Agreement between routine and research measurement of infant height and weight

In many countries, routine data relating to growth of infants are collected as a means of tracking health and illness up to school age. These have potential to be used in research. For health monitoring and research, data should be accurate and reliable. This study aimed to determine the agreement between length/height and weight measurements from routine infant records and researcher-collected data.

METHODS

Height/length and weight at ages 6, 12 and 24 months from the longitudinal UK birth cohort (born in Bradford; n=836-1280) were compared with routine data collected by health visitors within 2 months of the research data (n=104-573 for different comparisons). Data were age adjusted and compared using Bland Altman plots.

RESULTS

There was agreement between data sources, albeit weaker for height than for weight. Routine data tended to underestimate length/height at 6 months (0.5 cm (95% CI -4.0 to 4.9)) and overestimate it at 12 (-0.3 cm (95% CI -0.5 to 4.0)) and 24 months (0.3 cm (95% CI -4.0 to 3.4)). Routine data slightly overestimated weight at all three ages (range -0.04 kg (95% CI -1.2 to 0.9) to -0.04 (95% CI -0.7 to 0.6)). Limits of agreement were wide, particularly for height. Differences were generally random, although routine data tended to underestimate length in taller infants and underestimate weight in lighter infants.

CONCLUSIONS

Routine data can provide an accurate and feasible method of data collection for research, though wide limits of agreement between data sources may be observed. Differences could be due to methodological issues; but may relate to variability in clinical practice. Continued provision of appropriate training and assessment is essential for health professionals responsible for collecting routine data.

The prevalence of tail injuries in working and non-working breed dogs visiting veterinary practices in Scotland

The aim of this paper was to estimate the prevalence of tail injuries that required veterinary examination in different breeds of dog in Scotland. The study population included all dogs that had visited one of 16 veterinary practices located in Scotland between 2002 and early 2012. The overall prevalence of tail injuries in dogs visiting one of the 16 veterinary practices was 0.59 per cent. The prevalence of tail injuries in dogs of working breeds was estimated to be 0.90 per cent. Working dog breeds that were examined by a veterinary surgeon were at a significantly greater risk of sustaining a tail injury than non-working breeds (P<0.001). To prevent one such tail injury in these working breeds approximately 232 dogs would need to be docked as puppies. To prevent one tail amputation in spaniels, 320 spaniel puppies would need to be docked. Spaniels presented after January 2009 were 2.3 times more likely to have a tail injury than those presented before April 29, 2007 (date of the legislation that banned tail docking in Scotland). Given the results of this and the accompanying paper it may be appropriate to consider changes to the current legislation for specific breeds of working dogs.

Assessing community readiness for overweight and obesity prevention in pre-adolescent girls: a case study

BACKGROUND

Childhood overweight and obesity is a global public health concern. For girls in particular, being overweight or obese during pre-adolescence (aged 7-11 years) has intergenerational implications for both the mother and her future offspring. In the United Kingdom (UK) there is increasing interest in community targeted interventions but less is known about how to tailor these approaches to the needs of the community. This study applied the Community Readiness Model (CRM), for the first time in the UK, to demonstrate its applicability in designing tailored interventions.

METHODS

Community readiness assessment was conducted using semi-structured key informant interviews. The community's key informants were identified through focus groups with pre-adolescent girls. The interviews addressed the community's efforts; community knowledge of the efforts; leadership; community climate; community knowledge of the issue and resources available to support the issue. Interviews were conducted until the point of theoretical saturation and questions were asked separately regarding physical activity (PA) and healthy eating and drinking (HED) behaviours. The interviews were transcribed verbatim and were firstly analysed thematically and then scored using the assessment guidelines produced by the CRM authors.

RESULTS

Readiness in this community was higher for PA than for HED behaviours. The lowest scores related to the community's 'resources' and the 'community knowledge of the issue'; affirming these two issues as the most appropriate initial targets for intervention. In terms of resources, there is also a need for resources to support the development of HED efforts beyond the school. Investment in greater physical education training for primary school teachers was also identified as an intervention priority. To address the community's knowledge of the issue, raising the awareness of the prevalence of pre-adolescent girls' health behaviours is a priority at the local community level. Inconsistent school approaches contributed to tensions between schools and parents regarding school food policies.

