Impact of indexing resting metabolic rate against fat-free mass determined by different body composition models.

OBJECTIVE: To examine the differences arising from indexing resting metabolic rate (RMR) against fat-free mass (FFM) determined using two-, three- and four-compartment body composition models. DESIGN: All RMR and body composition measurements were conducted on the same day for each subject following compliance with premeasurement protocols. SUBJECTS: Data were generated from measurements on 104 males (age 32.1+/-12.1 y (mean+/-s.d.); body mass 81.15+/-12.85 kg; height 179.5+/-6.5 cm; body fat 20.6+/-7.6%). INTERVENTIONS: Body density (BD), total body water (TBW) and bone mineral mass (BMM) were measured by hydrodensitometry, deuterium dilution and dual energy X-ray absorptiometry (DXA), respectively. These measures were used to determine two (hydrodensitometry: BD; hydrometry: TBW)-, three (BD and TBW)- and four- compartment (BD, TBW and BMM) FFM values. DXA also provided three compartment derived FFM values. RMR was measured using open circuit indirect calorimetry. RESULTS: Three (body fat group: lean, moderate, high) x five (body composition determination: hydrodensitometry, hydrometry, three-compartment, DXA, four-compartment) ANOVAs were conducted on FFM and RMR kJ.kg FFM(-1).d(-1). Within-group comparisons revealed that hydrodensitometry and DXA were associated with significant (P<0.001) overestimations and underestimations of FFM and RMR kJ.kg FFM(-1).d(-1), respectively, compared with four-compartment-derived criterion values. A significant interaction (P<0.001) resulted from DXA's greater deviations from criterion values in lean subjects. While hydrometric means were not significantly (P> or =0.68) different from criterion values intraindividual differences were large (FFM: -1.5 to 2.9 kg; RMR: -6.0 to 3.2 kJ.kg FFM(-1).d(-1)). CONCLUSION: The relationship between RMR kJ.kg FFM(-1).d(-1) and exercise status would best be investigated using three (BD, TBW)- or four (BD, TBW, BMM)-compartment body composition models to determine FFM. Other models either significantly underestimate indexed RMR (hydrodensitometry, DXA) or display large intraindividual differences (hydrometry) compared with four-compartment derived criterion values. SPONSORSHIP: Australian Research Council (small grants scheme).

Use of anthropometric variables to predict relative body fat determined by a four-compartment body composition model.

OBJECTIVE: To generate equations for the prediction of percent body fat (% BF) via a four-compartment criterion body composition model from anthropometric variables and age. DESIGN: Multiple regression analyses were used to predict % BF from the best-weighted combinations of independent variables. SUBJECTS: In all 79 healthy males (X+/-s.d.: 35.0+/-12.2 y; 84.24+/-12.53 kg; 179.8+/-6.8 cm) aged 19-59 y were recruited from advertisements placed in a university newsletter and on community centres' noticeboards. INTERVENTIONS: The following measurements were conducted: % BF using a four-compartment (water, bone mineral mass, fat and residual) model and a restricted anthropometric profile (nine skinfolds, five girths and two bone breadths). RESULTS: Stepwise multiple regression selected six (subscapular, biceps, abdominal, thigh, calf and mid-axilla) of the nine skinfold measurements to predict % BF and using the sum of these six produced a quadratic equation with a standard error of estimate (SEE) and R(2) of 2.5% BF and 0.89, respectively. The inclusion of age as a predictor further improved the equation (% BF=-0.00057 x ( summation operator 6SF)(2)+0.298 x summation operator 6SF+0.078 x age - 1.13; SEE=2.2% BF, R(2)=0.91). However, the best equation used only the sum of three skinfold thicknesses (mid-axilla, calf and thigh) and age but also included waist girth and biepicondylar femur breadth as predictors (% BF=-0.00258 x ( summation operator 3SF)(2)+0.558 x summation operator 3SF+0.118 x age+0.282 x waist girth - 2.100 x femur breadth - 2.34; SEE=1.8% BF, R(2)=0.94). Analyses of two age groups, <30 and >/=30 y, demonstrated that for the same % BF, the former exhibited a higher sum of skinfold thicknesses. CONCLUSIONS: Equations were generated for the prediction of % BF via the four-compartment criterion body composition model from anthropometric variables and age. Agewise differences for the sum of skinfold thicknesses may be related to an increase in internal fat for the older subjects.

