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Biddle SJH, Gorely T, Marshall SJ, Cameron N. The prevalence of sedentary behavior and physical activity in leisure time: A study of Scottish adolescents using ecological momentary assessment. Prev Med 2009; 48:151-5. [PMID: 19046984 DOI: 10.1016/j.ypmed.2008.10.025] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 10/27/2008] [Accepted: 10/31/2008] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To report time and prevalence of leisure time sedentary and active behaviors in adolescents. METHOD Cross-sectional, stratified, random sample from schools in 14 districts in Scotland, 2002-03, using ecological momentary assessment (n=385 boys, 606 girls; mean age 14.1 years; range 12.6-16.7 years). This is a method of capturing current behavioral episodes. We used 15 min time intervals. RESULTS Television viewing occupied the most leisure time. The five most time consuming sedentary activities occupied 228 min per weekday and 396 min per weekend day for boys, and 244 min per weekday and 400 min per weekend day for girls, with TV occupying one-third to one-half of this time. In contrast, 62 min was occupied by active transport and sports/exercise per weekday and 91 min per weekend day for boys, with 55 min per weekday and 47 min per weekend day for girls. A minority watched more than 4 h of TV per day, with more at weekends. Other main sedentary behaviors for boys were homework, playing computer/video games, and motorised transport and, for girls, homework, motorised transport, and sitting and talking. CONCLUSION Scottish adolescents engage in a variety of sedentary and active behaviors. Research into sedentary behavior must assess multiple behaviors and not rely solely on TV viewing.
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Gorely T, Biddle SJH, Marshall SJ, Cameron N. The prevalence of leisure time sedentary behaviour and physical activity in adolescent boys: An ecological momentary assessment approach. ACTA ACUST UNITED AC 2009; 4:289-98. [PMID: 19922044 DOI: 10.3109/17477160902811181] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Griffiths PL, Rousham EK, Norris SA, Pettifor JM, Cameron N. Socio-economic status and body composition outcomes in urban South African children. Arch Dis Child 2008; 93:862-7. [PMID: 18456685 DOI: 10.1136/adc.2006.112649] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To determine which aspects of socio-economic status (SES) measured at birth and at ages 9 or 10 years, are associated with body composition at ages 9 or 10 years. DESIGN Mixed longitudinal cohort. SETTING Johannesburg-Soweto South Africa. PARTICIPANTS A sub-sample of the Birth to Twenty (Bt20) cohort (n = 281) with data on birth weight, height, weight, fat and lean tissue (whole body dual-energy x ray absorptiometry (DXA)), and birth and ages 9 or 10 years SES measures. MAIN OUTCOME MEASURES Linear regression was used to estimate the influence of birth and ages 9 or 10 years SES measures on three outcomes: fat mass index (FMI) (fat mass (kg)/height (m)4), lean mass index (LMI) (lean mass (kg)/height (m)2), and body mass index (BMI) at ages 9 or 10 years controlling for sex, age, birth weight and pubertal status. RESULTS Compared to the lowest SES tertile, being in the highest birth SES tertile was associated with increased LMI at ages 9 or 10 years (beta = 0.43, SE = 0.21 for white and black children and beta = 0.50, SE = 0.23 for black children only), whereas children in the high SES tertile at ages 9 or 10 years had increased FMI (beta = 0.46, SE = 0.22 for white and black children, and beta = 0.65, SE = 0.23 for black children only). SES at birth and at ages 9 or 10 years accounted for 8% and 6% of the variance in FMI and BMI, respectively (black children). CONCLUSIONS These findings underline the importance of examining SES across childhood ages when assessing nutrition inequalities. Results emphasise the need to consider lean and fat mass as well as BMI when studying SES and body composition in children.
