored bottled water (control) in 26 young healthy (22 ± 4 yrs., 24 ± 4 kg/m2) males (n = 13) and females (n = 13) after exercise-induced dehydration (~ 2.0%ΔBody Weight [BW]) in the heat (30 °C, 50% relative humidity [RH]). Hydration indicators (BW, salivary and urine osmolality [SOsm/UOsm], urine specific gravity [USG], urine volume [UV], urine color [UC]), thirst, fatigue, and recovery (heart rate [HR)], and HR variability [HRV]) were taken at baseline, post-exercise, 0.5, 1, and 2 h post-consumption of 1 L of MW or control.ResultsFollowing similar dehydration (~ 2%ΔBW), MW had no differential (p > 0.05) impact on any measure of rehydration. Likely due to greater beverage osmolality (81 ± 1.4 vs. 11 ± 0.7 mOsmol/kg), thirst sensation remained 12% higher with MW (p < 0.05). When sex was considered, females had lower UV, elevated UOsm (p < 0.05), trends for higher ΔBW, USG, but similar SOsm. Analysis of beverages and urine for antioxidant potential (AP) revealed a four-fold greater AP in MW, which increased peak urine AP (9.4 ± 0.7 vs. 7.6 ± 1.0 mmol, MW vs. control, p < 0.05).ConclusionElectrolyte-containing MW, was similar in effectiveness to water, but has antioxidant properties. Furthermore, trends for sex differences were discovered in urinary, but not salivary, hydration markers, with discrepancies in kinetics between fluid compartments both warranting further study.

Salivary Osmolality, Function, and Hydration Habits in Community-Dwelling Older Adults.

The aim of this study was to examine the relationship between hydration status as measured by salivary osmolality and personal hydration habits, selected demographic characteristics, and performance on a walking and balance test in older community-dwelling adults. This study used a descriptive observational design in a convenience sample of multiethnic, community-dwelling older adults (N = 53). We collected saliva for analysis on 3 days both in the morning and early afternoon, along with a hydration habit questionnaire, get up and go test and demographic information. An exploratory factor analysis of the hydration habit questionnaire revealed a two-factor solution including physical barriers and psychological barriers to drinking fluids. A linear mixed-model approach revealed that time of day (p < .01), race (p = .015), mobility (p < .01), and cognitive barriers (p = .023) are all significant predictors of salivary osmolality among noninstitutionalized seniors. There is also a significant interaction between psychological barriers to drinking fluids and time of day (p < .01). Average salivary osmolality was higher in this group of older adults than has been reported in younger adults. Controlling for all other variables, salivary osmolality is higher in the morning than in the afternoon, lower among Black or African American seniors than among White or Caucasian seniors, and higher among seniors with decreased mobility. An interaction between psychological barriers and salivary osmolality showed that those participants with more psychological barriers to drinking had higher salivary osmolality in the morning and an inverse relationship in the afternoon.

Effects of treatments for drooling on caries risk in children and adolescents with cerebral palsy.

BackgroundNeuromuscular impairment makes individuals with cerebral palsy (CP) more prone to drooling. Among the treatment options, there are procedures that interfere with saliva production. It is imperative to evaluate the effect of the different modalities since the reduction in salivary flow rate/production may exacerbate the risk of dental caries.Material and MethodsThe aim of this study was to compare the effects of different treatments for drooling on caries risk and salivary parameters in children and adolescents with CP.Study designA total of 142 children and adolescents with CP, aged 6 to 18 years, were assigned to groups based on the different treatments they had received for drooling: G1—anticholinergic drugs (n = 18), G2—botulinum toxin injection (n = 16), G3—salivary glands surgery (n = 16), G4—no treatment (n = 42), and G5—non-drooling subjects (n = 50). All participants were evaluated on the Simplified Oral Hygiene Index, and for the prevalence of dental caries (decayed, missing, and filled teeth index and white spot lesions). Unstimulated whole saliva was collected, and salivary flow rate and osmolality were measured. Chi-square, ANOVA and Poisson regression were calculated. Prevalence ratios and their respective 95 % confidence intervals were obtained. The significance level was fixed at 5%.ResultsNo differences were found in the decayed, missing, and filled teeth index (p = 0.128) and Simplified Oral Hygiene Index (p = 0.674) among the different groups. G3 presented significantly higher percentages of WSL (p<0.001), lower values of salivary flow rate (p<0.001), and higher values of osmolality (p<0.001). The white spot lesion prevalence ratio was higher only for G3 (Prevalence ratio = 14.36; IC 95% = 4.64-44.40; p<0.001).ConclusionsChildren and adolescents with CP who had received surgical treatment for drooling exhibited higher number of white spot lesions because of the reduced salivary flow rate and higher salivary osmolality. Key words:Cerebral palsy, saliva, sialorrhea, dental caries, osmolar concentration.