CONCLUSIONS

This study has identified the readiness level within a UK community to address the behaviours related to overweight and obesity prevention in pre-adolescent girls. The focus of an intervention in this community should initially be resources and raising awareness of the issue within the community.

Multi-level modelling of longitudinal child growth data from the Birth-to-Twenty Cohort: a comparison of growth models

Background: Different structural and non-structural models have been used to describe human growth patterns. However, few studies have compared the fitness of these models in an African transitioning population.

Aim: To find model(s) that best describe the growth pattern from birth to early childhood using mixed effect modelling.

Subjects and methods: The study compared the fitness of four structural (Berkey-Reed, Count, Jenss-Bayley and the adapted Jenss-Bayley) and two non-structural (2nd and 3rd order Polynomial) models. The models were fitted to physical growth data from an urban African setting from birth to 10 years using a multi-level modelling technique. The goodness-of-fit of the models was examined using median and maximum absolute residuals, Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC).

Results: There were variations in how the different models fitted to the data at different measurement occasions. The Jenss-Bayley and the polynomial models did not fit well to growth measurements in the early years, with very high or very low percentage of positive residuals. The Berkey-Reed model fitted consistently well over the study period.

Conclusion: The Berkey-Reed model, previously used and fitted well to infancy growth data, has been shown to also fit well beyond infancy into childhood.

Bone geometry according to menstrual function in female endurance athletes

Athletes have higher bone mineral density (BMD) relative to nonathletes. In amenorrheic athletes BMD may be compromised by estrogen deficiency, but it is unknown whether this is accompanied by structural differences. We compared femoral neck bone geometry and density of a-/oligomenorrheic athletes (AAs), eumenorrheic athletes (EAs), and eumenorrheic controls (ECs). We recruited 156 women: (68 endurance athletes and 88 controls). Femoral neck BMD, section modulus (Z), and width were measured using dual-energy X-ray absorptiometry. Menstrual function was assessed by questionnaire and classified as EA (≥10 periods/year) or AA (≤9 periods/year): 24 athletes were AA and 44 EA. Femoral neck BMD was significantly higher in EA than AA (8 %, difference) and EC (11 % difference): mean [SE] 1.118 [0.015], 1.023 [0.020] and 0.999 [0.014] g cm(-2), respectively; p < 0.001. Z was significantly higher in EA than EC (11 % difference): EA 667 [19], AA 625 [21], and EC 592 [10] cm(3); p < 0.001. Femoral neck width did not differ between groups. All differences persisted after adjustment for height, age, and body mass. The higher femoral neck Z and BMD in athletes, despite similar width, may indicate that exercise-related bone gains are endosteal rather than periosteal. Athletes with amenorrhea had smaller increments in bone mass rather than structural adaptation. The maintained femoral neck width in controls may be an adaptive mechanism to conserve bone strength in bending despite inactivity-related bone decrement.

UK-born Pakistani-origin infants are relatively more adipose than white British infants: findings from 8704 mother-offspring pairs in the Born-in-Bradford prospective birth cohort

Background

Previous studies have shown markedly lower birth weight among infants of South Asian origin compared with those of White European origin. Whether such differences mask greater adiposity in South Asian infants and whether they persist across generations in contemporary UK populations is unclear. Our aim was to compare birth weight, skinfold thickness and cord leptin between Pakistani and White British infants and to investigate the explanatory factors, including parental and grandparental birthplace.

Methods

We examined the differences in birth weight and skinfold thickness between 4649 Pakistani and 4055 White British infants born at term in the same UK maternity unit and compared cord leptin in a subgroup of 775 Pakistani and 612 White British infants.

Results

Pakistani infants were lighter (adjusted mean difference −234 g 95% CI −258 to −210) and were smaller in both subscapular and triceps skinfold measurements. The differences for subscapular and triceps skinfold thickness (mean z-score difference −0.27 95% CI −0.34 to −0.20 and −0.23 95% CI −0.30 to −0.16, respectively) were smaller than the difference in birth weight (mean z-score difference −0.52 95% CI −0.58 to −0.47) and attenuated to the null with adjustment for birth weight (0.03 95% CI −0.03 to 0.09 and −0.01 95% CI −0.08 to 0.05, respectively). Cord leptin concentration (indicator of fat mass) was similar in Pakistani and White British infants without adjustment for birth weight, but with adjustment became 30% higher (95% CI 17% to 44%) among Pakistani infants compared with White British infants. The magnitudes of difference did not differ by generation.

