Childhood Head Growth and Educational Attainment in an Indian Cohort.

BACKGROUND: There is minimal information about the association of head growth at different stages of childhood with cognitive ability. OBJECTIVE: To determine the relationship of newborn head size and head growth during infancy, childhood and adolescence with attained education, a proxy for cognitive ability. STUDY DESIGN: Prospective birth cohort study. SETTING: Married women living in South Delhi between 1969 and 1973. PARTICIPANTS: The New Delhi Birth Cohort study followed up 8030 newborns born in 1969-1973 with head circumference, weight and height measurements at birth and 6-12 monthly until adulthood. Of these, 1526 men and women were followed up at the age of 26-32 years. OUTCOMES: Association between years of schooling, as an indicator of cognitive ability, and newborn head circumference and conditional measures of head growth during infancy, childhood and adolescence. RESULTS: In unadjusted analyses, newborn head size was positively associated with years of education [(b (95% CI)=0.30 (0.14 to 0.47) years per SD head circumference], as was head growth from birth to 6 months [b (95% CI)=0.44 (0.28 to 0.60) years per SD conditional head growth], 6 months to 2 years [b (95% CI)=0.31 (0.15 to 0.47) years per SD conditional head growth] and 2 to 11 years [b (95% CI)=0.20 (0.03 to 0.36) years per SD conditional head growth]. There were similar findings for height and body mass index (BMI). In the adjusted model containing all growth measures, gestational age, and socio-economic status (SES) at birth as predictors, only SES was positively associated with educational attainment. CONCLUSION: Educational attainment in this population is positively associated with socioeconomic status and its influence on inter-related early life (fetal, infant and childhood) factors like nutritional status and brain growth.

Comparison of regional fat measurements by dual-energy X-ray absorptiometry and conventional anthropometry and their association with markers of diabetes and cardiovascular disease risk.

BACKGROUND/OBJECTIVES: Fat distribution is a strong and independent predictor of type 2 diabetes (T2D) and cardiovascular disease (CVD) and is usually determined using conventional anthropometry in epidemiological studies. Dual-energy X-ray absorptiometry (DXA) can measure total and regional adiposity more accurately. Nonetheless, whether DXA provides more precise estimates of cardiovascular risk in relation to total and regional adiposity is not known. We determined the strength of the associations between DXA- and conventional anthropometry determined fat distribution and T2D and CVD risk markers. SUBJECTS/METHODS: Waist (WC) and hip circumference (HC) and DXA was used to measure total and regional adiposity in 4950 (2119 men) participants aged 29-55 years from the Oxford Biobank without pre-existing T2D or CVD. Cross-sectional associations were compared between WC and HC vs. DXA-determined regional adiposity (all z-score normalised) with impaired fasting glucose, hypertriglyceridemia, hypertension and insulin resistance (IR). RESULTS: Following adjustment for total adiposity, upper body adiposity measurements showed consistently increased risk of T2D and CVD risk markers except for abdominal subcutaneous fat in both sexes, and arm fat in men, which showed protective associations. Among upper adiposity depots, visceral fat mass showed stronger odds ratios (OR) ranging from 1.69 to 3.64 compared with WC 1.07-1.83. Among lower adiposity depots, HC showed modest protection for IR in both sexes (men: OR 0.80 (95% confidence interval 0.67, 0.96); women: 0.69 (0.56, 0.86)), whereas gynoid fat and in particular leg fat showed consistent and strong protective effects for all outcomes in both men and women. The differential effect of body fat distribution on CVD and T2D were more pronounced at higher levels of total adiposity. CONCLUSIONS: Compared with DXA, conventional anthropometry underestimates the associations of regional adiposity with T2D and CVD risk markers. After correcting for overall adiposity, greater subcutaneous fat mass in particular in the lower body is protective relative to greater android or visceral adipose tissue mass.

Body size and body composition: a comparison of children in India and the UK through infancy and early childhood.

