Low birth weight and its relation to physical fitness parameters in children: Its negative effect on muscle strength and cardiorespiratory endurance

Birth weight and nutritional status in school-age children from Boane city, Mozambique

BACKGROUND

Birth weight is considered an important marker of inadequate maternal nutrition, and it is a critical indicator of the newborn's health and development.

OBJECTIVE

This study evaluated the influence of low birth weight (LBW) on body composition in 7-10-year-old school children from Boane City-Mozambique.

METHODS

A total of 220 children (female = 122 and male = 98) were divided into two groups according to their birth weight (LBW, n = 41; and normal birth weight, NBW, n = 179). Anthropometric indicators of nutritional status were analyzed by the indices weight-for-age, height-for-age, BMI-for-age, and weight-for-height.

RESULTS

LBW children showed reduced skinfolds, and weight-for-height when compared to NBW children. Birth weight was positively associated with all anthropometric variables, except for BMI, which was not associated with any other variable. The r2 value ranged from .09 (weight-for-age) to .72 (height-for-age). For body composition variables, older children had higher fat mass (β = .26; 95% CI = 0.05-0.48) and fat-free mass (β = 1.10; 95% CI = 0.71-1.48), and boys had lower fat percentage (β = -3.49; 95% CI = -4.35 to -2.65) and fat mass (β = -.92; 95% CI = -1.31 to -0.55) than girls. Birth weight was also positively associated with fat-free mass.

CONCLUSION

LBW seems to influence some growth indicators of children living in Boane, however, current environmental factors seem to weaken this association. Our results suggest that public policies involving healthy nutrition and physical activity can reverse the effects of low weight in children from Boane.

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

Association of body mass index with muscle strength and cardiorespiratory fitness: A cross-sectional study based on Chinese adolescents

BACKGROUND

Muscle strength and cardiorespiratory fitness are important components of physical fitness and are important for the physical and mental health development of university students. However, obesity is also an important factor affecting physical fitness, and there are few studies on how body mass index (BMI), which reflects obesity, is associated with muscle strength and cardiorespiratory fitness among Chinese university students. Therefore, this study analyzed the association between BMI and muscle strength and cardiorespiratory fitness among Chinese university students in order to provide a reference and basis for promoting the development of physical fitness among Chinese university students.

METHODS

A stratified whole-group sampling method was used to test physical fitness items in 27 973 (15 527 boys, 55.51%) university students in 800 first- to fourth-year university classes in Anhui, Fujian, Xinjiang, Shanghai, and Jiangxi, China. The physical fitness items included height, weight, standing long jump, 1000 m running (boys), and 800 m running (girls) items. Curvilinear regression analysis was used to analyze the correlations that existed between BMI and standing long jump and VO2max.

RESULTS

The BMI of Chinese 19-22 years old university students was (21.14 ± 2.92) kg/m2. The mean standing long jump score was (197.31 ± 34.07) cm. In general, the BMI reached the highest point of 207.92 cm when the BMI was 26.25 kg/m2, and then showed a decreasing trend with the increase of BMI. The overall relationship between BMI and vertical jump showed an inverted "U"-shaped curve. In terms of VO2max, the overall trend of VO2max increased gradually with the increase of BMI, and when BMI reached 40 kg/m2, VO2max was 4.34 L-kg-1-min-1.

CONCLUSION

Chinese university students showed an inverted "U" curve relationship between BMI and standing long jump in general, while VO2max showed a gradual increase with increasing BMI. Compared with the cardiorespiratory fitness of Chinese university students, the effect of BMI changes on muscle strength was greater.

Influence of Preterm Birth and Low Birthweight on Physical Fitness: A Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

Preterm birth and low birthweight (LBW) might be associated with reduced physical fitness, although evidence remains inconclusive.

OBJECTIVE

To examine the influence of preterm birth and LBW on physical fitness, as well as to assess whether variables such as gestational age, birthweight, or age at assessment moderate these effects.

METHODS

PubMed, Scopus, and PsycINFO were systematically searched from inception to 7 December 2023 for case-control and cohort studies analyzing the association between preterm birth or LBW (or gestational age or birthweight as continuous variables) with at least one physical fitness-related outcome (i.e., cardiorespiratory fitness (CRF), muscle strength, flexibility, speed, agility). Random-effects meta-analysis and meta-regression models were used to estimate the pooled effect size, as well as to examine potential associations between the magnitude of the effect and gestational age, birthweight, or age at assessment.

RESULTS

Fifty-two studies (n = 920,603 participants, average age ranging from 4.7 to 34.4 years) were included. Preterm birth was associated with reduced CRF (standardized mean difference (SMD) = -0.38, 95% confidence interval (CI) = -0.51 to -0.25) and muscle strength (SMD = -0.44, 95% CI = -0.79 to -0.08). LBW was associated with reduced CRF (SMD = -0.40, 95% CI = -0.64 to -0.17), muscle strength (SMD = -0.18, 95% CI = -0.24 to -0.13), flexibility (SMD = -0.11, 95% CI = -0.22 to -0.01), and agility (SMD = -0.99, 95% CI = -1.91 to -0.07). Meta-regression analyses showed that a lower gestational age or birthweight were associated with larger reductions in physical fitness, whereas no consistent association was found for the age at assessment.