Conclusions

Despite being markedly lighter, Pakistani infants had similar skinfold thicknesses and greater total fat mass, as indicated by cord leptin, for a given birth weight than White British infants. Any efforts to reduce ethnic inequalities in birth weight need to consider differences in adiposity and the possibility that increasing birth weight in South Asian infants might inadvertently worsen health by increasing relative adiposity.

Describing differences in weight and length growth trajectories between white and Pakistani infants in the UK: analysis of the Born in Bradford birth cohort study using multilevel linear spline models

OBJECTIVE

To describe the growth pattern from birth to 2 years of UK-born white British and Pakistani infants.

DESIGN

Birth cohort.

SETTING

Bradford, UK.

PARTICIPANTS

314 white British boys, 383 Pakistani boys, 328 white British girls and 409 Pakistani girls.

MAIN OUTCOME MEASURES

Weight and length trajectories based on repeat measurements from birth to 2 years.

RESULTS

Linear spline multilevel models for weight and length with knot points at 4 and 9 months fitted the data well. At birth Pakistani boys were 210 g lighter (95% CI -290 to -120) and 0.5 cm shorter (-1.04 to 0.02) and Pakistani girls were 180 g lighter (-260 to -100) and 0.5 cm shorter (-0.91 to -0.03) than white British boys and girls, respectively. Pakistani infants gained length faster than white British infants between 0 and 4 months (+0.3 cm/month (0.1 to 0.5) for boys and +0.4 cm/month (0.2 to 0.6) for girls) and gained more weight per month between 9 and 24 months (+10 g/month (0 to 30) for boys and +30 g/month (20 to 40) for girls). Adjustment for maternal height attenuated ethnic differences in weight and length at birth, but not in postnatal growth. Adjustment for other confounders did not explain differences in any outcomes.

CONCLUSIONS

Pakistani infants were lighter and had shorter predicted mean length at birth than white British infants, but gained weight and length quicker in infancy. By age 2 years both ethnic groups had similar weight, but Pakistani infants were on average taller than white British infants.

A systematic review to determine the effectiveness of interventions designed to prevent overweight and obesity in pre-adolescent girls

Childhood overweight/obesity is recognized as an increasing health problem. The objective of this review was to determine the effectiveness of interventions designed to prevent overweight and obesity in pre-adolescent girls. The papers included were those studying children (must include results for girls) from within the 7-11 years age range from any country and ethnic background. The included interventions lasted at least 12 weeks and modified a combination of nutrition, physical activity, knowledge, attitudes or health-related behaviours associated with the development of childhood overweight and obesity. Effect sizes were calculated where possible using Cohen's classifications of small (0.2-0.5), medium (0.5-0.8) and large (>0.8) effect sizes. Thirty studies met the inclusion criteria of which four were cluster randomized controlled trials, 14 were randomized controlled trials, 11 were controlled trials and one was a cohort pre-post trial. There were four weak, 11 moderate and 15 strong quality studies. Eleven studies were considered short term and 19 long term (≥12 months). There were 66 effect sizes less than 0.2, 56 categorized as low, 16 as medium and two as high. There is the potential for interventions aimed at pre-adolescent girls to reduce the risk factors associated with childhood overweight and obesity, although the sustainability of the effects of such interventions is less clear.

Small fibre neuropathy: role in the diagnosis of diabetic sensorimotor polyneuropathy

Small fibres constitute 70-90% of peripheral nerve fibres and regulate several key functions such as tissue blood flow, temperature and pain perception as well as sweating, all of which are highly relevant to the clinical presentation and adverse outcomes associated with foot ulcerations in patients with diabetes. Recent studies demonstrated significant abnormalities in the small fibres in subjects with impaired glucose tolerance and diabetes, despite normal electrophysiology, suggesting that the earliest nerve fibre damage is to the small fibres. Unfortunately, guidelines and consensus statements focus on large fibres and continue to advocate electrophysiology as a diagnostic modality and as a primary end point for the assessment of therapeutic benefit. (In part, this reflects the difficulties in quantifying small fibre dysfunction and damage.) We have therefore critically assessed currently available techniques that measure small fibre dysfunction in diabetic neuropathy, using quantitative sensory and sudomotor testing. We have assessed the role of identifying structural damage by quantifying intraepidermal nerve fibre density in skin biopsies and corneal nerve morphology using corneal confocal microscopy. Finally, we propose a definition for diabetic neuropathy that incorporates small fibre damage.

