Adult stature, body proportions and age at menarche in the United States National Health and Nutrition Survey (NHANES) III

Childhood adversity and accelerated reproductive events: a systematic review and meta-analysis

OBJECTIVE

Accelerated female reproductive events represent the early onset of reproductive events involving puberty, menarche, pregnancy loss, first sexual intercourse, first birth, parity, and menopause. This study aimed to explore the association between childhood adversity and accelerated female reproductive events.

DATA SOURCES

PubMed, Web of Science, and Embase were systematically searched from September 22, 2022 to September 23, 2022.

STUDY ELIGIBILITY CRITERIA

Observational cohort, cross-sectional, and case-control studies in human populations were included if they reported the time of reproductive events for female individuals with experience of childhood adversity and were published in English.

METHODS

Two reviewers independently screened studies, obtained data, and assessed study quality, and conflicts were resolved by a third reviewer. Dichotomous outcomes were evaluated using meta-analysis, and pooled odds ratios and 95% confidence intervals were generated using random-effects models. Moderation analysis and meta-regression were used to investigate heterogeneity.

RESULTS

In total, 21 cohort studies, 9 cross-sectional studies, and 3 case-control studies were identified. Overall, female individuals with childhood adversity were nearly 2 times more likely to report accelerated reproductive events than those with no adversity exposure (odds ratio, 1.91; 95% confidence interval, 1.33-2.76; I2=99.6%; P<.001). Moderation analysis indicated that effect sizes for the types of childhood adversity ranged from an odds ratio of 1.61 (95% confidence interval, 1.23-2.09) for low socioeconomic status to 2.13 (95% confidence interval, 1.14-3.99) for dysfunctional family dynamics. Among the 7 groups based on different reproductive events, including early onset of puberty, early menarche, early sexual initiation, teenage childbirth, preterm birth, pregnancy loss, and early menopause, early sexual initiation had a nonsignificant correlation with childhood adversity (odds ratio, 2.70; 95% confidence interval, 0.88-8.30; I2=99.9%; P<.001). Considerable heterogeneity (I2>75%) between estimates was observed for over half of the outcomes. Age, study type, and method of data collection could explain 35.9% of the variance.

CONCLUSION

The literature tentatively corroborates that female individuals who reported adverse events in childhood are more likely to experience accelerated reproductive events. This association is especially strong for exposure to abuse and dysfunctional family dynamics. However, the heterogeneity among studies was high, requiring caution in interpreting the findings and highlighting the need for further evaluation of the types and timing of childhood events that influence accelerated female reproductive events.

The Magnitude and Directions of the Associations between Early Life Factors and Metabolic Syndrome Differ across Geographical Locations among Migrant and Non-Migrant Ghanaians-The RODAM Study

BACKGROUND

Early-life factors (ELFs) such as childhood nutrition and childhood socio-economic status could be the drivers of the increase in metabolic syndrome (MetSyn) among African populations, but data are lacking. This study evaluated whether markers of childhood nutritional status and childhood socio-economic status were associated with MetSyn in adulthood among migrant Ghanaians living in Europe and non-migrant Ghanaians living in Ghana.

METHODS

Data from the Research on Obesity and Diabetes among African Migrants (RODAM) study, involving 2008 migrants and 2320 non-migrants aged ≥25 years, were analysed for this study. We used leg-length to height ratio (LHR), which is an anthropometric marker of childhood nutritional status, and parental education, which is a marker of childhood socio-economic status, as proxies. Adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) were calculated by logistic regression with adjustments for demographic and lifestyle factors.

RESULTS

Parental education was higher among Ghanaians in Europe than among residents in rural and urban Ghana. The prevalence of MetSyn was 18.5%, 27.7% and 33.5% for rural, urban, and migrant residents, respectively. LHR was inversely associated with MetSyn among migrants. Compared with high paternal education, individuals with low paternal education had lower odds of MetSyn in migrants (AOR 0.71 95% CI 0.54-0.94). In contrast, compared with high maternal education, individuals with intermediate maternal education had higher odds of MetSyn in urban Ghanaians (AOR 4.53 95% CI 1.50-3.74). No associations were found among rural Ghanaians.