Correlation of salivary immunoglobulin A with Body Mass Index and fat percentage in overweight/obese children.

Obesity is considered a risk factor for periodontal health due to the low- grade inflammation promoted by the increased adipose tissue. Objective: This study aimed to determine correlations and associations between gingival inflammation (Simplified Oral Hygiene Index, and Gingival Index), salivary immunoglobulin A (s-IgA), and salivary parameters (salivary flow and osmolality) in normal-weight and overweight/obese children. Material and Methods: Ninety-one children, aged 6 to 12 years old (8.6±1.9 years), were divided into two groups according to their body mass index (BMI), circumferences, skinfold measurements and body fat percentage: normal- weight group (NWG; n =50) and overweight/obese group (OG; n =41). A calibrated examiner performed the clinical examination using the Simplified Oral Hygiene Index, Gingival Index, and salivary collection. Data analysis included descriptive statistics and association tests ( p <0.05). Results: OG presented statistically higher s-IgA values compared with NWG, especially among the obese children ( p <0.05). Significant positive correlations between s-IgA and salivary osmolality in OG ( p <0.05), and between s-IgA and BMI values ( p <0.05) and body fat percentage ( p <0.05) were observed among all the children. Effect size varied from moderate for s-IgA values ( d =0.57) to large for BMI ( d =2.60). Conclusion: Gingival inflammation and salivary parameters were similar for NWG and OG; however, s-IgA presented higher values in OG, with correlations between BMI and body fat percentage.

A controlled study comparing salivary osmolality, caries experience and caries risk in patients with cerebral palsy

A controlled study comparing salivary osmolality, caries experience and caries risk in patients with cerebral palsy

Inflammatory markers in saliva as indicators of gingival inflammation in cerebral palsy children with and without cervical motor control.

To evaluate the relation among gingival inflammation, salivary osmolality, levels of IL-1β, IL-6, IL-8, TNF-α, and s-IgA concentrations in children with spastic CP with or without cervical motor control in a cross-sectional study. Unstimulated whole saliva and the gingival index were collected in 37 and 34 CP children with and without cervical motor control, respectively. The data were dichotomized as follows: (=0) absence of gingival inflammation and (≥0.1) presence of gingival inflammation. The group without cervical control presented statistically higher mean values of salivary osmolality, s-IgA, and cytokines. In addition, statistically positive correlation between the gingival index and salivary cytokines was observed in the group with cervical control. Salivary osmolality, salivary cytokines, and s-IgA from both groups presented a significant positive correlation. Significant differences (P = 0.00336) in the values of salivary osmolality were observed between the CP individuals with (93.9 ± 32.7) and without gingival inflammation (74.4 ± 16.6). ROC analysis was performed, and values of salivary osmolality >80 indicated a sensitivity of 0.54 and a specificity of 0.79. Children without cervical motor control presented a more pronounced oral inflammatory status that was characterized by higher levels of cytokines.