Bone mass and bone size in pre- or early pubertal 10-year-old black and white South African children and their parents

Genetic factors are thought to maintain bone mass in socioeconomically disadvantaged black South Africans. We compared bone mass between environmentally disadvantaged black and advantaged white children and their parents, after determining the most appropriate method by which to correct bone mineral content (BMC) for size. We collected data from 419 healthy black and white children of mean age 10.6 years (range 10.0-10.9), 406 biological mothers, and 100 biological fathers. Whole-body, femoral neck, lumbar spine, and mid- and distal one-third of radius bone area (BA) and BMC were measured by dual-energy X-ray absorptiometry. Power coefficients (PCs) were calculated from the linear-regression analyses of ln(BMC) on ln(BA) and used to correct site-specific BMC for bone size differences. Heritability (½h(2), %) by maternal and paternal descent was estimated by regressing children's Z scores on parents' Z scores. Correcting BMC for height, weight, and BA(PC) accounted for the greatest variance of BMC at all skeletal sites. In so doing, BMC in blacks was up to 2.6 times greater at the femoral neck and lumbar spine. Maternal and paternal heritability was estimated to be ~30% in both black and white subjects. These results may in part explain the lower prevalence of fragility fractures at the hip in black South African children when compared to whites. Heritability was comparable between environmentally disadvantaged black and advantaged white South African children and similar to that reported for Caucasians in other parts of the world.

Temporal and environmental patterns of sedentary and active behaviors during adolescents' leisure time

BACKGROUND

There is great interest in young people's overweight and obesity. Few data, however, describe when sedentary and physically active behaviors are likely to occur during the day or how these behaviors are related to location.

PURPOSE

The purpose of this study was to describe sedentary and active leisure-time behaviors of adolescents across the day and setting.

METHOD

Adolescents (male n = 579, female n = 967; aged 13-16 years) completed time-use diaries for three weekdays and one weekend day. At 15 min intervals, participants recorded what they were doing and where they were.

RESULTS

TV viewing and sports/exercise peaked at different times in the day, although TV viewing was two to three times more likely to occur than sports/exercise. TV viewing was most likely to occur during the middle to late evening. The playing of computer games was low, particularly for girls. Weekend data showed TV viewing was the most reported activity throughout the day. For boys, "being in the garden" was highly predictive of engaging in sports/exercise, but this declined rapidly with age. Motorized travel to school was reported twice as often as active travel.

CONCLUSION

Momentary assessments of behavior, in conjunction with contemporaneous reports of environmental factors, describe important patterns of leisure-time active and sedentary behaviors in youth.

[A non invasive method for assessing sexual development at adolescence]

INTRODUCTION

Observational assessments of puberty that invades the adolescent's privacy are not acceptable for research in population groups. Results based on self assessment have been variable, and in many cases poor.

OBJECTIVES

To evaluate the validity of a questionnaire with simple questions addressed to assess early, intermediate and advanced puberty periods rather than specific stages.

MATERIAL AND METHODS

In an outpatient clinic at the Service of Adolescence of a public hospital, 188 and 142 healthy girls and boys aged 8-18 years, and 36 girls and boys aged 8-9 years attending a public school were studied. Adolescents attended the Service for the first time. Those with chronic diseases were excluded from the study. Children answered the questionnaire before entering the doctor's office, where a trained professional clinically assessed their puberal development (Tanner's stage). The questionnaire was previously tested in 30 adolescents.

RESULTS

The highest concordance were found in the questions: "Have you started puberty?", with Tanner's stages III, IV or V (Kappa value= 0.60); "Have you already had your first menstrual period?" with stages IV-V (K= 0.69); and "Do you shave?" with stages IV-V (K= 0.66). In most cases, these questions showed high (> or = 0.80) sensitivity and specificity for detecting the mentioned puberty periods.

CONCLUSIONS

The method showed to be reliable, and its further evaluation in a non medical setting (schools, households, etc.) is recommended.

