Using SITAR (SuperImposition by Translation and Rotation) to estimate age at peak height velocity in Avon Longitudinal Study of Parents and Children

Cross-sectional associations between physical activity and sedentary time with cardiovascular health in children from the ALSPAC study using compositional data analysis

This study adopted a compositional framework to cross-sectionally examine the associations between physical activity (PA) and sedentary time (ST) with vascular structure and function and clustered cardiovascular disease (CVD) risk factors in 4277 children (2,226 girls), aged 10.6±0.2 years. Cardiovascular outcomes included flow mediated dilation, distensibility coefficient, pulse wave velocity and a clustered CVD risk factor score. Time spent in light PA (LPA) and moderate to vigorous PA (MVPA) and ST were determined using accelerometers. Multiple linear regression analyses were adjusted for key covariates with LPA, MVPA and ST entered as compositional exposure variables. Neither LPA, MVPA or ST were significantly associated with the vascular outcomes. The proportion of time spent in MVPA and ST were inversely (unstandardised b=-0.126; P=0.001) and positively (b=0.136; P=0.016) associated with clustered CVD risk in the whole group analysis, respectively. MVPA was negatively associated with clustered CVD risk in boys (b=-0.144; P=0.011) and girls (b=-0.110; P=0.032). Only girls had a positive association between ST and clustered CVD risk (b=0.199; P=0.005). Although no associations were observed for PA and ST with vascular outcomes, these data provide further support for interventions that promote MVPA and minimise ST for reducing risk factors for CVD in children.

Accelerometer-based sedentary time, light physical activity, and moderate-to-vigorous physical activity from childhood with arterial stiffness and carotid IMT progression: A 13-year longitudinal study of 1339 children

AIMS

We examined the longitudinal associations of sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous PA (MVPA) from childhood with carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness and carotid intima-media thickness (cIMT).

METHODS

We studied 1339 children, aged 11 years from Avon Longitudinal Study of Parents and Children, UK, followed up for 13 years. Accelerometer-based ST, LPA, and MVPA were assessed at ages 11, 15, and 24 years clinic visits. cfPWV and cIMT were measured with Vicorder and ultrasound, respectively, at ages 17 and 24 years.

RESULTS

Among 1339 [56.4% female] participants, mean ST increased from ages 11 through 24 years, while mean LPA and MVPA decreased. Persistently high ST tertile from childhood was associated with increased cfPWV progression, effect estimate 0.047 m/s; [(95% CI 0.005 to 0.090); p = 0.030], but not cIMT progression. Persistently high LPA tertile category was associated with decreased cfPWV progression in males -0.022 m/s; [(-0.028 to -0.017); p < 0.001] and females -0.027 m/s; [(-0.044 to -0.010); p < 0.001]. Cumulative LPA exposure decreased the odds of progressively worsening cfPWV [Odds ratio 0.994 (0.994-0.995); p < 0.0001] and cIMT. Persistent exposure to ≥60 min/day of MVPA was paradoxically associated with increased cfPWV progression in males 0.053 m/s; [(0.030 to 0.077); p < 0.001] and females 0.012 m/s; [(0.002 to 0.022); p = 0.016]. Persistent exposure to ≥60 min/day of MVPA was inversely associated with cIMT progression in females -0.017 mm; [(-0.026 to -0.009); p < 0.001].

CONCLUSION

LPA >3 h/day from childhood may attenuate progressively worsening vascular damage associated with increased ST in youth.

Mediating effect of fat mass, lean mass, blood pressure and insulin resistance on the associations of accelerometer-based sedentary time and physical activity with arterial stiffness, carotid IMT and carotid elasticity in 1574 adolescents

This study examined the mediating effect of total body fat mass, lean mass, blood pressure (BP) and insulin resistance on the associations of sedentary time (ST), light physical activity (LPA) and moderate-to-vigorous PA (MVPA) with carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT) and carotid elasticity in 1574 adolescents from the Avon Longitudinal Study of Parents and Children birth cohort, UK. ST, LPA and MVPA were assessed with ActiGraph accelerometer. ST and LPA were sex-categorised in tertiles as low (reference), moderate and high, while MVPA was categorised as <40 min/day (reference), 40-<60 min/day and ≥60 min/day. cfPWV, cIMT and carotid elasticity were measured with Vicorder and ultrasound. Fat mass and lean mass were assessed with dual-energy X-ray absorptiometry and homeostatic model assessment of insulin resistance (HOMA-IR) was computed. Mediation analyses structural equation models and linear mixed-effect models adjusted for cardiometabolic and lifestyle factors were conducted. Among 1574 adolescents [56.2% female; mean (SD) age 15.4 (0.24) years], 41% males and 17% females accumulated ≥60 min/day of MVPA. Higher ST was associated with lower cIMT partly mediated by lean mass. Higher LPA (standardized β = -0.057; [95% CI -0.101 to -0.013; p = 0.014]) and the highest LPA tertile were associated with lower cfPWV. BP had no significant mediating effect movement behaviour relations with vascular indices. Lean mass partially mediated associations of higher MVPA with higher cIMT (0.012; [0.007-0.002; p = 0.001], 25.5% mediation) and higher carotid elasticity (0.025; [0.014-0.039; p = 0.001], 28.1% mediation). HOMA-IR mediated the associations of higher MVPA with higher carotid elasticity (7.7% mediation). Engaging in ≥60 min/day of MVPA was associated with higher carotid elasticity. In conclusion, higher LPA was associated with lower arterial stiffness, but higher MVPA was associated with thicker carotid wall explained by higher lean mass.

Measures of puberty in the Avon Longitudinal Study of Parents and Children (ALSPAC) offspring cohort

Background

When studying the development of children through the preteen years into adolescence, it is often important to link features of their physical and mental health to the stage of puberty at the time. This is complex since individuals vary substantially in the ages at which they reach different pubertal milestones.

Methods

The Avon Longitudinal Study of Parents and Children (ALSPAC) is an ongoing longitudinal cohort study based in southwest England that recruited over 14000 women in pregnancy, with expected dates of delivery between April 1991 and December 1992. From 1999, information on puberty was collected using a number of different methods : (a) A series of annual questionnaires were administered when the index children were aged between eight and 17 years; these were mainly concerned with the physical changes associated with puberty; (b) identification of the age at peak height growth using the SITAR methodology; and (c) retrospective information from the girls on their age at onset of menstruation (menarche).

Results

The advantages and disadvantages of each method are discussed.

Conclusions

The data are available for analysis by interested researchers.

Effects of accelerometer-based sedentary time and physical activity on DEXA-measured fat mass in 6059 children

Globally, childhood obesity is on the rise and the effect of objectively measured movement behaviour on body composition remains unclear. Longitudinal and causal mediation relationships of accelerometer-based sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with dual-energy X-ray absorptiometry-measured fat mass were examined in 6059 children aged 11 years followed-up until age 24 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort. Over 13-year follow-up, each minute/day of ST was associated with 1.3 g increase in fat mass. However, each minute/day of LPA was associated with 3.6 g decrease in fat mass and each minute/day of MVPA was associated with 1.3 g decrease in fat mass. Persistently accruing ≥60 min/day of MVPA was associated with 2.8 g decrease in fat mass per each minute/day of MVPA, partly mediated by decrease insulin and low-density lipoprotein cholesterol. LPA elicited similar and potentially stronger fat mass-lowering effect than MVPA and thus may be targeted in obesity and ST prevention in children and adolescents, who are unable or unwilling to exercise.