CONCLUSION

The magnitude and direction of the associations between ELFs and MetSyn differ across geographical locations. Intermediate maternal education was positively associated with MetSyn among urban Ghanaians, while LHR and low paternal education were inversely associated with MetSyn among migrant Ghanaians. Further research into the interplay of genetics, environment and behaviour is needed to elucidate the underlying pathological mechanisms of MetSyn amongst migrants.

Medieval menarche: Changes in pubertal timing before and after the Black Death

OBJECTIVES

Bioarcheological evidence suggests stature increased in males but decreased in females after the Black Death (1348-1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague.

MATERIALS AND METHODS

Our sample comprises 74 adolescent females from St. Mary Spital, London (1120-1540 CE) within the age range during which menarche occurs (10-25 years). They were assessed as being pre- or post-menarcheal and divided into three groups: Early Pre-Black Death (n = 13), Late Pre-Black Death (n = 38), and Post-Black Death (n = 23). Changes in the ages of pre- and post-menarcheal females were assessed using Mann-Whitney tests.

RESULTS

The average age of post-menarcheal females increased from the Early- to Late Pre-Black Death periods and declined after the Black Death.

CONCLUSIONS

Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre- and post-menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology.

Reference ranges for knee height in Argentine children and adolescents aged 2 to 18 years

OBJECTIVES

Measurement of height is essential in the anthropometric assessment of growth and nutritional status. In some conditions, height measurement may be difficult or impossible. Proxy measurement such as knee height (KH) have been proposed to predict stature in such cases, but reference percentile ranges and charts for healthy, well-nourished children are currently unavailable. This study was designed to develop sex-specific KH reference percentile ranges and charts in Argentine children ranging from 2 to 18 years of age.

METHODS

We collected and analyzed cross-sectional data for KH from 861 Argentine children and adolescents aged 2 to 18 years. Generalized additive models for location, scale, and shape were used to calculate semiparametric smoothed percentile reference ranges, and charts by age and sex. Linear regression and correlation analyses were performed to know the association between KH and height.

RESULTS

The new reference ranges show that KH growth rose sharply until puberty. Peak KH velocity occurs 1 year earlier than peak height velocity. At puberty KH growth decelerated rapidly in females and increased slightly until 15 years and plateaued at this age, while it had a more gradual deceleration in males up to 11 years old, later increased slightly until 17 years and plateaued at this age. The correlation coefficient between height and KH was r = 0.98 for both sexes (p < .001).

CONCLUSIONS

The new reference percentile ranges for KH measures for healthy children and adolescents provide a useful growth and nutritional assessment tool in a wide variety of settings. KH has a strong agreement with stature.

Secular trends in weight, stature, and body mass index in Nova Scotia, Canada

OBJECTIVES

The present study aims to investigate the secular trends of weight, stature, and BMI values in a Nova Scotian sample from 1946 to 1999, with particular focus on how these trends may relate to nutrition and the evolving obesity epidemic.

METHODS

Data were collected from investigative (autopsy) records of 1645 individuals (1287 males, 358 females) of European descent at the Nova Scotia Medical Examiner Service. Secular trends were evaluated by linear regression of weight, stature, and BMI with respect to the year of birth. Further analysis of this sample was based on five time periods (birth cohorts), in order to determine whether dramatic shifts in diet and nutrition affected weight, stature, and BMI.

RESULTS

Overall, the results of this study demonstrate positive secular trends in weight, stature, and BMI from 1946 to 1999 in the Nova Scotian sample. Subsequent analysis among different time periods shows a secular increase in the weight of Nova Scotian males from 1946 to 1979, and a subsequent decrease in weight in after 1980. For Nova Scotian females, the results show a secular increase in weight from 1946 to 1989, and a subsequent decrease in weight after 1990. Such secular increases in weight coincide with the global nutrition transition, while recent decreasing median weight values may reflect economic growth and urbanization in Nova Scotia.