Assessment of Dehydration Using Salivary Osmolality and Urine Specific Gravity

Dehydration is a common problem in athletic and occupational settings, yet accurate and convenient methods to assess hydration status are lacking. PURPOSE: To determine how salivary osmolality (Sosm) and urine specific gravity (USG) change during exercise in the heat when dehydration is progressive (to 2.5%) or when dehydration is fixed at 1%. METHODS: Using a repeated measures design, 13 healthy, young men (age 22±1 yr; height 1.80±0.06 m; body mass 73.4±7.6 kg) completed three 30-min bouts (Bouts 1, 2, and 3) of cycling in a warm environment (environmental chamber; 30 °C, 50% relative humidity). Participants cycled at an intensity of 60-80% of age-predicted heart rate under 2 conditions: progressive dehydration and fixed dehydration in which fluid intake was restricted for Bout 1 only, followed by fluid intake sufficient to prevent further dehydration. Changes in hydration status were assessed using changes in body mass, USG, and Sosm before and after each exercise bout. Data were analyzed using a 2x3 repeated measures analysis (Condition x Time). When appropriate, Bonferroni-corrected alpha levels were employed. RESULTS: There was a significant time effect for change in body mass, USG, and Sosm in the progressive dehydration but not fixed dehydration condition. Progressive dehydration resulted in significantly more body mass loss compared with the fixed dehydration condition (2.5±0.4% vs. 1.0±0.4% respectively, p<0.001). USG was not different between conditions at any time point (p≥0.461). Sosm differed between conditions in Bout 3 (p=0.004).Table: No title available.CONCLUSION: During progressive dehydration, Sosm may be a more sensitive measure of hydration status than USG.

Gingivitis and salivary osmolality in children with cerebral palsy

To investigate the influence of salivary osmolality on the occurrence of gingivitis in children with cerebral palsy (CP). A total of 82 children with spastic CP were included in this cross-sectional study. Oral motor performance and gingival conditions were evaluated. Unstimulated saliva was collected using cotton swabs, and salivary osmolality was measured using a freezing point depression osmometer. Spearman's coefficient, receiver operating characteristic (ROC), and multiple logistic regression analyses were performed. Strong correlation (r > 0.7) was determined among salivary osmolality, salivary flow rate, visible plaque, dental calculus, and the occurrence of gingivitis. The area under the ROC to predict the influence of salivary osmolality on the occurrence of gingivitis was 0.88 (95% CI 0.81-0.96; P < 0.001). The cutoff value of 84.5 for salivary osmolality presented good sensitivity and specificity, both higher than 77%. The proportion of children presenting salivary osmolality ≤84.5 mOsm/kgH2 O and gingivitis was 22.5%, whereas for the group presenting osmolality >84.5 mOsm/kgH2 O, the proportion of children with gingivitis was 77.5%. Salivary osmolality above 84.5 increased the likelihood of gingivitis fivefold, whereas each additional 0.1 mL of salivary flow reduced the likelihood of gingivitis by 97%. Gingivitis occurs more frequently in children with CP showing increased values of salivary osmolality.

Oral hydration in children with cerebral palsy

AIM: To investigate whether oral motor performance is determinant for the hydration status and the effect of a supplemental oral fluid supply on salivary osmolality. METHODS: The sample consisted of 99 children with cerebral palsy aged 6 to 13 years old. In this study, children participated in 2-day evaluations: 1st day - baseline: saliva collection, caries experience and oral motor performance evaluations; and 2nd day: saliva collection after supplemental fluid supply. Prior to each evaluation, the participants were trained for saliva collection. Unstimulated whole saliva was collected using cotton roll at baseline, with the amount of fluid usually offered by caregivers, and 48 h after baseline, with as much as twice the normal daily fluid intake previously offered. Salivary osmolality was measured using a freezing point depression osmometer. Caries experience index for decayed, missed and filled teeth (DMFT) was evaluated. According to the Oral Motor Assessment Scale, the children were classified into subfunctional or functional groups. Chi-square, Student's t test and Pearson's correlation coefficient were used. RESULTS: The subfunctional group presented a higher percentage of quadriplegic children (p<0.001), with significantly higher values for caries experience (p<0.001) and salivary osmolality (p<0.001), which did not diminish when supplemental fluid supply was offered, compared with the functional group (p=0.001). CONCLUSIONS: The effectiveness of oral motor performance plays an important role in the hydration status of children with cerebral palsy and those with worse oral motor performance may be at higher risk of oral diseases.