Associations of accelerometer-based sedentary time, light physical activity and moderate-to-vigorous physical activity with resting cardiac structure and function in adolescents according to sex, fat mass, lean mass, BMI, and hypertensive status

BACKGROUND

This study examined the independent relationships of device-based measured sedentary time (ST) and physical activity (PA) in relation to cardiac structural and functional geometry among adolescents.

METHODS

From the Avon Longitudinal Study of Parents and Children, UK birth cohort, 530 (50% female) adolescents aged 17 years had complete ST, PA, cardiac, and covariate measures. Echocardiography cardiac measures were left ventricular mass indexed for height2.7 (LVMI2.7 ), relative wall thickness, LV diastolic function (LVDF), and LV filling pressure (LVFP). Overweight/obesity and elevated systolic/BP hypertension were categorized as body mass index >24.99 kg/m2 and ≥130 mmHg, respectively. Data were analyzed with linear regression models adjusting for cardiometabolic factors and lifestyle factors.

RESULTS

The prevalence of overweight/obesity in males and females was 17.9% and 24.5%, respectively. The prevalence of elevated systolic BP/hypertension was 11.6% in males and 1.1% among females. The average ST was 484 ± 78 min/day, light PA was 274 ± 62 min/day, and moderate-to-vigorous PA (MVPA) was 41 ± 24 min/day, among females. Average ST, LPA, and MVPA were 468 ± 87 min/day, 293 ± 70 min/day, and 56 ± 30 min/day, respectively, among males. Higher ST was associated with higher LVMI2.7 (standardized β = 0.16; p = 0.01) among females, but higher ST was associated with lower LVDF in males (β = -0.14; p = 0.04). Higher ST and MVPA were associated with higher LVMI2.7 in the total cohort, normal weight, and overweight/obese adolescents. Light PA was associated with higher LVDF in the total cohort and normotensives and lower LVFP among adolescents with high lean mass.

CONCLUSIONS

Higher ST and MVPA were associated with higher LVMI; however, ST-associated LVMI increase was threefold higher than MVPA-associated LVMI increase. Higher LPA was associated with better cardiac function. Reducing ST and increasing LPA may attenuate the risk of altered cardiac structure and function in adolescents.

Cumulative insulin resistance and hyperglycemia with arterial stiffness and carotid IMT progression in 1,779 adolescents: a 9-yr longitudinal cohort study

In pediatric population with diabetes and obesity, insulin resistance (HOMA-IR) has been associated with worsening vascular outcomes, however, the cumulative role of HOMA-IR, hyperglycemia, and hyperinsulinemia on repeatedly measured vascular outcomes in asymptomatic youth is unknown. We examined the longitudinal associations of fasting glucose, insulin, and HOMA-IR with carotid-femoral pulse wave velocity (cfPWV) and carotid intima-media thickness (cIMT). From the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, UK 1,779, 15-yr-old participants were followed up for 9 yr. Glucose, insulin, and HOMA-IR assessed at 15, 17, and 24 yr and sex-specifically dichotomized as ≥75th percentile, indicating high category and <75th percentile as reference. cfPWV and cIMT were measured at ages 17 and 24 yr. Associations were examined using linear mixed-effect models adjusted for cardiometabolic and lifestyle covariates. Among 1,779 participants [49.9% female], glucose, insulin, and HOMA-IR had a J- or U-shaped increase from ages 15 through 24 yr. The cumulative exposures to hyperinsulinemia effect estimate -0.019 mU/L; [95% CI -0.019 to -0.002; P = 0.033] and high HOMA-IR: -0.021; [-0.039 to -0.004; P = 0.019] from 15 to 24 yr of age were negatively associated with the 7-yr cfPWV progression. Only cumulative hyperinsulinemia and high HOMA-IR from ages 15 to 17 yr but not from ages 17 to 24 yr was associated with decreased cfPWV progression. There were no associations between cumulative hyperglycemia and cfPWV or cIMT progression. Hyperinsulinemia and HOMA-IR were not associated with cIMT progression. In conclusion, late adolescence may be an optimal timing for intervention targeted at sustaining the protective effect of the decline of insulin and insulin resistance on arterial stiffness progression.NEW & NOTEWORTHY Fasting plasma glucose, insulin, and insulin resistance had a J- or U-shaped increase from 15 to 24 yr with the base of the curve at age 17 yr. Cumulative high insulin and high insulin resistance from 15 to 24 yr were negatively associated with arterial stiffness progression from ages 17 to 24 yr. Age 17 yr may be an optimal timing for intervention targeted at sustaining the protective effect of the decline of insulin and insulin resistance on arterial stiffness progression.

Cumulative dyslipidemia with arterial stiffness and carotid IMT progression in asymptomatic adolescents: A simulated intervention longitudinal study using temporal inverse allocation model

BACKGROUND AND AIMS

We aimed to examine the longitudinal associations of total cholesterol (TC), non-high-density lipoprotein cholesterol (non-HDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride, and low-density lipoprotein cholesterol (LDL-C) with carotid-femoral pulse wave velocity (cfPWV) and carotid intima-media thickness (cIMT) progression.

METHODS

We studied 1779, 15-year-old participants from the Avon Longitudinal Study of Parents and Children, UK birth cohort, followed up for 9 years. Fasting TC, non-HDL-C, HDL-C, triglyceride, and LDL-C were measured at 15, 17, and 24 years and age-categorized as normal, elevated, and dyslipidemia based on National Heart, Lung, and Blood Institute lipid guidelines. cfPWV and cIMT were measured at 17 and 24 years. Associations were examined using linear mixed-effect models. To simulate the treatment of dyslipidemia we conducted temporal inverse allocation model analyses.

RESULTS

Among 1779 [49.9% female] participants, mean lipid levels and proportions at elevated or dyslipidemia categories increased from ages 15 through 24 years. Persistently elevated TC: effect estimate 0.026 mm; [95% CI 0.004 to 0.049; p = 0.024], elevated non-HDL-C, and elevated LDL-C were cumulatively associated with cIMT progression. Persistent borderline-low HDL-C: -0.027 mm; [-0.050 to -0.005; p = 0.019] and very-low HDL-C -0.035 mm; [-0.057 to -0.013; p = 0.002] levels were associated with cIMT progression. A temporal inverse allocation of elevated and dyslipidemic levels with normal lipid levels at age 17 years attenuated the associations of cumulative elevated TC, non-HDL-C, LDL-C, and low HDL-C with cIMT progression. Cumulative elevated lipids or dyslipidemia were not associated with cfPWV progression.