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Crowther NJ, Cameron N, Trusler J, Toman M, Norris SA, Gray IP. Influence of catch-up growth on glucose tolerance and beta-cell function in 7-year-old children: results from the birth to twenty study. Pediatrics 2008; 121:e1715-22. [PMID: 18519475 DOI: 10.1542/peds.2007-3147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate the effect of catch-up growth occurring at different stages of childhood on glucose levels and beta-cell function at 7 years of age. METHODS Oral glucose tolerance tests were performed on 152 7-year-old children. Anthropometric data were available from birth to 7 years of age. Children were split into catch-up, catch-down, and normal-growth groups on the basis of growth rates between birth and 1 year, birth and 5 years, and birth and 7 years. Fasting and 30- and 120-minute blood samples collected during the oral glucose tolerance tests were assayed for glucose, insulin, proinsulin, and des-31,32-proinsulin levels, and area-under-the-curve values were calculated. RESULTS Children with catch-up growth between birth and 5 years or birth and 7 years had greater area-under-the-curve insulin levels than the children with catch-down growth. Children with catch-up growth only between birth and 7 years exhibited higher proinsulin levels and a greater insulin secretory response to glucose than those who experienced catch-up growth between both birth and 1 year and birth and 7 years of age. Low birth weight children with no catch-up growth between birth and 7 years had the highest glucose and lowest insulinogenic index levels, whereas children with high birth weight and catch-up growth had the highest insulin levels. CONCLUSIONS Extremes of birth weight in conjunction with extremes of postnatal growth are all detrimental to childhood metabolism. The negative metabolic effects of catch-up growth between birth and 7 years may be attenuated if catch-up growth also occurs between birth and 1 year of age.
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Gorely T, Marshall SJ, Biddle SJH, Cameron N. The prevalence of leisure time sedentary behaviour and physical activity in adolescent girls: an ecological momentary assessment approach. ACTA ACUST UNITED AC 2008; 2:227-34. [PMID: 17852544 DOI: 10.1080/17477160701408833] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
STUDY OBJECTIVE To use ecological momentary assessment to describe how adolescent girls in the United Kingdom spend their leisure time. DESIGN Cross-sectional, stratified, random sample from secondary schools in 15 regions within the United Kingdom. The data are from a larger study of adolescent lifestyles (Project STIL). PARTICIPANTS A total of 923 girls with a mean age of 14.7 years (range 12.5-17.6 years). The majority were white-European (88.7%). MAIN RESULTS Across all behaviours, television viewing occupied the most leisure time on both weekdays and weekend days. The five most time consuming sedentary weekday activities occupied on average 262.9 minutes per weekday and 400 minutes per weekend day. In contrast, only 44.2 minutes was occupied by active transport or sports and exercise per weekday, and 53 minutes per weekend day. Only a minority watched more than 4 hours of TV per day (3.3% on weekdays and 20.7% on weekend days). Computer use is low in this group. Some differences were noted in the means and prevalences between weekend and weekdays, most likely reflecting the greater discretionary time available at the weekend. Few age differences were noted. CONCLUSIONS Adolescent girls engage in a variety of behaviours that contribute to an overall lifestyle that may be active or sedentary. Effective physical activity promotion strategies must focus on facilitating shifts towards healthy overall patterns of behaviour rather than shifts in any one single behaviour.
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Gorely T, Marshall SJ, Biddle SJH, Cameron N. Patterns of sedentary behaviour and physical activity among adolescents in the United Kingdom: Project STIL. J Behav Med 2007; 30:521-31. [PMID: 17712619 DOI: 10.1007/s10865-007-9126-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 07/31/2007] [Indexed: 10/22/2022]
Abstract
The purpose of this study was to use ecological momentary assessment to investigate the patterning of physical activity and sedentary behaviours in UK adolescents and to examine if different lifestyle groups differ on key explanatory variables. A total of 1,371 (38% boys, mean age 14.7 years) adolescents completed diaries every 15 min for 3 weekdays outside of school hours and 1 weekend day. Cluster analysis yielded five-cluster solutions for both boys and girls to explain the grouping of sedentary behaviours and physical activity. The clusters demonstrated that adolescents engage in many leisure time behaviours but have one activity that predominates. Active adolescents spend more time outside and more time with their friends. Few demographic and environmental variables distinguished between clusters. The findings suggest a potential need for different behavioural targets in interventions to reduce sedentary behaviour in sub groups of the adolescent population. Further research is required to examine the modifiable determinants of different sedentary lifestyles among young people.