BACKGROUND: Indian babies are characterised by the 'thin-fat phenotype' which comprises a 'muscle-thin but adipose' body composition compared with European babies. This body phenotype is of concern because it is associated with an increased risk of diabetes and cardiovascular disease. We examined whether the 'thin-fat phenotype' persists through early childhood, comparing Indian children with white Caucasians in the UK at birth, infancy and childhood, using comparable measurement protocols. METHODS: We used data from two cohorts, the Pune Maternal Nutrition Study (N=631) and the Southampton Women's Survey (N=2643). Measurements of weight, head circumference, mid-upper arm circumference, height, triceps and subscapular skinfold thickness were compared at birth, 1, 2, 3 and 6 years of age. SD scores were generated for the Pune children, using the Southampton children as a reference. Generalised estimating equations were used to examine the changes in SD scores across the children's ages. RESULTS: The Indian children were smaller at birth in all body measurements than the Southampton children and became relatively even smaller from birth to 2 years, before 'catching up' to some extent at 3 years, and more so by 6 years. The deficit for both skinfolds was markedly less than for other measurements at all ages; triceps skinfold showed the least difference between the two cohorts at birth, and subscapular skinfold at all ages after birth. CONCLUSIONS: The 'thin-fat phenotype' previously found in Indian newborns, remains through infancy and early childhood. Despite being shorter and lighter than UK children, Indian children are relatively adipose.

Parental childhood growth and offspring birthweight: pooled analyses from four birth cohorts in low and middle income countries.

OBJECTIVE: Associations between parental and offspring size at birth are well established, but the relative importance of parental growth at different ages as predictors of offspring birthweight is less certain. Here we model parental birthweight and postnatal conditional growth in specific age periods as predictors of offspring birthweight. METHODS: We analyzed data from 3,392 adults participating in four prospective birth cohorts and 5,506 of their offspring. RESULTS: There was no significant heterogeneity by study site or offspring sex. 1SD increase in maternal birthweight was associated with offspring birthweight increases of 102 g, 1SD in maternal length growth 0-2 year with 46 g, and 1SD in maternal height growth Mid-childhood (MC)-adulthood with 27 g. Maternal relative weight measures were associated with 24 g offspring birth weight increases (2 year- MC) and 49 g for MC-adulthood period but not with earlier relative weight 0-2 year. For fathers, birthweight, and linear/length growth from 0-2 year were associated with increases of 57 and 56 g in offspring birthweight, respectively but not thereafter. CONCLUSIONS: Maternal and paternal birthweight and growth from birth to 2 year each predict offspring birthweight. Maternal growth from MC-adulthood, relative weight from 2-MC and MC-adulthood also predict offspring birthweight. These findings suggest that shared genes and/or adequate nutrition during early life for both parents may confer benefits to the next generation, and highlight the importance of maternal height and weight prior to conception. The stronger matrilineal than patrilineal relationships with offspring birth weight are consistent with the hypothesis that improving the early growth conditions of young females can improve birth outcomes in the next generation.

Associations of infant feeding and timing of linear growth and relative weight gain during early life with childhood body composition.