CONCLUSIONS

Late adolescence is key to preventing, halting, and reversing dyslipidemic-related preclinical atherosclerosis progression, warranting universal lipid screening in the general pediatric population.

Puberty Timing and Sex-Specific Trajectories of Systolic Blood Pressure: a Prospective Cohort Study

BACKGROUND

Sex differences in systolic blood pressure (SBP) emerge during adolescence but the role of puberty is not well understood. We examined sex-specific changes in SBP preceding and following puberty and examined the impact of puberty timing on SBP trajectories in females and males.

METHODS

Trajectories of SBP before and after puberty and by timing of puberty in females and males in a contemporary birth cohort study were analyzed. Repeated measures of height from age 5 to 20 years were used to identify puberty timing (age at peak height velocity). SBP was measured on ten occasions from 3 to 24 years (N participants, 4062; repeated SBP measures, 29 172). Analyses were performed using linear spline multilevel models based on time before and after puberty and were adjusted for parental factors and early childhood factors.

RESULTS

Mean age at peak height velocity was 11.7 years (SD, 0.8) for females and 13.6 years (SD, 0.9) for males. Males had faster rates of increase in SBP before puberty leading to 10.19 mm Hg (95% CI, 6.80-13.57) higher mean SBP at puberty which remained similar at 24 years (mean difference, 11.43 mm Hg [95% CI, 7.22-15.63]). Puberty timing was associated with small transient differences in SBP trajectories postpuberty in both sexes and small differences at 24 years in females only.

CONCLUSIONS

A large proportion of the higher SBP observed in males compared with females in early adulthood is accrued before puberty. Interventions targeting puberty timing are unlikely to influence SBP in early adulthood.

Age and body mass index affect fit of spirometry GLI references in schoolchildren

Background

References from the Global Lung Function Initiative (GLI) are widely used to interpret children's spirometry results. We assessed fit for healthy schoolchildren.

Methods

LuftiBus in the School was a population-based cross-sectional study undertaken in 2013–2016 in the canton of Zurich, Switzerland. Parents and their children aged 6–17 years answered questionnaires about respiratory symptoms and lifestyle. Children underwent spirometry in a mobile lung function lab. We calculated GLI-based z-scores for forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC and forced expiratory flow for 25–75% of FVC (FEF_25–75) for healthy White participants. We defined appropriate fit to GLI references by mean values between +0.5 and −0.5 z-scores. We assessed whether fit varied by age, body mass index, height and sex using linear regression models.

Results

We analysed data from 2036 children with valid FEV₁ measurements, of whom 1762 also had valid FVC measurements. The median age was 12.2 years. Fit was appropriate for children aged 6–11 years for all indices. In adolescents aged 12–17 years, fit was appropriate for FEV₁/FVC z-scores (mean±sd −0.09±1.02), but not for FEV₁ (−0.62±0.98), FVC (−0.60±0.98) and FEF_25–75 (−0.54±1.02). Mean FEV₁, FVC and FEF_25–75 z-scores fitted better in children considered overweight (−0.25, −0.13 and −0.38, respectively) than normal weight (−0.55, −0.50 and −0.55, respectively; p-trend <0.001, 0.014 and <0.001, respectively). FEV₁, FVC and FEF_25–75 z-scores depended on both age and height (p-interaction 0.033, 0.019 and <0.001, respectively).

Conclusion

GLI-based FEV₁, FVC, and FEF_25–75 z-scores do not fit White Swiss adolescents well. This should be considered when using reference equations for clinical decision-making, research and international comparison.

This study suggests GLI-based FEV₁, FVC and FEF_25–75% z-scores over-detect abnormal lung function in Swiss adolescents, and more so among slimmer adolescents, which has important implications for clinical care, research and international comparisonshttps://bit.ly/3sbGtAS

Predictors of selection into an elite level youth football academy: A longitudinal study

Talent identification in football is complex. Research regarding talent indicators that predict selection into professional academies is increasingly multi-disciplinary, though is typically cross-sectional, failing to consider whether the rate of change of those indicators influences selection. The aim of this study was to determine if longitudinal changes in talent indicators are associated with selection into a professional football academy. A total of 110 Dutch male football players (aged 8-12) playing in a youth development programme of a professional club were included in the study. Players were assessed regularly on their anthropometry, physical fitness, gross motor coordination, technical ability, and psychosocial capacities over four years. A subset of players was then selected into the academy. Cross-sectional and longitudinal analyses revealed the indicators that best predicted selection. The best indicator was the 30 m sprint speed, with prediction not improving when including other predictors or their rate of change. The individuals that the club ultimately selected at age 12 could have been predicted well above chance levels using the sprint speeds at age nine or ten. The relative consistency of the rate of improvement in indicators across participants meant that the rate at which they developed played little role in selections.

Longitudinal associations between prepubertal childhood total energy and macronutrient intakes and subsequent puberty timing in UK boys and girls

PURPOSE

Early puberty is associated with adverse health outcomes. To identify potential modifiable factors for puberty timing, we examined the associations of prepubertal childhood macronutrient intakes with puberty timing in boys and girls.

METHODS

In the Avon Longitudinal Study of Parents and Children, macronutrient intakes at age 6 years were predicted using random intercepts linear regression models of dietary data at 3, 4, 7 (assessed by food frequency questionnaires) and 7.5 years (by 3-day food diaries). Timings of puberty onset (Tanner stage 2 genital or breast (B2) development) and puberty completion (voice breaking (VB) or menarche) were calculated from annual parental and child reports at 8-17 years. Age at peak height velocity (PHV) was derived from repeated height measurements at 5-20 years. Linear regression models were fit to estimate the associations of total energy (TEI) and macronutrient intakes (carbohydrate, fat, protein) with puberty timing traits, adjusting for maternal and infant characteristics.

RESULTS

Among 3811 boys, higher TEI, but no macronutrient, was associated with earlier VB. Among 3919 girls, higher TEI was associated with earlier ages at B2, PHV, and menarche. Higher protein intake but not carbohydrate or fat intake (in energy partition models) and substitution of dietary protein for carbohydrate (in nutrient density and residual models) was associated with earlier B2, PHV, and menarche in girls. Findings were not attenuated on additional adjustment for body fat percentage during adolescence.

CONCLUSIONS

These findings suggest habitual total energy intakes in children, and protein intakes in girls, as potential modifiable determinants of puberty timing.

Cardiorespiratory Fitness, Fat Mass, and Cardiometabolic Health with Endothelial Function, Arterial Elasticity, and Stiffness

PURPOSE

This study aimed to determine whether estimated cardiorespiratory fitness (CRF), fat mass (FM), lean mass (LM), and adiponectin bidirectionally associate with arterial function and structure and if CRF mediates the relationship between cardiometabolic health and arterial outcomes in 9- to 11-yr-old children drawn from the Avon Longitudinal Study of Parents and Children birth cohort, United Kingdom.

