Statistical methods for constructing gestational age-related reference intervals and centile charts for fetal size.
Explore the source record for details and available documents.
Fetal Development↗
Biomedical subjects
T J Cole
Publications and source records attributed to T J Cole.
Population-specific reference equations?
Explore the source record for details and available documents.
Body Height↗
A simplified approach to analysing bio-electrical impedance data in epidemiological surveys.
BACKGROUND: Bio-electrical impedance analysis (BIA) is widely used to estimate body composition. It is simple, quick and cheap, but less accurate than other methods. It has potential epidemiological value, but has conventionally required validation before application. AIMS: To develop a simple method of expressing weight, height and impedance data that avoids the need for population-specific validation equations in order to facilitate epidemiological application. METHODS: Body composition was measured using the four-component model in young adults (43 males, 90 females). Impedance (R) was measured hand-foot and foot-foot. Lean mass and fat mass were adjusted for height to give lean mass index (LMI) and fat mass index (FMI). Based on theoretical principles, we generated the index 1/R, which provides an index of body water adjusted for height. Sex-specific regression models were used to investigate the relationships between (a) 1/R and LMI, and (b) body mass index (BMI) adjusted for 1/R and FMI. The success of this approach was evaluated in relation to the conventional BIA approach, using correlation analysis. RESULTS: 1/R was a highly significant predictor of LMI. BMI adjusted for 1/R was a significant predictor of FMI. Our approach performed as well as the conventional approach for LMI, but not for FMI. DISCUSSION: Direct use of BIA data, rather than their combination with population-specific equations for the prediction of total body water, proved successful at ranking individuals of both sexes in terms of LMI and FMI. The index 1/R may prove particularly valuable in epidemiological studies where ranking of LMI is required.
Adipose Tissue↗
Body mass index has risen more steeply in tall than in short 3-year olds: serial cross-sectional surveys 1988-2003.
OBJECTIVE: To monitor the changing relationship between body mass index (BMI) and height in young children. DESIGN: Annual cross-sectional surveys using health-visitor-collected routine data 1988-2003. SETTING: Wirral, England. PARTICIPANTS: Fifty thousand four hundred and fifty-five children (49% female) each measured once at the age of 3 years. MAIN OUTCOME MEASURES: Weight, height and derived BMI (weight/height(2)) adjusted for age and sex (British 1990 revised reference) using standard deviation scores. RESULTS: From 1988 to 2003, mean BMI increased by 0.7 kg/m(2), whereas mean height fell by 0.5 cm. Over the same period, the weight-height correlation rose from 0.59 to 0.71 (P<0.0001) owing to BMI increasing faster in the taller than the shorter children. Among the shortest 10% of children, mean BMI rose by 0.12 (95% confidence interval: -0.05-0.28) kg/m(2) as against 1.38 (1.19-1.56) kg/m(2) among the tallest 10%, a 12-fold difference. Adjustment for age, sex, seasonality, birth-weight and deprivation did not alter the findings. CONCLUSIONS: Among 3-year-old children in Wirral, where BMI has been rising for 16 years, the largest increase in BMI has occurred in the tallest children, whereas in the shortest BMI has hardly changed. Tall stature has, therefore, become important for child obesity. It suggests a drive to increasing adiposity in young children that involves both growth and appetite, with fast growing and hungrier children now more exposed to the 'obesogenic' environment.
Birth Weight↗
Body composition in normal weight, overweight and obese children: matched case-control analyses of total and regional tissue masses, and body composition trends in relation to relative weight.