BACKGROUND: Growth and feeding during infancy have been associated with later life body mass index. However, the associations of infant feeding, linear growth and weight gain relative to linear growth with separate components of body composition remain unclear. METHODS: Of 5551 children with collected growth and infant-feeding data in a prospective cohort study (Amsterdam Born Children and their Development), body composition measured using bioelectrical impedance analysis at the age of 5-6 years was available for 2227 children. We assessed how feeding (duration of full breastfeeding and timing of introduction of complementary feeding) and conditional variables representing linear growth and relative weight gain were associated with childhood fat-free mass (FFM) and fat mass (FM). RESULTS: Birth weight was positively associated with both FFM and FM in childhood, and more strongly with FFM than FM. Faster linear growth and faster relative weight gain at all ages in infancy were positively associated with childhood FFM and FM. The associations with FM were stronger for relative weight gain than for linear growth (FM z score: ß coefficient 0.23 (95% con 0.19 to 0.26), P<0.001 and 0.14 (0.11 to 0.17), P<0.001 per s.d. change in relative weight gain and linear growth between 1 and 3 months, respectively). Compared with full breastfeeding <1 month, full breastfeeding >6 months was associated with lower FM (FM z score: -0.17 (-0.28 to -0.05), P=0.005) and lower FFM (FFM z score: -0.13 (-0.23 to -0.03), P=0.015), as was the introduction of complementary feeding >6 months (FM z score: -0.22 (-0.38 to -0.07), P=0.004), compared with <4 months. CONCLUSIONS: Faster infant weight gain is associated with a healthier childhood body composition when it is caused by faster linear growth. Full breastfeeding >6 months and introduction of complementary feeding >6 months are associated with lower childhood FM.

Trier social stress test in Indian adolescents.

OBJECTIVE: To test the Trier Social Stress Test for children (TSST-C) in a cohort of Indian adolescents. DESIGN: Cohort study. SETTING: Holdsworth Memorial Hospital, Mysore, India. PARTICIPANTS: Adolescent children (N=273, 134 males; mean age 13.6 yrs) selected from an ongoing birth cohort; 269 completed the test. INTERVENTION: Performance of 5-minutes each of public- speaking and mental arithmetic tasks in front of two unfamiliar 'evaluators'. OUTCOME MEASURES: Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Continuous measurements of heart rate, finger blood pressure, stroke volume, cardiac output and systemic vascular resistance were carried out before, during and for 10 minutes after the TSST-C using a finger cuff. RESULTS: Cortisol concentrations [mean increment (SD): 6.1 (6.9) ng/mL], heart rate [4.6 (10.1) bpm], systolic [24.2 (11.6) mmHg] and diastolic blood pressure [16.5 (7.3) mmHg], cardiac output [0.6 (0.7) L/min], stroke volume [4.0 (5.6) mL] and systemic vascular resistance [225 (282) dyn.s/cm5] increased significantly (P<0.001) from baseline after inducing stress. CONCLUSIONS: The TSST-C produces stress responses in Indian adolescents of a sufficient magnitude to be a useful tool for examining stress physiology and its relationships to disease outcomes in this population.

Size at birth, morning cortisol and cardiometabolic risk markers in healthy Indian children.

OBJECTIVE: Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis may link reduced foetal growth with higher adult chronic disease risk. South Asians have a high prevalence of low birth weight and a thin-fat phenotype, which is associated with subsequent type 2 diabetes and the metabolic syndrome. Altered HPA activity could be one of the pathological processes underlying this link. METHODS: Plasma morning cortisol and corticosteroid-binding globulin (CBG) concentrations were determined in 528 children aged 9·5 years from a prospective birth cohort in India. They had detailed anthropometry at birth, and current measurements of anthropometry, plasma glucose, insulin and lipid concentrations and blood pressure. Insulin resistance (Homeostasis Model Assessment) and insulin secretion (the 30-min insulin increment) were also assessed. RESULTS: None of the birth measurements were associated with cortisol concentrations, but both birth weight (P = 0·03) and length (P = 0·004) were inversely associated with CBG concentrations. Cortisol concentrations were inversely associated with current body mass index (P = 0·02), and positively associated with glucose (fasting: P < 0·001; 30-min: P = 0·002) concentrations, and systolic blood pressure (P = 0·005), but not insulin resistance or the insulin increment. CONCLUSION: Higher morning cortisol is associated with higher cardiometabolic risk markers in Indian children. Although cortisol concentrations did not appear to be related to birth size, small size at birth was associated with higher CBG levels, and may be one of the processes by which foetal undernutrition affects adult health. The findings suggest a need for dynamic testing of HPA axis activity (such as measuring stress responses).

Growth from birth to adulthood and peak bone mass and density data from the New Delhi Birth Cohort.