METHODS

Brachial artery flow-mediated dilation (FMD), distensibility coefficient (DC), and carotid-radial pulse wave velocity (PWV) were measured by ultrasonography; CRF was measured during the submaximal ergometer test; total FM, trunk FM, and LM were measured by dual-energy x-ray absorptiometry; plasma adiponectin was measured by enzyme assay; and cardiometabolic health was computed based on the International Diabetes Federation criteria for diagnosing metabolic syndrome. We tested bidirectionality by including CRF, FM, LM, and adiponectin as exposures and FMD, DC, and PWV as outcomes, alternatively.

RESULTS

Among 5566 participants (2816 (51%) girls; median age, 9.75 yr), CRF per body mass0.21 was directly related to DC (β (95% confidence interval) = 0.004 (<0.0001 to 0.008); P = 0.046), whereas CRF per LM0.54 was inversely associated with PWV (-0.034 (-0.063 to -0.003); 0.032) after adjusting for covariates. These associations remained in bidirectional analyses. Total FM, trunk FM, and LM were bidirectionally and positively associated with FMD and DC. Total FM and trunk FM but not LM had bidirectional and inverse associations with PWV. Adiponectin was not related to FMD, DC, or PWV. CRF partially mediated the associations of cardiometabolic health with FMD (1.5% mediation), DC (12.1% mediation), and PWV (3.5% mediation).

CONCLUSIONS

Associations of poor cardiometabolic health with adverse arterial structure and function in childhood may be mitigated by increasing CRF. Higher CRF was associated with better arterial structure whereas higher total FM and trunk FM were associated with better arterial function and structure. In the reverse analysis, healthy arterial structure and function were independently associated with increased total FM and trunk FM, suggesting an "arterial paradox."

The inflammatory potential of the diet in childhood is associated with cardiometabolic risk in adolescence/young adulthood in the ALSPAC birth cohort

PURPOSE

This study examined the association between a Dietary Inflammatory Score adapted for children (cDIS) and Cardiometabolic Risk (CMR) score in adolescence/early adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC).

METHODS

The cDIS was calculated at 7, 10 and 13 years using diet diary data. Anthropometric and biochemical data at 17 (N = 1937) and 24 (N = 1957) years were used to calculate CMR scores at each age [mean sex-specific z-scores from triacylglycerol, HDL-cholesterol, LDL-cholesterol, mean arterial blood pressure (MAP), homeostatic model assessment of insulin resistance (HOMA-IR) and fat-mass index (FMI)]. Multivariable linear regression models examined associations between cDIS at 7, 10 and 13 years and a continuous CMR z-score and individual CMR markers at 17 and 24 years.

RESULTS

In fully adjusted models, a higher cDIS (more pro-inflammatory diet) at 7 years was associated with an increase in CMR z-score at 17 years (β 0.19; 95% CI 0.03-0.35 for third versus first cDIS tertile) and at 24 years (β 0.28; 95% CI 0.11,0.44 for third versus first cDIS tertile). There was a weak association between a higher cDIS at 10 years and an increase in CMR z-score at 17 years (β 0.16; 95% CI - 0.003, 0.32 for third versus first cDIS tertile). No other clear associations were evident. FMI, MAP and HOMA-IR were the main CMR factors contributing to these associations.

CONCLUSION

A more pro-inflammatory diet during childhood was associated with a worse cardiometabolic profile in late adolescence/early adulthood. A childhood diet abundant in nutrients with anti-inflammatory properties could help reduce development of CMR factors.

MC3R links nutritional state to childhood growth and the timing of puberty

The state of somatic energy stores in metazoans is communicated to the brain, which regulates key aspects of behaviour, growth, nutrient partitioning and development1. The central melanocortin system acts through melanocortin 4 receptor (MC4R) to control appetite, food intake and energy expenditure2. Here we present evidence that MC3R regulates the timing of sexual maturation, the rate of linear growth and the accrual of lean mass, which are all energy-sensitive processes. We found that humans who carry loss-of-function mutations in MC3R, including a rare homozygote individual, have a later onset of puberty. Consistent with previous findings in mice, they also had reduced linear growth, lean mass and circulating levels of IGF1. Mice lacking Mc3r had delayed sexual maturation and an insensitivity of reproductive cycle length to nutritional perturbation. The expression of Mc3r is enriched in hypothalamic neurons that control reproduction and growth, and expression increases during postnatal development in a manner that is consistent with a role in the regulation of sexual maturation. These findings suggest a bifurcating model of nutrient sensing by the central melanocortin pathway with signalling through MC4R controlling the acquisition and retention of calories, whereas signalling through MC3R primarily regulates the disposition of calories into growth, lean mass and the timing of sexual maturation.

Prospective association between a Mediterranean-style dietary score in childhood and cardiometabolic risk in young adults from the ALSPAC birth cohort

PURPOSE

To investigate the prospective association between a children's relative Mediterranean-style diet score (C-rMED) in childhood and a Cardiometabolic Risk (CMR) score in adolescence/young adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC).

METHODS

A C-rMED was calculated at 7, 10 and 13 years from diet diary data. Anthropometric and biochemical data at 17 (N = 1940) and 24 years (N = 1961) were used to calculate CMR scores (sum of sex-specific log-transformed z-scores from triacylglycerol, HDL cholesterol, LDL cholesterol, mean arterial blood pressure, homeostatic model assessment of insulin resistance (HOMA-IR) and fat mass index (FMI)). Adjusted logistic regression models examined associations between C-rMED (categorical and 2-unit increments) and a high CMR score (≥ 80th percentile) and individual CMR components (≥ 80th percentile).

RESULTS

A high C-rMED at 13 was associated with a 32% (OR 0.68 (95% CI: 0.49, 0.94)) decreased adjusted odds of having a high CMR score at 24 years, compared to participants with a low C-rMED. No associations were evident at other ages. Tracking of the C-rMED across the three ages showed a stronger negative association between C-rMED and CMR at 24 years when children had at least two high C-rMED scores from 7 to 13 years (adjusted OR: 0.49, 95% CI: 0.29, 0.85), compared to all low scores. FMI and HOMA-IR were the main CMR components contributing to this association.

CONCLUSION

Higher Mediterranean-style diet scores in early adolescence were associated with a better CMR profile in young adults (24 year olds). This underscores the importance of establishing healthy eating habits early in life for future cardiometabolic health.

Body muscle gain and markers of cardiovascular disease susceptibility in young adulthood: A cohort study

BACKGROUND

The potential benefits of gaining body muscle for cardiovascular disease (CVD) susceptibility, and how these compare with the potential harms of gaining body fat, are unknown. We compared associations of early life changes in body lean mass and handgrip strength versus body fat mass with atherogenic traits measured in young adulthood.