Experiência de cárie e osmolaridade salivar em crianças com paralisia cerebral

INTRODUÇÃO: Estudos têm demonstrado que quanto maior a severidade do dano neurológico em crianças com paralisia cerebral (PC), maior é o risco de doenças orais. OBJETIVO: Correlacionar a experiência de cárie com a osmolaridade salivar em crianças com PC. MATERIAL E MÉTODO: Participaram do estudo 99 crianças (9,2±2,3 anos) com PC, em tratamento reabilitacional. A saliva de repouso foi coletada no período matutino, utilizando rolos absorventes (Salivette®) por cinco minutos. A osmolaridade salivar foi medida por depressão do ponto de congelamento em osmômetro. As avaliações incluíram a experiência de cárie pelo índice de dentes cariados, perdidos e obturados (CPOD), e o motor oral durante o processo de alimentação da criança. Foram utilizados os testes Qui-quadrado, t de Student, Correlação de Spearman e razão de chances (OR), com nível de significância de 5%. RESULTADO: O grupo 1 (G1) foi composto por 41 crianças livres de cárie e o grupo 2 (G2), por 58 crianças com cárie (CPOD=3,5±2,7). Os grupos foram homogêneos para gênero (p=0,884) e idade (p=0,174). Entretanto, diferiram significantemente com relação à motricidade oral, apresentando G2 maiores porcentagens de crianças com motor oral subfuncional (p&lt;0,001) e tetraparéticos (p=0,001). O G2 apresentou valores significantemente maiores (p&lt;0,001) para osmolaridade (99,6±36,7mOsml) quando comparado ao G1 (76,7±15,9mOsml). Observou-se uma correlação significante entre osmolaridade e experiência de cárie (p&lt;0,001). Apresentar osmolaridade superior a 76,7 (OR=5,18; 1,85 a 14,83) foi determinante individual de maior probabilidade de apresentar risco de cárie (CPOD&gt;0). CONCLUSÃO: Maiores valores de osmolaridade salivar aumentam o risco de cárie em crianças com PC.

Assessment of hydration biomarkers including salivary osmolality during passive and active dehydration

Hydration state can be assessed via body mass change (BMΔ), serum and urine osmolality (Sosm, Uosm), urine-specific gravity (Usg) and urine volume (Uvol). As no hydration index has been shown to be valid in all circumstances, value exists in exploring novel biomarkers such as salivary osmolality (Vosm). Utilizing acute BMΔ as the reference standard, this research examined the efficacy of Sosm, Vosm, Uosm, Uvol and Usg, during passive (PAS) and active (ACT) heat exposure. Twenty-three healthy men (age, 22±3 years; mass, 77.3±12.8 kg; height, 179.9±8.8cm; body fat, 10.6±4.5%) completed two randomized 5-h dehydration trials (36±1 °C). During PAS, subjects sat quietly, and during ACT, participants cycled at 68±6% maximal heart rate. Investigators measured all biomarkers at each 1% BMΔ. Average mass loss during PAS was 1.4±0.3%, and 4.1±0.7% during ACT. Significant between-treatment differences at -1% BMΔ were observed for Sosm (PAS, 296±4; ACT, 301±4 mOsm/kg) and Uosm (PAS, 895±207; ACT, 661±192 mOsm/kg). During PAS, only Uosm, Uvol and Usg increased significantly (-1 and -2% BMΔ versus baseline). During ACT, Vosm most effectively diagnosed dehydration 2% (sensitivity=86%; specificity=91%), followed by Sosm (sensitivity=83%; specificity=83%). Reference change values were validated for Sosm, Usg and BMΔ. The efficacy of indices to detect dehydration 2% differed across treatments. At rest (PAS), only urinary indices increased in concert with body water loss. During exercise (ACT), Sosm and Vosm exhibited the highest sensitivity and specificity. Sosm, Usg and BMΔ exhibited validity in serial measurements. These findings indicate hydration biomarkers should be selected by considering daily activities.