BACKGROUND: Childhood obesity is defined on the basis of weight and height, using body mass index (BMI). There is little detailed information on the body composition characteristic of overweight and obesity. OBJECTIVE: To evaluate total and regional body composition in overweight, obese and control children aged 7-14 years. DESIGN: Body composition was measured by the four-component model and dual X-ray absorptiometry in 38 age- and sex-matched pairs of obese and control children. Body composition trends were also evaluated by quintile of BMI standard deviation score (SDS) in these and 31 other children (n=107; BMI SDS range -1.0 to 4.3). RESULTS: Obese children were taller than controls (Delta=0.6 SDS; P=0.01) and had greater hydration of fat-free mass (FFM) (Delta=1.8 %, P<0.0001). After adjusting for these variables, obese children had greater FFM, fat mass (FM) and mineral (P<0.0001). Regional analyses showed that these differences were apparent in the arm, leg and trunk, but the three tissues had different proportional distributions of the excess. Fat was primarily in the trunk, but mineral in the leg. FM, FFM, hydration and mineral mass all increased across BMI SDS quintiles (P<0.0001), but the trend for FM was much the steepest. DISCUSSION: The greater weight of obese children is due to excess FFM including mineral as well as excess fatness. Increasing weight has a strong continuous relationship with increasing FM across the whole spectrum of weight.
Absorptiometry, Photon↗
Who changes body mass between adolescence and adulthood? Factors predicting change in BMI between 16 year and 30 years in the 1970 British Birth Cohort.
OBJECTIVE: To examine whether factors common to obesity prevention programmes in adolescence, namely exercise, sedentary activities, eating behaviours and psychological factors, predict change in BMI in 'free-living' adolescents followed into adulthood. DESIGN: Longitudinal national birth cohort study. SUBJECTS: 1970 British Birth Cohort: 4461 subjects with data on BMI at 16 years (1986) and 30 years (2000). MEASUREMENTS AND ANALYSIS: BMI z-score (zBMI) at 16 years (measured) and 30 years (self-reported). Obesity defined as BMI exceeding 95th British centile and 28.5 kg/m2, respectively. Self-report data on exercise, eating behaviours, dieting and measures of psychological function (depression, psychological distress, self-esteem) at 16 years. Models were produced for the regression of zBMI at 30 years on each variable at 16 years, adjusted for socioeconomic status, sex and zBMI at 16 years. RESULTS: In all, 467 (8.2%) were obese at 16 years and 730 (16.4%) were obese at 30 years. Of those obese at 16 years, 60.7% were also obese at 30 years. Loss of zBMI between 16 and 30 years was predicted by female sex (P=0.01), higher social class (P<0.0001) and higher frequency of playing sport, although this was of borderline significance (P=0.05). Increase in zBMI between 16 and 30 years was predicted by 4 or more hours per day of sedentary activities (P=0.01), eating takeaway meals twice or more per week (P=0.009), consuming two or more carbonated drinks per day (P=0.04) and a history of dieting to lose weight (P=0.04). CONCLUSION: These data from 'free-living' adolescents followed into adult life support the importance of known risk factors such as reduction of sedentary behaviours and reduction of unhealthy eating patterns (consumption of carbonated drinks and takeaway foods, dieting) in the prevention of the persistence of obesity from childhood into adult life.
Adolescent↗
The impact of childhood body mass index on timing of puberty, adult stature and obesity: a follow-up study based on adolescent anthropometry recorded at Christ's Hospital (1936-1964).