Predicting the resting metabolic rate of young Australian males.

OBJECTIVES: The aims of this study were: (a) to generate regression equations for predicting the resting metabolic rate (RMR) of 18 to 30-y-old Australian males from age, height, mass and fat-free mass (FFM); and (b) cross-validate RMR prediction equations, which are frequently used in Australia, against our measured and predicted values. DESIGN: A power analysis demonstrated that 38 subjects would enable us to detect (alpha = 0.05, power = 0.80) statistically and physiologically significant differences of 8% between our predicted/measured RMRs and those predicted from the equations of other investigators. SUBJECTS: Thirty-eight males (chi +/- s.d.: 24.3+/-3.3y; 85.04+/-13.82 kg; 180.6+/-8.3 cm) were recruited from advertisements placed in a university newsletter and on community centre noticeboards. INTERVENTIONS: The following measurements were conducted: skinfold thicknesses, RMR using open circuit indirect calorimetry and FFM via a four-compartment (fat mass, total body water, bone mineral mass and residual) body composition model. RESULTS: A multiple regression equation using the easily measured predictors of mass, height and age correlated 0.841 with RMR and the SEE was 521 kJ/day. Inclusion of FFM as a predictor increased both the R and the precision of prediction, but there was virtually no difference between FFM via the four-compartment model (R = 0.893, SEE = 433 kJ/day) and that predicted from skinfold thicknesses (R = 0.886, SEE = 440 kJ/day). The regression equations of Harris & Benedict (1919) and Schofield (1985) all overestimated the mean RMR of our subjects by 518 - 600 kJ/day (P < 0.001) and these errors were relatively constant across the range of measured RMR. The equations of Hayter & Henry (1994) and Piers et al (1997) only produced physiologically significant errors at the lower end of our range of measurement. CONCLUSIONS: Equations need to be generated from a large database for the prediction of the RMR of 18 to 30-y-old Australian males and FFM estimated from the regression of the sum of skinfold thicknesses on FFM via the four compartment body composition model needs to be further explored as an expedient RMR predictor.

Comparison of two hydrodensitometric methods for estimating percent body fat.

This study compared the two following hydrodensitometric methods for estimating percent body fat (%BF): 1) estimation of residual volume (RV) by helium dilution before and after measurement of immersed mass at RV, and 2) determination of immersed mass at a comfortable level of expiration (approximately functional residual capacity) with measurement of the associated gas volume by oxygen dilution. Twelve men [27.9 +/- 7.5 (SD) yr; 79.32 +/- 12.79 kg; 180.5 +/- 9.9 cm] were tested for %BF via both methods on each of two separate visits within 3 days by using a counterbalanced design. The two helium dilution measurements yielded a technical error of measurement of 0.2% BF and an intraclass correlation coefficient of 0.999. Corresponding values for the oxygen dilution method were 0.4% BF and 0.999, respectively. There was no difference (P = 0.80) between the helium dilution (16.9 +/- 9.3% BF) and oxygen dilution (16.9 +/- 9.4% BF) methods, and the individual differences ranged from -0.7 to 0.6% BF. The interclass correlation coefficient between the two methods was 0.999 with a SE of estimate of 0.4% BF. Whereas both methods were precise and reliable and yielded similar results, the oxygen dilution technique was more expedient and was preferred by the subjects because they were not required to exhale to RV.

Crepitation and clicking as signs of TMD in preschool children.

Children [N = 540, age 5.1 +/- 0.72 (SD)], were tested for association between temporomandibular (TM) joint sounds and symptoms of TM disorder (TMD). The prevalence of TMJ sounds as found by auscultation and confirmed by self-report was 16.7%. There was significant association after Bonferroni correction between the presence of TM joint sounds, as reported by the children, and all but one of the eleven pain/dysfunction variables. There was significant association also between crepitation as heard at auscultation and palpation tenderness in the TMJ and masseter areas (p < 0.001), but not between clicking and any of the TMD variables. Agreement between subjects and examiners regarding the presence of TMJ sounds was poor (kappa = 0.097). The results indicate that joint sounds and TMD symptoms are common already in small children and thus demonstrate a possible early onset of TMD. Patients' own reports of TMJ sounds may have more clinical relevance than auscultation findings.