CONCLUSIONS

Overall, the results of the present study indicate that temporal trends in nutrition may have contributed to positive secular changes in weight, stature, and BMI in Nova Scotia, Canada between 1946 and 1999.

Early-life exposures and cardiovascular disease risk among Ghanaian migrant and home populations: the RODAM study

Early-life environmental and nutritional exposures are considered to contribute to the differences in cardiovascular disease (CVD) burden. Among sub-Saharan African populations, the association between markers of early-life exposures such as leg length and sitting height and CVD risk is yet to be investigated. This study assessed the association between leg length, sitting height, and estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk among Ghanaian-born populations in Europe and Ghana. We constructed sex-specific quintiles for sitting height and leg length for 3250 participants aged 40-70 years (mean age 52 years; men 39.6%; women 60.4%) in the cross-sectional multicenter Research on Diabetes and Obesity among African Migrants study. Ten-year risk of ASCVD was estimated using the Pooled Cohort Equations; risk ≥7.5% was defined as "elevated" CVD risk. Prevalence ratios (PR) were estimated to determine the associations between sitting height, leg length, and estimated 10-year ASCVD risk. For both men and women, mean sitting height and leg length were highest in Europe and lowest in rural Ghana. Sitting height was inversely associated with 10-year ASCVD risk among all women (PR for 1 standard deviation increase of sitting height: 0.75; 95% confidence interval: 0.67, 0.85). Among men, an inverse association between sitting height and 10-year ASCVD risk was significant on adjustment for study site, adult, and parental education but attenuated when further adjusted for height. No association was found between leg length and estimated 10-year ASCVD risk. Early-life and childhood exposures that influence sitting height could be the important determinants of ASCVD risk in this adult population.

Distinctive lung function trajectories from age 10 to 26 years in men and women and associated early life risk factors - a birth cohort study

Pre-bronchodilator lung function including forced vital capacity (FVC), forced expiratory flow in 1 second (FEV1), their ratio (FEV1/FVC), and forced expiratory flow 25-75% (FEF25-75) measured at age 10, 18, and 26 years in the Isle of Wight birth cohort was analyzed for developmental patterns (trajectories). Early life risk factors before the age of 10 years were assessed for the trajectories.

METHOD

Members of the birth cohort (1989/90) were followed at age 1, 2, 4, 10, 18, and 26 years. Allergic sensitization and questionnaire data were collected. Spirometry tests were performed and evaluated according to the American Thoracic Society (ATS) criteria at 10, 18, and 26 years. To identify developmental trajectories for FVC, FEV1, FEV1/FVC, and FEF25-75 from 10 to 26 years, a finite mixture model was applied to the longitudinal lung function data, separately for males and females. Associations of early life factors with the respective lung function trajectories were assessed using log-linear and logistic regression analyses.

RESULTS

Both high and low lung function trajectories were observed in men and women. FVC continued to grow beyond 18 years in men and women, whereas FEV1 peaked at age 18 years in female trajectories and in one male trajectory. For the FEV1/FVC ratios and FEF25-75 most trajectories appeared highest at age 18 and declined thereafter. However, the low FEV1/FVC trajectory in both sexes showed an early decline at 10 years. Lower birth weight was linked with lower lung function trajectories in males and females. Eczema in the first year of life was a risk factor for later lung function deficits in females, whereas the occurrence of asthma at 4 years of age was a risk factor for later lung function deficits in males. A positive skin prick test at age four was a risk for the low FEV1 trajectory in females and for the low FEV1/FVC trajectory in males.

CONCLUSION

Men and women showed distinctive lung function trajectories and associated risk factors. Lower lung function trajectories can be explained by not achieving maximally attainable function at age 18 years and by a function decline from 18 to 26 years.