METHODS AND FINDINGS

Data were from 3,227 offspring of the Avon Longitudinal Study of Parents and Children (39% male; recruited in 1991-1992). Limb lean and total fat mass indices (kg/m2) were measured using dual-energy X-ray absorptiometry scans performed at age 10, 13, 18, and 25 y (across clinics occurring from 2001-2003 to 2015-2017). Handgrip strength was measured at 12 and 25 y, expressed as maximum grip (kg or lb/in2) and relative grip (maximum grip/weight in kilograms). Linear regression models were used to examine associations of change in standardised measures of these exposures across different stages of body development with 228 cardiometabolic traits measured at age 25 y including blood pressure, fasting insulin, and metabolomics-derived apolipoprotein B lipids. SD-unit gain in limb lean mass index from 10 to 25 y was positively associated with atherogenic traits including very-low-density lipoprotein (VLDL) triglycerides. This pattern was limited to lean gain in legs, whereas lean gain in arms was inversely associated with traits including VLDL triglycerides, insulin, and glycoprotein acetyls, and was also positively associated with creatinine (a muscle product and positive control). Furthermore, this pattern for arm lean mass index was specific to SD-unit gains occurring between 13 and 18 y, e.g., -0.13 SD (95% CI -0.22, -0.04) for VLDL triglycerides. Changes in maximum and relative grip from 12 to 25 y were both positively associated with creatinine, but only change in relative grip was also inversely associated with atherogenic traits, e.g., -0.12 SD (95% CI -0.18, -0.06) for VLDL triglycerides per SD-unit gain. Change in fat mass index from 10 to 25 y was more strongly associated with atherogenic traits including VLDL triglycerides, at 0.45 SD (95% CI 0.39, 0.52); these estimates were directionally consistent across sub-periods, with larger effect sizes with more recent gains. Associations of lean, grip, and fat measures with traits were more pronounced among males. Study limitations include potential residual confounding of observational estimates, including by ectopic fat within muscle, and the absence of grip measures in adolescence for estimates of grip change over sub-periods.

CONCLUSIONS

In this study, we found that muscle strengthening, as indicated by grip strength gain, was weakly associated with lower atherogenic trait levels in young adulthood, at a smaller magnitude than unfavourable associations of fat mass gain. Associations of muscle mass gain with such traits appear to be smaller and limited to gains occurring in adolescence. These results suggest that body muscle is less robustly associated with markers of CVD susceptibility than body fat and may therefore be a lower-priority intervention target.

Prepubertal Dietary and Plasma Phospholipid Fatty Acids Related to Puberty Timing: Longitudinal Cohort and Mendelian Randomization Analyses

Dietary intakes of polyunsaturated, monounsaturated and saturated fatty acids (FAs) have been inconsistently associated with puberty timing. We examined longitudinal associations of prepubertal dietary and plasma phospholipid FAs with several puberty timing traits in boys and girls. In the Avon Longitudinal Study of Parents and Children, prepubertal fat intakes at 3-7.5 years and plasma phospholipid FAs at 7.5 years were measured. Timings of Tanner stage 2 genital or breast development and voice breaking or menarche from repeated reports at 8-17 years, and age at peak height velocity (PHV) from repeated height measurements at 5-20 years were estimated. In linear regression models with adjustment for maternal and infant characteristics, dietary substitution of polyunsaturated FAs for saturated FAs, and higher concentrations of dihomo-γ-linolenic acid (20:3n6) and palmitoleic acid (16:1n7) were associated with earlier timing of puberty traits in girls (n = 3872) but not boys (n = 3654). In Mendelian Randomization models, higher genetically predicted circulating dihomo-γ-linolenic acid was associated with earlier menarche in girls. Based on repeated dietary intake data, objectively measured FAs and genetic causal inference, these findings suggest that dietary and endogenous metabolic pathways that increase plasma dihomo-γ-linolenic acid, an intermediate metabolite of n-6 polyunsaturated FAs, may promote earlier puberty timing in girls.

Puberty timing and markers of cardiovascular structure and function at 25 years: a prospective cohort study

BACKGROUND

Whether earlier onset of puberty is associated with higher cardiovascular risk in early adulthood is not well understood. Our objective was to examine the association between puberty timing and markers of cardiovascular structure and function at age 25 years.

METHODS

We conducted a prospective birth cohort study using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Participants were born between April 1, 1991, and December 31, 1992. Exposure of interest was age at peak height velocity (aPHV), an objective and validated growth-based measure of puberty onset. Outcome measures included cardiovascular structure and function at age 25 years: carotid intima-media thickness (CIMT), left ventricular mass index (LVMI) and relative wall thickness (RWT), pulse wave velocity (PWV) and systolic blood pressure (SBP). Multiple imputation was used to impute missing data on covariates and outcomes. Linear regression was used to examine the association between aPHV and each measure of cardiac structure and function, adjusting for maternal age, gestational age, household social class, maternal education, mother's partner's education, breastfeeding, parity, birthweight, maternal body mass index, maternal marital status, maternal prenatal smoking status and height and fat mass at age 9. All analyses were stratified by sex.

RESULTS

A total of 2752-4571 participants were included in the imputed analyses. A 1-year older aPHV was not strongly associated with markers of cardiac structure and function in males and females at 25 years and most results spanned the null value. In adjusted analyses, a 1-year older aPHV was associated with 0.003 mm (95% confidence interval (CI) 0.00001, 0.006) and 0.0008 mm (95% CI - 0.002, 0.003) higher CIMT; 0.02 m/s (95% CI - 0.05, 0.09) and 0.02 m/s (95% CI - 0.04, 0.09) higher PWV; and 0.003 mmHg (95% CI - 0.60, 0.60) and 0.13 mmHg (95% CI - 0.44, 0.70) higher SBP, among males and females, respectively. A 1-year older aPHV was associated with - 0.55 g/m2.7 (95% CI - 0.03, - 1.08) and - 0.89 g/m2.7 (95% CI - 0.45, - 1.34) lower LVMI and - 0.001 (95% CI - 0.006, 0.002) and - 0.002 (95% CI - 0.006, 0.002) lower RWT among males and females.

CONCLUSIONS

Earlier puberty is unlikely to have a major impact on pre-clinical cardiovascular risk in early adulthood.

Childhood adversity, pubertal timing and self-harm: a longitudinal cohort study

BACKGROUND

The occurrence of early childhood adversity is strongly linked to later self-harm, but there is poor understanding of how this distal risk factor might influence later behaviours. One possible mechanism is through an earlier onset of puberty in children exposed to adversity, since early puberty is associated with an increased risk of adolescent self-harm. We investigated whether early pubertal timing mediates the association between childhood adversity and later self-harm.

METHODS

Participants were 6698 young people from a UK population-based birth cohort (ALSPAC). We measured exposure to nine types of adversity from 0 to 9 years old, and self-harm when participants were aged 16 and 21 years. Pubertal timing measures were age at peak height velocity (aPHV - males and females) and age at menarche (AAM). We used generalised structural equation modelling for analyses.

RESULTS

For every additional type of adversity; participants had an average 12-14% increased risk of self-harm by 16. Relative risk (RR) estimates were stronger for direct effects when outcomes were self-harm with suicidal intent. There was no evidence that earlier pubertal timing mediated the association between adversity and self-harm [indirect effect RR 1.00, 95% confidence interval (CI) 1.00-1.00 for aPHV and RR 1.00, 95% CI 1.00-1.01 for AAM].