Classification of temporomandibular joint sounds based upon their reduced interference distribution.

Temporomandibular joint (TMJ) sounds were recorded in 98 orthodontic retention patients, mean age 19 +/- 8.6 (s.d.) years, by interview, auscultation and electronic recording. Sounds were found by auscultation in 41% and by interview in 32% of the subjects, more often in females than in males (P < 0.05). A new method for time-frequency analysis, the reduced interference distribution (RID), was used to classify the electronic sound recordings into five subclasses, RID types 1-5, based upon location and number of their energy peaks. RID types 1-3 had a few energy peaks close in time. RID types 4-5, typical of subjects with crepitation, had multiple energy peaks occurring close in time for a period of 20-300 ms. RID type 1, found in 45% of the subjects, typical of patients with clicking, had its dominant energy peak located in a frequency range < 600 Hz and was significantly more common in the female than in the male subjects (P < 0.01). RID type 2, found in 68% of the subjects, with the dominant peak in the range 600-1200 Hz, and RID type 3, found in 38% of the subjects, with the peak in the frequency range > 1200 Hz, were found to have a similar gender distribution. RID type 4, found in 49% of the subjects, had the energy peaks distributed in the frequency range < 600 Hz. RID type 5, found in 43% of the subjects, more often in females than in males (P < 0.05), had the peaks distributed over the whole frequency range from about 30 Hz up to about 3000 Hz. In conclusion, a more detailed classification could be made of the TMJ sounds by displaying the RIDs than by auscultation. This suggests that RID classification methods may provide a means for differentiating sounds indicating different types of pathology.

Oral parafunctions as temporomandibular disorder risk factors in children.

Oral parafunctions are generally considered to be important factors in the etiology of temporomandibular disorders (TMDs) and many reports have been published about their prevalence in adults and schoolchildren. However, few have included significant numbers of children below the age of 7. The aim of this study was to examine the association between parafunctions and oral/facial TMD-related pain in preschool children. Bruxism, nail biting, and thumb sucking were found to be significantly associated with important oral/facial pain symptoms of clinical interest in the diagnoses of TMD indicating that those parafunctions are risk factors. The study included 525 4- to 6-year-old African-American and Caucasian children, mean age 5.1 +/- 0.65 (SD). An alpha level of 5% was chosen for comparison with a Pearson Chi-Square test. Bonferroni correction was made and a p-value of < 0.005 was accepted as significance level. Only 28% of the children had no history of any parafunction. More girls (82%) than boys (63%) in the Caucasian subgroup had at least one parafunction (p approximately 0.00017). No such difference was found in the African-American subgroup where the corresponding figures were 71% for girls and 73% for boys. Thumb sucking was reported by 57% of the children, more often by Caucasian girls (69%) than by Caucasian boys (43%) (p < 0.00001). Thirty percent still had the habit. Forty-one percent had a history of nail biting. Bruxism was noted in 20% of the children, but occurred mostly in combination with other parafunctions and was seldom (in 3.4%) the only parafunction. Of the 10 pain variables, bruxism was significantly associated with eight, thumb sucking with three, and nail biting with two. Analysis with logistic regression confirmed the results. Association does not, however, tell if a parafunction is the cause or the consequence of pain, or if a third factor is causing both pain and increased prevalence of oral parafunctions. Further prospective longitudinal studies including higher age groups are needed to clarify those relations and to determine if there are long-term effects of childhood parafunctions.

Race and gender as TMD risk factors in children.