Age at menarche and the future risk of gestational diabetes: a systematic review and dose response meta-analysis

Published studies show an inconsistent association between age at menarche and the subsequent risk of developing gestational diabetes mellitus when pregnant. This systematic review and meta-analysis was performed to clarify any trends in this association in published observational population studies. We searched online databases for relevant studies, entered into them up until June 21st 2017. Five eligible studies were found and a pooled random effects dose response meta-analysis of results from these was conducted. This included coverage of 58,133 pregnancies, from which 3,035 women developed gestational diabetes. There was evidence of a non-linear association between age at menarche and gestational diabetes (overall p = 1.4 × 10^-8; p for non-linearity = 2.4 × 10^-4), along with evidence of relatively low heterogeneity (I² = 25.5%). The largest predicted risk of gestational diabetes was associated with having a low age at menarche; the mean (95% confidence interval) risk relative to that associated with menarche at age 13 years being: 9 years 2.0 (1.6, 2.4), 10 years 1.6 (1.4, 1.9), 11 years 1.3 (1.2, 1.4), 12 years 1.1 (1.1, 1.1), 13 years was the reference, 14 years 1.0 (1.0, 1.0), 15 years 1.1 (0.9, 1.2), 16 years 1.1 (0.9, 1.4). There was evidence of potential publication bias, such that the maximal true relative risk of gestational diabetes, associated with an age at menarche of 9 years, may be closer to 1.6 than 2. Nevertheless, the curvilinear relationship between age at menarche and the future risk of gestational diabetes in pregnancy appears robust.

Rural-urban variations in age at menarche, adult height, leg-length and abdominal adiposity in black South African women in transitioning South Africa

Background: The pre-pubertal socioeconomic environment may be an important determinant of age at menarche, adult height, body proportions and adiposity: traits closely linked to adolescent and adult health.

Aims: This study explored differences in age at menarche, adult height, relative leg-length and waist circumference between rural and urban black South African young adult women, who are at different stages of the nutrition and epidemiologic transitions.

Subjects and methods: We compared 18–23 year-old black South African women, 482 urban-dwelling from Soweto and 509 from the rural Mpumalanga province. Age at menarche, obstetric history and household socio-demographic and economic information were recorded using interview-administered questionnaires. Height, sitting-height, hip and waist circumference were measured using standardised techniques.

Results: Urban and rural black South African women differed in their age at menarche (at ages 12.7 and 14.5 years, respectively). In urban women, a one-year increase in age at menarche was associated with a 0.65 cm and 0.16% increase in height and relative leg-length ratio, respectively. In both settings, earlier age at menarche and shorter relative leg-length were independently associated with an increase in waist circumference.

Conclusions: In black South African women, the earlier onset of puberty, and consequently an earlier growth cessation process, may lead to central fat mass accumulation in adulthood.

Early-life nutritional status and metabolic syndrome: gender-specific associations from a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

OBJECTIVE

In the present study we investigated gender-specific associations of low birth weight (LBW) and shorter relative leg length with metabolic syndrome (MetS) after adjusting for sociodemographic characteristics and health-related behaviours. We also investigated whether these associations are independent of age at menarche and BMI at 20 years old.

DESIGN

Cross-sectional analysis.

SUBJECTS

Baseline data from 12 602 participants (35-74 years) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), 2008-2010.

SETTING

MetS was defined according to the revised National Cholesterol Education Program Adult Treatment Panel III guidelines. LBW (<2·5 kg) and age- and sex-standardized relative leg length (high, medium and low) were the explanatory variables studied. The strength of the associations between the explanatory variables and MetS was estimated by Poisson regression with robust variance.

RESULTS

MetS prevalence was 34·2 %; it was more prevalent in men (36·8 %) than in women (32·2 %). In multivariate analysis, LBW was associated (prevalence ratio; 95 % CI) with MetS only in women (1·28; 1·24, 1·45). Shorter leg length was associated with MetS in both men (1·21; 1·09, 1·35 and 1·46; 1·29, 1·65 for low and medium lengths, respectively) and women (1·12; 1·00, 1·25 and 1·40; 1·22, 1·59 for low and medium lengths, respectively). Additional adjustments for age at menarche and BMI at 20 years old did not change the associations.