Assessing salivary osmolality as a caries risk indicator in cerebral palsy children

Salivary osmolality reflects the hydration status of individuals with cerebral palsy (CP) necessary for an adequate unstimulated salivary flow rate. To investigate whether salivary osmolality could serve as a potential indicator of caries risk in children with spastic CP by displaying a stronger association with caries occurrence than salivary flow rate. The convenience sample consisted of 65 children with CP aged 6-13 years old. Unstimulated whole saliva was collected using cotton roll, and salivary osmolality was measured using a freezing point depression osmometer. The children's oral motor performance was evaluated during the feeding process using the Oral Motor Assessment Scale. Caries occurrence was also evaluated according the World Health Organization criteria. Motor skills were significantly associated with caries experience. Regarding the salivary parameters, osmolality presented a stronger association with caries experience than did the salivary flow rate. Children with worse oral motor performance presented a higher rate of caries occurrence. Osmolality exhibited a stronger association with caries occurrence than did salivary flow rate. This parameter, therefore, could be a potential caries risk indicator for spastic cerebral palsy children.

Quantifying Dehydration in the Fire Service Using Field Methods and Novel Devices

Objective. This study reports measurements of hydration status among firefighters prior to training, documents changes in hydration status after prolonged firefighting training, and reports the utility of salivary measurements to assess changes in hydration in field environments. Methods. Nude body mass measurements as well as urinary and salivary measurements of hydration status were taken before and after approximately three hours of firefighting training activities. Initial hydration status was assessed via urinary and salivary measures. Changes in body mass and total body water were measured following firefighting activity and correlated with changes in urinary and salivary measures of hydration. Results. The most important findings of this study were that a high percentage of firefighters arrived at training in a significantly or seriously dehydrated state; that firefighters lost a significant amount of body mass because of firefighting operations; and that portable salivary osmolality measurements showed much stronger correlation with changes in hydration status after firefighting operations than standard urinary measurements did. Conclusions. Firefighters arriving in a dehydrated state are at risk for heat injuries and may be in a physically and/or psychologically compromised state at the outset of firefighter training. Even during cool autumn days with ample fluids available, firefighters experience dehydration during typical firefighting activities, so the ability to measure hydration status throughout such activities may be important. Our data suggest that quantification of changes in hydration status through salivary osmolality measurements may provide a viable field measurement tool for such activities.

Use of Salivary Osmolality to Assess Dehydration

Objective. To investigate the ability of salivary osmolality to assess dehydration while subjects perform alternating work/rest cycles in personal protective equipment (PPE). Methods. Eight healthy men (mean ± standard deviation age: 23.5 ± 4.9 years; body fat: 17.8% ± 5.0%; maximum volume of oxygen consumption [VO2max]: 57.2 ± 5.5 mL·kg−1·min−1) performed two exercise trials: one while wearing shorts and a T-shirt (EX) and one while wearing firefighting PPE (EX+PPE). Saliva samples were taken before exercise, at minutes 40, 80, and 120 of the exercise trial, and during recovery. Results. Percent body mass loss (BML) was significantly greater while the subjects were wearing PPE (2.18% ± 0.54% vs. control 0.81% ± 0.30%). Salivary osmolality increased significantly in both trials (73.4 ± 12.4 to 125.1 ± 30.3 mOsm·kg−1 and 70.1 ± 12.5 to 83.6 ± 17.7 mOsm·kg−1); however, the increase in the EX+PPE trial was significantly greater than the increase in the EX trial. Plasma osmolality did not change significantly in either trial, whereas urinary osmolality increased significantly in both trials. Changes in salivary osmolality were strongly correlated with percent BML (r = 0.80; p < 0.01). Conclusion. Salivary osmolality may be a sensitive indicator of moderate dehydration under carefully controlled conditions. Key words: exercise; heat; dehydration; osmolality; saliva; personal protective equipment

Oral motor performance in spastic cerebral palsy individuals: are hydration and nutritional status associated?