CONCLUSIONS

A cumulative measure of exposure to multiple types of adversity does not confer an increased risk of self-harm via early pubertal timing, however both childhood adversity and early puberty are risk factors for later self-harm. Research identifying mechanisms underlying the link between childhood adversity and later self-harm is needed to inform interventions.

Sex differences in systemic metabolites at four life stages: cohort study with repeated metabolomics

BACKGROUND

Males experience higher rates of coronary heart disease (CHD) than females, but the circulating traits underpinning this difference are poorly understood. We examined sex differences in systemic metabolites measured at four life stages, spanning childhood to middle adulthood.

METHODS

Data were from the Avon Longitudinal Study of Parents and Children (7727 offspring, 49% male; and 6500 parents, 29% male). Proton nuclear magnetic resonance (1H-NMR) spectroscopy from a targeted metabolomics platform was performed on EDTA-plasma or serum samples to quantify 229 systemic metabolites (including lipoprotein-subclass-specific lipids, pre-glycaemic factors, and inflammatory glycoprotein acetyls). Metabolites were measured in the same offspring once in childhood (mean age 8 years), twice in adolescence (16 years and 18 years) and once in early adulthood (25 years), and in their parents once in middle adulthood (50 years). Linear regression models estimated differences in metabolites for males versus females on each occasion (serial cross-sectional associations).

RESULTS

At 8 years, total lipids in very-low-density lipoproteins (VLDL) were lower in males; levels were higher in males at 16 years and higher still by 18 years and 50 years (among parents) for medium-or-larger subclasses. Larger sex differences at older ages were most pronounced for VLDL triglycerides-males had 0.19 standard deviations (SD) (95% CI = 0.12, 0.26) higher at 18 years, 0.50 SD (95% CI = 0.42, 0.57) higher at 25 years, and 0.62 SD (95% CI = 0.55, 0.68) higher at 50 years. Low-density lipoprotein (LDL) cholesterol, apolipoprotein-B, and glycoprotein acetyls were generally lower in males across ages. The direction and magnitude of effects were largely unchanged when adjusting for body mass index measured at the time of metabolite assessment on each occasion.

CONCLUSIONS

Our results suggest that males begin to have higher VLDL triglyceride levels in adolescence, with larger sex differences at older ages. Sex differences in other CHD-relevant metabolites, including LDL cholesterol, show the opposite pattern with age, with higher levels among females. Such life course trends may inform causal analyses with clinical endpoints in specifying traits which underpin higher age-adjusted CHD rates commonly seen among males.

Puberty timing and adiposity change across childhood and adolescence: disentangling cause and consequence

STUDY QUESTION

Is earlier puberty more likely a result of adiposity gain in childhood than a cause of adiposity gain in adulthood?

SUMMARY ANSWER

Pre-pubertal fat mass is associated with earlier puberty timing but puberty timing is not associated with post-pubertal fat mass change.

WHAT IS KNOWN ALREADY

Age at puberty onset has decreased substantially in the last several decades. Whether reducing childhood adiposity prevents earlier puberty and if early puberty prevention itself also has additional independent benefits for prevention of adult adiposity is not well understood.

STUDY DESIGN, SIZE, DURATION

Prospective birth cohort study of 4176 participants born in 1991/1992 with 18 232 repeated measures of fat mass from age 9 to 18 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used repeated measures of height from 5 to 20 years to identify puberty timing (age at peak height velocity, aPHV) and repeated measures of directly measured fat mass from age 9 to 18 years, from a contemporary UK birth cohort study to model fat mass trajectories by chronological age and by time before and after puberty onset. We then examined associations of these trajectories with puberty timing separately in females and males.

MAIN RESULTS AND THE ROLE OF CHANCE

In models by chronological age, a 1-year later aPHV was associated with 20.5% (95% confidence interval (CI): 18.6-22.4%) and 23.4% (95% (CI): 21.3-25.5%) lower fat mass in females and males, respectively, at 9 years. These differences were smaller at age 18 years: 7.8% (95% (CI): 5.9-9.6%) and 12.4% (95% (CI): 9.6-15.2%) lower fat mass in females and males per year later aPHV. Trajectories of fat mass by time before and after puberty provided strong evidence for an association of pre-pubertal fat mass with puberty timing, and little evidence of an association of puberty timing with post-pubertal fat mass change. The role of chance is likely to be small in this study given the large sample sizes available.

LIMITATIONS, REASONS FOR CAUTION

Participants included in our analyses were more socially advantaged than those excluded. The findings of this work may not apply to non-White populations and further work examining associations of puberty timing and fat mass in other ethnicities is required.

WIDER IMPLICATIONS OF THE FINDINGS

Previous research has relied on self-reported measures of puberty timing such as age of voice breaking in males, has lacked data on pre-and post-pubertal adiposity together and relied predominantly on indirect measures of adiposity such as BMI. This has led to conflicting results on the nature and direction of the association between puberty timing and adiposity in females and males. Our work provides important clarity on this, suggesting that prevention of adiposity in childhood is key for prevention of early puberty, adult adiposity and associated cardiovascular risk. In contrast, our findings suggest that prevention of early puberty without prevention of childhood adiposity would have little impact on prevention of adult adiposity.

STUDY FUNDING/COMPETING INTEREST(S)

The UK Medical Research Council and Wellcome (Grant ref: 102215/2/13/2) and the University of Bristol provide core support for Avon Longitudinal Study of Parents and Children (ALSPAC). L.M.O.K. is supported by a UK Medical Research Council Population Health Scientist fellowship (MR/M014509/1) and a Health Research Board (HRB) of Ireland Emerging Investigator Award (EIA-FA-2019-007 SCaRLeT). J.A.B. is supported by the Elizabeth Blackwell Institute for Health Research, University of Bristol and the Wellcome Trust Institutional Strategic Support Fund (204813/Z/16/Z). L.D.H. and A.F. are supported by Career Development Awards from the UK Medical Research Council (grants MR/M020894/1 and MR/M009351/1, respectively). All authors work in a unit that receives funds from the UK Medical Research Council (grant MC_UU_00011/3, MC_UU_00011/6). No competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Tanner's tempo of growth in adolescence: recent SITAR insights with the Harpenden Growth Study and ALSPAC

Background: James Tanner emphasised the “tempo” of growth, i.e. the adolescent spurt as summarised by its timing (age at peak velocity or APV) and intensity (peak velocity, PV).

Aim: The paper applies the SITAR growth curve model to pubertal growth data with the aim of clarifying the growth pattern across multiple measurements and the spectrum of APV and PV.

Subjects and methods: Data for 7–20 years on ten anthropometric measurements in 619 children from the Harpenden Growth Study, and on height in 10410 children from the ALSPAC study, were analysed using SITAR (SuperImposition by Translation And Rotation). SITAR models pubertal growth as a mean curve with APV and PV fitted as subject-specific random effects, and a random measurement intercept.

Results: Mean APV for Harpenden girls and boys averaged 12.0 and 13.9 years across the ten measurements. PV expressed as percent per year lay in the narrow range 4–8%. Splitting the ALSPAC subjects into 9 by 5 APV and PV groups and fitting separate SITAR models to each group confirmed SITAR’s good fit while highlighting the spectrum of growth patterns.