OBJECTIVE: To examine the impact of childhood body mass index (BMI) on timing of puberty, adult stature and obesity. DESIGN: A retrospective school-based cohort follow-up study. SUBJECTS: A total of 1520 men born between 1927 and 1956 with serial height and weight measurements from the age of 9 to 18, followed up in adulthood at a mean age of 63 years. MEASUREMENTS: Prepubertal (child) BMI; age at peak height velocity (APHV); adult leg length, waist and hip circumference (self-reported), and height and weight (measured). RESULTS: Boys with a higher childhood BMI tended to have an earlier puberty (per s.d. increase in child BMI: -0.31 years, 95% confidence interval (CI): -0.23 to -0.39, P < 0.001). Childhood BMI correlated strongly and positively with adult adiposity, as measured by BMI (1.24 kg/m(2), 95% CI: 1.04-1.45, P < 0.001), waist (1.94 cm, 95% CI: 1.50-2.37, P < 0.001) and hip (1.91 cm, 95% CI: 1.55-2.28, P < 0.001). It correlated inversely with leg length (-0.40 cm, 95% CI: -0.68 to -0.12, P = 0.005), but not significantly with height or trunk length. Boys with a later puberty tended to be taller (per s.d. increase in APHV: 0.57 cm, 95% CI: 0.17-0.97, P = 0.006) and less adipose as adults (-0.55 kg/m(2), 95% CI: -0.33 to -0.77, P < 0.001). CONCLUSION: The long-term consequences of childhood obesity into adulthood are well known, but the potential impact on early pubertal maturation is less well appreciated. The factors that contribute to the onset and persistence of childhood obesity require more public health focus.
Adolescent↗
Body fat reference curves for children.
OBJECTIVE: To refine the diagnosis of childhood obesity by creating new sex-specific centile curves for body fat and to base these references on a simple and affordable method that could be widely adopted in clinical practice and surveys. DESIGN: Body fat was measured by bio-impedance in 1985 Caucasian children aged 5-18 years from schools in Southern England. Smoothed centile charts were derived using the LMS method. RESULTS: The new body fat curves reflect the known differences in the development of adiposity between boys and girls. The curves are similar by sex until puberty but then diverge markedly, with males proportionately decreasing body fat and females continuing to gain. These sex differences are not revealed by existing curves based on body mass index. We present charts in which cutoffs to define regions of 'underfat', 'normal', 'overfat' and 'obese' are set at the 2nd, 85th and 95th centiles. These have been designed to yield similar proportions of overweight/overfat and obese children to the IOTF body mass index cutoffs. CONCLUSIONS: Direct assessment of adiposity, the component of overweight that leads to pathology, represents a significant advance over body mass index. Our new charts will be published by the Child Growth Foundation for clinical monitoring of body fat, along with the software to convert individual measurements to Z-scores.
Adiposity↗
Is infant growth changing?
Weight gain between birth and 9 months of 12 903 term Millennium Cohort Study infants was investigated in order to determine differences according to sex, ethnicity and country of birth. The standardised weights and weight gains were also compared with a cohort of mainly white infants born 10 years earlier to determine whether weight gain has changed over the last decade. There were significant differences between ethnic groups, with black infants showing the largest weight gain and Asians the smallest. White boys born in England and Scotland grew relatively faster than girls, but there were no significant gender differences among the other ethnic groups or among infants born in Ireland and Wales. There was very little difference in weight gain between white English Millennium cohort infants and the earlier cohort, suggesting that the current epidemic of childhood obesity starts after 9 months of age.
Asian People↗
Re: "Why evidence for the fetal origins of adult disease might be a statistical artifact: the 'reversal paradox' for the relation between birth weight and blood pressure in later life".
Explore the source record for details and available documents.
Birth Weight↗
Evaluation of three biochemical markers in the monitoring of Gaucher disease.
Several markers have been developed for the biochemical monitoring of Gaucher disease. Three of the most commonly used markers are acid phosphatase, angiotensin-converting enzyme (ACE) and chitotriosidase. The rationale for using all three concurrently is not clear. A retrospective study was therefore carried out on data collected from 28 paediatric patients treated with enzyme replacement therapy. All three markers fell with time. However, chitotriosidase showed the steepest time trend, the largest trend by case interaction, and the lowest residual variance, making it the most reliable of the three. ACE correlated strongly with chitotriosidase, but acid phosphatase did not correlate well with either and also had the largest residual variance, indicating that it was too 'noisy' to be informative. The absence of a 'gold standard' for assessing Gaucher disease complicates the interpretation of these findings, but they suggest that acid phosphatase be dropped from routine clinical practice, and that chitriosidase be used in preference to ACE.
