Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults.We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5-19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5-19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity).Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (-0·01 kg/m2 per decade; 95% credible interval -0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69-1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64-1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (-0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50-1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4-1·2) in 1975 to 5·6% (4·8-6·5) in 2016 in girls, and from 0·9% (0·5-1·3) in 1975 to 7·8% (6·7-9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0-12·9) in 1975 to 8·4% (6·8-10·1) in 2016 in girls and from 14·8% (10·4-19·5) in 1975 to 12·4% (10·3-14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7-29·6) among girls and 30·7% (23·5-38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44-117) million girls and 117 (70-178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24-89) million girls and 74 (39-125) million boys worldwide were obese.The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high levels, but have accelerated in parts of Asia, with trends no longer correlated with those of adults.Wellcome Trust, AstraZeneca Young Health Programme.
We have previously reported that the six-minute-walk test (6MWT) is a reliable and valid functional test for assessing exercise tolerance and endurance. There is a lack of pediatric standard reference for the 6MWT.To construct height-specific standards for the 6MWT for children aged 7 to 16 years.The anthropometric data, spirometric lung function, and six-minute-walk distance (6MWD) of Chinese children aged 7 to 16 years were prospectively measured using standardized protocols. The findings were used to construct height-specific standards for the 6MWT. The least mean square (LMS) method using maximum penalized likelihood was used to facilitate model fitting. Factors significantly associated with 6MWD were also determined.From January 2005 to April 2006, a total of 1,445 subjects were studied. The measured variables showed a normal distribution. Height-specific reference standards for 6MWT were constructed for both male and female children. Forward stepwise multiple regression analysis revealed height and difference in heart rate before and after the walk test to be important clinical variables associated with 6MWD.These 6MWD standards will provide useful references for the care of pediatric patients.
The usual recommended intake of vitamin D for healthy infants is 400 international unit (IU) daily. However, a high dose of vitamin D at 2000-3000 IU daily is needed for those with vitamin D deficiency (VDD). This study aimed to assess the natural history of a group of healthy infants with VDD and the associated factors for persistent VDD.
Despite concerns about the negative effects of social distancing and prolonged school closures on children’s lifestyle and physical activity (PA) during the COVID-19 pandemic, robust evidence is lacking on the impact of the pandemic-related school closures and social distancing on children’s wellbeing and daily life. This study aimed to examine changes in the PA levels, sleep patterns, and screen time of school-aged children during the different phases of the COVID-19 outbreak in Hong Kong using a repeated cross-sectional design. School students (grades 1 to 12) were asked to report their daily electronic device usage and to fill in a sleep diary, recording their daily sleep onset and wake-up time. They were equipped with a PA monitor, Actigraph wGT3X-BT, to obtain objective data on their PA levels and sleep patterns. Students were recruited before the pandemic (September 2019–January 2020; n = 577), during school closures (March 2020–April 2020; n = 146), and after schools partially reopened (October 2020–July 2021; n = 227). Our results indicated lower PA levels, longer sleep duration, and longer screen time among participants recruited during school closures than those recruited before the COVID-19 outbreak. Primary school students were found to sleep on average for an extra hour during school closures. The later sleep onset and increased screen time documented during school closures persisted when schools partially reopened. Our findings illustrate the significant impact of social distancing policies during the COVID-19 pandemic on the sleep pattern, screen time, and PA level in school-aged children in Hong Kong. Professionals should urgently reinforce the importance of improving physically activity, good sleep hygiene, and regulated use of electronic devices for parents and school-aged children during this unprecedented time.
The worldwide spread of COVID-19 has caused significant damage to people's health and economics. Many works have leveraged machine learning models to facilitate the control and treatment of COVID-19. However, most of them focus on clinical medicine and few on understanding the spatial dynamics of the high-risk population for transmission of COVID-19 in real-world settings. This study aims to investigate the association between population features and COVID-19 transmission risk in Hong Kong, which can help guide the allocation of medical resources and the implementation of preventative measures to control the spread of the pandemic. First, we built machine learning models to predict the number of COVID-19 cases based on the population features of different tertiary planning units (TPUs). Then, we analyzed the distribution of cases and the prediction results to find specific characteristics of TPUs leading to large-scale outbreaks of COVID-19. We further evaluated the importance and influence of various population features on the prediction results using SHAP values to identify indicators for high-risk populations for COVID-19 transmission. The evaluation of COVID-19 cases and the TPU dataset in Hong Kong shows the effectiveness of the proposed methods. The top three most important indicators are identified as people in accommodation and food services, low income, and high population density.
Background Reticulocyte haemoglobin equivalent (RET-He) is a useful tool for evaluating recent iron usage irrespective of inflammatory status. This study aims to establish a reference for RET-He among Hong Kong healthy children under the age of 5 years and to investigate the association between RET-He and various blood parameters. Methods A total of 946 children aged 2–48 months from July 2019 to December 2022 were recruited in this cross-sectional study. The RET-He and other haematological parameters were measured by the haematology analyser from Sysmex XN-9100/XN-1500. The ferritin test was performed with the electrochemiluminescence immunoassay. Interval 2.5th percentile to 97.5th percentile represented the normal RET-He ranges. Linear multiple regression analysis was performed to examine the relation between RET-He and various blood parameters. Receiver-operating characteristic curve analysis revealed the sensitivity and specificity of RET-He in identifying iron deficiency. Results The RET-He in the study population was approximately normally distributed. The age-specific lower limit of RET-He ranges from 25.81 pg (25–36 months) to 27.15 pg (13–24 months). RET-He was found to be lower in the age group 2–6 months (mean=29.47 pg) and 7–12 months (mean=29.41 pg). Changes in RET-He and haemoglobin in relation to age were observed in both sexes (both p<0.001). RET-He was influenced by age, some red blood cell parameters and reticulocyte concentrations (all p<0.05). A cut-off value of RET-He ≤27.8 pg was determined for identifying iron deficiency. Conclusions RET-He levels varied with age, with a relatively lower level in infants than in other age groups. The value below the age-specific lower limit of the reference range of RET-He can be used as a limit for preliminary iron-deficiency screening.
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