Conclusion: SITAR works well to summarise pubertal growth. The disappointment is that Tanner did not live to see it in action.

Role of the Metabolic Profile in Mediating the Relationship Between Body Mass Index and Left Ventricular Mass in Adolescents: Analysis of a Prospective Cohort Study

Background We aimed to quantify the role of the plasma metabolic profile in explaining the effect of adiposity on cardiac structure. Methods and Results Body mass index (BMI) was measured at age 11 in the Avon Longitudinal Study of Parents and Children. Left ventricular mass indexed to height^2.7 (LVMI) was assessed by echocardiography at age 17. The metabolic profile was quantified via ¹H-nuclear magnetic resonance spectroscopy at age 15. Multivariable confounder (maternal age, parity, highest qualification, maternal smoking, prepregnancy BMI, prepregnancy height, household social class, adolescent birthweight, adolescent smoking, fruit and vegetable consumption, and physical activity)-adjusted linear regression estimated the association of BMI with LVMI and mediation by metabolic traits. We considered 156 metabolomic traits individually and jointly as principal components explaining 95% of the variance in the nuclear magnetic resonance platform and assessed whether the principal components for the metabolic traits added to the proportion of the association explained by putative cardiovascular risk factors (systolic and diastolic blood pressures, insulin, triglycerides, low-density lipoprotein cholesterol, and glucose). A 1 kg/m² higher BMI was associated with a 0.70 g/m^2.7 (95% CI, 0.53-0.88 g/m^2.7) and 0.66 g/m^2.7 (95% CI, 0.53-0.79 g/m^2.7) higher LVMI in males (n=437) and females (n=536), respectively. Putative risk factors explained 3% (95% CI, 2%-5%) of this association in males, increasing to 10% (95% CI, 8%-13%) when including metabolic principal components. In females, the standard risk factors explained 3% (95% CI, 2%-5%) of the association and did not increase when including the metabolic principal components. Conclusions The addition of the nuclear magnetic resonance-measured metabolic traits appears to mediate more of the association of BMI on LVMI than the putative risk factors alone in adolescent males, but not females.

Pubertal timing and self-harm: a prospective cohort analysis of males and females

AIMS

Early puberty is associated with an increased risk of self-harm in adolescent females but results for males are inconsistent. This may be due to the use of subjective measures of pubertal timing, which may be biased. There is also limited evidence for the persistence of pubertal timing effects beyond adolescence, particularly in males. The primary aim of the current study was therefore to examine the association between pubertal timing and self-harm in both sexes during adolescence and young adulthood, using an objective measure of pubertal timing (age at peak height velocity; aPHV). A secondary aim was to examine whether this association differs for self-harm with v. without suicidal intent.

METHODS

The sample (n = 5369, 47% male) was drawn from the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective birth cohort study. Mixed-effects growth curve models were used to calculate aPHV. Lifetime history of self-harm was self-reported at age 16 and 21 years, and associated suicidal intent was examined at age 16 years. Associations were estimated using multivariable logistic regression adjusted for a range of confounders. Missing data were imputed using Multiple Imputation by Chained Equations.

RESULTS

Later aPHV was associated with a reduced risk of self-harm at 16 years in both sexes (females: adjusted per-year increase in aPHV OR 0.85; 95% CI 0.75-0.96; males: OR 0.72; 95% CI 0.59-0.88). Associations were similar for self-harm with and without suicidal intent. There was some evidence of an association by age 21 years in females (adjusted per-year increase in aPHV OR 0.91; 95% CI 0.80-1.04), although the findings did not reach conventional levels of significance. There was no evidence of an association by age 21 years in males (adjusted per-year increase in aPHV OR 0.99; 95% CI 0.74-1.31).

CONCLUSIONS

Earlier developing adolescents represent a group at increased risk of self-harm. This increased risk attenuates as adolescents transition into adulthood, particularly in males. Future research is needed to identify the modifiable mechanisms underlying the association between pubertal timing and self-harm risk in order to develop interventions to reduce self-harm in adolescence.

The emergence of sex differences in PTSD symptoms across development: evidence from the ALSPAC cohort

BACKGROUND

Cross-sectional evidence suggests females in late adolescence exhibit higher rates of post-traumatic stress symptoms (PTSS) than males and younger age groups. However, longitudinal evidence is limited, and underlying factors are not well understood. We investigated the emergence of sex differences in PTSS from childhood to adolescence in a large, longitudinal UK cohort, and tested whether these could be explained by overlap between PTSS and depressive symptoms, or onset of puberty.

METHODS

Trauma exposure and PTSS were assessed at ages 8, 10, 13 (parent-report) and 15 (self-report) years in a sub-sample of 9966 children and adolescents from the ALSPAC cohort-study. Analyses of PTSS focused on those who reported potential trauma-exposure at each time-point (ranged from n = 654 at 15 years to n = 1231 at 10 years). Age at peak-height velocity (APHV) was used as an indicator of pubertal timing.

RESULTS

There was no evidence of sex differences in PTSS at ages 8 and 10, but females were more likely to show PTSS at ages 13 (OR 1.54, p = 0.002) and 15 (OR 2.04, p = .001), even once symptoms related to depression were excluded. We found little evidence that the emergence of sex differences was related to pubertal timing (as indexed by APHV).

CONCLUSIONS

Results indicate that females show higher levels of PTSS in adolescence but not during childhood. The emergence of this sex difference does not seem to be explained by overlap with depressive symptoms, while the influence of pubertal status requires further investigation.

Sex differences in proximal femur shape: findings from a population-based study in adolescents

Hip shape is an important determinant of hip osteoarthritis (OA), which occurs more commonly in women. However, it remains unclear to what extent differences in OA prevalence are attributed to sex differences in hip shape. Here, we explore sex differences in proximal femur shape in a cohort of adolescents. Hip morphology was quantified using hip DXA scans from the Avon Longitudinal Study of Parents and Children. Independent modes of variation (hip shape mode (HSM) scores) were generated for each image using an adult reference statistical shape model (N = 19,379). Linear regression was used to examine sex differences for the top ten HSMs, adjusting for age, height, lean and fat mass. Complete outcome and covariate data were available for 4,428 and 4,369 participants at ages 14 and 18 years, respectively. Several HSMs showed sex differences at both time points. The combined effect of sex on hip shape at age 14 reflected flatter femoral head and smaller lesser trochanter in females compared with males and, following adjustment for age and body size, these differences became more pronounced. At age 18, smaller lesser trochanter and femoral neck width (FNW) in females still remained although differences in femoral head, femoral shaft and FNW were largely attenuated following adjustment. Sexual dimorphism in proximal femur shape can be discerned in adolescence and early adulthood. Observed differences in proximal femur shape, particularly at age 14 were largely independent of body size, however to what extent differences in hip shape in early life play a role in predisposing to hip OA in later life remains to be determined.