The aim of this study was to record the prevalence in preschool children of oral/facial pain symptoms of clinical interest in the diagnoses of temporomandibular disorders (TMD) and to analyze the association with the race and gender factors. Children, 525 4-6 year olds, mean age 5.1 +/- 0.65 (SD), 326 Caucasian and 199 African American, from a preschool and kindergarten program in a low income industrial area, who participated in a voluntary oral health examination, were examined. Comparisons were made using Chi-Square test. An alpha-level of 5% was chosen, and the effect of making multiple comparisons was compensated for by Bonferroni correction. No gender differences were found, but racial differences were observed regarding six of the 10 variables. Twenty-five percent of the children had recurrent (at least one to two times per week) headache. Thirteen percent had recurrent earache, African-American children more often than Caucasian children (p approximately 0.0038). Thirteen percent had recurrent temporomandibular joint (TMJ) pain, and 11% had recurrent neck pain. Pain or tiredness in the jaws during chewing was reported by 29% of the children, more often by African-American than by Caucasian (p < 0.00001). Pain at jaw opening occurred in 13% of the children, more often in the African-American than in the Caucasian children (p approximately 0.00004). Palpation pain was found in the posterior TMJ area in 28%, in the lateral TMJ area in 22%, in the masseter area in 19%, in the anterior temporalis area in 15% and was found more often in all of those regions in the African-American than in the Caucasian children (p approximately 0.00001), except for the temporalis area. In conclusion, this study showed that mild, but distinct, TMD-related oral/facial pain symptoms occur already by ages 4-6 with significant differences in distribution observed between the African-American and the Caucasian races. While gender seems to play a negligible role in this age group, this does not necessarily mean that race is a causative factor. The pain symptoms may be caused by other factors with different distribution in the two racial subgroups.

Prevalence of signs and symptoms of craniomandibular disorders and orofacial parafunction in 4-6-year-old African-American and Caucasian children.

Children, 4-6 years old, 153 Caucasian and 50 African-American, from a pre-school and kindergarten programme in a low income industrial area, who participated in a voluntary oral health examination, were questioned and examined for signs and symptoms of craniomandibular disorders (CMD) and of oral parafunctions. Most of the CMD signs and symptoms were mild. Eight per cent had recurrent (at least 1-2 times per week) TMJ pain, and 5% had recurrent neck pain, African-American children more often than Caucasian children (P < 0.05). Seventeen per cent had recurrent headache. Three per cent had recurrent earache. Pain or tiredness in the jaws during chewing was reported by 25% of the children, more often by African-American than by Caucasian children (P < 0.001) and more often by girls than by boys (P < 0.05). Pain at jaw opening occurred in 10% of the children, more often in the African-American than in the Caucasian group (P < 0.001). Thirteen per cent of the children had problems in opening the mouth. Deviation during opening was observed in 17% and reduced opening in 2%. Reduced lateral movements, locking or luxation were not observed in any child. Palpation pain was found in the lateral TMJ area in 16%, in the posterior TMJ area in 25%, in the temporalis and masseter areas in 10%, and pain for all regions was found more often in the African-American than in the Caucasian children (P < 0.01). Thirty-four per cent of the African-American, and 15% of the Caucasian children admitted to having ear noises (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Association between CMD signs and symptoms, oral parafunctions, race and sex, in 4-6-year-old African-American and Caucasian children.

The associations between oral parafunctions, signs and symptoms of craniomandibular disorders (CMD), race, and sex were analysed in recordings from 203 4-6-year-old African-American and Caucasian children. Significant correlations were found between bruxism, nail biting, thumb sucking and most of the CMD signs and symptoms. There were also significant associations between most of the signs and symptoms and race, while significant association with sex was found only regarding headache, TMJ sounds and chewing pain. Significant associations were found between most CMD signs and TMJ sounds supporting the view that joint sound recordings have diagnostic value. There were also significant associations between the pain variables recorded by questionnaire and those recorded by palpation, which indicates that reliable data can be obtained by interviewing children as young as five. The results of this study support the concept that oral parafunctions have a significant role in the aetiology of CMD. The results also show that race and sex need to be considered when analysing the possible aetiological role of oral parafunctions in CMD. Longitudinal studies, beginning with low age groups are needed to better determine the role of childhood oral parafunctions in CMD aetiology.

Self-reported health behavior and dental knowledge of a migrant worker population.

In conjunction with operation of a summer school-based dental program in Michigan, 101 children from migrant families, primarily Mexican-American, completed questionnaires relating demographic background, past dental experience, and knowledge of caries preventive methods. A smaller number of available mothers were asked these questions plus others relating to family dental problems, diet and knowledge of periodontal disease. Adults and children reported similar demographic backgrounds. Most children (68.7%) listed brushing as the best way to prevent cavities as did 60% of the mothers. Less than 2% of the children considered use of fluoride in any form as the best way to prevent cavities and only two of 20 mothers mentioned fluoride in this context. Members of this selected population were weak in their knowledge of the relation between a sweet diet and caries, the relation between oral hygiene and periodontal health, and the role of fluorides in caries prevention.