CONCLUSION

Both preterm birth and LBW seem associated with reduced physical fitness regardless of age, with larger reductions overall observed in individuals with lower gestational age or birthweight. These findings might support the implementation of preventive strategies (e.g., fitness monitoring and physical exercise interventions) in these populations through the life course. PROSPERO registration: CRD42021231845.

Prevalence and risk factors of low birth weight in the United States: An analysis of 2016-2021 data

BACKGROUND

Low birthweight (LBW), infants weighing less than 2,500 g, is a global health concern associated with high infant morbidity and mortality rates. This study investigates LBW prevalence and its relation to maternal sociodemographic characteristics and lifestyle behaviors factors in the United States (US).

METHODS

This analysis used the National Survey of Children's Health (NSCH) data from 2016 to 2021, including n = 225,443 children aged 0-17 years. 18,131 had LBW (<2,500 g), and 2810 had very LBW (VLBW) (<1,500 g). Logistic regression calculated odds ratios (OR) using LBW as the dependent variable, adjusting for various factors.

RESULTS

Between 2016 and 2021 in the United States, LBW prevalence averaged 9.31%, with VLBW at 1.50%. Mothers aged 18-35, White, had the lowest LBW (7.63%) and VLBW (1.17%) rates. Mothers aged ≤18 years, black, had the highest LBW (15.45%) and VLBW infants (4.70%). Maternal age emerged as a significant LBW factor, with an OR of 1.27 for ≤18 and 1.19 for >35. Children in poor health had the highest OR (2.87). Race/ethnicity and other disparities were observed.

CONCLUSION

Our study highlights LBW risk among non-White mothers with specific criteria, emphasizing the need for continued exploration of intersectional targets for change that are exacerbating LBW disparities among marginalized populations which may be artificially attributed to biologic determinants and individual-level risk factors. In-depth analysis of repressive structures at the root of inequalities demand continued research on macro levels of influence. Customized healthcare reform holds the greatest potential to disrupt the patterns contributing to poor health outcomes among LBW children, and will ultimately maximize the reach and effectiveness of health promotion strategies and clinical practices aimed to improve universal maternal and infant health.

Paediatric dominant and non-dominant handgrip reference curves and the association with body composition

BACKGROUND

Lack of paediatric reference data limits the utility of handgrip strength as a measure of fitness and well-being.

AIM

To develop paediatric handgrip reference curves and evaluate associations with body size and composition and race/ethnicity group.

SUBJECTS AND METHODS

Handgrip, body size and composition data were obtained from National Health and Nutrition Examination Survey 2011-2014 participants aged 6-20 years. Densitometry-derived fat and appendicular lean soft tissue mass index Z-scores (FMIZ, ALSTMIZ) were generated in participants >8 years. Dominant and non-dominant handgrip reference curves were created using the LMS method. Analyses included sample weights to produce nationally representative estimates.

RESULTS

Differences in handgrip strength according to hand dominance increased with age. Handgrip strength was associated with height and arm length Z-scores (R = 0.42 to 0.47) and ALSTMIZ (R = 0.54). Handgrip strength was higher in the non-Hispanic Black group and lower in the Mexican American compared to non-Hispanic White group. Group differences were attenuated when adjusted for height, arm length or ALSTMIZ.

CONCLUSION

Paediatric handgrip reference curves were generated from which individual Z-scores can be calculated separately for dominant versus non-dominant hand and adjusted for body size. Association with ALSTMIZ suggests handgrip Z-score may be used as a measure of functional body composition.

Sibling rivalry between twins in utero and childhood: Evidence from birthweight and survival of 95 919 twin pairs in 72 low- and middle-income countries

BACKGROUND

This study explores the magnitude and timing of sex and gender disparities in child development by describing differences in health outcomes for male and female siblings, comparing twins to control for all aspects of life circumstances other than sex and gender.

METHODS

We construct a repeat cross-sectional dataset of 191 838 twins among 1.7 million births recorded in 214 nationally representative household surveys for 72 countries between 1990 and 2016. To test for biological or social mechanisms that might favor the health of male or female infants, we describe differences in birthweights, attained heights, weights, and survival to distinguish gestational health from care practices after each child is born.

RESULTS

We find that male fetuses grow at the expense of their co-twin, significantly reducing their sibling's birthweight and survival probabilities, but only if the other fetus is male. Female fetuses are born significantly heavier when they share the uterus with a male co-twin and have no significant difference in survival probability whether they happen to draw a male or a female co-twin. These findings demonstrate that sex-specific sibling rivalry and male frailty begin in utero, prior to gender bias after birth that typically favors male children.

CONCLUSIONS

Sex differences in child health may have competing effects with gender bias that occurs during childhood. Worse health outcomes for males with a male co-twin could be linked to hormone levels or male frailty, and could lead to underestimates of the effect sizes of later gender bias against girls. Gender bias favoring surviving male children may explain the lack of differences in height and weight observed for twins with either male or female co-twins.