UNLABELLED: Growth in early life may predict adult bone health. Our data showed that greater height and body mass index (BMI) gain in utero and infancy are associated with higher peak bone mass, and greater BMI gain in childhood/adolescence with higher peak bone density. These associations are mediated by attained adult height and BMI. INTRODUCTION: To study the relationship of height and BMI during childhood with adult bone mineral content (BMC), areal density (aBMD) and apparent density (BMAD, estimated volumetric density). METHODS: Participants comprised 565 men and women aged 33-39 years from the New Delhi Birth Cohort, India, whose weight and height were recorded at birth and annually during infancy (0-2 years), childhood (2-11 years) and adolescence (11 years-adult). Lumbar spine, femoral neck and forearm BMC and aBMD were measured using dual X-ray absorptiometry; lumbar spine and femoral neck BMAD were calculated. RESULTS: Birth length, and height and height gain during infancy, childhood and adolescence were positively correlated with adult BMC (p≤0.01 all sites except birth length with femoral neck). Correlations increased with height from birth to 6 years, then remained constant for later height measurements. There were no associations with BMAD. BMI at birth, and during childhood and adolescence was also positively correlated with BMC (p < 0.01 all sites). BMI at 11 years, and BMI gain in childhood and adolescence, were correlated with aBMD and BMAD (p < 0.001 for all); these correlations strengthened with increasing age of BMI measurement. The associations with height and BMI in early life became non-significant after adjustment for adult height and BMI. CONCLUSIONS: Greater skeletal growth and BMI gain in utero and during infancy are associated with higher peak BMC, and greater BMI gain in childhood and adolescence is associated with higher peak aBMD and BMAD. These associations are mediated by the attainment of adult height and BMI, respectively.

Birth size and physical activity in a cohort of Indian children aged 6-10 years.

There is evidence of a reduction in children's physical activity in India in the last decade. Our objective was to assess whether size and body composition at birth are associated with physical activity in school-aged children. Children from a prospective observational cohort study born in Mysore, South India between 1997 and 1998 (n = 663) had neonatal anthropometric measurements made within 72 h of delivery [weight, mid-upper arm circumference (MUAC), chest, abdomen and head circumference, crown-heel, crown-buttock and leg length, triceps and subscapular skinfolds]. At 6-10 years, children (n = 449) were asked to wear AM7164 or GT1M Actigraph accelerometers for 7 days. Body composition was measured within 6 months of activity monitoring. Arm muscle area at birth and time of activity monitoring was calculated from MUAC and skinfold measurements. Activity outcome measures were: mean accelerometer counts per minute (cpm); counts per day and proportion of time spent in moderate and vigorous activity. The mean (S.D.) number of days with ≥500 min of recorded accelerometer data was 7.0 (1.1). Linear regression models showed no significant associations between any of the neonatal anthropometric measures and the activity variables. Body fat percentage at 7.5 years was negatively associated with all activity variables (B = -4.69, CI: -7.31, -2.07 for mean cpm). In conclusion, this study showed no associations between body size and skinfold thickness at birth and objectively measured physical activity in childhood.

Association of genetic variation in FTO with risk of obesity and type 2 diabetes with data from 96,551 East and South Asians.

AIMS/HYPOTHESIS: FTO harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for FTO in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the FTO locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians. METHODS: All studies published on the association between FTO-rs9939609 (or proxy [r (2) > 0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes. RESULTS: The FTO-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (p = 9.0 × 10(-19)), overweight by 1.13-fold/allele (p = 1.0 × 10(-11)) and type 2 diabetes by 1.15-fold/allele (p = 5.5 × 10(-8)). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, p = 6.6 × 10(-5)). The FTO-rs9939609 minor allele increased BMI by 0.26 kg/m(2) per allele (p = 2.8 × 10(-17)), WHR by 0.003/allele (p = 1.2 × 10(-6)), and body fat percentage by 0.31%/allele (p = 0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12-20%) than South Asians (30-33%), the effect of FTO variation on obesity-related traits and type 2 diabetes was similar in the two populations. CONCLUSIONS/INTERPRETATION: FTO is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, FTO is also associated with type 2 diabetes independently of BMI.