Acid Phosphatase↗
Dual X-ray absorptiometry (DXA) of the lumbar spine in a clinical paediatric setting: does the method of size-adjustment matter?
UNLABELLED: Dual X-ray absorptiometry (DXA) is increasingly used in a clinical setting to evaluate bone mass in children. Areal Bone Mineral Density (aBMD) measurements are known to be influenced by body size, but there is no consensus on the optimal way to deal with this for individual patients. AIM: To compare parameters of bone mass with varying degrees of size correction and to determine the effect on the categorisation of patients as normal or abnormal. SUBJECTS AND METHODS: Healthy children (n = 78) and 4 groups of patients (n = 194) underwent DXA scans of the lumbar spine (L2-4, GE Lunar Prodigy). Five measures of bone mass were derived, all adjusted for age and sex: aBMD, BMAD (BMC/BA (1.5)), BMCh (BMC/height3), BMCa (BMC adjusted for BA), BMCt (BMC adjusted for BA and height). SD scores were calculated for each parameter for patients using data from healthy controls. RESULTS: Compared to healthy children, all patient groups had significantly reduced BMD SD scores (P < 0.001). Mean BMAD, BMCa and BMCt SD scores were significantly lower in only 2/4 patient groups, whilst BMCh SD scores were low only in one group. BMCt showed no advantage over BMCa. The proportion of patients with SD scores <-2 was 27% for aBMD but between 10-13% for BMAD, BMCh and BMCa. CONCLUSIONS: All size-corrected parameters of bone mass performed similarly and classified significantly fewer patients as abnormal than did aBMD. The use of one of these parameters should reduce the number of patients diagnosed inappropriately with 'low bone mass'. However, without validation against an outcome measure or 'gold standard' of bone density or structure, it is not possible to determine which parameter is most correct.
Absorptiometry, Photon↗
What is the best measure of adiposity change in growing children: BMI, BMI %, BMI z-score or BMI centile?
BACKGROUND: Weight control programs for obese children monitor change in body mass index (BMI) adjusted for age. However, change can be measured in several ways: raw (kg/m2) units, percentage, z-scores or centiles. The suitability of the different measures is not known. AIM: To identify the optimal BMI measure for change, whose short-term variability is most consistent for children across the spectrum of adiposity. SETTING: An Italian kindergarten. SUBJECTS: A total of 135 (66 female) children aged 29-68 months at baseline, with BMI measured three times over a 9-month period. METHODS: Each child's short-term variability in adiposity was summarized by the standard deviation (s.d.) of BMI and BMI % adjusted for age, and BMI z-score and BMI centile. The s.d.'s were then compared in obese and nonobese children, and also correlated with each child's baseline BMI z-score. RESULTS: The within-child s.d.s of BMI z-score and BMI centile were significantly smaller in obese than nonobese children, while the s.d.s of BMI and BMI % were similar in the two groups. Also, the within-child s.d.s of z-score and centile, and to a lesser extent BMI %, were significantly inversely correlated with baseline z-score, whereas the s.d. of BMI was not. The changes in adiposity over time, as assessed by the four measures, were very highly correlated with each other, particularly for BMI with BMI %. DISCUSSION: Even though BMI z-score is optimal for assessing adiposity on a single occasion, it is not necessarily the best scale for measuring change in adiposity, as the within-child variability over time depends on the child's level of adiposity. Better alternatives are BMI itself or BMI %. Our results underscore the importance of using a relatively stable method to assess adiposity change when following children at risk of obesity.
Adipose Tissue↗
Reliability of calculating body mass index centile.
OBJECTIVE: Body mass index (BMI) centile is recommended for assessing body fatness in children. We compared the reliability of two methods of deriving BMI centile. METHOD: A total of 42 dietitians calculated the BMI centiles of six children, half using the Cole Calculator (a slide rule) and half calculating by hand and plotting on the BMI centile chart. RESULTS: The centile chart method was more reliable than the Cole Calculator, probably due to its greater familiarity.