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Richter L, Norris S, Pettifor J, Yach D, Cameron N. Cohort Profile: Mandela's children: the 1990 Birth to Twenty study in South Africa. Int J Epidemiol 2007; 36:504-11. [PMID: 17355979 PMCID: PMC2702039 DOI: 10.1093/ije/dym016] [Citation(s) in RCA: 226] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Lindley MR, Beynon C, Cameron N. Morphological Changes in Young Adult Males Over a 40 Year Period; The Loughborough University Alumni Study. Med Sci Sports Exerc 2007. [DOI: 10.1249/01.mss.0000274474.73057.e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nyati LH, Norris SA, Cameron N, Pettifor JM. Effect of ethnicity and sex on the growth of the axial and appendicular skeleton of children living in a developing country. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2006; 130:135-41. [PMID: 16345070 DOI: 10.1002/ajpa.20318] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Bones in the axial and appendicular skeletons exhibit heterogeneous growth patterns between different ethnic and sex groups. However, the influence of this differential growth on the expression of bone mineral content is not yet established. The aims of the present study were to investigate: 1) whether there are ethnic and sex differences in axial and appendicular dimensions of South African children; and 2) whether regional segment length is a better predictor of bone mass than stature. Anthropometric measurements of stature, weight, sitting height, and limb lengths were taken on 368 black and white, male and female 9-year-old children. DXA (dual-energy x-ray absorptiometry) scans of the distal ulna, distal radius, and hip and lumbar spine were also obtained. Analyses of covariance were performed to assess differences in limb lengths, adjusted for differences in stature. Multiple regression analyses were used to assess significant predictors of site-specific bone mass. Stature-adjusted means of limb lengths show that black boys have longer legs and humeri but shorter trunks than white boys. In addition, black children have longer forearms than white children, and girls have longer thighs than boys. The regression analysis demonstrated that site-specific bone mass was more strongly associated with regional segment length than stature, but this had little effect on the overall pattern of ethnic and sex differences. In conclusion, there is a differential effect of ethnicity and sex on the growth of the axial and appendicular skeletons, and regional segment length is a better predictor of site-specific bone mass than stature.
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Taljaard J, Cameron N, Cotton M, Van Zyl G, Vurgarellis P, Preiser W. The Namibian poliomyelitis outbreak and its consequences for South Africa. S Afr Fam Pract (2004) 2006. [DOI: 10.1080/20786204.2006.10873415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Vidulich L, Norris SA, Cameron N, Pettifor JM. Differences in bone size and bone mass between black and white 10-year-old South African children. Osteoporos Int 2006; 17:433-40. [PMID: 16362145 DOI: 10.1007/s00198-005-0004-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Accepted: 09/01/2005] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Black and white South Africans hail from vastly disparate cultural and socio-economic backgrounds the result of which exposes black children to numerous factors known to impact negatively on bone mass. Thus, we studied ethnic differences in bone size and bone mass between 476 10-year-old black and white South African girls and boys (black boys n=182, white boys n=72, black girls n=158, white girls n=64) who formed part of a longitudinal cohort of children born in Johannesburg, South Africa, during 1990. METHODS Bone area (BA) and bone mineral content (BMC) were measured at the whole body, total hip, femoral neck, lumbar spine (L1-L4) and mid- and distal radii by dual energy X-ray absorptiometry (DXA). Vertebral heights and metacarpal indices were measured. Anthropometry, skeletal maturity and pubertal development were also assessed. RESULTS After correction for height, weight, gender and puberty, black children had greater BMC at the femoral neck (P<0.0001), total hip (P<0.05) and mid-radius (P<0.001) than white children.. At the whole body, lumbar spine, and distal one-third of the radius, there were no differences in BMC between black and white children after correction for differences in body size. After correction for height and puberty, vertebral heights were less in black children than white children, and cortical areas at the second metacarpal were greater in black children. CONCLUSION These findings suggest that, at the femoral neck, total hip and mid-radius, these differences are not a result of differences in anthropometry, bone age or pubertal stage, or environmental factors but are most likely to result from genetic differences.