Mother's lifetime nutrition and the size, shape and efficiency of the placenta.

BACKGROUND: Studies have shown that the shape and size of the placenta at birth predict blood pressure in later life. The influences that determine placental morphology are largely unknown. We have examined the role of mother's body size. METHODS: We studied 522 neonates who were born in a maternity hospital in Mysore, South India. The weight of the placenta and the length and breadth of its surface, were measured after delivery. RESULTS: Higher maternal fat mass predicted a larger placental surface (p = 0.02), while larger maternal head circumference predicted a more oval placental surface (p = 0.03). Higher maternal fat mass and larger maternal head circumference were associated with greater placental efficiency, indicated by lower ratios of the length (p = 0.0003 and p = 0.0001 respectively) and breadth (p = 0.0002 and p < 0.0001) of the surface to birthweight. In a sub-sample of 51 mothers whose own birthweight was available, higher maternal birthweight was related to lower ratios of the length and breadth of the surface to birthweight (p = 0.01 and 0.002). Maternal height was unrelated to placental size or shape. CONCLUSIONS: Higher maternal fat mass, reflecting the mother's current nutritional state, and larger maternal head circumference, reflecting the mother's fetal/infant growth, are associated with changes in the shape and size of the placental surface and greater placental efficiency. We suggest that these associations reflect effects of the mother's nutrition at different stages of her lifecourse on the development of the placenta and on materno-placento-fetal transfer of nutrients.

Prediction of body-fat percentage from skinfold and bio-impedance measurements in Indian school children.

BACKGROUND/OBJECTIVES: Few equations for calculating body-fat percentage (BF%) from field methods have been developed in South-Asian children. The objective of this study was to assess agreement between BF% derived from primary reference methods and that from skinfold equations and bio-impedance analysis (BIA) in Indian children. SUBJECTS/METHODS: We measured BF% in two groups of Indian children. In Pune, 570 rural children aged 6-8 years underwent dual-energy X-ray absorptiometry (DXA) scans. In Mysore (18)O in doubly labeled water was administered to 59 urban children aged 7-9 years. We conducted BIA at 50 kHz and anthropometry, including sub-scapular and triceps skinfold thicknesses. We used the published equations of Wickramasinghe, Shaikh, Slaughter and Dezenburg to calculate BF% from anthropometric data and the manufacturer's equation for BIA measurements. We assessed agreement with values derived from DXA and doubly labeled water using Bland-Altman analysis. RESULTS: Children were light and thin on average compared with international standards. There was poor agreement between the reference BF% values and those from all equations. Assumptions for Bland-Altman analysis were not met for Wickramasinghe, Shaikh and Slaughter equations. The Dezenberg equations under-predicted BF% for most children (mean difference in Pune -13.4, LOA -22.7, -4.0 and in Mysore -7.9, LOA (-13.7 and -2.2). The mean bias for the BIA equation in Pune was +5.0% and in Mysore +1.95%, and the limits of agreement were wide; -5.0, 15.0 and -7.8, 11.7 respectively. CONCLUSIONS: Currently available skinfold equations do not accurately predict BF% in Indian children. We recommend development of BIA equations in this population using a four-compartment model.

Glucose tolerance and insulin resistance in Indian children: relationship to infant feeding pattern.