Rapid infant weight gain and advanced skeletal maturation in childhood

OBJECTIVE

To test the hypothesis that rapid infant weight gain is associated with advanced skeletal maturity in children from the United States and South Africa.

STUDY DESIGN

Longitudinal data from 467 appropriate-for-gestational-age infants in the Fels Longitudinal Growth Study (Dayton, Ohio) and 196 appropriate-for-gestational-age infants in the Birth to Twenty birth cohort study (Johannesburg, South Africa) were used. Multiple linear regression models tested the association between internal SD score change in weight from 0 to 2 years and relative skeletal age at 9 years, adjusting for body mass index, stature, and other covariates.

RESULTS

In both studies, faster infant weight gain was associated with more advanced skeletal maturity (approximately 0.2 years or 2.4 months per SD score) at age 9 years (P <.0001-.005), even when adjusting for the positive associations of both birth weight and body mass index at age 9 years. This effect appeared to be accounted for by the greater childhood stature of subjects with more rapid infant weight gain.

CONCLUSIONS

Relatively rapid infant weight-gain is associated with advanced skeletal development in late childhood, perhaps via effects on stature.

How well do waist circumference and body mass index reflect body composition in pre-pubertal children?

OBJECTIVE

To investigate the quantitative relationship between waist circumference (WC) and height (Ht), and subsequently the association between waist circumference index (WCI), body mass index (BMI) and body composition in pre-pubertal children.

DESIGN

Cross-sectional sample (n=227; boys=127) of pre-pubertal black children (age range 8.8-11.0 years) from the Bone Health sub-study of the Bt20 birth cohort study set in Soweto-Johannesburg, South Africa. Measures of height, weight and WC by anthropometry, total and truncal fat and lean mass by dual-energy X-ray absorptiometry were used in the analysis. Pearson's correlation coefficients were used to examine the associations between BMI, WC and body composition outcomes.

RESULTS

WC was independent of height when height was raised to a power of approximately 0.8. BMI and WCI (WC/Ht) were significantly associated with total and truncal fat and lean mass in both sexes (all P<0.001). BMI showed consistently and significantly higher correlations with body composition than WCI and this association was significantly greater for fat mass than lean mass.

CONCLUSION

BMI, rather than WCI, would be a better screening tool for total and truncal fat mass in both sexes before puberty.

BASIC programs for the assessment of skeletal maturity and the prediction of adult height using the Tanner-Whitehouse method

A family of BASIC microcomputer programs is described that carry out the computations required for the assessment of skeletal maturity and the prediction of adult height according to the Tanner- Whitehouse techniques. These programs significantly reduce the tedious computations required for these assessments and present final data in a comprehensible format. Both the original, Mark 1, and the newer, Mark 2, prediction methods are included because even though the latter is intended to replace the former, this replacement will naturally take some time and comparability studies will inevitably be undertaken. The programs are written in Applesoft BASIC but may be easily modified for other microcomputers or main-frames with the facility for BASIC compilation.

Socio-economic predictors of stunting in preschool children--a population-based study from Johannesburg and Soweto

BACKGROUND

Stunting continues to be a child public health concern in many African countries, including South Africa. This study uses data from the Birth to Twenty study, held in Johannesburg, to investigate a range of household-level socioeconomic and social support predictors of stunting in children aged less than 30 months.

DESIGN

Logistical regression models were constructed using a conceptual framework to investigate the association between early life measures of socio-economic status and stunting (<--2 standard deviations from the WHO (2006) standard), using data collected in the Birth to Twenty study.

RESULTS

Stunting prevalence was 18.0% (213/1 186). In unadjusted analyses, numerous socio-economic status exposures showed significant associations with stunting; however, in final multivariable models, decreased likelihood of stunting was seen in children born to mothers who were employed (adjusted odds ratio (AOR) = 0.60, 95% confidence interval (CI) 0.40-0.88), those with fathers who had completed secondary school (AOR = 0.59, 95% CI 0.40-0.85), and whose parents employed a domestic worker (AOR = 0.40, 95% CI 0.19-0.83), while increased likelihood of stunting was seen in male children (AOR = 1.40, 95% CI 1.03-1.91), and those born of low birth weight (AOR = 2.56, 95% CI 1.54-4.26).