CONCLUSIONS

Poor nutritional status as estimated by LBW and lower leg length in childhood was associated with a higher prevalence of MetS, although LBW was a significant factor only among women.

Heavier birth weight associated with taller height but not age at menarche in US women born 1991-1998

OBJECTIVES

Heavier birth weight predicts taller adult height, but it remains unknown the extent to which this additional height increment results from a faster average growth rate versus an extension of the growth period. Aiming to distinguish these effects, this study examined associations between birth weight (BW), age at menarche (an established proxy for growth duration), and near-adult height in a cohort of US young women born in the 1990s.

METHODS

Multiple regression evaluated age-adjusted height as an outcome of BW, age at menarche, indicators of family socioeconomic status, and other potential confounders in a sample of US teens who participated in the National Health and Nutrition Examination Survey between 2007 and 2012 (N = 342). Relevant interactions were also evaluated.

RESULTS

Mean ± SD was 11.9 ± 1.2 years and 3262 ± 592 g for age at menarche and BW, respectively. BW did not predict age at menarche (β = -.01, p = .838). Girls were 1.3 cm taller per year delay in menarche (p < .001) and 2.9 cm taller per 1 kg increase in BW (p < .001). Additionally, the greatest gain in height associated with delayed menarche was observed among the heaviest BW quartile.

CONCLUSIONS

Girls born heavier were taller but experienced menarche at similar ages to girls born lighter. To the extent that age at menarche reflected growth duration, these results demonstrate faster average growth among heavier-born girls. Consistent with fetal programming of average growth rate, these results held after adjustment for confounders of postnatal growth like family socioeconomic status.

Association between age at menarche and cardiovascular disease: A systematic review on risk and potential mechanisms

Age at menarche (AAM) has been reported to be associated with the risk of cardiovascular disease (CVD), but the shape of and the mechanisms behind this association remain unclear. We reviewed the data on the association between AAM and different subtypes of CVD, and used shared genetic loci to identify possible mechanisms underlying this association using shared genetic association. We searched the databases of PubMed, Web of Science and Embase through to April 2017. We included articles with any clinically manifest CVD endpoint and for any ethnicity. We identified single nucleotide polymorphisms (SNPs) for AAM in genome-wide association studies (GWAS) in Caucasians through PubMed and HuGE Navigator, and searched whether these SNPs or any of their proxies were associated with any CVD-related trait. Eight studies in Caucasian populations reported an inverse linear relation between AAM and CVD risk, whereas one large study reported a significant U-shaped relation between them. Data from Asian populations were contradictory and inconclusive. In total, 122 AAM SNPs were identified at a genome-wide significance level (p<5×10^-8). Of those, 18 were also associated with various CVD-related traits, primarily body mass index (BMI), obesity, and height. In conclusion, early AAM and possibly also late AAM increase the risk of CVD in Caucasian populations. Weight and height may be part of the mechanism underlying the relation between AAM and CVD risk in Caucasians. Data on other ethnicities are too limited for meaningful analysis and conclusions.

Exercise and Sports Medicine Issues in Underserved Populations

Primary care providers can make a strong argument for exercise promotion in underserved communities. The benefits are vitally important in adolescent physical, cognitive, and psychological development as well as in adult disease prevention and treatment. In counseling such patients, we should take into account a patient's readiness for change and the barriers to exercise.

Sexual dimorphism in growth in the relative length of the forearm and relative knee height during adolescence

There are numerous studies concerning sexual dimorphism in body proportions, but only a few have investigated growth in the relative length of particular segments of the upper and lower limbs during adolescence. The aim of the study is an assessment of sex differences of longitudinal growth in the relative length of the forearm and knee height among adolescents. Sample involved 121 boys and 111 girls, participants of the Wroclaw Growth Study, examined annually between 8 and 18 years of age. Sexual dimorphism in six ratios: forearm length and knee height relatively to: trunk, height, and limb length were analyzed using a two-way analysis of variance with repeated measurements. The sex and age relative to an estimate of maturity timing (3 years before, and after age class at peak height velocity [PHV]) were independent variables. All of the ratios showed significant sex differences in interaction with age relative to age at PHV. The relative length of the forearm, in boys, did not change significantly with the years relative to age at PHV, whereas in girls, was the lowest in the two first age classes and afterward significantly increased just 1 year before and during the adolescent growth spurt, remaining unchanged in further age classes. For relative knee height no clear pattern for sex differences was noticed. It is proposed that relatively longer forearms, particularly in relation to the trunk in girls, could have evolved as an adaptation to more efficient infant carrying and protection during breastfeeding.