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Marshall SJ, Biddle SJH, Gorely T, Cameron N, Murdey I. Relationships between media use, body fatness and physical activity in children and youth: a meta-analysis. Int J Obes (Lond) 2004; 28:1238-46. [PMID: 15314635 DOI: 10.1038/sj.ijo.0802706] [Citation(s) in RCA: 702] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To review the empirical evidence of associations between television (TV) viewing, video/computer game use and (a) body fatness, and (b) physical activity. DESIGN Meta-analysis. METHOD Published English-language studies were located from computerized literature searches, bibliographies of primary studies and narrative reviews, and manual searches of personal archives. Included studies presented at least one empirical association between TV viewing, video/computer game use and body fatness or physical activity among samples of children and youth aged 3-18 y. MAIN OUTCOME MEASURE The mean sample-weighted corrected effect size (Pearson r). RESULTS Based on data from 52 independent samples, the mean sample-weighted effect size between TV viewing and body fatness was 0.066 (95% CI=0.056-0.078; total N=44,707). The sample-weighted fully corrected effect size was 0.084. Based on data from six independent samples, the mean sample-weighted effect size between video/computer game use and body fatness was 0.070 (95% CI=-0.048 to 0.188; total N=1,722). The sample-weighted fully corrected effect size was 0.128. Based on data from 39 independent samples, the mean sample-weighted effect size between TV viewing and physical activity was -0.096 (95% CI=-0.080 to -0.112; total N=141,505). The sample-weighted fully corrected effect size was -0.129. Based on data from 10 independent samples, the mean sample-weighted effect size between video/computer game use and physical activity was -0.104 (95% CI=-0.080 to -0.128; total N=119,942). The sample-weighted fully corrected effect size was -0.141. CONCLUSION A statistically significant relationship exists between TV viewing and body fatness among children and youth although it is likely to be too small to be of substantial clinical relevance. The relationship between TV viewing and physical activity is small but negative. The strength of these relationships remains virtually unchanged even after correcting for common sources of bias known to impact study outcomes. While the total amount of time per day engaged in sedentary behavior is inevitably prohibitive of physical activity, media-based inactivity may be unfairly implicated in recent epidemiologic trends of overweight and obesity among children and youth. Relationships between sedentary behavior and health are unlikely to be explained using single markers of inactivity, such as TV viewing or video/computer game use.
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McVeigh JA, Norris SA, Cameron N, Pettifor JM. Associations between physical activity and bone mass in black and white South African children at age 9 yr. J Appl Physiol (1985) 2004; 97:1006-12. [PMID: 15132999 DOI: 10.1152/japplphysiol.00068.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated differences in physical activity (PA) levels between black and white South African 9-yr-old children and their association with bone mineral content (BMC) and density (BMD) by using dual-energy X-ray absorptiometry. PA was analyzed in terms of a metabolic (METPA; weighted metabolic score of intensity, frequency, and duration) and a mechanical (MECHPA; sum of all ground reaction forces multiplied by duration) component. There were significant ethnic differences in patterns of activity. White children expended a significantly greater energy score (METPA of 21.7 +/- 2.9) than black children (METPA of 9.5 +/- 0.5) (P < 0.001). When children were divided into quartiles according to the amount and intensity of sport played, the most active white children (using METPA scores) had significantly higher whole body BMD and higher hip and spine BMC and BMD than less active children. White children in the highest MECHPA quartile also showed significantly higher whole body, hip, and spine BMC and BMD than those children in the lowest quartile. No association between exercise and bone mass of black children was found. In this population, PA has an osteogenic association with white children, but not black children, which may be explained by the lower levels of PA in the black children. Despite this, black children had significantly greater bone mass at the hip and spine (girls only) (P < 0.001) even after adjustment for body size. The role of exercise in increasing bone mass may become increasingly critical as a protective mechanism against osteoporosis in both ethnic groups, especially because the genetic benefit exhibited by black children to higher bone mass may be weakened with time, as environmental influences become stronger.