AIMS/HYPOTHESIS: Our objective was to examine whether longer duration of breast-feeding and later introduction of complementary foods are associated with lower glucose concentrations and insulin resistance (IR-HOMA) in Indian children. METHODS: Breast-feeding duration (six categories from <3 to ≥18 months) and age at introduction of complementary foods (four categories from <4 to ≥6 months) were recorded at 1, 2 and 3 year follow-up of 568 children from a birth cohort in Mysore, India. At 5 and 9.5 years of age, 518 children were assessed for glucose tolerance and IR-HOMA. RESULTS: All the children were initially breast-fed; 90% were breast-fed for ≥6 months and 56.7% started complementary foods at or before the age of 4 months. Each category increase in breast-feeding duration was associated with lower fasting insulin concentration (ß = -0.05 pmol/l [95% CI -0.10, -0.004]; p = 0.03) and IR-HOMA (ß = -0.05 [95% CI -0.10, -0.001]; p = 0.046) at 5 years, adjusted for the child's sex, age, current BMI, socioeconomic status, parent's education, rural/urban residence, birthweight and maternal gestational diabetes status. Longer duration of breastfeeding was associated with higher 120-min glucose concentration at 5 years (ß = 0.08 mmol/l [95% CI 0.001, 0.15; p = 0.03]) but lower 120-min glucose concentration at 9.5 years (ß = -0.09 [95% CI -0.16, -0.03]; p = 0.006). Age at starting complementary foods was unrelated to the children's glucose tolerance and IR-HOMA. CONCLUSIONS/INTERPRETATION: Within this cohort, in which prolonged breast-feeding was the norm, there was evidence of a protective effect of longer duration of breast-feeding against glucose intolerance at 9.5 years. At 5 years longer duration of breast-feeding was associated with lower IR-HOMA.

Childhood cognitive ability: relationship to gestational diabetes mellitus in India.

AIMS/HYPOTHESIS: Our aim was to test the hypothesis that gestational diabetes mellitus (GDM) in mothers is associated with poorer cognitive ability in their offspring in India. METHODS: During 1997 to 1998 maternal GDM status was assessed by OGTT at 30 +/- 2 weeks of gestation. Between 2007 and 2008, at a mean age of 9.7 years, 515 children (32 offspring of GDM mothers [ODM]; 483 offspring of non-GDM mothers [controls]) from the Mysore Parthenon birth cohort underwent cognitive function assessment using tests from the Kaufman Assessment Battery for Children--Second Edition and additional tests measuring learning, long-term storage/retrieval, short-term memory, reasoning, attention and concentration, and visuo-spatial and verbal abilities. RESULTS: Compared with controls, ODM scored higher in tests for learning, long-term retrieval/storage (p = 0.008), reasoning (p = 0.02), verbal ability (p = 0.01), and attention and concentration (p = 0.003). In multiple regression, adjusted for the child's age, sex, gestation, neonatal weight and head circumference, maternal age, parity and BMI, and the parent's socioeconomic status, education and rural/urban residence, this difference remained significant only for learning, long-term retrieval/storage (beta = 0.4 SD (95% CI 0.01-0.75); p = 0.04) and verbal ability (beta = 0.5 SD (95% CI 0.09-0.83); p = 0.02), and not with other test scores. CONCLUSIONS/INTERPRETATION: In this population of healthy Indian children, there was no evidence of lower cognitive ability in ODM. In fact some cognitive scores were higher in ODM.

Adiposity, insulin resistance and cardiovascular risk factors in 9-10-year-old Indian children: relationships with birth size and postnatal growth.

Lower birthweight, and rapid childhood weight gain predict elevated cardiovascular risk factors in children. We examined associations between serial, detailed, anthropometric measurements from birth to 9.5 years of age and cardiovascular risk markers in Indian children. Children (n = 663) born at the Holdsworth Memorial Hospital, Mysore, India were measured at birth and 6-12 monthly thereafter. At 9.5 years, 539 (255 boys) underwent a 2-h oral glucose tolerance test, and blood pressure (BP) and fasting lipid concentrations were measured. Insulin resistance was calculated using the HOMA equation. These outcomes were examined in relation to birth measurements and changes in measurements (growth) during infancy (0-2 years), 2-5 years and 5-9.5 years using conditional s.d. scores. Larger current weight, height and skinfold thickness were associated with higher risk markers at 9.5 years (P < 0.05). Lower weight, smaller length and mid-arm circumference at birth were associated with higher fasting glucose concentrations at 9.5 years (P ⩽ 0.01). After adjusting for current weight/height, there were inverse associations between birthweight and/or length and insulin concentrations, HOMA, systolic and diastolic BP and plasma triglycerides (P < 0.05). Increases in conditional weight and height between 0-2, 2-5 and 5-9.5 years were associated with higher insulin concentrations, HOMA and systolic BP. In conclusion, in 9-10-year-old Indian children, as in other studies, cardiovascular risk factors were highest in children who were light or short at birth but heavy or tall at 9 years. Greater infant and childhood weight and height gain were associated with higher risk markers.