Previous studies reported alterations in salivary parameters in cerebral palsy (CP) individuals; however, none of these considered oral motor performance as possibly responsible for these conditions. The aim of this study was to investigate the influence of oral motor performance on the nutritional status and salivary parameters in individuals with CP. Forty-three individuals aged 11-19 years-old, with spastic CP were included in this study. Oral motor performance was evaluated using the Oral Motor Assessment Scale, which classified the individuals into two groups: subfunctional or functional. Unstimulated saliva was collected and the flow rate was calculated (ml/min). Salivary osmolality was measured using a freezing point depression osmometer. Blood samples were collected to evaluate complete blood count, total protein, albumin/globulin ratio and transferrin levels. The subfunctional (n = 21) and the functional group (n = 22) did not differ regarding sex (P = 0.193), however the functional group was older (P = 0.023) and had a higher mean BMI (P < 0.001). The subfunctional CP group presented a reduction in salivary flow rate (36.4%) (P < 0.01) and an increase in salivary osmolality (35.5%) (P < 0.001) compared to the functional group. Slightly lower values for red blood cells (millions/mm(3) ) (P < 0.001), hemoglobin (g/dl) (P < 0.009), hematocrit (%) (P = 0.001), number of platelets (N/mm(3) ), total protein (g/dl) and albumin/globulin ratio (P = 0.003 and P = 0.036, respectively) were determined for the subfunctional group, but within the normal range of normality. Cerebral palsy individuals appear to present impaired adequate hydration due to compromised oral motor performance.

Limitations of Salivary Osmolality as a Marker of Hydration Status

Salivary osmolality (Sosm) is a potentially useful hydration marker but may be confounded by oral artifacts. This study aimed to determine the efficacy of Sosm for detecting hypohydration and evaluate the effect of a simple mouth rinse. Eight healthy volunteers (six males and two females; age = 22 ± 7 yr, body mass = 83.7 ± 14.9 kg, height = 176.9 ± 9.2 cm) were measured for nude body mass (BM), plasma osmolality (Posm), and Sosm when euhydrated (EUH) and again when hypohydrated (HYP) by exercise-heat exposure with fluid restriction. After the initial saliva sample during HYP, a 10-s mouth rinse with 50 mL of water was provided, and saliva samples were obtained 1 min (RIN01), 15 min (RIN15), and 30 min (RIN30) after rinse. The ability of Sosm to detect HYP was compared with Posm. Volunteers were hypohydrated by -4.0% ± 1.2% of BM (range = -2.2% to -5.3%). Sosm was elevated above EUH after hypohydration (EUH 58 ± 8 mmol · kg vs HYP 96 ± 28 mmol · kg, P < 0.05). Sosm baseline and change values displayed more variability than Posm based on ANOVA and regression analyses. After the oral rinse, saliva decreased in concentration (RIN01 = 61 ± 17 mmol · kg, P < 0.05) but returned to prerinse values within 15 min (RIN15 = 101 ± 25 mmol · kg) and remained similar 30 min after (RIN30 = 103 ± 33 mmol · kg). Sosm was remarkably altered 1 min after a brief water mouth rinse. Fifteen minutes proved an adequate recovery time, indicating that the timing of oral artifacts and saliva sample collection is critical when considering Sosm for hydration assessment. Given the inherent variability and profound effect of oral intake, use of Sosm as a marker of hydration status is dubious.