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Murdey ID, Cameron N, Biddle SJH, Marshall SJ, Gorely T. Pubertal development and sedentary behaviour during adolescence. Ann Hum Biol 2004; 31:75-86. [PMID: 14742166 DOI: 10.1080/03014460310001636589] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Assessing time spent in sedentary behaviours in relation to pubertal status, anthropometric differences, and body image will improve insight into the prevalence and determinants of such behaviours during adolescence. AIM The study aimed to investigate the effects of age, puberty, gender, body composition, and sleep on sedentary behaviour. PARTICIPANTS AND METHODS Participants were 64 boys and 55 girls in Year 6 (10.0-10.9 years of age), Year 8 (12.0-12.9 years) and Year 10 (14.0-14.9 years). Body mass index and percentage body fat were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed using momentary-time sampling. Body image was measured using the Children's Physical Self-Perception Profile. Pubertal status was assessed from self-report of secondary sexual characteristics. RESULTS After controlling for sleep time, no differences in sedentary time were seen for puberty onset or increased pubertal development. Correlations between pubertal status, body composition, and body image were stronger in girls than in boys. Correlations between body image and sedentary behaviour were not strong enough to infer behavioural choice differences. CONCLUSIONS Reduced sleep time rather than changing body image and body composition during adolescence is associated with greater sedentary behaviour.
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Biddle SJ, Gorely T, Marshall SJ, Murdey I, Cameron N. Physical activity and sedentary behaviours in youth: issues and controversies. ACTA ACUST UNITED AC 2004; 124:29-33. [PMID: 14971190 DOI: 10.1177/146642400312400110] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
There is growing concern over the effects of sedentary lifestyles on the health of young people. Recent rapid increases in juvenile obesity have received a great deal of attention in the scientific and popular press and have been attributed partly to television viewing, computer games and other sedentary behaviours. These are thought to compete with physical activity. There is a 'moral panic' concerning the 'couch kids' culture in modern western society. Project STIL (Sedentary Teenagers and Inactive Lifestyles) at Loughborough University is investigating 'what young people do' and focuses on active and inactive pursuits chosen in their leisure time. The following issues are addressed in this paper with specific reference to young people: how do we define 'sedentary behaviour' and do key sedentary behaviours displace physical activity? Are key sedentary behaviours obesogenic? What are the secular trends for children and youth for TV viewing? Our results for young people suggest that: 1. TV viewing and video-game playing are largely uncorrelated with physical activity, suggesting that there is time for both 2. meta-analytic findings show that body fatness is not related in any clinically meaningful way with key sedentary behaviours 3. although more children and youth have greater access to TVs than in previous generations, the amount of TV watched per head has not changed for 40 years. Preliminary findings from Project STIL suggest that inactivity is more complex that we sometimes think. Indeed, measures of 'couch potato-ism', such as TV viewing, may be inappropriate markers of inactivity.