CONCLUSIONS

Stunting and child malnutrition remain policy priorities for the South African Department of Health, and this study suggests that policies that aim to increase parental education level and reduce unemployment or target additional support to families with low education or unemployed parents may reduce stunting in preschool-age children in this setting.

Implications of adopting the WHO 2006 Child Growth Standards: case study from urban South Africa, the Birth to Twenty cohort

BACKGROUND

The World Health Organization (WHO) recently developed growth standards to overcome the limitations of previous references.

AIM

The aim of this study was to compare the growth patterns of a cohort of children using the National Centre for Health Statistics (NCHS), the Centre for Disease Control (CDC), and WHO 2006 references/standards, and to evaluate the implications of adopting WHO standards.

SUBJECTS AND METHODS

Using growth data (0-5 years) from the 1990 South African Birth to Twenty cohort in Johannesburg-Soweto, Z-scores were derived for weight-for-age, length/height-for age, and weight-for-length/height from the NCHS and CDC references, and WHO 2006 standards.

RESULTS

The pattern of mean Z-score change observed when applying the NCHS and CDC references was similar to one another, but different to that obtained when using the WHO 2006 standard. WHO 2006 identified children as being generally more stunted and more overweight.

CONCLUSION

Discourse on the implementation of WHO 2006 and the impact on the primary health care system and public health monitoring in South Africa is needed, and sufficient planning is critical around not only the implementation of WHO 2006 but also maintaining comparability with historical malnutrition data.

Polymer Flood Application to Improve Heavy Oil Recovery at East Bodo

Abstract

The East Bodo, Lloydminster SS heavy oil pool has been exploited using primary recovery and waterflood. IOR screening showed that a polymer flood would be a preferred IOR technique. Subsequent coreflood tests indicated that the polymer flood could recover 20% OOIP incremental oil, after waterflooding, to a 95% water cut. Data gathered from the coreflood was used to fine tune the reservoir simulation model to help design the pilot and predict potential economic reserve capture for a commercial field-wide polymer flood. Subsequently, a pilot was initiated. During the pilot operation, achieving the target polymer viscosity, dependant on water quality, proved to be a significant challenge. Early field response is being observed through an increase in injection pressure, reduced water cut and polymer breakthrough. Further positive response of this polymer pilot allows for the expansion of the polymer flood technology to other parts of this reservoir; some with bottomwater and gas cap. This paper reviews the progress of the East Bodo polymer flood, from laboratory concept to working field application, in four major steps:IOR screening using simulations and coreflooding,field pilot design/implementation,pilot performance, andnext steps.

Introduction

Pengrowth has targeted East Bodo (Alberta side) and Cosine (Saskatchewan side) for waterflood optimization and subsequent enhanced oil recovery applications. Currently, the most practical EOR technology for this heavy oil reservoir seems to be the polymer flood technology in combination with horizontal wells. Several investigators(1–4) have demonstrated the potential of the polymer flood technology for improved oil recovery in heavy oil reservoirs.

The East Bodo/Cosine Reservoir produces from the Lloydminster Formation, which is part of the Lower Cretaceous Mannville Group. Pengrowth provided some of the reservoir characteristics, as summarized in Table 1. This particular reservoir is separated into two parallel lobes trending North/West to South/East.

To complicate matters, local gas caps are found primarily on the Saskatchewan side of the reservoir. Thus, the current waterflood patterns are located on the Alberta side. In the future, optimized waterflood and EOR schemes need to include those parts of the reservoir which are overlain by gas caps or influenced by bottomwater. A plan of progression aligned with the priorities of Pengrowth was laid out as follows:Optimize existing waterflood;Step out waterflood into limited gas cap areas;Then, target areas with a more extensive gas cap;Determine enhanced waterflood potential, for instance polymer flood; andArrange well patterns to benefit both waterflood and subsequent EOR process.

IOR Screening

Several IOR technologies were considered for application in the East Bodo Field. What follows is a list of IOR processes that were initially considered, but screened out after technical or economical issues could not be overcome.Thermal Recovery: Pay is too thin - heat loss to overburden is too large; oil not viscous enough to form a stable steam chamber; fireflood has potential, but a previous pilot on a neighbouring McLaren pool yielded poor results.