Using the SITAR Method to Estimate Age at Peak Height Velocity of Children in Rural South Africa: Ellisras Longitudinal Study

Various studies have been conducted on children using the Ellisras Longitudinal Study Survey in South Africa, but none of these has addressed growth variations of children in this rural location. The aim of this paper is to assess the age at peak height velocity using the superimposition by translation and rotation (SITAR) method for both boys and girls in rural South Africa. The study is part of the on-going Ellisras Longitudinal Study, and has employed secondary data during the period from November 1996 to November 2003. The data was collected biannually in May and November each year. The Ellisras study initially followed a cluster sampling method. All participating children underwent a series of anthropometric measurements of height and weight according to the standard procedures recommended by the International Society for the Advancement of Kinanthropometry. The analysis was done using the SITAR model. Age at peak height velocity for Ellisras rural children was at 14.45 years for boys at 11.82 years for girls. Ellisras rural girls had their age at peak height velocity way earlier than Ellisras rural boys did by an estimated 2.63 years. Ellisras rural children and their growth variations were comparable to other studies.

The effect of pubertal timing, as reflected by height tempo, on proximal femur shape: Findings from a population-based study in adolescents

OBJECTIVE

To examine the relationship between pubertal timing (using measures of height tempo) and proximal femur shape in a large adolescent cohort.

METHODS

Hip DXA scans were obtained in offspring from the Avon Longitudinal Study of Parents and Children. To quantify hip morphology, the images were analyzed using Shape software based on a 53-point statistical shape model and independent modes of variation (hip shape mode (HSM) scores) for each image were generated. Height tempo (which corresponds to age at peak height velocity (aPHV)) was estimated from serial height measurements collected between age 5-20 years. Multivariable linear regression was used to examine cross-sectional associations between height tempo and the top ten HSMs at age 14 and 18, adjusting for sex and fat mass index (FMI).

RESULTS

Complete outcome and covariate data were available from 3827 and 3507 participants at age 14 and 18 years, respectively. Mean aPHV was 13.5 and 11.8 years for males and females, respectively. At age 14, height tempo was associated with a majority of modes, except for HSM4 and there was strong evidence of interaction by sex. In males, all modes showed evidence of an association with tempo, independent of FMI, with the strongest observed for HSM8 (adjusted β 0.38 (0.33, 0.43) p = 4.1 × 10-50). Compared with males, the associations were generally weaker in females, with the strongest effect observed for HSM8 (adjusted β 0.10 (0.05, 0.14) p = 1.6 × 10-5). The overall effect of later pubertal timing on proximal femur shape in males was a narrower femoral neck and larger superolateral head, whereas in females these changes were hard to discern. When assessed at age 18, there was little relationship between tempo and proximal femur shape in either sex.

CONCLUSION

Our results indicate that significant changes in hip shape occur during puberty, including aspects of shape which may be related to future risk of hip OA and/or fracture. However, puberty timing per se does not appear to exert long lasting effects on proximal femur shape.

Association Between Age at Puberty and Bone Accrual From 10 to 25 Years of Age

Importance

Bone health in early life is thought to influence the risk of osteoporosis in later life.

Objective

To examine whether puberty timing is associated with bone mineral density accrual up to adulthood.

Design, Setting, and Participants

This cohort study used data from the Avon Longitudinal Study of Parents and Children, a prospective population-based birth cohort initiated in 1991 to 1992 in southwest England. The participants were 6389 healthy British people who underwent regular follow-up, including up to 6 repeated bone density scans from ages 10 to 25 years. Data analysis was performed from June 2018 to June 2019.

Exposures

Age at puberty from estimated age at peak height velocity (years).

Main Outcomes and Measures

Gains per year in whole-body bone mineral density (grams per square centimeter), assessed by dual-energy x-ray absorptiometry at ages 10, 12, 14, 16, 18, and 25 years and modeled using linear splines.

Results

A total of 6389 participants (3196 [50.0%] female) were included. The mean (SD) age at peak height velocity was 13.5 (0.9) years for male participants and 11.6 (0.8) years for female participants. Male participants gained bone mineral density at faster rates than did female participants, with the greatest gains in both male participants (0.139 g/cm2/y; 95% CI, 0.127-0.151 g/cm2/y) and female participants (0.106 g/cm2/y; 95% CI, 0.098-0.114 g/cm2/y) observed between the year before and 2 years after peak height velocity. When aligned by chronological age, per 1-year older age at puberty was associated with faster subsequent gains in bone mineral density; the magnitudes of faster gains were greatest between ages 14 and 16 years in both male participants (0.013 g/cm2/y; 95% CI, 0.011-0.015 g/cm2/y) and female participants (0.014 g/cm2/y; 95% CI, 0.014-0.015 g/cm2/y), were greater in male participants (0.011 g/cm2/y; 95% CI, 0.010-0.013 g/cm2/y) than in female participants (0.003 g/cm2/y; 95% CI, 0.003-0.004 g/cm2/y) between ages 16 and 18 years, and were least in both male participants (0.002 g/cm2/y; 95% CI, 0.001-0.003 g/cm2/y) and female participants (0.000 g/cm2/y; 95% CI, -0.001 to 0.000 g/cm2/y) between ages 18 and 25 years. Despite faster gains, older age at puberty was associated with persistently lower bone mineral density, changing from 0.050 g/cm2 (95% CI, -0.056 to -0.045 g/cm2) lower at age 14 years to 0.047 g/cm2 (95% CI, -0.051 to -0.043 g/cm2) lower at age 25 years in male participants and from 0.044 g/cm2 (95% CI, -0.046 to -0.041 g/cm2) to 0.034 g/cm2 (95% CI, -0.036 to -0.032 g/cm2) lower at the same ages in female participants.

Conclusions and Relevance

People with older pubertal age should be advised on how to maximize bone mineral density and minimize its decrease in later life to help prevent fracture and osteoporosis.

Adult height, body mass index change, and body shape change in relation to esophageal squamous cell carcinoma risk: A population-based case-control study in China

The relationship between risk of esophageal squamous cell carcinoma (ESCC) and adult height, changes in individual body mass index (BMI) and body shape is not established. We performed a large population‐based case‐control study, which enrolled a total of 1414 ESCC cases and 1989 controls in a high‐incidence area in China. Using face‐to‐face interview with a structured questionnaire, information on participants' heights, weights, and perceived body shapes at 20 years of age was collected. Additionally, data on weight and perceived body shape among the same participants 10 years prior to ascertainment were collected using the same method. Odd ratios (ORs) of ESCC risk in relation to BMI and body shape were estimated using unconditional logistic regression models. The adjusted results indicated that ESCC risk in adults rapidly rose as height increased, plateauing at 170 cm among men and 157 cm among women. Among participants who were underweight, normal weight, or thinner than body shape 4, body weight loss was associated with increased risk of ESCC, and body weight gain was associated with decreased incidence of ESCC (ORs ranging from 0.40 to 0.76). Notably, however, changes in body weight did not significantly affect ESCC risk among participants who were overweight, obese, or larger than body shape 3. Maintaining a fit body shape and a reasonable BMI is advisable and of vital importance to reduce the risk of ESCC, especially in high‐risk areas.