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Hiemstra R, Rabie H, Schaaf HS, Eley B, Cameron N, Mehtar S, Janse van Rensburg A, Cotton MF. Unexplained HIV-1 infection in children--documenting cases and assessing for possible risk factors. S Afr Med J 2004; 94:188-93. [PMID: 15098278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND In the year 2000 we reported possible horizontal transmission of HIV-1 infection between two siblings. An investigation of three families, each with an HIV-infected child but seronegative parents, permitted this finding. Sexual abuse and surrogate breast-feeding were thought unlikely. The children had overlapping hospitalisation in a regional hospital. Since then several cases of unexplained HIV infection in children have been reported. A registry was established at Tygerberg Children's Hospital for collection of data on the extent of horizontal or unexplained transmission of HIV in children. STUDY DESIGN Retrospective chart review. RESULTS Fourteen children were identified, 12 from the Western Cape and 1 each from the Eastern Cape and KwaZulu-Natal. Thirteen (92%) had been hospitalised previously. In the Western Cape, children had been hospitalised in 8 hospitals. Ten of 13 (77%) were admitted as neonates and 9 of 13 (69%) had 2 or more admissions. Intravascular cannulation and intravenous drug administration occurred in all but 2 children before HIV diagnosis. CONCLUSION We have confirmed HIV infection in a number of cases where the source of infection has been inadequately explained. Circumstantial evidence supports but does not prove nosocomial transmission. Further studies and identification of medical procedures conducive to the spread of HIV are urgently needed.
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Demerath EW, Cameron N, Gillman MW, Towne B, Siervogel RM. Telomeres and Telomerase in the Fetal Origins of Cardiovascular Disease: A Review. Hum Biol 2004; 76:127-46. [PMID: 15222684 PMCID: PMC2801408 DOI: 10.1353/hub.2004.0018] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Telomeres are noncoding functional DNA repeat sequences at the ends of chromosomes that decrease in length by a predictable amount at each cell division. When the telomeres become critically short, the cell is no longer able to replicate and enters cellular senescence. Recent work has shown that within individuals, telomere length tracks with cardiovascular health and aging and is also affected by growth variation, both prenatally and postnatally. Therefore telomere length can be a marker of both growth history (cell division) and tissue function (senescence). Relationships between early growth and later health have emerged as a research focus in the epidemiology of chronic diseases of aging, such as heart disease and diabetes. The "fetal origins" literature has demonstrated that hormonal and nutritional aspects of the intrauterine environment not only affect fetal growth but also can permanently alter the metabolic program of the individual. Smaller infants tend to have a higher risk of developing cardiovascular disease. Much less attention has been paid to possible genetic links between the processes of early growth and later disease. Our aim in this review is to summarize evidence for one such genetic mechanism, telomere attrition, that may underlie the fetal origins of cardiovascular disease and to discuss this mechanism in light of the evolution of senescence.
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Biddle SJ, Marshall SJ, Gorely PJ, Cameron N, Murdey I. SEDENTARY BEHAVIORS, BODY FATNESS AND PHYSICAL ACTIVITY IN YOUTH. Med Sci Sports Exerc 2003. [DOI: 10.1097/00005768-200305001-00987] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cameron N. Human growth, nutrition, and health status in Sub-Saharan Africa. YEARBOOK OF PHYSICAL ANTHROPOLOGY 2002; 34:211-50. [PMID: 12343663 DOI: 10.1002/ajpa.1330340611] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wright CM, Booth IW, Buckler JMH, Cameron N, Cole TJ, Healy MJR, Hulse JA, Preece MA, Reilly JJ, Williams AF. Growth reference charts for use in the United Kingdom. Arch Dis Child 2002; 86:11-4. [PMID: 11806873 PMCID: PMC1719041 DOI: 10.1136/adc.86.1.11] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Since the introduction of new growth charts in the mid 1990s, there has been confusion about which charts should be used, with many districts using more than one version. Because of this uncertainty, an expert working party, the Growth Reference Review Group, was convened by the Royal College of Paediatrics and Child Health to provide guidance on the validity and comparability of the different charts currently in use. This paper describes the technical background to the construction and evaluation of growth charts and outlines the group's findings on the validity of each growth reference in relation to contemporary British children. The group concluded that for most clinical purposes the UK90 reference is superior and for many measures is the only usable reference that can be recommended, while the original Tanner-Whitehouse and the Gairdner-Pearson charts are no longer reliable for use at any age. After the age of 2 the revised Buckler-Tanner references are still suitable for assessing height. There are presently no reliable head circumference reference charts for use beyond infancy. The group propose that apart from refinements of chart design and layout, the new UK90 reference should now be "frozen", with any future revisions only undertaken after careful planning and widespread consultation.