Adolescent↗
The Oxford Brookes basal metabolic rate database--a reanalysis.
OBJECTIVE: To produce prediction equations for basal metabolic rate (BMR) derived from weight and height covering the age range from birth to old age. DESIGN: Cross-sectional data on BMR, sex, age, weight, height, ethnicity and measurement technique from the Oxford Brookes BMR database. SETTING: Worldwide. SUBJECTS: Data for 13,910 men, women and children from 174 papers published between 1914 and 2001. RESULTS: Absolute and proportional regression models were developed for each sex, showing a steep rise in predicted BMR with age until 15 years, more pronounced in males than females, then a gradual fall through adulthood. Predicted BMR increased by 6% and 1.4%, respectively, per standard deviation increase in weight and height. Predicted BMR in Caucasians was 4% higher than in non-Caucasians, though the effect size was sensitive to the inclusion or exclusion of data from certain influential publications. The effect of measurement technique on BMR, closed-circuit versus open-circuit, was small, near 1%. CONCLUSIONS: It is possible to develop prediction equations that avoid splitting the data into arbitrary age groups. Heterogeneity between publications is greater than might be expected by chance, probably due to undocumented differences in technique.
Adolescent↗
Assessing the acceptability and feasibility of the MEND Programme in a small group of obese 7-11-year-old children.
BACKGROUND AND AIMS: An uncontrolled, pilot study to evaluate feasibility and acceptability of a new community based childhood obesity treatment programme. METHODS: The mind, exercise, nutrition and diet (MEND) programme was held at a sports centre, twice-weekly, for 3 months. The programme consists of behaviour modification, physical activity and nutrition education. The primary outcome measure was waist circumference. Secondary outcomes were body mass index (BMI), cardiovascular fitness (heart rate, blood pressure and number of steps in 2 min), self-esteem and body composition. BMI of parents was also measured. See http://www.mendprogramme.org. RESULTS: Eleven obese children (7-11 years) and their families were recruited. Mean attendance was 78% (range 63-88%) with one drop out. Waist circumference, cardiovascular fitness and self-esteem were all significantly improved at 3 months and continued to improve at 6 months. BMI was significantly improved at 3 months but lost significance by 6 months. Deuterium studies showed a beneficial trend but were not significant. Of the 17 parents measured, seven were obese (BMI >/= 30) and eight overweight (BMI >/= 25). CONCLUSIONS: Although limited by the small number of participants and no control group, the MEND programme was acceptable to families and produced significant improvements in a range of risk factors associated with obesity that persisted over 3 months.
Body Mass Index↗
Prediction of total body water in infants and children.
BACKGROUND: In paediatric clinical practice treatment is often adjusted in relation to body size, for example the calculation of pharmacological and dialysis dosages. In addition to use of body weight, for some purposes total body water (TBW) and surface area are estimated from anthropometry using equations developed several decades previously. Whether such equations remain valid in contemporary populations is not known. METHODS: Total body water was measured using deuterium dilution in 672 subjects (265 infants aged <1 year; 407 children and adolescents aged 1-19 years) during the period 1990-2003. TBW was predicted (a) using published equations, and (b) directly from data on age, sex, weight, and height. RESULTS: Previously published equations, based on data obtained before 1970, significantly overestimated TBW, with average biases ranging from 4% to 11%. For all equations, the overestimation of TBW was greatest in infancy. New equations were generated. The best equation, incorporating log weight, log height, age, and sex, had a standard error of the estimate of 7.8%. CONCLUSIONS: Secular trends in the nutritional status of infants and children are altering the relation between age or weight and TBW. Equations developed in previous decades significantly overestimate TBW in all age groups, especially infancy; however, the relation between TBW and weight may continue to change. This scenario is predicted to apply more generally to many aspects of paediatric clinical practice in which dosages are calculated on the basis of anthropometric data collected in previous decades.
Adolescent↗