Dataset Information

Evaluation of Linear Growth at Higher Altitudes.

ABSTRACT: Importance:Irrespective of their genetic makeup, children living in an ideal home environment that supports healthy growth have similar growth potential. However, whether this potential is true for children residing at higher altitudes remains unknown. Objective:To investigate whether altitude is associated with increased risk of linear growth faltering and evaluate the implications associated with the use of the 2006 World Health Organization growth standards, which have not been validated for populations residing 1500 m above sea level. Design, Settings, and Participants:Analysis of 133 nationally representative demographic and health cross-sectional surveys administered in 59 low- and middle-income countries using local polynomial and multivariate regression was conducted. A total of 964?299 height records from 96?552 clusters at altitudes ranging from -372 to 5951 m above sea level were included. Demographic and Health Surveys were conducted between 1992 and 2018. Exposures:Residence at higher altitudes, above and below 1500 m above sea level, and in ideal home environments (eg, access to safe water, sanitation, and health care). Main Outcomes and Measures:The primary outcome was child linear growth deficits expressed in length-for-age/height-for-age z scores (HAZ). Associations between altitude and height among all children and those residing in ideal home environments were assessed. Child growth trajectories above and below 1500 m above sea level were compared and the altitude-mediated height deficits were estimated using multivariable linear regression. Results:In 2010, a total of 842 million people in the global population (approximately 12%) lived 1500 m above sea level or higher, with 67% in Asia and Africa. Eleven percent of the sample was children who resided 1500 m above sea level or higher. These children were born at shorter length and remained on a lower growth trajectory than children residing in areas less than 1500 m above sea level. The negative association between altitude and HAZ was approximately linear through most part of the altitude distribution, indicating no clear threshold for an abrupt decrease in HAZ. A 1000-m above sea level increase in altitude was associated with a 0.163-unit (95% CI, -0.205 to -0.120 units) decrease in HAZ after adjusting for common risk factors using multivariable linear regressions. The HAZ distribution of children residing in ideal home environments was similar to the 2006 World Health Organization HAZ distribution, but only up to 500 m above sea level. Conclusions and Relevance:The findings of this study suggest that residing at a higher altitude may be associated with child growth slowing even for children living in ideal home environments. Interventions addressing altitude-mediated growth restrictions during pregnancy and early childhood should be identified and implemented.

SUBMITTER: Baye K

PROVIDER: S-EPMC7445632 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evaluation of Linear Growth at Higher Altitudes.

Baye Kaleab K Hirvonen Kalle K

JAMA pediatrics 20201001 10

<h4>Importance</h4>Irrespective of their genetic makeup, children living in an ideal home environment that supports healthy growth have similar growth potential. However, whether this potential is true for children residing at higher altitudes remains unknown.<h4>Objective</h4>To investigate whether altitude is associated with increased risk of linear growth faltering and evaluate the implications associated with the use of the 2006 World Health Organization growth standards, which have not been ...[more]

PMID: 32832998

Similar Datasets

Project description:In computational modelling of sensory-motor control, the dynamics of muscle contraction is an important determinant of movement timing and joint stiffness. This is particularly so in animals with many slow muscles, as is the case in insects-many of which are important models for sensory-motor control. A muscle model is generally used to transform motoneuronal input into muscle force. Although standard models exist for vertebrate muscle innervated by many motoneurons, there is no agreement on a parametric model for single motoneuron stimulation of invertebrate muscle. Although several different models have been proposed, they have never been evaluated using a common experimental data set. We evaluate five models for isometric force production of a well-studied model system: the locust hind leg tibial extensor muscle. The response of this muscle to motoneuron spikes is best modelled as a non-linear low-pass system. Linear first-order models can approximate isometric force time courses well at high spike rates, but they cannot account for appropriate force time courses at low spike rates. A linear third-order model performs better, but only non-linear models can account for frequency-dependent change of decay time and force potentiation at intermediate stimulus frequencies. Some of the differences among published models are due to differences among experimental data sets. We developed a comprehensive toolbox for modelling muscle activation dynamics, and optimised model parameters using one data set. The "Hatze-Zakotnik model" that emphasizes an accurate single-twitch time course and uses frequency-dependent modulation of the twitch for force potentiation performs best for the slow motoneuron. Frequency-dependent modulation of a single twitch works less well for the fast motoneuron. The non-linear "Wilson" model that optimises parameters to all data set parts simultaneously performs better here. Our open-access toolbox provides powerful tools for researchers to fit appropriate models to a range of insect muscles.

Project description:BackgroundUndernutrition in early life underlies 45% of child deaths globally. Stunting malnutrition (suboptimal linear growth) also has long-term negative effects on childhood development. Linear growth deficits accrue in the first 1000 d of life. Understanding the patterns and timing of linear growth faltering or recovery during this period is critical to inform interventions to improve infant nutritional status.ObjectiveWe aimed to identify the pattern and determinants of linear growth trajectories from birth through 24 mo of age in a cohort of Zimbabwean infants.DesignWe performed a secondary analysis of longitudinal data from a subset of 3338 HIV-unexposed infants in the Zimbabwe Vitamin A for Mothers and Babies trial. We used k-means clustering for longitudinal data to identify linear growth trajectories and multinomial logistic regression to identify covariates that were associated with each trajectory group.ResultsFor the entire population, the mean length-for-age z score declined from -0.6 to -1.4 between birth and 24 mo of age. Within the population, 4 growth patterns were identified that were each characterized by worsening linear growth restriction but varied in the timing and severity of growth declines. In our multivariable model, 1-U increments in maternal height and education and infant birth weight and length were associated with greater relative odds of membership in the least-growth restricted groups (A and B) and reduced odds of membership in the more-growth restricted groups (C and D). Male infant sex was associated with reduced odds of membership in groups A and B but with increased odds of membership in groups C and D.ConclusionIn this population, all children were experiencing growth restriction but differences in magnitude were influenced by maternal height and education and infant sex, birth weight, and birth length, which suggest that key determinants of linear growth may already be established by the time of birth. This trial was registered at clinicaltrials.gov as NCT00198718.

Dataset Information

Evaluation of Linear Growth at Higher Altitudes.

Publications

Evaluation of Linear Growth at Higher Altitudes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets