Maternal height and its relationship to offspring birth weight and adiposity in 6- to 10-year-old Maya children from poor neighborhoods in Merida, Yucatan

Association of early menarche with elevated BMI, lower body height and relative leg length among 14- to 16-year-old post-menarcheal girls from a Maya community in Yucatan, Mexico

Human body segments have different timing and tempo of growth. Early menarche (EM) as an indicator of early reproductive maturity results in a shortened height and leg length. Relatively larger trunk may increase risk for more body fat deposit and higher body mass index (BMI) due to the allometry of total body fat with body proportions. The objective of the study was to assess the association of EM with BMI, absolute body size [height, sitting height (SH), subischial leg length (SLL)] and relative body dimensions [sitting height to subischial leg length ratio (SHSLLR), relative subischial leg length (RSLL)] among 14- to 16-year-old post-menarcheal girls from a rural Maya community in Quintana Roo, Yucatan, Mexico. In a cross-sectional study, post-menarcheal girls (n=51) aged 14 to 16 years had EM (n=22) (<12 years of age) and not early menarche (NEM, n=29). Anthropometric measurements of height, weight, and SH were recorded. Derived variables were BMI, height and BMI-for-age z-scores, SLL, SHSLLR, and RSLL. Mean value of age at menarche (AM) was 13 years (EM 11 years, NEM 14 years). Mean values of height (EM 159 cm, NEM 164 cm), BMI (EM 20 kg/m2, NEM 19 kg/m2), sitting height (EM 81 cm, NEM 78 cm), SLL (EM 79 cm, NEM 85 cm), SHSLLR (EM 102.93%, NEM 92.03%), and RSLL (EM 49%, NEM 52%) were different (p<0.05) in the two groups. BMI showed significant negative correlation with AM (Pearson’s r=-0.29, p<0.04). Linear regression models adjusted for age showed that EM had different interrelationships (p<0.05) with body dimensions: positive with BMI, SH, SHSLLR, and negative with height, SLL, and RSLL. Earlier AM was associated with higher BMI, SH, SHSLLR and lower SLL, RSLL, explaining lower body height and leg length among the participant EM girls. In the light of life history theory, EM results in a growth trade-off, short stature and larger trunk relative to leg length that might enhance risk for body fat gain.

Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and narrative synthesis

BACKGROUND

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI), a measure of weight for height, has been extensively reviewed in children, showing consistent associations between disadvantaged SEP and higher BMI in high-income countries (HICs) and lower BMI in middle-income countries (MICs). Fat mass (FM), a more accurate measure of adiposity, and fat-free mass (FFM) are not captured by BMI, but have been shown to track from childhood to adulthood, and be important for cardiovascular health and functional outcomes in later life. It is not clear whether body composition is associated with SEP. We systematically reviewed the association between SEP and body composition in childhood.

METHODS

A systematic review was carried out following PRISMA guidelines. The protocol was pre-registered with PROSPERO (CRD42019119937). Original studies in the English language, which examined the association between SEP and body composition in childhood, were included. An electronic search of three databases was conducted. Two independent reviewers carried out screening, data extraction and quality assessment. Due to heterogeneity in results, a narrative synthesis was conducted. Heterogeneity in findings according to SEP, sex, body composition measure and country income level was investigated.

RESULTS

50 papers were included, the majority from HICs. No papers were from low-income countries. Disadvantage in childhood was associated with greater FM and lower FFM in HICs, but with lower FM and lower FFM in MICs. When measures of FFM indexed to height were used there was no evidence of associations with SEP. In HICs, more studies reported associations between disadvantaged SEP and higher FM among girls comparative to boys.

CONCLUSIONS

Inequalities in FM are evident in HICs and, in the opposite direction, in MICs and follow similar trends to inequalities for BMI. Inequalities in height are likely important in understanding inequalities in FFM.

Maternal pre-pregnancy body mass index and the risk for gestational diabetes mellitus in women with twin pregnancy in South Korea

OBJECTIVE

To investigate the association between maternal pre-pregnancy body mass index (BMI) and the risk for gestational diabetes mellitus (GDM) in women with twin pregnancy in South Korea.

MATERIALS AND METHODS

We performed a single-center, retrospective cohort study involving 1028 women with twin pregnancy from January 2006 to December 2018 in South Korea. Pregnancies with monoamnionic twins, twin-twin transfusion syndrome, fetal death in utero before 24 weeks, pre-gestational diabetes mellitus, and unknown BMI or GDM status were excluded. Subjects were grouped into four groups based on pre-pregnancy BMI: underweight (<18.5 kg/m²), normal (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), and obese (≥25.0 kg/m²).

RESULTS

Among 1028 women who were included in the analysis, 169 (16.4%), 655 (63.7%), 111 (10.8%), and 93 (9.0%) women were underweight, normal, overweight, and obese, respectively, before pregnancy. The incidence of GDM was 8.9% in the total study population: 4.7%, 8.2%, 11.7%, and 17.2% in the underweight, normal, overweight, and obese group, respectively (p = 0.005). The incidence of GDM significantly increased according to the increase in pre-pregnancy BMI (p < 0.001). Women in the obese group were more likely to be affected by GDM compared to the normal group (adjusted odds ratio = 2.20, 95% confidence interval = 1.19-4.08) after controlling for maternal age, parity, type of conception, and chorionicity.

CONCLUSION

In twin pregnancies in South Korea, the risk of GDM increased as maternal pre-pregnancy BMI increased and obese women before pregnancy were more likely to be affected by GDM.

Balancing fertility and livelihood diversity in mixed economies

Mixed economies provide a unique context for testing theories of fertility change. Because they have a stake in two traditions, mixed-economy households balance the demands of both a labor-based subsistence economy, which benefits from a large family, and a wage-labor economy, which benefits from reduced fertility. Additionally, household size changes over the course of its life-cycle and shapes available economic opportunities. Here we argue that in mixed economies, fertility may reflect opportunities for livelihood diversity rather than simply responding to the restricted socioeconomic benefits of small families. While low fertility may in some cases have an economic benefit, low fertility can also limit the livelihood diversity of a household which is a key strategy for long-term economic success. We test this prediction with longitudinal data from a Maya community undergoing both a sustained decline in fertility and rapid integration into the market economy. Using household-level fertility, number of adults, and livelihood diversity at two time points, we find that household size is positively related to livelihood diversity, which in turn is positively related to household income per-capita. However, household size also has a negative association with income per capita. The results reflect a balancing act whereby households attempt to maximize the economic diversity with as few members as possible. Broadly, these results suggest that theories of fertility decline must account for how households pool resources and diversify economic activities in the face of increasing market integration, treating fertility as both an outcome and an input into economic and reproductive decision-making.

Birth weight and body composition in 6-to-8 years old Maya children

OBJECTIVE

To test the hypothesis that fetal growth, indexed by birth weight (BW), induce metabolic adjustments in the fetus that will be reflected in differences in body composition in a sample of 6-to 8-years old urban Maya children from Yucatan, Mexico.

METHODS

We measured height (cm), weight (kg) and triceps skinfold (mm) in 260 children (boys: 132, girls: 128), and height (cm) and weight (kg) in their mothers. Body composition was estimated in children through bioelectrical impedance analysis. Outcome variables were fat free-mass index (FFMI = fat-free mass [kg]/height [m]² ) and fat mass index (FMI = fat mass [kg]/height [m]² ). The main independent variable was BW z-scores. Multiple linear regression models were used to analyze the association between BW z-scores and outcome variables measured during childhood. Separate analyses were done for boys and girls. Complementary models were run using outcomes as z-scores. Models were adjusted for location, children's and mothers' age, mother's body mass index and household overcrowding index.

RESULTS

BW in boys was positively associated with FFMI and FMI. FFMI increase 0.34 kg/m² per 1-SD increase in BW and FMI increase 0.40 kg/m² per 1-SD increase in BW. When outcomes were used as z-scores, FFMI increase 0.24 SD and FMI increase 0.18 SD per 1-SD increase in BW, respectively.

CONCLUSION

Our results are in contrast with previous findings that birth weight is more consistently associated with subsequent lean mass than with fat mass. Associations, detected only in boys, may be explained by sex differences in sensitivity to early life environments.

From conception to infancy - early risk factors for childhood obesity

Maternal lifestyle during pregnancy, as well as early nutrition and the environment infants are raised in, are considered relevant factors for the prevention of childhood obesity. Several models are available for the prediction of childhood overweight and obesity, yet most have not been externally validated. Moreover, the factors considered in the models differ among studies as the outcomes manifest after birth and depend on maturation processes that vary between individuals. The current Review examines and interprets data on the early determinants of childhood obesity to provide relevant strategies for daily clinical work. We evaluate a selection of prenatal and postnatal factors associated with child adiposity. Actions to be considered for preventing childhood obesity include the promotion of healthy maternal nutrition and weight status at reproductive age and during pregnancy, as well as careful monitoring of infant growth to detect early excessive weight gain. Paediatricians and other health-care professionals should provide scientifically validated, individual nutritional advice to families to counteract excessive adiposity in children. Based on systematic reviews, original papers and scientific reports, we provide information to help with setting up public health strategies to prevent overweight and obesity in childhood.

Caesarean birth and adiposity parameters in 6- to 8-year-old urban Maya children from two cities of Yucatan, Mexico

OBJECTIVES

The purpose of this study was to analyze the association between birth mode and fat mass index (FMI = fat mass [kg]/height [m]² ), and z-score values of waist circumference (WCZ) and sum of triceps and subscapular skinfolds (SumSkfZ) in a sample of 256 6- to 8-year-old urban Maya children from the cities of Merida and Motul in Yucatan, Mexico.

METHODS

From September 2011 to January 2014, we measured height, weight, waist circumference and skinfolds in children, and height and weight in their mothers. Body composition was estimated in both generations through bioelectrical impedance analysis. Data on children's birth mode and birth weight were obtained from birth certificates. A pre-validated questionnaire for mothers was used regarding household living conditions. Multiple regression models were used to analyze the association between birth mode and adiposity parameters, adjusting for the effect of place of residence, household crowding index, children's birth weight, and maternal fat mass. Separate regression models were run for boys and girls.

RESULTS

Caesarean-born children comprised 43% of the entire sample. Caesarean section (CS) was found to be associated with higher values of body adiposity in girls, but not in boys. Specifically, our models predicted that girls born by CS had an increased value of 0.817 kg/m² in FMI and showed higher SDs values for WCZ and SumskfZ (0.29 and 0.32 SD, respectively) than girls who were delivered vaginally.

DISCUSSION

Our results support the hypothesis that CS is associated with increased levels of adiposity in childhood, but only in girls.

Geographic variation in the growth status of indigenous school children and youth in Mexico

OBJECTIVE

To analyze variation in the growth status of indigenous children and youth attending bilingual schools, escuelas albergues, for the indigenous population in México.

MATERIALS AND METHODS

The children and youth attended escuelas albergues in 1,009 localities in 21 Mexican states in 2012. Heights and weights of 31,448 boys and 27,306 girls 6-18 years of age were measured by trained staff at each school; the BMI was calculated. The students were divided into five geographic regions for analysis: North, Central, South-Gulf, South-Pacific, and South-Southeast. Growth status was compared to United States reference percentiles (P).

RESULTS

Mean heights of children and youth from the five regions varied between P10 and P5 of the reference until about 13 years (girls) and 14 years (boys); subsequently, heights were ≤P5. Mean weights in both sexes were at P25 of the reference between 6 and 12 years, and then varied between P25 and P10 in boys and were ≥P25 in girls. Given the elevated weights relative to heights compared to the reference, mean BMIs of indigenous boys and girls were at or above the reference medians. Children and youth in the North and Central regions were, on average, taller than those in the South-Pacific and South-Southeast regions, while heights of those in the South-Gulf region were generally intermediate. In contrast, mean weights and BMIs differed negligibly among the regions.

CONCLUSIONS

The geographic gradient in heights of indigenous children and youth was consistent with a north-to-south pattern noted among indigenous adults in studies spanning 1898 through 2013. Variation in height among children and youth likely reflected ethnic-specific and geographic variation interacting with economic and nutritional factors.

Body mass index trajectories in the first two years and subsequent childhood cardio-metabolic outcomes: a prospective multi-ethnic Asian cohort study

We investigated body mass index (BMI) trajectories in the first 2 years of life in 1170 children from an Asian mother-offspring cohort in Singapore, and examined their predictors and associations with childhood cardio-metabolic risk measures at 5 years. Latent class growth mixture modelling analyses were performed to identify distinct BMI z-score (BMIz) trajectories. Four trajectories were identified: 73.2%(n = 857) of the children showed a normal BMIz trajectory, 13.2%(n = 155) a stable low-BMIz trajectory, 8.6%(n = 100) a stable high-BMIz trajectory and 5.0%(n = 58) a rapid BMIz gain after 3 months trajectory. Predictors of the stable high-BMIz and rapid BMIz gain trajectories were pre-pregnancy BMI, gestational weight gain, Malay and Indian ethnicity, while predictors of stable low-BMIz trajectory were preterm delivery and Indian ethnicity. At 5 years, children with stable high-BMIz or rapid BMIz gain trajectories had increased waist-to-height ratios [B(95%CI) 0.02(0.01,0.03) and 0.03(0.02,0.04)], sum of skinfolds [0.42(0.19,0.65) and 0.70(0.36,1.03)SD units], fat-mass index [0.97(0.32,1.63)SD units] and risk of obesity [relative risk 3.22(1.73,6.05) and 2.56 (1.19,5.53)], but not higher blood pressure. BMIz trajectories were more predictive of adiposity at 5 years than was BMIz at 2 years. Our findings on BMIz trajectories in the first 2 years suggest important ethnic-specific differences and impacts on later metabolic outcomes.