The relationship of birthweight, muscle size at birth and post-natal growth to grip strength in 9-year-old Indian children: findings from the Mysore Parthenon study.

Foetal development may permanently affect muscle function. Indian newborns have a low mean birthweight, predominantly due to low lean tissue and muscle mass. We aimed to examine the relationship of birthweight, and arm muscle area (AMA) at birth and post-natal growth to handgrip strength in Indian children. Grip strength was measured in 574 children aged 9 years, who had detailed anthropometry at birth and every 6-12 months post-natally. Mean (standard deviation (s.d.)) birthweight was 2863 (446) g. At 9 years, the children were short (mean height s.d. -0.6) and light (mean weight s.d. -1.1) compared with the World Health Organization growth reference. Mean (s.d.) grip strength was 12.7 (2.2) kg (boys) and 11.0 (2.0) kg (girls). Weight, length and AMA at birth, but not skinfold measurements at birth, were positively related to 9-year grip strength (ß = 0.40 kg/s.d. increase in birthweight, P < 0.001; and ß = 0.41 kg/s.d. increase in AMA, P < 0.001). Grip strength was positively related to 9-year height, body mass index and AMA and to gains in these measurements from birth to 2 years, 2-5 years and 5-9 years (P < 0.001 for all). The associations between birth size and grip strength were attenuated but remained statistically significant for AMA after adjusting for 9-year size. We conclude that larger overall size and muscle mass at birth are associated with greater muscle strength in childhood, and that this is mediated mainly through greater post-natal size. Poorer muscle development in utero is associated with reduced childhood muscle strength.

Relationship between physical activity measured using accelerometers and energy expenditure measured using doubly labelled water in Indian children.

BACKGROUND/OBJECTIVES: To test the association between physical activity measured using accelerometer counts (Actigraph) and energy expenditure (EE) measured using the doubly labelled water (DLW) method in free-living children in India. The aim of this study was to explore the usefulness of Actigraphs in estimating EE. SUBJECTS/METHODS: Total EE (TEE) was measured in 58 children aged 8-9 years over a period of 2 weeks using the DLW technique. Physical activity level (PAL) was estimated from TEE, and the basal metabolic rate was predicted from weight. Physical activity was measured simultaneously using the Actigraph accelerometers (MTI AM7164 and GT1M). TEE was also calculated from the Actigraph counts using a published equation. RESULTS: TEE (mean: 6.6 vs 5.7 MJ, P=0.04) and Actigraph counts (counts/minute: 557 vs 465, P=0.02; total counts: 445 534 vs 354 748, P=0.004) were higher in boys than in girls. There were no significant correlations between either total Actigraph counts (r=0.15, P=0.3) or counts/minute (r=0.18, P=0.2), and TEE estimated using DLW. Similarly, there were no significant correlations between Actigraph counts and PAL (r=0.10, P=0.5; r=0.17, P=0.2, respectively). The Bland-Altman analysis showed poor agreement between TEE estimated using the DLW method and TEE derived from the Actigraph equation. CONCLUSIONS: Activity measured using Actigraph accelerometers was not related to TEE and PAL derived using the DLW technique in children in Mysore. Actigraphs may not be useful in predicting EE in this setting, but may be better used for judging activity patterns.