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Cameron N. British growth charts for height and weight with recommendations concerning their use in auxological assessment. Ann Hum Biol 2002; 29:1-10. [PMID: 11822481 DOI: 10.1080/03014460110057990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PRIMARY OBJECTIVE To review the appropriateness of current British growth charts for height and weight. METHODS AND PROCEDURES A review of their structure and function in the context of the problems posed by (1) secular trends for increasing size, (2) the external validity of source samples, (3) differences in the design and application of cross-sectional and longitudinal charts, and (4) the clinical significance of differences between current charts. MAIN OUTCOMES AND RESULTS Charts pre-dating the Freeman et al. 1995 and the Buckler-Tanner 1995 charts should be considered obsolete for the purposes of growth assessment on a sample or individual basis. Either the Freeman or the Buckler-Tanner chart is suitable for screening, surveillance or monitoring prior to adolescence but the Freeman chart is recommended for screening and surveillance of samples of children throughout childhood and adolescence. When comprehensive growth and development data are available it is advantageous to use the Buckler-Tanner chart during adolescence for the diagnosis and monitoring of individual children.
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Lejarraga H, Pascucci MC, Krupitzky S, Kelmansky D, Bianco A, Martínez E, Tibaldi F, Cameron N. Psychomotor development in Argentinean children aged 0-5 years. Paediatr Perinat Epidemiol 2002; 16:47-60. [PMID: 11856454 DOI: 10.1046/j.1365-3016.2002.00388.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Argentina, there is no information on ages of attainment of developmental milestones and very few data about environmental factors that influence them. A national survey on the psychomotor development of children under 6 years of age was carried out with the help of 129 paediatricians. Logistic regression was applied to a final sample of 3573 healthy, normal children in order to estimate selected centiles (25th, 50th, 75th and 90th), together with their respective confidence intervals, of the ages of attainment of 78 developmental items belonging to the following areas: personal-social (18 items), fine motor (19), language (18) and gross motor (23). The 50th centile obtained for each of the 43 comparable items was compared with those obtained in previously standardised tests: DDST, Denver II, Bayley and Chilean scales. Neither significant nor systematic differences were found between our results and those described in the tests used for comparison. Multiple logistic regressions showed that social class, maternal education and sex (female) were associated with earlier attainment of some selected developmental items, achieved at ages later than 1 year. Selected items achieved before the first year of life were not affected by any of the independent environmental variables studied. The information is useful in helping paediatricians in their daily practice for surveillance of development, as baseline information for epidemiological studies on development in our country and for cross-cultural analysis.
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Abstract
OBJECTIVE To determine the accuracy of recalled height and weight, and calculated body mass index (BMI), over a 27-37 y period. DESIGN Comparison of measured height and weight with recalled height and weight 27-37 y later. PARTICIPANTS Two hundred and twenty-five men measured aged 18-24 y as physical education students at Loughborough Training College, UK, between 1958 and 1967. RESULTS Initial body weights were over-estimated by 3.1 +/- 4.5 kg and heights by 1.1 +/- 1.8 cm, on average. Some 42% (95) of recalls were within 2.5 kg and 79% (178) within 2.5 cm, resulting in 58% (130) of the differences in BMI calculated from recalled and actual heights and weights to be within 1 kg/m2. However, 29% (66) of recalls were more than 5 kg and 8% (19) more than 10 kg from the measured values. Weight errors (actual-recalled) were negatively related (r = -0.43, P < 0.001) to weight gain over the 27-37 y interval. CONCLUSIONS Middle-aged men who were formerly physical education students recalled their previous height and weight well, in most cases, 27-37 y later. The bias from recalled data would be to underestimate weight gain by 3 kg and BMI by 1 kg/m2, on average. Errors of more than 5 kg in 29% of participants and of more than 10 kg in 8% would be expected to interfere seriously with attempts to show epidemiological relations between early weight based on recall and subsequent outcomes.