Pubertal development and prostate cancer risk: Mendelian randomization study in a population-based cohort

BACKGROUND

Epidemiological studies have observed a positive association between an earlier age at sexual development and prostate cancer, but markers of sexual maturation in boys are imprecise and observational estimates are likely to suffer from a degree of uncontrolled confounding. To obtain causal estimates, we examined the role of pubertal development in prostate cancer using genetic polymorphisms associated with Tanner stage in adolescent boys in a Mendelian randomization (MR) approach.

METHODS

We derived a weighted genetic risk score for pubertal development, combining 13 SNPs associated with male Tanner stage. A higher score indicated a later puberty onset. We examined the association of this score with prostate cancer risk, stage and grade in the UK-based ProtecT case-control study (n = 2,927), and used the PRACTICAL consortium (n = 43,737) as a replication sample.

RESULTS

In ProtecT, the puberty genetic score was inversely associated with prostate cancer grade (odds ratio (OR) of high- vs. low-grade cancer, per tertile of the score: 0.76; 95 % CI, 0.64-0.89). In an instrumental variable estimation of the causal OR, later physical development in adolescence (equivalent to a difference of one Tanner stage between pubertal boys of the same age) was associated with a 77 % (95 % CI, 43-91 %) reduced odds of high Gleason prostate cancer. In PRACTICAL, the puberty genetic score was associated with prostate cancer stage (OR of advanced vs. localized cancer, per tertile: 0.95; 95 % CI, 0.91-1.00) and prostate cancer-specific mortality (hazard ratio amongst cases, per tertile: 0.94; 95 % CI, 0.90-0.98), but not with disease grade.

CONCLUSIONS

Older age at sexual maturation is causally linked to a reduced risk of later prostate cancer, especially aggressive disease.

Relative leg length is associated with type 2 diabetes differently according to pubertal timing: the Brazilian longitudinal study of adult health

OBJECTIVES

Studies from developed societies have shown that individuals with short legs relative to height have higher risk of type 2 diabetes. This has been much less explored in less developed populations where influences on relative leg length and diabetes may differ. The Brazilian Longitudinal Study of Adult Health (in Portuguese, ELSA-Brasil) allows us to test, in a cohort born (1934-1975) and raised when undernutrition was common, whether short legs relative to height is positively associated with diabetes, independent of early-life factors, including birth weight, age at menarche, and young-adult BMI.

METHODS

We used baseline, cross-sectional data from 15,105 participants aged 35-74 years participating in ELSA-Brasil. We created age-and-sex-specific Z scores for leg length index (leg length/height × 100) according to an external reference. Diabetes was defined by self-reported physician diagnosis, medication use, fasting and 2-h post-75-g-load glucose, and A1C.

RESULTS

A one-unit decrement in leg-length-index Z score was associated with 12% (8-17%) higher prevalence of diabetes in Brazilian adults, after adjustment through Poisson regression for confounders, including race, maternal education, and birth weight. This association persisted after further adjustment for menarche age, BMI (at age 20), buttocks circumference, and waist circumference. It was stronger among women with early menarche (P interaction = 0.02). Leg length index was also inversely associated with fasting glucose, fasting insulin, 2-h glucose, and A1C (P < 0.05).

CONCLUSIONS

In contemporary Brazilian adults, short legs relative to height is positively associated with diabetes independent of measures of intrauterine growth, pubertal timing, and young-adult adiposity. This association is stronger in women with early menarche.

Genome-wide association study of sexual maturation in males and females highlights a role for body mass and menarche loci in male puberty

Little is known about genes regulating male puberty. Further, while many identified pubertal timing variants associate with age at menarche, a late manifestation of puberty, and body mass, little is known about these variants' relationship to pubertal initiation or tempo. To address these questions, we performed genome-wide association meta-analysis in over 11 000 European samples with data on early pubertal traits, male genital and female breast development, measured by the Tanner scale. We report the first genome-wide significant locus for male sexual development upstream of myocardin-like 2 (MKL2) (P = 8.9 × 10(-9)), a menarche locus tagging a developmental pathway linking earlier puberty with reduced pubertal growth (P = 4.6 × 10(-5)) and short adult stature (p = 7.5 × 10(-6)) in both males and females. Furthermore, our results indicate that a proportion of menarche loci are important for pubertal initiation in both sexes. Consistent with epidemiological correlations between increased prepubertal body mass and earlier pubertal timing in girls, body mass index (BMI)-increasing alleles correlated with earlier breast development. In boys, some BMI-increasing alleles associated with earlier, and others with delayed, sexual development; these genetic results mimic the controversy in epidemiological studies, some of which show opposing correlations between prepubertal BMI and male puberty. Our results contribute to our understanding of the pubertal initiation program in both sexes and indicate that although mechanisms regulating pubertal onset in males and females may largely be shared, the relationship between body mass and pubertal timing in boys may be complex and requires further genetic studies.

Grandparental education, parental education and child height: evidence from Hong Kong's "Children of 1997" birth cohort

PURPOSE

Adult height is the sum of growth during fetal, infancy, childhood, and puberty, controlled by different biological factors. In long-term developed Western populations, height is positively associated with socioeconomic position, but less clearly so in recently developing populations. We aimed to elucidate socioeconomic influences on height at different growth phases.

METHODS

We examined the associations of parents' education and grandparents' education with birth weight and height gain z-scores during infancy (birth to <2 years), childhood (2 to <8 years), and puberty (8 to <14 years) adjusted for parents' height using generalized estimating equations in Hong Kong's "Children of 1997" birth cohort (n = 8264).

RESULTS

Parents' education, but not grandparents', was positively associated with birth weight (z-score, 0.07; 95% confidence interval [CI] 0.01-0.12 for grade ≥12 compared with grade ≤9) and height gain during infancy (0.11; 95% CI, 0.05-0.18), adjusted for gender, gestational age, initial size, parity, parents' age, parents' birthplace, and parents' height. Conversely, similarly adjusted, grandparents' education, but not parents', was associated with height gain during childhood (0.11; 95% CI, 0.04-0.18).

CONCLUSIONS

Parental education was associated with fetal and infant, but not childhood, linear growth, suggesting the mechanism underlying socioeconomic influences on height at different growth phases may be contextually specific.

The effect of prepubertal calcium carbonate supplementation on the age of peak height velocity in Gambian adolescents

BACKGROUND

Limited evidence suggests that calcium intake before puberty influences adolescent height growth and the timing of puberty. Such an effect might be particularly marked in populations in whom low calcium intake, stunting, and delayed puberty are common.

OBJECTIVE

The objective was to test whether 12 mo of calcium supplementation at age 8-12 y to increase intakes toward international recommendations had long-term effects on adolescent growth and pubertal development in rural Gambian children.

DESIGN

This was a longitudinal study of 160 Gambian boys (n = 80) and girls (n = 80) who had participated in a 12-mo, randomized, double-blind, placebo-controlled, calcium carbonate supplementation trial (1000 mg Ca/d, 5 d/wk) at age 8-12 y. Anthropometric measures were made every 1-2 y until age 21-25 y; pubertal status and menarche data were collected. Repeated-measures ANCOVA and Superimposition by Translation and Rotation Method (SITAR) growth models were used to assess the effects of treatment.