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Crowther NJ, Trusler J, Cameron N, Toman M, Gray IP. Relation between weight gain and beta-cell secretory activity and non-esterified fatty acid production in 7-year-old African children: results from the Birth to Ten study. Diabetologia 2000; 43:978-85. [PMID: 10990074 DOI: 10.1007/s001250051479] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
AIMS/HYPOTHESIS This study aimed to assess the effects of fetal and childhood growth on beta-cell activity and insulin sensitivity in 7-year-old children. METHODS Insulin, des-31,32 proinsulin, proinsulin, non-esterified fatty acids and glucose concentrations were measured in oral glucose tolerance tests in 152 South African children for whom longitudinal weight data was available. RESULTS Children with low weights at birth and 7 years (low-low) had relatively low beta-cell activity whereas children with low birth weight and high weight at 7 years (low-high) had relatively high beta-cell activity. The low-low group had higher 30-min glucose concentrations than children with high birth weights. When each insulin-related peptide was expressed as a percentage of all these peptides the low-low children had the highest percentage of insulin but the lowest of the prohormones. The low-high children had the lowest percentage of insulin but the highest of the prohormones. Non-esterified fatty acid concentrations were lowest and their suppression post-glucose load highest in the low-high group. CONCLUSION/INTERPRETATION Poor fetal and neonatal growth give rise to low beta-cell numbers compensated for by increased efficiency of proinsulin processing to insulin. Poor fetal followed by higher postnatal growth results in low beta-cell numbers and reduced whole-body glucose uptake which leads to reduced efficiency in the processing of proinsulin. Growth in utero and postnatally therefore have profound effects on beta-cell activity and insulin sensitivity with poor fetal coupled with high postnatal growth being detrimental to these processes but not detrimental to the suppression of lipolysis.
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Steyn K, de Wet T, Richter L, Cameron N, Levitt NS, Morrell C. Cardiovascular disease risk factors in 5-year-old urban South African children--the Birth to Ten Study. S Afr Med J 2000; 90:719-26. [PMID: 10985136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND A birth cohort study, the Birth to Ten (BTT) study, commenced in the greater Johannesburg/Soweto metropole in South Africa in 1990. The overall BTT project collected antenatal, birth and early development information on these children as well as information that could help identify factors related to the emergence of risk of cardiovascular diseases (CVDs) in children. OBJECTIVE To determine CVD risk profiles and their determinants in 5-year-old children living in an urban environment in South Africa. METHODS Demographic and birth characteristics were collected on a sample of 964 5-year-olds whose parents agreed for blood samples to be taken from their children. The children's height and weight were measured using standardised procedures; blood pressure (BP) was measured with a Dinamap Vital Signs Monitor, and a non-fasting blood sample was drawn for lipid determinations. Information on exposure to tobacco smoke and additional health-related data were obtained by interview. RESULTS No differences were found between the birth weight and gestational age of the 5-year-old CVD participants and the remainder of the children studied at birth. The systolic BP was significantly different between ethnic groups, with the BP of the black children significantly higher than that of the Indian and white children, while the diastolic BP of black children was also the highest. White children had the highest mean total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC) levels, significantly higher than those in the black community. The coloured children's TC level was also significantly lower than that of the whites, while the LDLC level of the Indian children was significantly higher than that of the blacks. Overall, 64% of the children were exposed to environmental tobacco smoke (ETS), with the white group having the lowest rate (45% exposed to ETS). The coloured children were most frequently exposed to ETS, with 40.6% having primary caregivers who smoked; of these children 42% lived in homes with two or more smokers. CONCLUSIONS Tobacco control legislation will protect South Africans against tobacco sales promotions. This will be the first step towards increasing the priority of chronic disease prevention, health promotion and appropriate care for chronic diseases and their risk factors on the South African health policy agenda. The groups of children that were studied carried differing but significant levels of CVD risk. This suggests that the promotion of a healthy lifestyle should start in childhood, and should target the risk factors found in each group.
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