RESULTS

In boys, midadolescent height growth was advanced in the calcium group, which resulted in greater stature at a mean age of 15.5 y (mean ± SEM: 2.0 ± 0.8 cm; P = 0.01) and an earlier age of peak height velocity by 7.4 ± 2.9 mo. Subsequently, the calcium group stopped growing earlier (P = 0.02) and was 3.5 ± 1.1 cm shorter (P = 0.002) at a mean age of 23.5 y. Weight and midupper arm circumference paralleled height. No significant effects were observed in girls, but a sex-by-supplement interaction on height growth could not be confirmed.

CONCLUSION

Calcium supplementation of boys in late childhood advanced the age of peak height velocity and resulted in shorter adult stature in a population in whom low calcium intakes and delayed puberty are common. This trial was registered at isrctn.org as ISRCTN28836000.

A trial of sugar-free or sugar-sweetened beverages and body weight in children

BACKGROUND

The consumption of beverages that contain sugar is associated with overweight, possibly because liquid sugars do not lead to a sense of satiety, so the consumption of other foods is not reduced. However, data are lacking to show that the replacement of sugar-containing beverages with noncaloric beverages diminishes weight gain.

METHODS

We conducted an 18-month trial involving 641 primarily normal-weight children from 4 years 10 months to 11 years 11 months of age. Participants were randomly assigned to receive 250 ml (8 oz) per day of a sugar-free, artificially sweetened beverage (sugar-free group) or a similar sugar-containing beverage that provided 104 kcal (sugar group). Beverages were distributed through schools. At 18 months, 26% of the children had stopped consuming the beverages; the data from children who did not complete the study were imputed.

RESULTS

The z score for the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) increased on average by 0.02 SD units in the sugar-free group and by 0.15 SD units in the sugar group; the 95% confidence interval (CI) of the difference was -0.21 to -0.05. Weight increased by 6.35 kg in the sugar-free group as compared with 7.37 kg in the sugar group (95% CI for the difference, -1.54 to -0.48). The skinfold-thickness measurements, waist-to-height ratio, and fat mass also increased significantly less in the sugar-free group. Adverse events were minor. When we combined measurements at 18 months in 136 children who had discontinued the study with those in 477 children who completed the study, the BMI z score increased by 0.06 SD units in the sugar-free group and by 0.12 SD units in the sugar group (P=0.06).

CONCLUSIONS

Masked replacement of sugar-containing beverages with noncaloric beverages reduced weight gain and fat accumulation in normal-weight children. (Funded by the Netherlands Organization for Health Research and Development and others; DRINK ClinicalTrials.gov number, NCT00893529.).

Age at menarche, the leg length to sitting height ratio, and risk of diabetes in middle-aged and elderly Chinese men and women

AIMS

To evaluate the associations of age at menarche and the leg length-to-sitting-height ratio, markers of adolescent growth, with risk of diabetes in later life.

MATERIALS AND METHODS

Information from 69,385 women and 55,311 men, aged 40-74 years from the Shanghai Women's Health Study and Shanghai Men's Health Study, were included in the current analyses. Diabetes status was ascertained through biennial in person follow-up. Cox models, with age as the time scale, were used.

RESULTS

There were 2369 cases of diabetes (1831 women; 538 men) during an average of 7.3 and 3.6 years of follow-up of the women and men, respectively. In females, menarche age was inversely associated with diabetes risk after adjustment for birth cohort, education, and income (HR = 0.95, 0.92-0.98). In both genders, leg length-to-sitting-height ratio was inversely related to diabetes (HR = 0.88, 0.80-0.97 for men; HR = 0.91, 0.86-0.96 for women) after adjustment for birth cohort, education, and income. Further adjustment for adult BMI at study enrollment completely eliminated the associations of age at menarche (HR = 0.99, 0.96-1.02) and the leg length-to-sitting-height ratio (HR = 1.00, 0.91-1.10 for men; HR = 1.01, 0.96-1.07 for women) with diabetes risk.

CONCLUSIONS

Our study suggests that markers of an early age at peak height velocity, i.e. early menarche age and low leg-length-to-sitting height ratio, may be associated with diabetes risk later in life and this association is likely to be mediated through obesity.